OROS Wiki - User contributions [en]

Human Vibration

2020-12-23T14:52:11Z

NHoffman: /* Usage in the toolkit */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the effect of vibrations on the human body suggest that parts of the body don't have the same response to vibrations as others, and will be more sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human body, ISO standards define time-weighting that must applied to the signal according to the environmental conditions. The following part shows how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allows you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player the same way as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are described in the ISO 5349. This type of vibration is transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-23T14:34:17Z

NHoffman: /* Time-weighted signal */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the effect of vibrations on the human body suggest that parts of the body don't have the same response to vibrations as others, and will be more sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human body, ISO standards define time-weighting that must applied to the signal according to the environmental conditions. The following part shows how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are described in the ISO 5349. This type of vibration is transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-23T14:33:09Z

NHoffman: /* Time-weighted signal */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the effect of vibrations on the human body suggest that parts of the body don't have the same response to vibrations as others, and will be more sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are described in the ISO 5349. This type of vibration is transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-23T14:31:55Z

NHoffman: /* Time-weighted signal */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the effect of vibrations on the human body suggest that parts of the body don't have the same response to vibrations as others, and will be more sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human body, ISO standards define time-weighting that must applied to the signal according to the environmental conditions. The following part shows how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are described in the ISO 5349. This type of vibration is transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-23T14:29:23Z

NHoffman: /* Time-weighted signal */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the effect of vibrations on the human body suggest that parts of the body don't have the same response to vibrations as others, and will be more sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are described in the ISO 5349. This type of vibration is transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

NVGate DC Simulated Manager

2020-12-22T19:19:21Z

NHoffman: /* Davis instruments weather station */

This Add on is a tools to use the DC simulated in NVGate.
It provide a GPS and can deal the weather station.

==Download==

Latest version (07.12.2020) can be donwloaded here : [https://orossas.sharepoint.com/:u:/g/support/EePDXb-MBEpIlRIvCUXYXHIBtPLjjzpC7eQ-Ndrx2_SDiA?e=u4NalF DC simulated manager v1.0]

Configuration needed : 
- NVGate 2021 or upper 
- DC simulated channels (ORNV-VIDC option)

=GPS=

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

== Serial GPGGA GPS ==

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can advise using the GPS USB Navilock NL-602U but other GPS models will also work. 

[[File:gps_navilock.jpg|200]]

== Android GPS ==
[[File:GPS_phone.png]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position inside NVGate.

[[File:GPS_android.png|600px]]

Procedure:

- Activate android developers option. ( To enable developer options, on android settings/"about phone" tap the Build Number option 7 times.
- Enable USB debugging (on developers options menu)

process is [https://www.howtogeek.com/129728/how-to-access-the-developer-options-menu-and-enable-usb-debugging-on-android-4.2/ here]

- Plug your android phone into your PC.
- Allow the incoming USB debugging connection and check "always allow from this computer".

You can test the connection using the ADB connection button.

[[File:gps_ADB.jpg]]

Also be sure the GPS is enabled on your phone, then you need to have an application which is running and using the GPS at the foreground of the phone (exemple: [https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=fr&gl=US Google Maps] or [https://play.google.com/store/apps/details?id=com.exatools.gpsdata&hl=fr&gl=US GPS Data])

== How to use ==

Once the gps is plugged and configured, click on inject data, this will put the value in the DC simulated inputs.

[[File:GPS process 2.png|400]]

Then you can use these channels in NVGate.

If you need to record the data,
click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png]]

If you have record the data you will be able to create a .gpx file

== Creating and visualize .gpx file ==

We can create a .gpx from an .oxf (OROS) signal file.

You need to click on Convertsignaltogpx.
[[File:GPS_creategpx.png]]

This will open the window below.
[[File:signal_gpx.png]]

Select the signal file that you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put in the "attachment" folder of the NVGate project.

If you want to visualize the .gpx we advise using the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens an website allowing you to plot the gpx on a map.

=Weather station=

== Manual ==

The user can enter manually the weather value.

[[File:weather_manual.png]] 

==Davis instruments weather station ==

[[File:weather.png|framed|200px|right]]

You need the 3 elements to make it work.

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provides accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield; wind speed and direction; and rainfall.

Note : '''The weather Station need to pass by OROS SA for configuration.'''

== Other weather statio ==

Please contact OROS to check the posibility to import the data. (paid service)

NVGate DC Simulated Manager

2020-12-22T19:18:38Z

NHoffman: /* Creating and visualize .gpx file */

This Add on is a tools to use the DC simulated in NVGate.
It provide a GPS and can deal the weather station.

==Download==

Latest version (07.12.2020) can be donwloaded here : [https://orossas.sharepoint.com/:u:/g/support/EePDXb-MBEpIlRIvCUXYXHIBtPLjjzpC7eQ-Ndrx2_SDiA?e=u4NalF DC simulated manager v1.0]

Configuration needed : 
- NVGate 2021 or upper 
- DC simulated channels (ORNV-VIDC option)

=GPS=

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

== Serial GPGGA GPS ==

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can advise using the GPS USB Navilock NL-602U but other GPS models will also work. 

[[File:gps_navilock.jpg|200]]

== Android GPS ==
[[File:GPS_phone.png]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position inside NVGate.

[[File:GPS_android.png|600px]]

Procedure:

- Activate android developers option. ( To enable developer options, on android settings/"about phone" tap the Build Number option 7 times.
- Enable USB debugging (on developers options menu)

process is [https://www.howtogeek.com/129728/how-to-access-the-developer-options-menu-and-enable-usb-debugging-on-android-4.2/ here]

- Plug your android phone into your PC.
- Allow the incoming USB debugging connection and check "always allow from this computer".

You can test the connection using the ADB connection button.

[[File:gps_ADB.jpg]]

Also be sure the GPS is enabled on your phone, then you need to have an application which is running and using the GPS at the foreground of the phone (exemple: [https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=fr&gl=US Google Maps] or [https://play.google.com/store/apps/details?id=com.exatools.gpsdata&hl=fr&gl=US GPS Data])

== How to use ==

Once the gps is plugged and configured, click on inject data, this will put the value in the DC simulated inputs.

[[File:GPS process 2.png|400]]

Then you can use these channels in NVGate.

If you need to record the data,
click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png]]

If you have record the data you will be able to create a .gpx file

== Creating and visualize .gpx file ==

We can create a .gpx from an .oxf (OROS) signal file.

You need to click on Convertsignaltogpx.
[[File:GPS_creategpx.png]]

This will open the window below.
[[File:signal_gpx.png]]

Select the signal file that you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put in the "attachment" folder of the NVGate project.

If you want to visualize the .gpx we advise using the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens an website allowing you to plot the gpx on a map.

=Weather station=

== Manual ==

The user can enter manually the weather value.

[[File:weather_manual.png]] 

==Davis instruments weather station ==

[[File:weather.png|framed|200px|right]]

You need the 3 elements to make it work.

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provide Accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield; wind speed and direction; and rainfall.

Note : '''The weather Station need to pass by OROS SA for configuration.'''

== Other weather statio ==

Please contact OROS to check the posibility to import the data. (paid service)

NVGate DC Simulated Manager

2020-12-22T19:17:06Z

NHoffman: /* How to use */

This Add on is a tools to use the DC simulated in NVGate.
It provide a GPS and can deal the weather station.

==Download==

Latest version (07.12.2020) can be donwloaded here : [https://orossas.sharepoint.com/:u:/g/support/EePDXb-MBEpIlRIvCUXYXHIBtPLjjzpC7eQ-Ndrx2_SDiA?e=u4NalF DC simulated manager v1.0]

Configuration needed : 
- NVGate 2021 or upper 
- DC simulated channels (ORNV-VIDC option)

=GPS=

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

== Serial GPGGA GPS ==

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can advise using the GPS USB Navilock NL-602U but other GPS models will also work. 

[[File:gps_navilock.jpg|200]]

== Android GPS ==
[[File:GPS_phone.png]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position inside NVGate.

[[File:GPS_android.png|600px]]

Procedure:

- Activate android developers option. ( To enable developer options, on android settings/"about phone" tap the Build Number option 7 times.
- Enable USB debugging (on developers options menu)

process is [https://www.howtogeek.com/129728/how-to-access-the-developer-options-menu-and-enable-usb-debugging-on-android-4.2/ here]

- Plug your android phone into your PC.
- Allow the incoming USB debugging connection and check "always allow from this computer".

You can test the connection using the ADB connection button.

[[File:gps_ADB.jpg]]

Also be sure the GPS is enabled on your phone, then you need to have an application which is running and using the GPS at the foreground of the phone (exemple: [https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=fr&gl=US Google Maps] or [https://play.google.com/store/apps/details?id=com.exatools.gpsdata&hl=fr&gl=US GPS Data])

== How to use ==

Once the gps is plugged and configured, click on inject data, this will put the value in the DC simulated inputs.

[[File:GPS process 2.png|400]]

Then you can use these channels in NVGate.

If you need to record the data,
click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png]]

If you have record the data you will be able to create a .gpx file

== Creating and visualize .gpx file ==

We can create a .gpx from an .oxf (OROS) signal file.

You need to click on Convertsignaltogpx.
[[File:GPS_creategpx.png]]

This will open the windows below.
[[File:signal_gpx.png]]

Select the signal file than you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put on the folder "attachement" of the NVGate project.

If you want to visualize the .gpx we advice to use the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens an website allowing you to plot the gpx on a map.

=Weather station=

== Manual ==

The user can enter manually the weather value.

[[File:weather_manual.png]] 

==Davis instruments weather station ==

[[File:weather.png|framed|200px|right]]

You need the 3 elements to make it work.

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provide Accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield; wind speed and direction; and rainfall.

Note : '''The weather Station need to pass by OROS SA for configuration.'''

== Other weather statio ==

Please contact OROS to check the posibility to import the data. (paid service)

NVGate DC Simulated Manager

2020-12-22T19:16:16Z

NHoffman: /* How to used */

This Add on is a tools to use the DC simulated in NVGate.
It provide a GPS and can deal the weather station.

==Download==

Latest version (07.12.2020) can be donwloaded here : [https://orossas.sharepoint.com/:u:/g/support/EePDXb-MBEpIlRIvCUXYXHIBtPLjjzpC7eQ-Ndrx2_SDiA?e=u4NalF DC simulated manager v1.0]

Configuration needed : 
- NVGate 2021 or upper 
- DC simulated channels (ORNV-VIDC option)

=GPS=

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

== Serial GPGGA GPS ==

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can advise using the GPS USB Navilock NL-602U but other GPS models will also work. 

[[File:gps_navilock.jpg|200]]

== Android GPS ==
[[File:GPS_phone.png]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position inside NVGate.

[[File:GPS_android.png|600px]]

Procedure:

- Activate android developers option. ( To enable developer options, on android settings/"about phone" tap the Build Number option 7 times.
- Enable USB debugging (on developers options menu)

process is [https://www.howtogeek.com/129728/how-to-access-the-developer-options-menu-and-enable-usb-debugging-on-android-4.2/ here]

- Plug your android phone into your PC.
- Allow the incoming USB debugging connection and check "always allow from this computer".

You can test the connection using the ADB connection button.

[[File:gps_ADB.jpg]]

Also be sure the GPS is enabled on your phone, then you need to have an application which is running and using the GPS at the foreground of the phone (exemple: [https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=fr&gl=US Google Maps] or [https://play.google.com/store/apps/details?id=com.exatools.gpsdata&hl=fr&gl=US GPS Data])

== How to use ==

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400]]

Then you can use these channels on NVGate.

If you need to record the data.
click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png]]

If you have record the data you will be able to create a .gpx file

== Creating and visualize .gpx file ==

We can create a .gpx from an .oxf (OROS) signal file.

You need to click on Convertsignaltogpx.
[[File:GPS_creategpx.png]]

This will open the windows below.
[[File:signal_gpx.png]]

Select the signal file than you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put on the folder "attachement" of the NVGate project.

If you want to visualize the .gpx we advice to use the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens an website allowing you to plot the gpx on a map.

=Weather station=

== Manual ==

The user can enter manually the weather value.

[[File:weather_manual.png]] 

==Davis instruments weather station ==

[[File:weather.png|framed|200px|right]]

You need the 3 elements to make it work.

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provide Accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield; wind speed and direction; and rainfall.

Note : '''The weather Station need to pass by OROS SA for configuration.'''

== Other weather statio ==

Please contact OROS to check the posibility to import the data. (paid service)

NVGate DC Simulated Manager

2020-12-22T19:11:43Z

NHoffman: /* Android GPS */

This Add on is a tools to use the DC simulated in NVGate.
It provide a GPS and can deal the weather station.

==Download==

Latest version (07.12.2020) can be donwloaded here : [https://orossas.sharepoint.com/:u:/g/support/EePDXb-MBEpIlRIvCUXYXHIBtPLjjzpC7eQ-Ndrx2_SDiA?e=u4NalF DC simulated manager v1.0]

Configuration needed : 
- NVGate 2021 or upper 
- DC simulated channels (ORNV-VIDC option)

=GPS=

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

== Serial GPGGA GPS ==

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can advise using the GPS USB Navilock NL-602U but other GPS models will also work. 

[[File:gps_navilock.jpg|200]]

== Android GPS ==
[[File:GPS_phone.png]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position inside NVGate.

[[File:GPS_android.png|600px]]

Procedure:

- Activate android developers option. ( To enable developer options, on android settings/"about phone" tap the Build Number option 7 times.
- Enable USB debugging (on developers options menu)

process is [https://www.howtogeek.com/129728/how-to-access-the-developer-options-menu-and-enable-usb-debugging-on-android-4.2/ here]

- Plug your android phone into your PC.
- Allow the incoming USB debugging connection and check "always allow from this computer".

You can test the connection using the ADB connection button.

[[File:gps_ADB.jpg]]

Also be sure the GPS is enabled on your phone, then you need to have an application which is running and using the GPS at the foreground of the phone (exemple: [https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=fr&gl=US Google Maps] or [https://play.google.com/store/apps/details?id=com.exatools.gpsdata&hl=fr&gl=US GPS Data])

== How to used ==

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400]]

Then you can use these channels on NVGate.

