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Identification of time varying modal parameters

Published online by Cambridge University Press:  04 July 2016

J. E. Cooper
J. E. Cooper*
Affiliation:
Department of Aeronautical Engineering, University of Manchester
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Abstract

The ability to track time varying frequency and damping parameters using on-line versions of seven time domain system identification algorithms; Least Squares, Double Least Squares, Correlation Fit, Instrumental Variables, Instrumental Matrix with Delayed Observations, Extended Least Squares and Maximum Likelihood, is examined. Comparisons are made on results obtained from data generated from various simulated time varying systems, corrupted with both input and measurement noise, as a preliminary step before advancing onto real data. Only the Maximum Likelihood and Double Least Squares methods gave acceptable results on the most difficult data sets that were considered. The choice of an exponential weighting factor is crucial to the performance of the on-line methods when applied to data from time varying systems. The effect of assigning various values of the weighting factor is demonstrated. Further work is required to determine the optimum schemes for defining this parameter.

Type
Research Article
Information
The Aeronautical Journal , Volume 94 , Issue 938 , October 1990 , pp. 271 - 278
Copyright
Copyright © Royal Aeronautical Society 1990 

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Footnotes

*

Formerly of the Materials & Structures Department, Royal Aerospace Establishment, Farnborough.

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