MIMO Modal Parameters Identification in Frequency Domain
This tool allows to identify modal parameters, eigenfrequency, modal damping factor and modal residues using complex Frequency Response Function (FRF) of a MIMO system. The least-squares problem is solved using fast implementation of the normal equations based on fft to improve the efficiency of the algorithm.
The algorithm is based on
- the Linear Square Complex Frequency Estimator (LSCF) using discrete-time z-model to estimate eigenfrequency and modal damping.
- the Least-Squares Frequency-Domain estimator (LSFD) to estimate modal residues.
The choice of the identification order and the selection of the physical poles are assisted by a stabilization chart using frequency and damping convergence criteria. The stabilization chart can then be automatically interpreted.
The folder contains:
- A file example (file_example.m) based on a numerical 4 dofs system (omg.mat, FRF_tot.mat).
- the function time2frf.m allows to load time data (time, input, output) in .txt format and returns complex FRF and natural frequency vector.
- the function select_frf.m allows to select a part of the FRF in the specified frequency range.
- the function lscf.m estimates eigenfrequency and modal damping factor using a stabilization chart in a specified order range and computes identified FRF using discrete z-model.
- the function plotstabchart.m plot the stabilization chart
- the function select_stabchart.m allows to select physical stable poles in the stabilization chart.
- the function lsfd.m estimates complex residues and identified FRF using s-model.
Cite As
Baptiste Chomette (2024). MIMO Modal Parameters Identification in Frequency Domain (https://www.mathworks.com/matlabcentral/fileexchange/82380-mimo-modal-parameters-identification-in-frequency-domain), MATLAB Central File Exchange. Retrieved .
MATLAB Release Compatibility
Platform Compatibility
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MPIFD_MIMO
Version | Published | Release Notes | |
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1.0.5 | New implementation in
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1.0.4 | improvement of lsfd function using scaled frequency to avoid poor conditioning |
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1.0.3 | Corrections in lsfd and new file test based on a 4 dofs system with proportional damping. |
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1.0.2 | corrections in lsfd |
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1.0.1 | Correction of the lsfd function line 87: rntotCls = (Cls'*Cls) \ (Cls'*frf(:, ifrf)) ; |
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1.0.0 |