If you need to record the data.
click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png]]

If you have record the data you will be able to create a .gpx file

== Creating and visualize .gpx file ==

We can create a .gpx from an .oxf (OROS) signal file.

You need to click on Convertsignaltogpx.
[[File:GPS_creategpx.png]]

This will open the windows below.
[[File:signal_gpx.png]]

Select the signal file than you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put on the folder "attachement" of the NVGate project.

If you want to visualize the .gpx we advice to use the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens an website allowing you to plot the gpx on a map.

=Weather station=

== Manual ==

The user can enter manually the weather value.

[[File:weather_manual.png]] 

==Davis instruments weather station ==

[[File:weather.png|framed|200px|right]]

You need the 3 elements to make it work.

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provide Accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield; wind speed and direction; and rainfall.

Note : '''The weather Station need to pass by OROS SA for configuration.'''

== Other weather statio ==

Please contact OROS to check the posibility to import the data. (paid service)

Human Vibration

2020-12-22T19:10:37Z

NHoffman: /* Hand-Arm Measurement */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are described in the ISO 5349. This type of vibration is transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T19:07:55Z

NHoffman: /* Whole-Body Measurement */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

NVGate DC Simulated Manager

2020-12-22T19:07:38Z

NHoffman: /* Serial GPGGA GPS */

This Add on is a tools to use the DC simulated in NVGate.
It provide a GPS and can deal the weather station.

==Download==

Latest version (07.12.2020) can be donwloaded here : [https://orossas.sharepoint.com/:u:/g/support/EePDXb-MBEpIlRIvCUXYXHIBtPLjjzpC7eQ-Ndrx2_SDiA?e=u4NalF DC simulated manager v1.0]

Configuration needed : 
- NVGate 2021 or upper 
- DC simulated channels (ORNV-VIDC option)

=GPS=

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

== Serial GPGGA GPS ==

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can advise using the GPS USB Navilock NL-602U but other GPS models will also work. 

[[File:gps_navilock.jpg|200]]

== Android GPS ==
[[File:GPS_phone.png]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position inside NVGate.

[[File:GPS_android.png|600px]]

Procedure:

- Activate android developers option. ( To enable developer options, on android settings/"about phone" tap the Build Number option 7 times.
- Enable USB debugging (on developers options menu)

process is [https://www.howtogeek.com/129728/how-to-access-the-developer-options-menu-and-enable-usb-debugging-on-android-4.2/ here]

- Plug your android phone with USB plug on the PC.
- Allow the incoming USB debugging connection and check "always allow from this computer".

You can test the connection using the ADB connection button.

[[File:gps_ADB.jpg]]

Also be sure the GPS is enabled on your phone, then you need to have an application which is running and using the GPS at the foreground of the phone (exemple: [https://play.google.com/store/apps/details?id=com.google.android.apps.maps&hl=fr&gl=US Google Maps] or [https://play.google.com/store/apps/details?id=com.exatools.gpsdata&hl=fr&gl=US GPS Data])

== How to used ==

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400]]

Then you can use these channels on NVGate.

If you need to record the data.
click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png]]

If you have record the data you will be able to create a .gpx file

== Creating and visualize .gpx file ==

We can create a .gpx from an .oxf (OROS) signal file.

You need to click on Convertsignaltogpx.
[[File:GPS_creategpx.png]]

This will open the windows below.
[[File:signal_gpx.png]]

Select the signal file than you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put on the folder "attachement" of the NVGate project.

If you want to visualize the .gpx we advice to use the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens an website allowing you to plot the gpx on a map.

=Weather station=

== Manual ==

The user can enter manually the weather value.

[[File:weather_manual.png]] 

==Davis instruments weather station ==

[[File:weather.png|framed|200px|right]]

You need the 3 elements to make it work.

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provide Accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield; wind speed and direction; and rainfall.

Note : '''The weather Station need to pass by OROS SA for configuration.'''

== Other weather statio ==

Please contact OROS to check the posibility to import the data. (paid service)

Human Vibration

2020-12-22T19:07:07Z

NHoffman: /* Whole-Body Measurement */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T19:06:13Z

NHoffman: /* Whole-Body Measurement */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject moves. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specifies that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T19:03:16Z

NHoffman: /* Whole-Body Measurement */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T19:02:21Z

NHoffman: /* Whole-Body Measurement */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three directions: X, Y and Z. As different weighting will be used for each direction, it is really important that each sensor is oriented according to the same direction. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allows you to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyze. In order to analyze signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensor over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:58:23Z

NHoffman: /* Whole-Body Measurement */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are described in ISO2631. This type of vibration will mainly occur in transportation and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried out on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, gives indication of the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:56:26Z

NHoffman: /* Practical information about measurements */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical information about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happens in vehicles during transportation, in buildings, and when using vibrating equipment and tools, such as electric drills, blowers. Since the last century, studies have shown that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the years, and have translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:49:46Z

NHoffman: /* Unit in NVGate */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:48:32Z

NHoffman: /* Unit in NVGate */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:47:45Z

NHoffman: /* Unit in NVGate */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formula needs to be entered as the calculations are already built-in to the toolkit. You will only need to enter the unit and your display preferences.
 

==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:44:08Z

NHoffman: /* In the toolkit */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in seconds. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:41:47Z

NHoffman: /* In the toolkit */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:40:11Z

NHoffman: /* In the toolkit */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:39:25Z

NHoffman: /* In the toolkit */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each direction. Filters will be selected in accordance with the desired result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hour measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommends using 1sec. This is the default value of the setting. 

Once the filters are selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicators for the "Seat_Pad_Measurement" signal. This signal contains 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be found in the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contains the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture shows the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name of the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". Here is an example for Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 

====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:29:56Z

NHoffman: /* Dk */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:28:14Z

NHoffman: /* Dk */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T18:27:30Z

NHoffman: /* Dk */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advises calculating the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T16:42:49Z

NHoffman: /* VDV */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the fourth power. The fourth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T16:27:58Z

NHoffman: /* Peak */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T16:27:12Z

NHoffman: /* Peak */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represents the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T16:24:42Z

NHoffman: /* Aw */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 

======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T16:02:09Z

NHoffman: /* VDV */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to assess the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>

======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:53:19Z

NHoffman: /* Usage in the toolkit */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:52:22Z

NHoffman: /* Usage in the toolkit */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player the same as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:46:04Z

NHoffman: /* Time-weighted signal */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:45:11Z

NHoffman: /* Time-weighted signal */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the effect of vibrations on the human body suggest that different parts of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient components of vibration signals. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part shows how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:38:13Z

NHoffman: /* How to use */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appears. The results and weighted signal will have been added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:34:14Z

NHoffman: /* How to use */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyze in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appear. The results and weighted signal have added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:26:39Z

NHoffman: /* How to use */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurements present in the project (only the measurements where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyse in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appear. The results and weighted signal have added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:20:28Z

NHoffman: /* Download & install */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurement present in the project (only the measurement where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyse in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appear. The results and weighted signal have added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

Human Vibration

2020-12-22T15:19:40Z

NHoffman: /* Download & install */

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the steps of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. This way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurement present in the project (only the measurement where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyse in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appear. The results and weighted signal have added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

NVGate 2021: Release note

2020-12-22T15:09:02Z

NHoffman: /* How much does this body shake? */

OROS strives to be closer to its users, carefully listening to needs and requests. For that reason, OROS regularly releases new versions. Customers under contract automatically benefit from each release.

[[File:Screenshot 2020-12-21 102850.png|500px]]
 
The NVGate® 2021 major version became available in January 2021. This release of the OROS 3-Series analyzer’s software platform brings additional functionalities and significant performance improvements. Below is a summary of the main enhancements of your NVGate experience: 

{| class="wikitable" style="width: 90%;"
|-
| style="width: 25%"| [[File:1250px-Wikipedia_logo_(svg).svg.png|50px|link=NVGate_2021:_Release_note#Here_is_OROS_Wiki_on_the_line.2C_how_can_I_help_you.3F]] ''' On line OROS Wiki, how can I help you?''' Help is now available online with a powerful search engine. An offline version is available as well for when you are in the field.
| style="width: 25%"| [[File:filter__2021.png|50px]] '''Relax the limits of filtering!''' Cut off frequencies of filters, Butterworth and '''new Chebyshev type I and II''', can now be chosen very flexibly.
| style="width: 25%"| [[File:kinematik_2021.png|50px]] '''Tracking my bearing frequencies on RPMs variations''' Kinematik markers are now tracking the frequency lines as the speed fluctuates
| style="width: 25%"| [[File:gps_2021.png|50px]] Enrich your measurements in real time with '''GPS''' information'''
|-
| [[File:simulated_dc.png|200px]] Using the '''DC simulated''' function, one can now associate NVGate results with information from external software in real time using NVDrive
| [[File:orbit_2021.jpg|50px]] '''Draw those orbits!''' Orbits can now be displayed directly in NVGate with FFt-Diag option
| [[File:calibration_2021.png|50px]] dynamical input can now calibrate DC sensor with y = ax + b formula
| [[File:human_2021.png|50px]] '''How much does this body shake?''' A new add-on is available to apply human vibrations filters and calculate associated quantities.
|}
This release note describes the content of version, with operating details.
 
'''Compatibility:'''
NVGate 2021 is compatible with all OROS instruments that have not been discontinued. Depending on the hardware options and version, some instrument features may or may not be available.

= Here is OROS Wiki on the line, how can I help you? =

All the documentation and help have been completely renewed. We have put an online wiki-based documentation with videos, manual, application notes, download.

This page is in free access and can be consulted here: https://wiki.oros.com/wiki/index.php/Home

== Online Help: wiki ==
We advise being connected to internet to enjoy the new documentation page. 

If you are connected to Internet, the following buttons will bring you to the NVGate wiki page. 

[[NVGate|https://wiki.oros.com/wiki/index.php/NVGate]]

<gallery>
File:help_menu.png
File:Help_ribbon.png
File:Help_asb.png
</gallery>

Be aware than this wiki page have a powerful research button if you need to search any setting. 
[[File:help search.png]]

If you are using NVGate in a different language than english, the wikipage will be opened with /XX at the end (XX correspond to the unicode language. 

For example if you are using NVGate in Japanese, help will bring you to the page:
https://wiki.oros.com/wiki/index.php/NVGate/ja (==> ja is the international Japanese code)

== Off line Help: PDF manual ==
If you are not connected to internet which may often happen in the field, the NVGate.pdf manual will be opened. This file is located in the "Manuals" folder in the installation directory of NVGate.

== Tutorials Videos ==

The OROS Youtube channel is available here featuring a full panel of videos on how to use OROS products :

[[File:youtube.png|600px]] 

[https://www.youtube.com/user/OROSanalyzers/ OROS Youtube channels page]

We have included tutorial videos in this wiki to help you to use the OROS software.

= Tracking bearing frequencies on RPMs variations =

== Kinematik markers follow FFT tachometer==

The Kinematik marker can now be associated to the speed of the tachometer.
So during a Run up the kinematik marker will automatically move inside FFT spectrum with the speed.

How to use it :
Select a Tachometer on the FFT tab from GoToResult page.

[[File:kiné_fft.png|500px]]

Then display a FFT spectrum. Select a kinematik marker and put it on the window.

[[File:kiné_select.png|400px]]

Now this marker will be linked to the FFT speed.

Then on properties, you can link (or not) this marker to the speed.

[[File:kiné_select_active.png|300px]]

== Automatic installation of the database ==

Now the excel kinematic database including bearings from NSK, SKF, FAG, SNRn, GMN, INA, RHP is installed automatically.

You can find it in the installation folder: "NVGate Data\Markers\Kinematic\"

== Direct access to database==

When clicking on the "open folder" button, you will directly access the folder where the Excel kinematic database is stored
so you can edit the database easily if you need to add the kinematic configuration of a rotating machine.

[[File:kiné_select_edit.png|400px]]

= Enrich your measurements in real time: from GPS to environmental metadata =

The DC simulated inputs allow you to inject up to 32 external DC channels in NVGate from external source (exemple : GPS, weather station, external can bus...). The frequency sampling is up to 15 samples / second.
Thanks to the python developer toolkit, a developer can easily develop an interface to inject the values into NVGate. The GPS and weather station below have been developed using the DC simulated.

This option is included with the reference ORNV-VI-DC (which also includes the Virtual input).

How to use it:
 

on the Acquisition Tab, select connect input, select the DC inputs and select the DC simulated channels.

[[File:DC simulat.png|600px]]

These channels can be activated and connected to the recorder and/or waterfall like any other DC channels.

[[File:DC_simul.png]]

The settings '''Value''' (which can be controlled by an external software) will change the value of the inputs.

[[NVGate_Front_End#Simulated_DC_Inputs|The other DC simulated settings details]] are explained on the front end settings page.

== GPS ==
Thanks to the "DC simulated channels" we have created an Add-on to record GPS data.

The GPS have the following features

* Record the X-Y GPS coordinates.
* Record and display the speed profile.
* Use the speed profile as a waterfall reference.
* Creat a .gpx and display it on an internet website if you have an Internet connection).

You can visit the dedicated page to download it and advanced configuration. : https://wiki.oros.com/wiki/index.php/NVGate_DC_Simulated_Manager

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

=== Serial GPGGA GPS ===

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can recommend the GPS USB Navilock NL-602U but other GPS units will work as well. 

[[File:gps_navilock.jpg|200px]]

=== Android GPS ===
[[File:GPS_phone.png|500px]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position into NVGate.

=== How to use it ===

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400px]]

Then you can use these channels on NVGate.

If you need to record the data, click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png|600px]]

If you have recorded the data you will be able to create a .gpx file

=== Creating and visualize .gpx file ===

We can create a .gpx from an .oxf (OROS) signal file. a .gpx is gps file to follow the geographic information of the signal on a map.

