Modal ODS and Modal(EMA-OMA) identification - Revision history

Lmagimel at 09:16, 26 November 2024

2024-11-26T09:16:15Z

← Older revision		Revision as of 11:16, 26 November 2024
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	[[category:Modal]]		[[category:Modal]]
			[[category:WikiOros]]
	==ODS & Modal Analysis==		==ODS & Modal Analysis==

ChaoranDu: /* OMA BroBand (OBFD) */

2021-05-31T10:23:04Z

OMA BroBand (OBFD)

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 =====Estimate the HPSD=====
 =====Begin Modal Identification=====
 The modal identification procedure is the same as [[Modal_ODS_and_Modal(EMA-OMA)_identification#EMA_Broadband_.28BBFD.29|EMA BroBand]].

ChaoranDu: /* OMA BroBand (OBFD) */

2021-05-31T10:11:56Z

OMA BroBand (OBFD)

← Older revision		Revision as of 12:11, 31 May 2021
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	=====Begin Modal Identification=====		=====Begin Modal Identification=====

	The ~~procedures~~ modal identification is the same as [[Modal_ODS_and_Modal(EMA-OMA)_identification#EMA_Broadband_.28BBFD.29\|EMA BroBand]].		The modal identification procedure is the same as [[Modal_ODS_and_Modal(EMA-OMA)_identification#EMA_Broadband_.28BBFD.29\|EMA BroBand]].

ChaoranDu: /* Begin Modal Identification */

2021-05-31T10:07:57Z

Begin Modal Identification

← Older revision		Revision as of 12:07, 31 May 2021
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	=====Begin Modal Identification=====		=====Begin Modal Identification=====

	The procedures modal identification is the same as [[EMA ~~Broadband (BBFD~~)\|EMA BroBand]].		The procedures modal identification is the same as [[Modal_ODS_and_Modal(EMA-OMA)_identification#EMA_Broadband_.28BBFD.29\|EMA BroBand]].

ChaoranDu: /* OMA BroBand (OBFD) */

2021-05-31T10:01:04Z

OMA BroBand (OBFD)

← Older revision		Revision as of 12:01, 31 May 2021
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	The BroBand Modal Identification Modula is bases on the algorithm of Polyreference Least Squares Complex Frequency (p-LSCF), developed in 2003. p-LSCF is a frequency MIMO modal identification algorithm which has superior performance compared to most time domain MIMO techniques, such as Polyreference Least Squares Complex Exponential (PRCE or LSCE), Extended Ibrahim Time Domain (EITD), and Eigensystem Realization Algorithm(ERA). EMA BroBand makes use of measured Frequency Response Function (FRF) as source data. OMA BroBand, which shares the same modal identification algorithm, on the other hand uses measured Half Power Spectrum Density (HPSD) as source data. As a result, a signal processing procedure to estimate the HPSD is required before the modal identification.		The BroBand Modal Identification Modula is bases on the algorithm of Polyreference Least Squares Complex Frequency (p-LSCF), developed in 2003. p-LSCF is a frequency MIMO modal identification algorithm which has superior performance compared to most time domain MIMO techniques, such as Polyreference Least Squares Complex Exponential (PRCE or LSCE), Extended Ibrahim Time Domain (EITD), and Eigensystem Realization Algorithm(ERA). EMA BroBand makes use of measured Frequency Response Function (FRF) as source data. OMA BroBand, which shares the same modal identification algorithm, on the other hand uses measured Half Power Spectrum Density (HPSD) as source data. As a result, a signal processing procedure to estimate the HPSD is required before the modal identification.

			=====Estimate the HPSD=====



			=====Begin Modal Identification=====

			The procedures modal identification is the same as [[EMA Broadband (BBFD)\|EMA BroBand]].