You need to click on "Convert signal to gpx".
[[File:GPS_creategpx.png|150px]]

This will open the windows below.
[[File:signal_gpx.png|400px]]

Select the signal file that you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put in the "attachement" folder of the NVGate project.

If you want to visualize the .gpx we advise using the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens a website allowing you to plot the gpx on a map.

== Weather station==

Precipitation, wind speed/direction, pressure, temperature, and pressure can prejudice sound pressure levels or need to be recorded when you are doing sound measurement.

Thanks to the DC simulated channels, we can now enter manually the value or we can connect a weather station to NVGate.

=== Manual ===

The user can enter manually the weather value.

[[File:weather_manual.png|400px]] 

===Davis instruments weather station ===

[[File:weather.png|200px|right]]

3 elements are required to make it work

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provides accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield, wind speed and direction, and rainfall.

Note : The weather Station needs to pass by OROS SA for configuration.

=== Other weather stations ===

Please contact OROS to check the possibility to import the data (paid service).

= Relax the limits of filtering! =

All details on the filters can be read [[NVGate_Filter_Builder|here]]

===New prototype filters===
In addition to the Butterworth filter, now you can build the IIR filters with the Chebyshev type I (band-pass ripple) filter or Chebyshev type II (stop-band ripple) filter.

The Butterworth filter has flat response in both the pass band and stop band, but its transition band is wide.

The Chebyshev type I (band-pass ripple filter) has the steepest roll-off among the three filters, and its response in the stop band is flat. However, it has ripples in the pass band.

The Chebyshev type II (stop-band ripple) filter has flat response in the pass band, but it has ripples in the stop band. Its transition band is narrower than the Butterworth filter, but wider than the Chebyshev type I.

Below is an example showing these three filters with the same filter order.

[[File:filters_3.png|600px]]

Thanks to its maximal flat frequency response in the pass band, the Butterworth filter is commonly used in applications where signal distortion should be minimized, such as audio noise reduction. It is also widely used for anti-aliasing. The Chebyshev filters are optimized to provide steep roll-off, and they are usually used in applications where the maximum rejection of the nearby frequencies is required.

==Increased filter order==
The order of the filter affects the steepness of its roll-off. The higher the order is, the sharper the transition between the pass band and the stop band is. An example demonstrating the impact of the filter order is shown below.

[[File:butterworth_freq_response.png|600px]]

For the high pass and low pass filters, the filter order can be selected from 1 to 40 in the Office mode, and from 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum filter order was 6.

For the band pass and band stop filters, the filter order is 2*N, and N can be selected from 1 to 30 in the Office mode, and between 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum value of N was 5.

===Relaxed constraints on the cut-off frequency===

To guarantee the stability of the filter, there are certain constraints on the value of the cut-off frequency. Compared with previous version of NVGate, such constraints are relaxed significantly now.

[[File:image_2020-11-27_095451.png|600px]]

For the high pass and low pass filters, the maximum value of the cut-off frequency is the input frequency range '''FR'''. The minimum value is '''FR''' / 50000 in the Office mode, and '''FR''' / 40000 in the Connected mode. In the previous NVGate version, the minimum value was '''FR''' / 40 for the low pass filter, and '''FR''' / 400 for the high pass filter.

For the band pass and band stop filters, the low cut-off frequency ''f''low and the high cut-off frequency ''f''high need to meet the following conditions in the Office mode:

* ''f''low ≥ 0.0001 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0004 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.9998 * '''FR'''

And in the Connected mode, the conditions are as below:

* ''f''low ≥ 0.0005 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.000675 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

In the previous NVGate version, the conditions on the cut-off frequencies were:

* ''f''low ≥ 0.055 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0075 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

==Improved precision==
Now, the filters are calculated in 64-bit floating point format in the Office mode, and in 40-bit floating point format in the Connected mode. In the previous NVGate version, the 32-bit floating point format was used in both modes.

===Octave overall no limitation===

1/n Octave Overall levels frequency range plug-ins are now editable. You can define the min and max.
This overall is computed in the time domain (weighting filter and detector). Processing weighting in the time domain provides accurate measurement for non-stationary signals (impulsive).

[[File:octave_filter.png|400px]]

'''Full range mode''' computes the overall on the whole frequency range excluding the DC component. (The minimum range is defined by "CPB filters Lower central frequency"/5).
'''Limited range''' lets the user define the range by changing the low cut off frequency and high cut off frequency.

===Application===
=== global level with filter===
=== remove noise from spectrum===
===Listen signal with filter===

=DC Dynamical sensor y = ax+b calibration =

It is now possible to calibrate a dynamical sensor in "DC" or "DC floating" coupling using 2 values, then the software will automatically compute sensitivity and offset to obtain the "y = ax + b" formula.

This function is practical for 4-20 mA sensors or “quasi-static” sensors acquired on dynamic channels. Wire sensor displacement sensor calibrated with a rule, pressure sensor with a calibrated compressor, proximity probe calibrated with a micrometer.

For using it, first create a DC sensor on the sensor database. Then apply this sensor to a channel.

Now on the calibration part, you can calibrate it using 2 values. Then the software will automatically apply the sensitivity and offset.

[[File:calibrator.png|500px]]
== Remove a sensor from history ==

If you have made a mistake during a sensor calibration, you can now delete a value from calibration sensor history.
[[File:remove_caibration.png|600px]]

You need to go on history, select the sensor, select the value that you need to delete, then click on remove.

= How much does this body shake? =

The OROS Body Vibration tool allows you to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standards define measurement practice and vibration signal analysis to evaluate the effect on health and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describes the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. 
 
This is a post analysis toolkit, operating after the recording of the signal. It will calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 

[[Image:OROS_BodyVib.png|400px|none]]
'''Standards compatible''': international standards about whole/body vibration including: ISO 5349, ISO 8041, ISO 2631-1 and ISO 2631-5. 

'''Whole/body Vibration Indicators include ''': VDV, MSDV, MTVV, Weighted raw, al(ISO 2631-5), D(ISO 2631-5) are available. RMS, Peak, Crest, peak-Peak, are also available in NVGate plug in.
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the effect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|Daily maximal exposure value (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|}

'''Signal fitering including''':
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|}

How to use it:
https://wiki.oros.com/wiki/index.php/Human_Vibration

This Add-on is free of charge for NVGate 2021 users and TDA (?)

= Orbit display included in FFT diag or ORD diag =

For customer with option FFT-Diag or ORD-Diag, they will now have the Orbit display available in NVGate.

[[File:Display_Graphs_Traces_122.png|400px]] 

The orbit is available using the add/remove windows.

For more details, please check the [[NVGate_Display#Orbit|orbit dipslay page.]]

=Miscellaneous=

== Displaying Time in Zoomed signal==

== NVdrive : SetViewmeterLevels ==

Using NVdrive, you can now control and set the alarm level, high level and low level.
[[File:Viewmeter.jpg|none]]

Check the NVDrive toolkit for more info.

=Bug fixing=
 

* 13728: [Fractional Tachometer] Using a fractional tachometer lead to DSP error -
* 13729: [Drec] : Impossible to record more than 38 ch in Drec
* 13672: Delta RPM with source DC tach (from monitor) - do not trig the waterfall
* 10572: Low pass response for ICP and AC coupling poorly specified
* 13811: NVDrive GetResultEx error while running without displaying result
* 13774: Orbit display improvement
* 13790: Change the number of displayed orbits
* 13794: A problem of DRPM stop at 5000 RPM instead of 6000.
* 13953: [General] A-weighting can be applied several times (report 13912)
* 13938: Input type: Xpod bridge, one channel 5 doesn't work if 1 activated
* 13767: Create a new unit : do not go on a "empty" windows, keep the previous configuration.

Human Vibration

2020-12-22T15:08:02Z

NHoffman:

The OROS Body Vibration tool allows users to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standard define measurement practice and vibration signal analysis to evaluate the effect on health and and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describe the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the effect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. In the following, we will see how to use OROS to evaluate these effects. 
 
This is a post analysis toolkit, operating alongside NVGate after the recording of the signal and will help you to calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 
[[Image:OROS_BodyVib2.png|800px|none]]
 
==Download & install==
Download the program here (version from 03/12/2020) :
https://orossas.sharepoint.com/:u:/g/support/EXCVJE_bLGZMgHg1mr4p1hwB5ICqdqKBXTK3kH9stxozKg?e=UJg72W

Once downloaded, you can unzip the folder and lunch the installer program Setup_OROS_BodyVibration_Tool_vXX.exe. Follow the step of the program to properly install the software. 

The program will be installed in "C:\OROS\Programs\ExternalTools". Shortcuts are created on the main desktop, in the Windows Start program and in the "Link" repertory of NVGate. By that way you can directly run the program from NVGate.

==How to use==

<ol>
<li>Launch NVGate </li>
<li>Launch OROS_BodyVibration_Tool.exe </li>
<li>Open a project in NVGate </li>

[[File:Open_Proj.png]]
 
<li>In the tool, Click on list measurement to list all the measurement present in the project (only the measurement where the signal files are actually on the disk will be displayed. Ensure you have [[NVGate_Project_manager#Uploading.2FDownloading|downloaded signal from the OR3X disk]]) </li>
[[Image:List_Meas.png|400px|none]]
<li>Add the measurement you want to analyse in the "selected list" area using the ">>" button. Use the "<<" button to remove file if needed. </li>
[[Image:Add_Rmv.png|400px|none]]
<li>Click on "Select Directions" to set the direction and sensor for each channel (This step is not necessary if you only want the time-weighted signals). </li>
[[Image:Select_DOF.png|400px|none]]
<li>Select the weighting you want to apply on the time signal </li>
[[Image:Select_Filter.png|400px|none]]
<li>Select the weighting you want to apply for each direction X, Y and Z used for the indicators </li>
[[Image:Select_Process_Filt.png|400px|none]]
<li>Select the metrics you want to calculate </li>
[[Image:Select_Metric.png|400px|none]]
<li>Click on "Start Processing" </li>
[[Image:Strat_Proc.png|400px|none]]
<li>The processing is completed when a the following pop-up window appear. The results and weighted signal have added to the current NVGate project. See the next sections for details. </li>
[[Image:The_End.png|400px|none]]
</ol>

==Toolkit results==
===Time-weighted signal===
Studies of the affect of vibrations on the human body suggest that part of the body don't have the same response to vibrations, and will be sensitive to specific frequencies and transient component of vibration signal. In order to represent the sensitivity of the human boy, ISO standards defined time-weighting that must applied to the signal according to the environmental conditions. The following part present you how to apply time-weighting filters to your signal using the toolkit.
====Time-weighting filters====
As defined in the standards, specific time weighting must be applied to the acceleration signal in order to represent the effect of vibrations on health and comfort. Here is the list of the different time-weighting filters implemented in the toolkit : 
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1; older version)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_m</math>
|Time weighting for all directions for buildings vibration measurement (ISO 2651-2)
|}

Filters have been validated from 0.5 to 10kHz at 25.6kSample/second.

====Usage in the toolkit====
The toolkit allow you to calculate the filtered raw signal with any of the above weighting filters. This will allow you to display [[NVGate FFT Analyzer|spectrums]] and calculate RMS via [[NVGate_Post_Analysis|post-analysis]] in NVGate.

To calculate the raw weighted signal, simply select the filters you want in the "Time signal filters" section :

[[Image:Filter2.png]]

Once the processing is completed, a new measurement containing the filtered signal for each selected filter is created in [[NVGate Project manager|NVGate Project Manager]] :

[[Image:Filtered_Sig.png|400px]]
 
You can then load the new signals in the player as any NVGate signal. Each track of the signal is filtered with the corresponding filter. 

[[Image:Sig_In_ Player.png|800px]]

===Health and comfort indicator===
In addition to the time-weighting filters, the ISO standards present a series of specific metrics to evaluate the affect of vibrations on the Human body. The following section will present you how to use the toolkit to access these metrics.
====Indicators====

{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|RMS of the weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>a_v</math>
|Total RMS value calculated as a quadratic average of the three direction for each tri-axial sensor.
|-
|style="height:30px; width:100px;"|<math>A_h</math>
|RMS of the <math>W_h</math> weighted acceleration magnitude.
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>Se</math>
|The equivalent Static compression stress on the spine, caused by repeated shocks
|}

======Aw======

The <math>A_w</math> is the RMS of the weighted acceleration signal. The weighting is applied in accordance with the direction set for each channel and the weighting filter defined for the direction. 

For each channel, the <math>A_w</math> and <math>A_w(T)</math> will be calculated. The <math>A_w(T)</math> is the Daily exposure value, defined as : 
<math display="block" forcemathmode="5">A_w(T) = A_w*k_{i}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. the <math>k_i</math> factor is defined in the ISO 2631 as <math>k_X = k_Y = 1.4</math> and <math>k_Z = 1</math>.

When comparing result from one measurement point in the three direction, the maximum of the Daily exposure value must be used as the total daily exposure value at that point : 
<math display="block" forcemathmode="5">A_w(T) = max(A_{wX}(T), A_{wY}(T), A_{wZ}(T)) </math>
 
======av======
The <math>a_v</math> is the total RMS vibration value of the weighted acceleration signal. This value will only be calculated if a sensor have been defined in the definition of direction window.

For each tri-axial sensor, the <math>a_v</math> will be calculated as a quadratic average of the weighted RMS value in the three directions : 

<math display="block" forcemathmode="5">a_v = \sqrt{{a_{vX}}^{2}*{k_{X}}^{2} + {a_{vY}}^{2}*{k_{Y}}^{2} + {a_{vZ}}^{2}*{k_{Z}}^{2}}</math> 
With <math>k_{X,Y,Z}</math> a factor defined in the ISO 2631 as <math>k_{X}=k_{Y}=1.4</math> and <math>k_{Z}=1</math>
 
======Ah======
The <math>A_h</math> is the RMS of the <math>W_h</math> weighted acceleration signal for hand-arms vibration measurement. For each channel, the <math>A_h</math> and <math>A_h(T)</math> will be calculated. The <math>A_h(T)</math> is the Daily exposure value, defined as : 

<math display="block" forcemathmode="5">A_h(T) = A_h*\sqrt{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter. 

If any sensor is defined, the total <math>A_h</math> and <math>A_h(T)</math> will be calculated for each sensor as a quadratic average of the three direction of the sensor : 
<math display="block" forcemathmode="5">A_{h Total} = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}</math>
 
and : 
 
<math display="block" forcemathmode="5">A_{h Total}(T) = \sqrt{{a_{hX}}^{2}*{k_{X}}^{2} + {a_{hY}}^{2}*{k_{Y}}^{2} + {a_{hZ}}^{2}*{k_{Z}}^{2}}*\sqrt{\frac{T}{T_m}}</math>
 
With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=k_{Z}=1</math>
 

======Peak======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|peak amplitude]] of the vibration signal. It represent the maximal amplitude of the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======Crest Factor======

This indicator is the [[NVGate_Time_Domain_Analysis#Available_results|Crest Factor]] of the vibration signal. It represent the importances of the transient event in the signal as the ratio of the maximal Peak amplitude over the RMS level for the weighted signal. This indicator can be obtained in NVGate by [[NVGate Post Analysis|post-analysing]] the weighted signal with the [[NVGate Time Domain Analysis|TDA plugin of NVGate]].

======MTVV======
The MTVV is the Maximal Transient Vibration Value, is the maximum of the running RMS of the weighted acceleration. This value is calculated for each channel and is expressed in m/s².

The MTVV Tau is the integration time, expressed in seconds. This value can be edited before the calculation, but the ISO 2631 recommand to use 1 second. Therefore this is the default value of this parameter.

======VDV======
The VDV is the forth power Vibration Dose Value. It is calculated as a cumulative sum of the weighted acceleration at the forth power. The forth power is used to give more weight to the transient event of the signal over the periodic event. Therefore, this indicator must be used to asses the effect of shock on human health and comfort. The VDV is calculated for each channel and expressed in m/s^(1.75). 

If the "VDVTexp" box is checked, an evaluation of the VDV value over a longer time period will be calculated of each channel as : 
<math display="block" forcemathmode="5">VDV_{X,Y,Z}(T) = VDV_{X,Y,Z}*k_{X,Y,Z}*\sqrt[4]{\frac{T}{T_m}}</math> 

With <math>T_m</math> the duration of the measurement and <math>T</math> the total exposure duration represented by the "Reference time" parameter, and <math>k_{X}=k_{Y}=1.4</math>, and <math>k_{Z}=1</math>
======MSDV======
This metric is the Motion Sickness Dose Value, used to evaluate the ride comfort in in-vehicle measurement. It is expressed in m.s^(1.5). 

Although this value will be calculated for each direction, only the Z-direction will have a prominent relevance to assess ride comfort.
======Dk======
<math>D_k</math> is the acceleration dose. It is use to evaluate the effect of vibrations on the human spine, and calculated as the 6th root of the sum of the peaks in the acceleration signal raised at the 6th power. it is expressed in m/s². Peaks are defined as the absolute maximum of the acceleration signal between two zeros crossing. In the Z direction, only the positive peak will be considered, were all positive and negative peaks are used for the X and Y directions. 

Specific filters are used to weight the acceleration signal before calculating the <math>D_k</math>. These filter are different for the vertical and horizontal direction, and are defined for a sampling rate of 160 Sample/second. Therefore, we advise to [[NVGate Recorder|record]] the signal with a low [[NVGate_Front_End#Input_settings|sampling rate]] in NVGate. 

Assessing the affect of the vibration on human spine most is important when dealing with transportation vehicular, especially from driver seat. for a better evaluation, the ISO 2631-5 advise to calculate the daily acceleration dose, defined as : 

<math display="block" forcemathmode="5">D_{X,Y,Z}(T) = D_{X,Y,Z}*\sqrt[6]{\frac{T}{T_m}}</math> 

This value will be calculated if the box "Dk Texp" is checked.

======Se======
The Se is the compressive stress on the human spine, expressed in MPa. It is calculated by the combination the Dk in the three direction. Therefore, it will only be calculated if sensors are defined in the "Select Direction" window. One value of Se will be calculated for each sensor by the formula : 
<math display="block" forcemathmode="5">Se = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}*m_{k})^6}</math> 

Where <math>m_{X} = 0,015</math> MPa/(m/s²), <math>m_{Y} = 0,035</math> MPa/(m/s²) and <math>m_{Z} = 0,032</math> MPa/(m/s²). 

To evaluate the lumbar stress over a daily exposition time, the Se(T) will also be calculated as : 
<math display="block" forcemathmode="5">Se(T) = \sqrt[6]{\sum_{k=X,Y,Z}(D_{k}(T)*m_{k})^6}</math> 

T being the total exposure duration represented by the "Reference time" parameter. 

====In the toolkit====
Before calculating the indicators in the toolkit, you must define a filter for each directions. Filters will be selected in accordance with the wanted result (Hand-arms; Whole-Body, ..) and the direction of the measurement as specified in the table [[Human_Vibration#Time-weighting_filters|describing the filters]]. Filters will be applied to the signal before calculating the indicators, but the time-filtered signal will not be saved. 
[[Image:proc_filt.png]]
 
You will then need to enter the reference time you want to use to estimate the parameters on a greater duration. This duration must be entered in second. The default value is 288500 second, corresponding to a 8 hours measurement: 
[[Image:Ref_Time.png]]

You will finally need to enter the MTVV Tau value. The MTVV Tau is the integration time in seconds used for the calculation of the MTVV. The ISO 2651 recommand to use 1sec. This is the default value of the setting. 

Once the filters selected and the parameters competed, you can select the metrics you want to calculate by checking the different boxes. 
[[Image:all_proc.png]] 
You can then start the processing to calculate the indicators. 

Here, we are calculating all the indicator for the "Seat_Pad_Measurement" signal. This signal contain 3 Tracks, one for each channel X, Y and Z of a three axis accelerometer. As we want to calculate the multi-axis metrics, we also define a sensor on the three tracks, called "Seat_Pas_3axis". 
[[Image:Set_up_seatPad.png|500px]]
 
Once completed, the result can be find the currently opened project in the [[NVGate Project manager]]. A new measurement called "NAME_OF_THE_Signal_out" containing the result is created. 

[[Image:ResInProjMAn2.png|300px]] 

Each indicator is calculated for each direction and for each track of the signal. The name of the result contain the name of the track, the considered direction and the filter used for that direction (except for the <math>D_k</math> which use specific filters). 
The following picture show the indicators for the first track (SeatPadX) of the signal : 
[[Image:Resut_SeatPad.png|300px]]
 

For the metrics estimated on the "Reference Time", the name the indicator is followed by "(Ref_Time_in_Second"). Here an example with the VDV metric, the name of the indicator is displayed in the window title : 
[[Image:VDV_andTexp.png|800px]]
 

The metrics combining the three directions (av, Se, Ah,...) are named as following : "METRICS_Name : Sensor". By example here for the Se :

[[Image:Se.png|400px]]
 
You can then display the result in NVGate by double clicking.
 
====Unit in NVGate====
To display the right unit for the MSDV;, VDV and Se indicators, you need to modify the [[NVGate_User_Preferences#Physical_quantity|Spare units of NVGate]] as :
* Spare1 : <math>m/{s}^{1.75}</math> for the VDV
* Spare2 : <math>m/{s}^{1.5}</math> for the MSDV
* Spare3 : <math>Pa</math> for the Se (you can adapt the display as MPa).
 
No formulae need to be entered as the calculations are already made in the toolkit. You will only need to enter the unit and your display preferences.
 
==Practical information about measurements==

This section will provide you with some practical informations about Human Vibration evaluations.

Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms. 
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm. 

===Type of measurement===
====Whole-Body Measurement====
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, extracted from the standard, give indication over the orientation of the sensors : 

[[Image:Axis_WholeBody.png]] 

For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine. 

Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [https://www.dytran.com/Model-5313A-Triaxial-Seat-Pad-Accelerometer-P2161/|Seat Pad accelerometer] allow to acquire vibrations at the buttocks : 
[[Image:DytranSeatPad.png]] 
If necessary, the same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor. 
 
The length of the measurement should be representative of the whole exposure duration during a day. However, as it is not always possible to acquire long signal, the ISO 2631 specify that measurement must be taken for at least 20 minutes, and 2h measurement are preferable. Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

====Hand-Arm Measurement====

Measurement procedures for hand-arm vibration evaluation are describe in the ISO 5349. That type of vibration are transmitted to the body by the hands and the amrs when using hand-tools and equipment, holding a vibrating object (like the steering wheel in a vehicle), or feeding a machine (wood cutting or turning). 

Here, the direction of the sensor is not important, however, at least two directions must be acquired at each point in the direction perpendicular to the handle axis. The most important part is to measure vibration at the contact point of the hand and the tool. Specific adaptor can be used to hold the accelerometer with the handle.

 
The length of the measurement should be representative of the whole exposure duration during a day. Therefore, it can vary from very short measurement (when feeding the machine) to longer measurement (steering wheel). 
Using the OROS tool kit, long signals file can be take a lot of time to analyse. In order to analyse signal files longer than 30 minutes, we advise to : 
* reduce the Sampling rate, as frequency bandwidth for Whole-body vibration will note exceed 1kHz.
* Split each sensors over several files
 
Please contact OROS customer care team for advices.
 

The main indicator used for hand-arm vibration will be the Ah and Ah(8) metrics.

NVGate 2021: Release note

2020-12-22T15:04:32Z

NHoffman: /* How much does this body shake? */

OROS strives to be closer to its users, carefully listening to needs and requests. For that reason, OROS regularly releases new versions. Customers under contract automatically benefit from each release.

[[File:Screenshot 2020-12-21 102850.png|500px]]
 
The NVGate® 2021 major version became available in January 2021. This release of the OROS 3-Series analyzer’s software platform brings additional functionalities and significant performance improvements. Below is a summary of the main enhancements of your NVGate experience: 

{| class="wikitable" style="width: 90%;"
|-
| style="width: 25%"| [[File:1250px-Wikipedia_logo_(svg).svg.png|50px|link=NVGate_2021:_Release_note#Here_is_OROS_Wiki_on_the_line.2C_how_can_I_help_you.3F]] ''' On line OROS Wiki, how can I help you?''' Help is now available online with a powerful search engine. An offline version is available as well for when you are in the field.
| style="width: 25%"| [[File:filter__2021.png|50px]] '''Relax the limits of filtering!''' Cut off frequencies of filters, Butterworth and '''new Chebyshev type I and II''', can now be chosen very flexibly.
| style="width: 25%"| [[File:kinematik_2021.png|50px]] '''Tracking my bearing frequencies on RPMs variations''' Kinematik markers are now tracking the frequency lines as the speed fluctuates
| style="width: 25%"| [[File:gps_2021.png|50px]] Enrich your measurements in real time with '''GPS''' information'''
|-
| [[File:simulated_dc.png|200px]] Using the '''DC simulated''' function, one can now associate NVGate results with information from external software in real time using NVDrive
| [[File:orbit_2021.jpg|50px]] '''Draw those orbits!''' Orbits can now be displayed directly in NVGate with FFt-Diag option
| [[File:calibration_2021.png|50px]] dynamical input can now calibrate DC sensor with y = ax + b formula
| [[File:human_2021.png|50px]] '''How much does this body shake?''' A new add-on is available to apply human vibrations filters and calculate associated quantities.
|}
This release note describes the content of version, with operating details.
 
'''Compatibility:'''
NVGate 2021 is compatible with all OROS instruments that have not been discontinued. Depending on the hardware options and version, some instrument features may or may not be available.

= Here is OROS Wiki on the line, how can I help you? =

All the documentation and help have been completely renewed. We have put an online wiki-based documentation with videos, manual, application notes, download.

This page is in free access and can be consulted here: https://wiki.oros.com/wiki/index.php/Home

== Online Help: wiki ==
We advise being connected to internet to enjoy the new documentation page. 

If you are connected to Internet, the following buttons will bring you to the NVGate wiki page. 

[[NVGate|https://wiki.oros.com/wiki/index.php/NVGate]]

<gallery>
File:help_menu.png
File:Help_ribbon.png
File:Help_asb.png
</gallery>

Be aware than this wiki page have a powerful research button if you need to search any setting. 
[[File:help search.png]]

If you are using NVGate in a different language than english, the wikipage will be opened with /XX at the end (XX correspond to the unicode language. 

For example if you are using NVGate in Japanese, help will bring you to the page:
https://wiki.oros.com/wiki/index.php/NVGate/ja (==> ja is the international Japanese code)

== Off line Help: PDF manual ==
If you are not connected to internet which may often happen in the field, the NVGate.pdf manual will be opened. This file is located in the "Manuals" folder in the installation directory of NVGate.

== Tutorials Videos ==

The OROS Youtube channel is available here featuring a full panel of videos on how to use OROS products :

[[File:youtube.png|600px]] 

[https://www.youtube.com/user/OROSanalyzers/ OROS Youtube channels page]

We have included tutorial videos in this wiki to help you to use the OROS software.

= Tracking bearing frequencies on RPMs variations =

== Kinematik markers follow FFT tachometer==

The Kinematik marker can now be associated to the speed of the tachometer.
So during a Run up the kinematik marker will automatically move inside FFT spectrum with the speed.

How to use it :
Select a Tachometer on the FFT tab from GoToResult page.

[[File:kiné_fft.png|500px]]

Then display a FFT spectrum. Select a kinematik marker and put it on the window.

[[File:kiné_select.png|400px]]

Now this marker will be linked to the FFT speed.

Then on properties, you can link (or not) this marker to the speed.

[[File:kiné_select_active.png|300px]]

== Automatic installation of the database ==

Now the excel kinematic database including bearings from NSK, SKF, FAG, SNRn, GMN, INA, RHP is installed automatically.

You can find it in the installation folder: "NVGate Data\Markers\Kinematic\"

== Direct access to database==

When clicking on the "open folder" button, you will directly access the folder where the Excel kinematic database is stored
so you can edit the database easily if you need to add the kinematic configuration of a rotating machine.