ChaoranDu at 09:56, 31 May 2021

2021-05-31T09:56:17Z

← Older revision		Revision as of 11:56, 31 May 2021
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	[[File:image_2021-05-31_115322.png\|800px]]		[[File:image_2021-05-31_115322.png\|800px]]


			====OMA BroBand (OBFD)====

			The BroBand Modal Identification Modula is bases on the algorithm of Polyreference Least Squares Complex Frequency (p-LSCF), developed in 2003. p-LSCF is a frequency MIMO modal identification algorithm which has superior performance compared to most time domain MIMO techniques, such as Polyreference Least Squares Complex Exponential (PRCE or LSCE), Extended Ibrahim Time Domain (EITD), and Eigensystem Realization Algorithm(ERA). EMA BroBand makes use of measured Frequency Response Function (FRF) as source data. OMA BroBand, which shares the same modal identification algorithm, on the other hand uses measured Half Power Spectrum Density (HPSD) as source data. As a result, a signal processing procedure to estimate the HPSD is required before the modal identification.

ChaoranDu: /* OMA NarBand Full (FSDD) */

2021-05-31T09:53:34Z

OMA NarBand Full (FSDD)

← Older revision		Revision as of 11:53, 31 May 2021
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	[[File:image_2021-05-31_114409.png\|800px]]		[[File:image_2021-05-31_114409.png\|800px]]

			=====Auto Identification=====

			After selecting the peak, you should '''double click''' to finish this identification. The identified results will be shown in the MIF plot, mode list and output shortcut pane. Each identified mode will be marker with a [[Image:image_2021-05-31_114937.png]] shape symbol. Its middle pane indicates the position of peak, and the line points to the identified frequency. The mode selected in the mode list will be marked yellow in the MIF plot while the others are blue.

			[[File:image_2021-05-31_115104.png\|800px]]

			=====Checking curve fitting and refitting=====

			You can check the quality of curve fitting by selecting some mode in the mode list and then turning to the 'Enhanced' tab page. Seen from below, the blue is the enhanced PSD curve, and the red is its fitting curve. Sometimes the identification result is not good because of the automatically selected band is not the best. Thus you can move the two cursors to select a better band, then double click to identify this mode again. It should be noted that you should check the fitting curve for each setup, and refit for each setup if necessary. You can switch between each setup by the 'Setup No.' list box in the standard toolbar.

			[[File:image_2021-05-31_115322.png\|800px]]

ChaoranDu: /* OMA NarBand Full (FSDD) */

2021-05-31T09:46:26Z

OMA NarBand Full (FSDD)

← Older revision		Revision as of 11:46, 31 May 2021
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	Press the [[Image:Modal_Manual_142.png]] button in the toolbar, and click the MIF plot to activate it. A red cross marker will appear, who is able to find the local peak automatically. The index and coordinate value of the marker are shown in the top left corner of MIF graph. In the figure below, (201,1):[32.71,-1.25e+002] means that the cross cursor is now at the 201st point of the first MIF curve, and the coordinate is (32.71Hz, -125dB).		Press the [[Image:Modal_Manual_142.png]] button in the toolbar, and click the MIF plot to activate it. A red cross marker will appear, who is able to find the local peak automatically. The index and coordinate value of the marker are shown in the top left corner of MIF graph. In the figure below, (201,1):[32.71,-1.25e+002] means that the cross cursor is now at the 201st point of the first MIF curve, and the coordinate is (32.71Hz, -125dB).

	[[File:image_2021-05-~~31_114129~~.png\|~~framed\|none~~]]		[[File:image_2021-05-31_114409.png\|800px]]

ChaoranDu at 09:43, 31 May 2021

2021-05-31T09:43:10Z

← Older revision		Revision as of 11:43, 31 May 2021
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	\|}		\|}


			====OMA NarBand Full (FSDD)====

			Frequency Spatial Domain Decomposition (FSDD), is an OMA modal identification algorithm in the frequency domain. FSDD an easy-to-use method. You should use it as the following steps.

			=====Selecting a Peak=====

			Press the [[Image:Modal_Manual_142.png]] button in the toolbar, and click the MIF plot to activate it. A red cross marker will appear, who is able to find the local peak automatically. The index and coordinate value of the marker are shown in the top left corner of MIF graph. In the figure below, (201,1):[32.71,-1.25e+002] means that the cross cursor is now at the 201st point of the first MIF curve, and the coordinate is (32.71Hz, -125dB).

			[[File:image_2021-05-31_114129.png\|framed\|none]]

Admin at 08:54, 10 September 2020

2020-09-10T08:54:19Z

← Older revision		Revision as of 10:54, 10 September 2020
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			[[category:Modal]]
	==ODS & Modal Analysis==		==ODS & Modal Analysis==