[[File:kiné_select_edit.png|400px]]

= Enrich your measurements in real time: from GPS to environmental metadata =

The DC simulated inputs allow you to inject up to 32 external DC channels in NVGate from external source (exemple : GPS, weather station, external can bus...). The frequency sampling is up to 15 samples / second.
Thanks to the python developer toolkit, a developer can easily develop an interface to inject the values into NVGate. The GPS and weather station below have been developed using the DC simulated.

This option is included with the reference ORNV-VI-DC (which also includes the Virtual input).

How to use it:
 

on the Acquisition Tab, select connect input, select the DC inputs and select the DC simulated channels.

[[File:DC simulat.png|600px]]

These channels can be activated and connected to the recorder and/or waterfall like any other DC channels.

[[File:DC_simul.png]]

The settings '''Value''' (which can be controlled by an external software) will change the value of the inputs.

[[NVGate_Front_End#Simulated_DC_Inputs|The other DC simulated settings details]] are explained on the front end settings page.

== GPS ==
Thanks to the "DC simulated channels" we have created an Add-on to record GPS data.

The GPS have the following features

* Record the X-Y GPS coordinates.
* Record and display the speed profile.
* Use the speed profile as a waterfall reference.
* Creat a .gpx and display it on an internet website if you have an Internet connection).

You can visit the dedicated page to download it and advanced configuration. : https://wiki.oros.com/wiki/index.php/NVGate_DC_Simulated_Manager

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

=== Serial GPGGA GPS ===

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can recommend the GPS USB Navilock NL-602U but other GPS units will work as well. 

[[File:gps_navilock.jpg|200px]]

=== Android GPS ===
[[File:GPS_phone.png|500px]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position into NVGate.

=== How to use it ===

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400px]]

Then you can use these channels on NVGate.

If you need to record the data, click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png|600px]]

If you have recorded the data you will be able to create a .gpx file

=== Creating and visualize .gpx file ===

We can create a .gpx from an .oxf (OROS) signal file. a .gpx is gps file to follow the geographic information of the signal on a map.

You need to click on "Convert signal to gpx".
[[File:GPS_creategpx.png|150px]]

This will open the windows below.
[[File:signal_gpx.png|400px]]

Select the signal file that you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put in the "attachement" folder of the NVGate project.

If you want to visualize the .gpx we advise using the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens a website allowing you to plot the gpx on a map.

== Weather station==

Precipitation, wind speed/direction, pressure, temperature, and pressure can prejudice sound pressure levels or need to be recorded when you are doing sound measurement.

Thanks to the DC simulated channels, we can now enter manually the value or we can connect a weather station to NVGate.

=== Manual ===

The user can enter manually the weather value.

[[File:weather_manual.png|400px]] 

===Davis instruments weather station ===

[[File:weather.png|200px|right]]

3 elements are required to make it work

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provides accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield, wind speed and direction, and rainfall.

Note : The weather Station needs to pass by OROS SA for configuration.

=== Other weather stations ===

Please contact OROS to check the possibility to import the data (paid service).

= Relax the limits of filtering! =

All details on the filters can be read [[NVGate_Filter_Builder|here]]

===New prototype filters===
In addition to the Butterworth filter, now you can build the IIR filters with the Chebyshev type I (band-pass ripple) filter or Chebyshev type II (stop-band ripple) filter.

The Butterworth filter has flat response in both the pass band and stop band, but its transition band is wide.

The Chebyshev type I (band-pass ripple filter) has the steepest roll-off among the three filters, and its response in the stop band is flat. However, it has ripples in the pass band.

The Chebyshev type II (stop-band ripple) filter has flat response in the pass band, but it has ripples in the stop band. Its transition band is narrower than the Butterworth filter, but wider than the Chebyshev type I.

Below is an example showing these three filters with the same filter order.

[[File:filters_3.png|600px]]

Thanks to its maximal flat frequency response in the pass band, the Butterworth filter is commonly used in applications where signal distortion should be minimized, such as audio noise reduction. It is also widely used for anti-aliasing. The Chebyshev filters are optimized to provide steep roll-off, and they are usually used in applications where the maximum rejection of the nearby frequencies is required.

==Increased filter order==
The order of the filter affects the steepness of its roll-off. The higher the order is, the sharper the transition between the pass band and the stop band is. An example demonstrating the impact of the filter order is shown below.

[[File:butterworth_freq_response.png|600px]]

For the high pass and low pass filters, the filter order can be selected from 1 to 40 in the Office mode, and from 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum filter order was 6.

For the band pass and band stop filters, the filter order is 2*N, and N can be selected from 1 to 30 in the Office mode, and between 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum value of N was 5.

===Relaxed constraints on the cut-off frequency===

To guarantee the stability of the filter, there are certain constraints on the value of the cut-off frequency. Compared with previous version of NVGate, such constraints are relaxed significantly now.

[[File:image_2020-11-27_095451.png|600px]]

For the high pass and low pass filters, the maximum value of the cut-off frequency is the input frequency range '''FR'''. The minimum value is '''FR''' / 50000 in the Office mode, and '''FR''' / 40000 in the Connected mode. In the previous NVGate version, the minimum value was '''FR''' / 40 for the low pass filter, and '''FR''' / 400 for the high pass filter.

For the band pass and band stop filters, the low cut-off frequency ''f''low and the high cut-off frequency ''f''high need to meet the following conditions in the Office mode:

* ''f''low ≥ 0.0001 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0004 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.9998 * '''FR'''

And in the Connected mode, the conditions are as below:

* ''f''low ≥ 0.0005 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.000675 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

In the previous NVGate version, the conditions on the cut-off frequencies were:

* ''f''low ≥ 0.055 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0075 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

==Improved precision==
Now, the filters are calculated in 64-bit floating point format in the Office mode, and in 40-bit floating point format in the Connected mode. In the previous NVGate version, the 32-bit floating point format was used in both modes.

===Octave overall no limitation===

1/n Octave Overall levels frequency range plug-ins are now editable. You can define the min and max.
This overall is computed in the time domain (weighting filter and detector). Processing weighting in the time domain provides accurate measurement for non-stationary signals (impulsive).

[[File:octave_filter.png|400px]]

'''Full range mode''' computes the overall on the whole frequency range excluding the DC component. (The minimum range is defined by "CPB filters Lower central frequency"/5).
'''Limited range''' lets the user define the range by changing the low cut off frequency and high cut off frequency.

===Application===
=== global level with filter===
=== remove noise from spectrum===
===Listen signal with filter===

=DC Dynamical sensor y = ax+b calibration =

It is now possible to calibrate a dynamical sensor in "DC" or "DC floating" coupling using 2 values, then the software will automatically compute sensitivity and offset to obtain the "y = ax + b" formula.

This function is practical for 4-20 mA sensors or “quasi-static” sensors acquired on dynamic channels. Wire sensor displacement sensor calibrated with a rule, pressure sensor with a calibrated compressor, proximity probe calibrated with a micrometer.

For using it, first create a DC sensor on the sensor database. Then apply this sensor to a channel.

Now on the calibration part, you can calibrate it using 2 values. Then the software will automatically apply the sensitivity and offset.

[[File:calibrator.png|500px]]
== Remove a sensor from history ==

If you have made a mistake during a sensor calibration, you can now delete a value from calibration sensor history.
[[File:remove_caibration.png|600px]]

You need to go on history, select the sensor, select the value that you need to delete, then click on remove.

= How much does this body shake? =

The OROS Body Vibration tool allows you to evaluate the affect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standards define measurement practice and vibration signal analysis to evaluate the affect on health and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describes the affect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the affect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. 
 
This is a post analysis toolkit, operating after the recording of the signal. It will calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 

[[Image:OROS_BodyVib.png|400px|none]]
'''Standards compatible''': international standards about whole/body vibration including: ISO 5349, ISO 8041, ISO 2631-1 and ISO 2631-5. 

'''Whole/body Vibration Indicators include ''': VDV, MSDV, MTVV, Weighted raw, al(ISO 2631-5), D(ISO 2631-5) are available. RMS, Peak, Crest, peak-Peak, are also available in NVGate plug in.
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|Daily maximal exposure value (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|}

'''Signal fitering including''':
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|}

How to use it:
https://wiki.oros.com/wiki/index.php/Human_Vibration

This Add-on is free of charge for NVGate 2021 users and TDA (?)

= Orbit display included in FFT diag or ORD diag =

For customer with option FFT-Diag or ORD-Diag, they will now have the Orbit display available in NVGate.

[[File:Display_Graphs_Traces_122.png|400px]] 

The orbit is available using the add/remove windows.

For more details, please check the [[NVGate_Display#Orbit|orbit dipslay page.]]

=Miscellaneous=

== Displaying Time in Zoomed signal==

== NVdrive : SetViewmeterLevels ==

Using NVdrive, you can now control and set the alarm level, high level and low level.
[[File:Viewmeter.jpg|none]]

Check the NVDrive toolkit for more info.

=Bug fixing=
 

* 13728: [Fractional Tachometer] Using a fractional tachometer lead to DSP error -
* 13729: [Drec] : Impossible to record more than 38 ch in Drec
* 13672: Delta RPM with source DC tach (from monitor) - do not trig the waterfall
* 10572: Low pass response for ICP and AC coupling poorly specified
* 13811: NVDrive GetResultEx error while running without displaying result
* 13774: Orbit display improvement
* 13790: Change the number of displayed orbits
* 13794: A problem of DRPM stop at 5000 RPM instead of 6000.
* 13953: [General] A-weighting can be applied several times (report 13912)
* 13938: Input type: Xpod bridge, one channel 5 doesn't work if 1 activated
* 13767: Create a new unit : do not go on a "empty" windows, keep the previous configuration.

NVGate 2021: Release note

2020-12-22T15:00:12Z

NHoffman: /* How much does this body shake? */

NVGate 2021: Release note

2020-12-22T14:59:01Z

NHoffman: /* How much does this body shake? */

OROS strives to be closer to its users, carefully listening to needs and requests. For that reason, OROS regularly releases new versions. Customers under contract automatically benefit from each release.

[[File:Screenshot 2020-12-21 102850.png|500px]]
 
The NVGate® 2021 major version became available in January 2021. This release of the OROS 3-Series analyzer’s software platform brings additional functionalities and significant performance improvements. Below is a summary of the main enhancements of your NVGate experience: 

{| class="wikitable" style="width: 90%;"
|-
| style="width: 25%"| [[File:1250px-Wikipedia_logo_(svg).svg.png|50px|link=NVGate_2021:_Release_note#Here_is_OROS_Wiki_on_the_line.2C_how_can_I_help_you.3F]] ''' On line OROS Wiki, how can I help you?''' Help is now available online with a powerful search engine. An offline version is available as well for when you are in the field.
| style="width: 25%"| [[File:filter__2021.png|50px]] '''Relax the limits of filtering!''' Cut off frequencies of filters, Butterworth and '''new Chebyshev type I and II''', can now be chosen very flexibly.
| style="width: 25%"| [[File:kinematik_2021.png|50px]] '''Tracking my bearing frequencies on RPMs variations''' Kinematik markers are now tracking the frequency lines as the speed fluctuates
| style="width: 25%"| [[File:gps_2021.png|50px]] Enrich your measurements in real time with '''GPS''' information'''
|-
| [[File:simulated_dc.png|200px]] Using the '''DC simulated''' function, one can now associate NVGate results with information from external software in real time using NVDrive
| [[File:orbit_2021.jpg|50px]] '''Draw those orbits!''' Orbits can now be displayed directly in NVGate with FFt-Diag option
| [[File:calibration_2021.png|50px]] dynamical input can now calibrate DC sensor with y = ax + b formula
| [[File:human_2021.png|50px]] '''How much does this body shake?''' A new add-on is available to apply human vibrations filters and calculate associated quantities.
|}
This release note describes the content of version, with operating details.
 
'''Compatibility:'''
NVGate 2021 is compatible with all OROS instruments that have not been discontinued. Depending on the hardware options and version, some instrument features may or may not be available.

= Here is OROS Wiki on the line, how can I help you? =

All the documentation and help have been completely renewed. We have put an online wiki-based documentation with videos, manual, application notes, download.

This page is in free access and can be consulted here: https://wiki.oros.com/wiki/index.php/Home

== Online Help: wiki ==
We advise being connected to internet to enjoy the new documentation page. 

If you are connected to Internet, the following buttons will bring you to the NVGate wiki page. 

[[NVGate|https://wiki.oros.com/wiki/index.php/NVGate]]

<gallery>
File:help_menu.png
File:Help_ribbon.png
File:Help_asb.png
</gallery>

Be aware than this wiki page have a powerful research button if you need to search any setting. 
[[File:help search.png]]

If you are using NVGate in a different language than english, the wikipage will be opened with /XX at the end (XX correspond to the unicode language. 

For example if you are using NVGate in Japanese, help will bring you to the page:
https://wiki.oros.com/wiki/index.php/NVGate/ja (==> ja is the international Japanese code)

== Off line Help: PDF manual ==
If you are not connected to internet which may often happen in the field, the NVGate.pdf manual will be opened. This file is located in the "Manuals" folder in the installation directory of NVGate.

== Tutorials Videos ==

The OROS Youtube channel is available here featuring a full panel of videos on how to use OROS products :

[[File:youtube.png|600px]] 

[https://www.youtube.com/user/OROSanalyzers/ OROS Youtube channels page]

We have included tutorial videos in this wiki to help you to use the OROS software.

= Tracking bearing frequencies on RPMs variations =

== Kinematik markers follow FFT tachometer==

The Kinematik marker can now be associated to the speed of the tachometer.
So during a Run up the kinematik marker will automatically move inside FFT spectrum with the speed.

How to use it :
Select a Tachometer on the FFT tab from GoToResult page.

[[File:kiné_fft.png|500px]]

Then display a FFT spectrum. Select a kinematik marker and put it on the window.

[[File:kiné_select.png|400px]]

Now this marker will be linked to the FFT speed.

Then on properties, you can link (or not) this marker to the speed.

[[File:kiné_select_active.png|300px]]

== Automatic installation of the database ==

Now the excel kinematic database including bearings from NSK, SKF, FAG, SNRn, GMN, INA, RHP is installed automatically.

You can find it in the installation folder: "NVGate Data\Markers\Kinematic\"

== Direct access to database==

When clicking on the "open folder" button, you will directly access the folder where the Excel kinematic database is stored
so you can edit the database easily if you need to add the kinematic configuration of a rotating machine.

[[File:kiné_select_edit.png|400px]]

= Enrich your measurements in real time: from GPS to environmental metadata =

The DC simulated inputs allow you to inject up to 32 external DC channels in NVGate from external source (exemple : GPS, weather station, external can bus...). The frequency sampling is up to 15 samples / second.
Thanks to the python developer toolkit, a developer can easily develop an interface to inject the values into NVGate. The GPS and weather station below have been developed using the DC simulated.

This option is included with the reference ORNV-VI-DC (which also includes the Virtual input).

How to use it:
 

on the Acquisition Tab, select connect input, select the DC inputs and select the DC simulated channels.

[[File:DC simulat.png|600px]]

These channels can be activated and connected to the recorder and/or waterfall like any other DC channels.

[[File:DC_simul.png]]

The settings '''Value''' (which can be controlled by an external software) will change the value of the inputs.

[[NVGate_Front_End#Simulated_DC_Inputs|The other DC simulated settings details]] are explained on the front end settings page.

== GPS ==
Thanks to the "DC simulated channels" we have created an Add-on to record GPS data.

The GPS have the following features

* Record the X-Y GPS coordinates.
* Record and display the speed profile.
* Use the speed profile as a waterfall reference.
* Creat a .gpx and display it on an internet website if you have an Internet connection).

You can visit the dedicated page to download it and advanced configuration. : https://wiki.oros.com/wiki/index.php/NVGate_DC_Simulated_Manager

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

=== Serial GPGGA GPS ===

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can recommend the GPS USB Navilock NL-602U but other GPS units will work as well. 

[[File:gps_navilock.jpg|200px]]

=== Android GPS ===
[[File:GPS_phone.png|500px]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position into NVGate.

=== How to use it ===

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400px]]

Then you can use these channels on NVGate.

If you need to record the data, click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png|600px]]

If you have recorded the data you will be able to create a .gpx file

=== Creating and visualize .gpx file ===

We can create a .gpx from an .oxf (OROS) signal file. a .gpx is gps file to follow the geographic information of the signal on a map.

You need to click on "Convert signal to gpx".
[[File:GPS_creategpx.png|150px]]

This will open the windows below.
[[File:signal_gpx.png|400px]]

Select the signal file that you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put in the "attachement" folder of the NVGate project.

If you want to visualize the .gpx we advise using the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens a website allowing you to plot the gpx on a map.

== Weather station==

Precipitation, wind speed/direction, pressure, temperature, and pressure can prejudice sound pressure levels or need to be recorded when you are doing sound measurement.

Thanks to the DC simulated channels, we can now enter manually the value or we can connect a weather station to NVGate.

=== Manual ===

The user can enter manually the weather value.

[[File:weather_manual.png|400px]] 

===Davis instruments weather station ===

[[File:weather.png|200px|right]]

3 elements are required to make it work

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provides accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield, wind speed and direction, and rainfall.

Note : The weather Station needs to pass by OROS SA for configuration.

=== Other weather stations ===

Please contact OROS to check the possibility to import the data (paid service).

= Relax the limits of filtering! =

All details on the filters can be read [[NVGate_Filter_Builder|here]]

===New prototype filters===
In addition to the Butterworth filter, now you can build the IIR filters with the Chebyshev type I (band-pass ripple) filter or Chebyshev type II (stop-band ripple) filter.

The Butterworth filter has flat response in both the pass band and stop band, but its transition band is wide.

The Chebyshev type I (band-pass ripple filter) has the steepest roll-off among the three filters, and its response in the stop band is flat. However, it has ripples in the pass band.

The Chebyshev type II (stop-band ripple) filter has flat response in the pass band, but it has ripples in the stop band. Its transition band is narrower than the Butterworth filter, but wider than the Chebyshev type I.

Below is an example showing these three filters with the same filter order.

[[File:filters_3.png|600px]]

Thanks to its maximal flat frequency response in the pass band, the Butterworth filter is commonly used in applications where signal distortion should be minimized, such as audio noise reduction. It is also widely used for anti-aliasing. The Chebyshev filters are optimized to provide steep roll-off, and they are usually used in applications where the maximum rejection of the nearby frequencies is required.

==Increased filter order==
The order of the filter affects the steepness of its roll-off. The higher the order is, the sharper the transition between the pass band and the stop band is. An example demonstrating the impact of the filter order is shown below.

[[File:butterworth_freq_response.png|600px]]

For the high pass and low pass filters, the filter order can be selected from 1 to 40 in the Office mode, and from 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum filter order was 6.

For the band pass and band stop filters, the filter order is 2*N, and N can be selected from 1 to 30 in the Office mode, and between 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum value of N was 5.

===Relaxed constraints on the cut-off frequency===

To guarantee the stability of the filter, there are certain constraints on the value of the cut-off frequency. Compared with previous version of NVGate, such constraints are relaxed significantly now.

[[File:image_2020-11-27_095451.png|600px]]

For the high pass and low pass filters, the maximum value of the cut-off frequency is the input frequency range '''FR'''. The minimum value is '''FR''' / 50000 in the Office mode, and '''FR''' / 40000 in the Connected mode. In the previous NVGate version, the minimum value was '''FR''' / 40 for the low pass filter, and '''FR''' / 400 for the high pass filter.

For the band pass and band stop filters, the low cut-off frequency ''f''low and the high cut-off frequency ''f''high need to meet the following conditions in the Office mode:

* ''f''low ≥ 0.0001 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0004 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.9998 * '''FR'''

And in the Connected mode, the conditions are as below:

* ''f''low ≥ 0.0005 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.000675 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

In the previous NVGate version, the conditions on the cut-off frequencies were:

* ''f''low ≥ 0.055 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0075 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

==Improved precision==
Now, the filters are calculated in 64-bit floating point format in the Office mode, and in 40-bit floating point format in the Connected mode. In the previous NVGate version, the 32-bit floating point format was used in both modes.

===Octave overall no limitation===

1/n Octave Overall levels frequency range plug-ins are now editable. You can define the min and max.
This overall is computed in the time domain (weighting filter and detector). Processing weighting in the time domain provides accurate measurement for non-stationary signals (impulsive).

[[File:octave_filter.png|400px]]

'''Full range mode''' computes the overall on the whole frequency range excluding the DC component. (The minimum range is defined by "CPB filters Lower central frequency"/5).
'''Limited range''' lets the user define the range by changing the low cut off frequency and high cut off frequency.

===Application===
=== global level with filter===
=== remove noise from spectrum===
===Listen signal with filter===

=DC Dynamical sensor y = ax+b calibration =

It is now possible to calibrate a dynamical sensor in "DC" or "DC floating" coupling using 2 values, then the software will automatically compute sensitivity and offset to obtain the "y = ax + b" formula.

This function is practical for 4-20 mA sensors or “quasi-static” sensors acquired on dynamic channels. Wire sensor displacement sensor calibrated with a rule, pressure sensor with a calibrated compressor, proximity probe calibrated with a micrometer.

For using it, first create a DC sensor on the sensor database. Then apply this sensor to a channel.

Now on the calibration part, you can calibrate it using 2 values. Then the software will automatically apply the sensitivity and offset.

[[File:calibrator.png|500px]]
== Remove a sensor from history ==

If you have made a mistake during a sensor calibration, you can now delete a value from calibration sensor history.
[[File:remove_caibration.png|600px]]

You need to go on history, select the sensor, select the value that you need to delete, then click on remove.

= How much does this body shake? =

The OROS Body Vibration tool allows you to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standards define measurement practice and vibration signal analysis to evaluate the effect on health and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describes the effect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the affect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. 
 
This is a post analysis toolkit, operating after the recording of the signal. It will calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 

[[Image:OROS_BodyVib.png|400px|none]]
'''Standards compatible''': international standards about whole/body vibration including: ISO 5349, ISO 8041, ISO 2631-1 and ISO 2631-5. 

'''Whole/body Vibration Indicators include ''': VDV, MSDV, MTVV, Weighted raw, al(ISO 2631-5), D(ISO 2631-5) are available. RMS, Peak, Crest, peak-Peak, are also available in NVGate plug in.
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|Daily maximal exposure value (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|}

'''Signal fitering including''':
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|}

How to use it:
https://wiki.oros.com/wiki/index.php/Human_Vibration

This Add-on is free of charge for NVGate 2021 users and TDA (?)

= Orbit display included in FFT diag or ORD diag =

For customer with option FFT-Diag or ORD-Diag, they will now have the Orbit display available in NVGate.

[[File:Display_Graphs_Traces_122.png|400px]] 

The orbit is available using the add/remove windows.

For more details, please check the [[NVGate_Display#Orbit|orbit dipslay page.]]

=Miscellaneous=

== Displaying Time in Zoomed signal==

== NVdrive : SetViewmeterLevels ==

Using NVdrive, you can now control and set the alarm level, high level and low level.
[[File:Viewmeter.jpg|none]]

Check the NVDrive toolkit for more info.

=Bug fixing=
 

* 13728: [Fractional Tachometer] Using a fractional tachometer lead to DSP error -
* 13729: [Drec] : Impossible to record more than 38 ch in Drec
* 13672: Delta RPM with source DC tach (from monitor) - do not trig the waterfall
* 10572: Low pass response for ICP and AC coupling poorly specified
* 13811: NVDrive GetResultEx error while running without displaying result
* 13774: Orbit display improvement
* 13790: Change the number of displayed orbits
* 13794: A problem of DRPM stop at 5000 RPM instead of 6000.
* 13953: [General] A-weighting can be applied several times (report 13912)
* 13938: Input type: Xpod bridge, one channel 5 doesn't work if 1 activated
* 13767: Create a new unit : do not go on a "empty" windows, keep the previous configuration.

NVGate 2021: Release note

2020-12-22T14:54:00Z

NHoffman: /* How much does this body shake? */

OROS strives to be closer to its users, carefully listening to needs and requests. For that reason, OROS regularly releases new versions. Customers under contract automatically benefit from each release.

[[File:Screenshot 2020-12-21 102850.png|500px]]
 
The NVGate® 2021 major version became available in January 2021. This release of the OROS 3-Series analyzer’s software platform brings additional functionalities and significant performance improvements. Below is a summary of the main enhancements of your NVGate experience: 

{| class="wikitable" style="width: 90%;"
|-
| style="width: 25%"| [[File:1250px-Wikipedia_logo_(svg).svg.png|50px|link=NVGate_2021:_Release_note#Here_is_OROS_Wiki_on_the_line.2C_how_can_I_help_you.3F]] ''' On line OROS Wiki, how can I help you?''' Help is now available online with a powerful search engine. An offline version is available as well for when you are in the field.
| style="width: 25%"| [[File:filter__2021.png|50px]] '''Relax the limits of filtering!''' Cut off frequencies of filters, Butterworth and '''new Chebyshev type I and II''', can now be chosen very flexibly.
| style="width: 25%"| [[File:kinematik_2021.png|50px]] '''Tracking my bearing frequencies on RPMs variations''' Kinematik markers are now tracking the frequency lines as the speed fluctuates
| style="width: 25%"| [[File:gps_2021.png|50px]] Enrich your measurements in real time with '''GPS''' information'''
|-
| [[File:simulated_dc.png|200px]] Using the '''DC simulated''' function, one can now associate NVGate results with information from external software in real time using NVDrive
| [[File:orbit_2021.jpg|50px]] '''Draw those orbits!''' Orbits can now be displayed directly in NVGate with FFt-Diag option
| [[File:calibration_2021.png|50px]] dynamical input can now calibrate DC sensor with y = ax + b formula
| [[File:human_2021.png|50px]] '''How much does this body shake?''' A new add-on is available to apply human vibrations filters and calculate associated quantities.
|}
This release note describes the content of version, with operating details.
 
'''Compatibility:'''
NVGate 2021 is compatible with all OROS instruments that have not been discontinued. Depending on the hardware options and version, some instrument features may or may not be available.

= Here is OROS Wiki on the line, how can I help you? =

All the documentation and help have been completely renewed. We have put an online wiki-based documentation with videos, manual, application notes, download.

This page is in free access and can be consulted here: https://wiki.oros.com/wiki/index.php/Home

== Online Help: wiki ==
We advise being connected to internet to enjoy the new documentation page. 

If you are connected to Internet, the following buttons will bring you to the NVGate wiki page. 

[[NVGate|https://wiki.oros.com/wiki/index.php/NVGate]]

<gallery>
File:help_menu.png
File:Help_ribbon.png
File:Help_asb.png
</gallery>

Be aware than this wiki page have a powerful research button if you need to search any setting. 
[[File:help search.png]]

If you are using NVGate in a different language than english, the wikipage will be opened with /XX at the end (XX correspond to the unicode language. 

For example if you are using NVGate in Japanese, help will bring you to the page:
https://wiki.oros.com/wiki/index.php/NVGate/ja (==> ja is the international Japanese code)

== Off line Help: PDF manual ==
If you are not connected to internet which may often happen in the field, the NVGate.pdf manual will be opened. This file is located in the "Manuals" folder in the installation directory of NVGate.

== Tutorials Videos ==

The OROS Youtube channel is available here featuring a full panel of videos on how to use OROS products :

[[File:youtube.png|600px]] 

[https://www.youtube.com/user/OROSanalyzers/ OROS Youtube channels page]

We have included tutorial videos in this wiki to help you to use the OROS software.

= Tracking bearing frequencies on RPMs variations =

== Kinematik markers follow FFT tachometer==

The Kinematik marker can now be associated to the speed of the tachometer.
So during a Run up the kinematik marker will automatically move inside FFT spectrum with the speed.

How to use it :
Select a Tachometer on the FFT tab from GoToResult page.

[[File:kiné_fft.png|500px]]

Then display a FFT spectrum. Select a kinematik marker and put it on the window.

[[File:kiné_select.png|400px]]

Now this marker will be linked to the FFT speed.

Then on properties, you can link (or not) this marker to the speed.

[[File:kiné_select_active.png|300px]]

== Automatic installation of the database ==

Now the excel kinematic database including bearings from NSK, SKF, FAG, SNRn, GMN, INA, RHP is installed automatically.

You can find it in the installation folder: "NVGate Data\Markers\Kinematic\"

== Direct access to database==

When clicking on the "open folder" button, you will directly access the folder where the Excel kinematic database is stored
so you can edit the database easily if you need to add the kinematic configuration of a rotating machine.

[[File:kiné_select_edit.png|400px]]

= Enrich your measurements in real time: from GPS to environmental metadata =

The DC simulated inputs allow you to inject up to 32 external DC channels in NVGate from external source (exemple : GPS, weather station, external can bus...). The frequency sampling is up to 15 samples / second.
Thanks to the python developer toolkit, a developer can easily develop an interface to inject the values into NVGate. The GPS and weather station below have been developed using the DC simulated.

This option is included with the reference ORNV-VI-DC (which also includes the Virtual input).

How to use it:
 

on the Acquisition Tab, select connect input, select the DC inputs and select the DC simulated channels.

[[File:DC simulat.png|600px]]

These channels can be activated and connected to the recorder and/or waterfall like any other DC channels.

[[File:DC_simul.png]]

The settings '''Value''' (which can be controlled by an external software) will change the value of the inputs.

[[NVGate_Front_End#Simulated_DC_Inputs|The other DC simulated settings details]] are explained on the front end settings page.

== GPS ==
Thanks to the "DC simulated channels" we have created an Add-on to record GPS data.

The GPS have the following features

* Record the X-Y GPS coordinates.
* Record and display the speed profile.
* Use the speed profile as a waterfall reference.
* Creat a .gpx and display it on an internet website if you have an Internet connection).

You can visit the dedicated page to download it and advanced configuration. : https://wiki.oros.com/wiki/index.php/NVGate_DC_Simulated_Manager

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

=== Serial GPGGA GPS ===

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can recommend the GPS USB Navilock NL-602U but other GPS units will work as well. 

[[File:gps_navilock.jpg|200px]]

=== Android GPS ===
[[File:GPS_phone.png|500px]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position into NVGate.

=== How to use it ===

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400px]]

Then you can use these channels on NVGate.

If you need to record the data, click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png|600px]]

If you have recorded the data you will be able to create a .gpx file

=== Creating and visualize .gpx file ===

We can create a .gpx from an .oxf (OROS) signal file. a .gpx is gps file to follow the geographic information of the signal on a map.

You need to click on "Convert signal to gpx".
[[File:GPS_creategpx.png|150px]]

This will open the windows below.
[[File:signal_gpx.png|400px]]

Select the signal file that you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put in the "attachement" folder of the NVGate project.

If you want to visualize the .gpx we advise using the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens a website allowing you to plot the gpx on a map.

== Weather station==

Precipitation, wind speed/direction, pressure, temperature, and pressure can prejudice sound pressure levels or need to be recorded when you are doing sound measurement.

Thanks to the DC simulated channels, we can now enter manually the value or we can connect a weather station to NVGate.

=== Manual ===

The user can enter manually the weather value.

[[File:weather_manual.png|400px]] 

===Davis instruments weather station ===

[[File:weather.png|200px|right]]

3 elements are required to make it work

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provides accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield, wind speed and direction, and rainfall.

Note : The weather Station needs to pass by OROS SA for configuration.

=== Other weather stations ===

Please contact OROS to check the possibility to import the data (paid service).

= Relax the limits of filtering! =

All details on the filters can be read [[NVGate_Filter_Builder|here]]

===New prototype filters===
In addition to the Butterworth filter, now you can build the IIR filters with the Chebyshev type I (band-pass ripple) filter or Chebyshev type II (stop-band ripple) filter.

The Butterworth filter has flat response in both the pass band and stop band, but its transition band is wide.

The Chebyshev type I (band-pass ripple filter) has the steepest roll-off among the three filters, and its response in the stop band is flat. However, it has ripples in the pass band.

The Chebyshev type II (stop-band ripple) filter has flat response in the pass band, but it has ripples in the stop band. Its transition band is narrower than the Butterworth filter, but wider than the Chebyshev type I.

Below is an example showing these three filters with the same filter order.

[[File:filters_3.png|600px]]

Thanks to its maximal flat frequency response in the pass band, the Butterworth filter is commonly used in applications where signal distortion should be minimized, such as audio noise reduction. It is also widely used for anti-aliasing. The Chebyshev filters are optimized to provide steep roll-off, and they are usually used in applications where the maximum rejection of the nearby frequencies is required.

==Increased filter order==
The order of the filter affects the steepness of its roll-off. The higher the order is, the sharper the transition between the pass band and the stop band is. An example demonstrating the impact of the filter order is shown below.

[[File:butterworth_freq_response.png|600px]]

For the high pass and low pass filters, the filter order can be selected from 1 to 40 in the Office mode, and from 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum filter order was 6.

For the band pass and band stop filters, the filter order is 2*N, and N can be selected from 1 to 30 in the Office mode, and between 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum value of N was 5.

===Relaxed constraints on the cut-off frequency===

To guarantee the stability of the filter, there are certain constraints on the value of the cut-off frequency. Compared with previous version of NVGate, such constraints are relaxed significantly now.

[[File:image_2020-11-27_095451.png|600px]]

For the high pass and low pass filters, the maximum value of the cut-off frequency is the input frequency range '''FR'''. The minimum value is '''FR''' / 50000 in the Office mode, and '''FR''' / 40000 in the Connected mode. In the previous NVGate version, the minimum value was '''FR''' / 40 for the low pass filter, and '''FR''' / 400 for the high pass filter.

For the band pass and band stop filters, the low cut-off frequency ''f''low and the high cut-off frequency ''f''high need to meet the following conditions in the Office mode:

* ''f''low ≥ 0.0001 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0004 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.9998 * '''FR'''

And in the Connected mode, the conditions are as below:

* ''f''low ≥ 0.0005 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.000675 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

In the previous NVGate version, the conditions on the cut-off frequencies were:

* ''f''low ≥ 0.055 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0075 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

==Improved precision==
Now, the filters are calculated in 64-bit floating point format in the Office mode, and in 40-bit floating point format in the Connected mode. In the previous NVGate version, the 32-bit floating point format was used in both modes.

===Octave overall no limitation===

1/n Octave Overall levels frequency range plug-ins are now editable. You can define the min and max.
This overall is computed in the time domain (weighting filter and detector). Processing weighting in the time domain provides accurate measurement for non-stationary signals (impulsive).

[[File:octave_filter.png|400px]]

'''Full range mode''' computes the overall on the whole frequency range excluding the DC component. (The minimum range is defined by "CPB filters Lower central frequency"/5).
'''Limited range''' lets the user define the range by changing the low cut off frequency and high cut off frequency.

===Application===
=== global level with filter===
=== remove noise from spectrum===
===Listen signal with filter===

=DC Dynamical sensor y = ax+b calibration =

It is now possible to calibrate a dynamical sensor in "DC" or "DC floating" coupling using 2 values, then the software will automatically compute sensitivity and offset to obtain the "y = ax + b" formula.

This function is practical for 4-20 mA sensors or “quasi-static” sensors acquired on dynamic channels. Wire sensor displacement sensor calibrated with a rule, pressure sensor with a calibrated compressor, proximity probe calibrated with a micrometer.

For using it, first create a DC sensor on the sensor database. Then apply this sensor to a channel.

Now on the calibration part, you can calibrate it using 2 values. Then the software will automatically apply the sensitivity and offset.

[[File:calibrator.png|500px]]
== Remove a sensor from history ==

If you have made a mistake during a sensor calibration, you can now delete a value from calibration sensor history.
[[File:remove_caibration.png|600px]]

You need to go on history, select the sensor, select the value that you need to delete, then click on remove.

= How much does this body shake? =

The OROS Body Vibration tool allows you to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standards define measurement practice and vibration signal analysis to evaluate the effect on health and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describes the affect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the affect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. 
 
This is a post analysis toolkit, operating after the recording of the signal. It will calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 

[[Image:OROS_BodyVib.png|400px|none]]
'''Standards compatible''': international standards about whole/body vibration including: ISO 5349, ISO 8041, ISO 2631-1 and ISO 2631-5. 

'''Whole/body Vibration Indicators include ''': VDV, MSDV, MTVV, Weighted raw, al(ISO 2631-5), D(ISO 2631-5) are available. RMS, Peak, Crest, peak-Peak, are also available in NVGate plug in.
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|Daily maximal exposure value (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|}

'''Signal fitering including''':
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|}

How to use it:
https://wiki.oros.com/wiki/index.php/Human_Vibration

This Add-on is free of charge for NVGate 2021 users and TDA (?)

= Orbit display included in FFT diag or ORD diag =

For customer with option FFT-Diag or ORD-Diag, they will now have the Orbit display available in NVGate.

[[File:Display_Graphs_Traces_122.png|400px]] 

The orbit is available using the add/remove windows.

For more details, please check the [[NVGate_Display#Orbit|orbit dipslay page.]]

=Miscellaneous=

== Displaying Time in Zoomed signal==

== NVdrive : SetViewmeterLevels ==

Using NVdrive, you can now control and set the alarm level, high level and low level.
[[File:Viewmeter.jpg|none]]

Check the NVDrive toolkit for more info.

=Bug fixing=
 

* 13728: [Fractional Tachometer] Using a fractional tachometer lead to DSP error -
* 13729: [Drec] : Impossible to record more than 38 ch in Drec
* 13672: Delta RPM with source DC tach (from monitor) - do not trig the waterfall
* 10572: Low pass response for ICP and AC coupling poorly specified
* 13811: NVDrive GetResultEx error while running without displaying result
* 13774: Orbit display improvement
* 13790: Change the number of displayed orbits
* 13794: A problem of DRPM stop at 5000 RPM instead of 6000.
* 13953: [General] A-weighting can be applied several times (report 13912)
* 13938: Input type: Xpod bridge, one channel 5 doesn't work if 1 activated
* 13767: Create a new unit : do not go on a "empty" windows, keep the previous configuration.

NVGate 2021: Release note

2020-12-22T14:53:02Z

NHoffman: /* How much does this body shake? */

OROS strives to be closer to its users, carefully listening to needs and requests. For that reason, OROS regularly releases new versions. Customers under contract automatically benefit from each release.

[[File:Screenshot 2020-12-21 102850.png|500px]]
 
The NVGate® 2021 major version became available in January 2021. This release of the OROS 3-Series analyzer’s software platform brings additional functionalities and significant performance improvements. Below is a summary of the main enhancements of your NVGate experience: 

{| class="wikitable" style="width: 90%;"
|-
| style="width: 25%"| [[File:1250px-Wikipedia_logo_(svg).svg.png|50px|link=NVGate_2021:_Release_note#Here_is_OROS_Wiki_on_the_line.2C_how_can_I_help_you.3F]] ''' On line OROS Wiki, how can I help you?''' Help is now available online with a powerful search engine. An offline version is available as well for when you are in the field.
| style="width: 25%"| [[File:filter__2021.png|50px]] '''Relax the limits of filtering!''' Cut off frequencies of filters, Butterworth and '''new Chebyshev type I and II''', can now be chosen very flexibly.
| style="width: 25%"| [[File:kinematik_2021.png|50px]] '''Tracking my bearing frequencies on RPMs variations''' Kinematik markers are now tracking the frequency lines as the speed fluctuates
| style="width: 25%"| [[File:gps_2021.png|50px]] Enrich your measurements in real time with '''GPS''' information'''
|-
| [[File:simulated_dc.png|200px]] Using the '''DC simulated''' function, one can now associate NVGate results with information from external software in real time using NVDrive
| [[File:orbit_2021.jpg|50px]] '''Draw those orbits!''' Orbits can now be displayed directly in NVGate with FFt-Diag option
| [[File:calibration_2021.png|50px]] dynamical input can now calibrate DC sensor with y = ax + b formula
| [[File:human_2021.png|50px]] '''How much does this body shake?''' A new add-on is available to apply human vibrations filters and calculate associated quantities.
|}
This release note describes the content of version, with operating details.
 
'''Compatibility:'''
NVGate 2021 is compatible with all OROS instruments that have not been discontinued. Depending on the hardware options and version, some instrument features may or may not be available.

= Here is OROS Wiki on the line, how can I help you? =

All the documentation and help have been completely renewed. We have put an online wiki-based documentation with videos, manual, application notes, download.

This page is in free access and can be consulted here: https://wiki.oros.com/wiki/index.php/Home

== Online Help: wiki ==
We advise being connected to internet to enjoy the new documentation page. 

If you are connected to Internet, the following buttons will bring you to the NVGate wiki page. 

[[NVGate|https://wiki.oros.com/wiki/index.php/NVGate]]

<gallery>
File:help_menu.png
File:Help_ribbon.png
File:Help_asb.png
</gallery>

Be aware than this wiki page have a powerful research button if you need to search any setting. 
[[File:help search.png]]

If you are using NVGate in a different language than english, the wikipage will be opened with /XX at the end (XX correspond to the unicode language. 

For example if you are using NVGate in Japanese, help will bring you to the page:
https://wiki.oros.com/wiki/index.php/NVGate/ja (==> ja is the international Japanese code)

== Off line Help: PDF manual ==
If you are not connected to internet which may often happen in the field, the NVGate.pdf manual will be opened. This file is located in the "Manuals" folder in the installation directory of NVGate.

== Tutorials Videos ==

The OROS Youtube channel is available here featuring a full panel of videos on how to use OROS products :

[[File:youtube.png|600px]] 

[https://www.youtube.com/user/OROSanalyzers/ OROS Youtube channels page]

We have included tutorial videos in this wiki to help you to use the OROS software.

= Tracking bearing frequencies on RPMs variations =

== Kinematik markers follow FFT tachometer==

The Kinematik marker can now be associated to the speed of the tachometer.
So during a Run up the kinematik marker will automatically move inside FFT spectrum with the speed.

How to use it :
Select a Tachometer on the FFT tab from GoToResult page.

[[File:kiné_fft.png|500px]]

Then display a FFT spectrum. Select a kinematik marker and put it on the window.

[[File:kiné_select.png|400px]]

Now this marker will be linked to the FFT speed.

Then on properties, you can link (or not) this marker to the speed.

[[File:kiné_select_active.png|300px]]

== Automatic installation of the database ==

Now the excel kinematic database including bearings from NSK, SKF, FAG, SNRn, GMN, INA, RHP is installed automatically.

You can find it in the installation folder: "NVGate Data\Markers\Kinematic\"

== Direct access to database==

When clicking on the "open folder" button, you will directly access the folder where the Excel kinematic database is stored
so you can edit the database easily if you need to add the kinematic configuration of a rotating machine.

[[File:kiné_select_edit.png|400px]]

= Enrich your measurements in real time: from GPS to environmental metadata =

The DC simulated inputs allow you to inject up to 32 external DC channels in NVGate from external source (exemple : GPS, weather station, external can bus...). The frequency sampling is up to 15 samples / second.
Thanks to the python developer toolkit, a developer can easily develop an interface to inject the values into NVGate. The GPS and weather station below have been developed using the DC simulated.

This option is included with the reference ORNV-VI-DC (which also includes the Virtual input).

How to use it:
 

on the Acquisition Tab, select connect input, select the DC inputs and select the DC simulated channels.

[[File:DC simulat.png|600px]]

These channels can be activated and connected to the recorder and/or waterfall like any other DC channels.

[[File:DC_simul.png]]

The settings '''Value''' (which can be controlled by an external software) will change the value of the inputs.

[[NVGate_Front_End#Simulated_DC_Inputs|The other DC simulated settings details]] are explained on the front end settings page.

== GPS ==
Thanks to the "DC simulated channels" we have created an Add-on to record GPS data.

The GPS have the following features

* Record the X-Y GPS coordinates.
* Record and display the speed profile.
* Use the speed profile as a waterfall reference.
* Creat a .gpx and display it on an internet website if you have an Internet connection).

You can visit the dedicated page to download it and advanced configuration. : https://wiki.oros.com/wiki/index.php/NVGate_DC_Simulated_Manager

We have 2 ways to acquire the GPS position, android phone or GPS Compliant with NMEA 0183 standard.

=== Serial GPGGA GPS ===

We are compatible with GPS USB Serial Interface Compliant with NMEA 0183 standard GPGGA 

We can recommend the GPS USB Navilock NL-602U but other GPS units will work as well. 

[[File:gps_navilock.jpg|200px]]

=== Android GPS ===
[[File:GPS_phone.png|500px]]

GPS data can also be retrieved using Android ADB (Android Debug Bridge).
If you plug your android phone, we can inject the GPS position into NVGate.

=== How to use it ===

Once the gps is plugged and configured, click on inject data, this will put the value on the DC simulated inputs.

[[File:GPS process 2.png|400px]]

Then you can use these channels on NVGate.

If you need to record the data, click on connect input, go on DC input tab, then drag and drop the DC simulated channels on recorder.
[[File:GPS process.png|600px]]

If you have recorded the data you will be able to create a .gpx file

=== Creating and visualize .gpx file ===

We can create a .gpx from an .oxf (OROS) signal file. a .gpx is gps file to follow the geographic information of the signal on a map.

You need to click on "Convert signal to gpx".
[[File:GPS_creategpx.png|150px]]

This will open the windows below.
[[File:signal_gpx.png|400px]]

Select the signal file that you need to convert and click on load data.
You can modify the channels if needed.
Click on create .gpx.
The .gpx will be put in the "attachement" folder of the NVGate project.

If you want to visualize the .gpx we advise using the website : https://www.gpsvisualizer.com/
Clicking on "Click here to visualize the .gpx on a website" opens a website allowing you to plot the gpx on a map.

== Weather station==

Precipitation, wind speed/direction, pressure, temperature, and pressure can prejudice sound pressure levels or need to be recorded when you are doing sound measurement.

Thanks to the DC simulated channels, we can now enter manually the value or we can connect a weather station to NVGate.

=== Manual ===

The user can enter manually the weather value.

[[File:weather_manual.png|400px]] 

===Davis instruments weather station ===

[[File:weather.png|200px|right]]

3 elements are required to make it work

- [https://www.davisinstruments.com/product/wireless-vantage-pro2-integrated-sensor-suite/ 6322OV Wireless Vantage Pro2 Integrated Sensor Suite]

- [https://www.davisinstruments.com/product/wireless-weather-envoy/ 6316 Wireless Envoy]

- [https://www.davisinstruments.com/product/weatherlink-windows-usb/ 6510USB WeatherLink Data Logger].

This weather station provides accurate, reliable weather monitoring with real-time data updates every 2.5 seconds. Sensor suite includes outside temperature and humidity sensors in a passive radiation shield, wind speed and direction, and rainfall.

Note : The weather Station needs to pass by OROS SA for configuration.

=== Other weather stations ===

Please contact OROS to check the possibility to import the data (paid service).

= Relax the limits of filtering! =

All details on the filters can be read [[NVGate_Filter_Builder|here]]

===New prototype filters===
In addition to the Butterworth filter, now you can build the IIR filters with the Chebyshev type I (band-pass ripple) filter or Chebyshev type II (stop-band ripple) filter.

The Butterworth filter has flat response in both the pass band and stop band, but its transition band is wide.

The Chebyshev type I (band-pass ripple filter) has the steepest roll-off among the three filters, and its response in the stop band is flat. However, it has ripples in the pass band.

The Chebyshev type II (stop-band ripple) filter has flat response in the pass band, but it has ripples in the stop band. Its transition band is narrower than the Butterworth filter, but wider than the Chebyshev type I.

Below is an example showing these three filters with the same filter order.

[[File:filters_3.png|600px]]

Thanks to its maximal flat frequency response in the pass band, the Butterworth filter is commonly used in applications where signal distortion should be minimized, such as audio noise reduction. It is also widely used for anti-aliasing. The Chebyshev filters are optimized to provide steep roll-off, and they are usually used in applications where the maximum rejection of the nearby frequencies is required.

==Increased filter order==
The order of the filter affects the steepness of its roll-off. The higher the order is, the sharper the transition between the pass band and the stop band is. An example demonstrating the impact of the filter order is shown below.

[[File:butterworth_freq_response.png|600px]]

For the high pass and low pass filters, the filter order can be selected from 1 to 40 in the Office mode, and from 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum filter order was 6.

For the band pass and band stop filters, the filter order is 2*N, and N can be selected from 1 to 30 in the Office mode, and between 1 to 10 in the Connected mode now. In the previous NVGate version, the maximum value of N was 5.

===Relaxed constraints on the cut-off frequency===

To guarantee the stability of the filter, there are certain constraints on the value of the cut-off frequency. Compared with previous version of NVGate, such constraints are relaxed significantly now.

[[File:image_2020-11-27_095451.png|600px]]

For the high pass and low pass filters, the maximum value of the cut-off frequency is the input frequency range '''FR'''. The minimum value is '''FR''' / 50000 in the Office mode, and '''FR''' / 40000 in the Connected mode. In the previous NVGate version, the minimum value was '''FR''' / 40 for the low pass filter, and '''FR''' / 400 for the high pass filter.

For the band pass and band stop filters, the low cut-off frequency ''f''low and the high cut-off frequency ''f''high need to meet the following conditions in the Office mode:

* ''f''low ≥ 0.0001 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0004 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.9998 * '''FR'''

And in the Connected mode, the conditions are as below:

* ''f''low ≥ 0.0005 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.000675 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

In the previous NVGate version, the conditions on the cut-off frequencies were:

* ''f''low ≥ 0.055 * '''FR'''

* ''f''high ≤ '''FR'''

* 0.0075 * '''FR''' ≤ ''f''high - ''f''low ≤ 0.99 * '''FR'''

==Improved precision==
Now, the filters are calculated in 64-bit floating point format in the Office mode, and in 40-bit floating point format in the Connected mode. In the previous NVGate version, the 32-bit floating point format was used in both modes.

===Octave overall no limitation===

1/n Octave Overall levels frequency range plug-ins are now editable. You can define the min and max.
This overall is computed in the time domain (weighting filter and detector). Processing weighting in the time domain provides accurate measurement for non-stationary signals (impulsive).

[[File:octave_filter.png|400px]]

'''Full range mode''' computes the overall on the whole frequency range excluding the DC component. (The minimum range is defined by "CPB filters Lower central frequency"/5).
'''Limited range''' lets the user define the range by changing the low cut off frequency and high cut off frequency.

===Application===
=== global level with filter===
=== remove noise from spectrum===
===Listen signal with filter===

=DC Dynamical sensor y = ax+b calibration =

It is now possible to calibrate a dynamical sensor in "DC" or "DC floating" coupling using 2 values, then the software will automatically compute sensitivity and offset to obtain the "y = ax + b" formula.

This function is practical for 4-20 mA sensors or “quasi-static” sensors acquired on dynamic channels. Wire sensor displacement sensor calibrated with a rule, pressure sensor with a calibrated compressor, proximity probe calibrated with a micrometer.

For using it, first create a DC sensor on the sensor database. Then apply this sensor to a channel.

Now on the calibration part, you can calibrate it using 2 values. Then the software will automatically apply the sensitivity and offset.

[[File:calibrator.png|500px]]
== Remove a sensor from history ==

If you have made a mistake during a sensor calibration, you can now delete a value from calibration sensor history.
[[File:remove_caibration.png|600px]]

You need to go on history, select the sensor, select the value that you need to delete, then click on remove.

= How much does this body shake? =

The OROS Body Vibration tool allows you to evaluate the effect of vibration on the human body according to standards ISO 2651 and ISO 5349. These standards define measurement practice and vibration signal analysis to evaluate the affect on health and comfort of environmental and equipment vibrations on the Human body. 

The ISO 2651 describes the affect on health and comfort of vibration on the whole-body in transportation system, and the ISO 5349 the affect on health of vibration on hands and arms when manipulating machine-tools or vibrating objects. 
 
This is a post analysis toolkit, operating after the recording of the signal. It will calculate time-weighted signal of acceleration and specific indicators both defined in the standards. 

[[Image:OROS_BodyVib.png|400px|none]]
'''Standards compatible''': international standards about whole/body vibration including: ISO 5349, ISO 8041, ISO 2631-1 and ISO 2631-5. 

'''Whole/body Vibration Indicators include ''': VDV, MSDV, MTVV, Weighted raw, al(ISO 2631-5), D(ISO 2631-5) are available. RMS, Peak, Crest, peak-Peak, are also available in NVGate plug in.
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Body vibration indicators''
|-
|style="height:30px; width:100px;"|<math>MTVV</math>
|Maximum Transient Vibration Value, represent the maximal RMS value of the signal
|-
|style="height:30px; width:100px;"|<math>VDV</math>
|Vibration Dose Value, taking into account the temporal shocks in the signal
|-
|style="height:30px; width:100px;"|<math>MSDV</math>
|Motion Sickness Dose Value, representing the comfort in transportation measurement
|-
|style="height:30px; width:100px;"|<math>D_k</math>
|The Acceleration Dose, representing the affect of the vibration on the spine
|-
|style="height:30px; width:100px;"|<math>A_w</math>
|Daily maximal exposure value (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Peak</math>
|Amplitude Peak of the vibration; maximal amplitude of the signal from the 0 (Calculated from Post processing in NVGate)
|-
|style="height:30px; width:100px;"|<math>Crest factor</math>
|Ratio between the Peak level and the RMS of the weighted signal(Calculated from Post processing in NVGate)
|}

'''Signal fitering including''':
{| class="wikitable" style="margin: auto;"
|+style="caption-side:bottom;"|''Time-weighting filters''
|-
|style="height:30px; width:100px;"|<math>W_k</math>
|Time weighting for the Z axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_d</math>
|Time weighting for the X and Y axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_h</math>
|Time weighting for the hand-arms measurement in any direction (ISO 5349-1)
|-
|style="height:30px; width:100px;"|<math>W_f</math>
|Time weighting for motion sickness measurement in the vertical direction (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_c</math>
|Time weighting for the X axis for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_e</math>
|Time weighting for all rotational directions for whole-body measurement (ISO 2651-1)
|-
|style="height:30px; width:100px;"|<math>W_j</math>
|Time weighting for the Z axis for head comfort measurement (ISO 2651-1)
|}

How to use it:
https://wiki.oros.com/wiki/index.php/Human_Vibration

This Add-on is free of charge for NVGate 2021 users and TDA (?)

= Orbit display included in FFT diag or ORD diag =

For customer with option FFT-Diag or ORD-Diag, they will now have the Orbit display available in NVGate.

[[File:Display_Graphs_Traces_122.png|400px]] 

The orbit is available using the add/remove windows.

For more details, please check the [[NVGate_Display#Orbit|orbit dipslay page.]]

=Miscellaneous=

== Displaying Time in Zoomed signal==

== NVdrive : SetViewmeterLevels ==

Using NVdrive, you can now control and set the alarm level, high level and low level.
[[File:Viewmeter.jpg|none]]

Check the NVDrive toolkit for more info.

=Bug fixing=
 

* 13728: [Fractional Tachometer] Using a fractional tachometer lead to DSP error -
* 13729: [Drec] : Impossible to record more than 38 ch in Drec
* 13672: Delta RPM with source DC tach (from monitor) - do not trig the waterfall
* 10572: Low pass response for ICP and AC coupling poorly specified
* 13811: NVDrive GetResultEx error while running without displaying result
* 13774: Orbit display improvement
* 13790: Change the number of displayed orbits
* 13794: A problem of DRPM stop at 5000 RPM instead of 6000.
* 13953: [General] A-weighting can be applied several times (report 13912)
* 13938: Input type: Xpod bridge, one channel 5 doesn't work if 1 activated
* 13767: Create a new unit : do not go on a "empty" windows, keep the previous configuration.