Frequency Domain System Identification

Abstract

This chapter discusses the identification of linear dynamic systems using frequency domain measurement data. Frequency domain curve-fitting is a technique to fit a transfer function matrix (TFM) closely into the observed FRF data. Like other system identification techniques, this is a two-step procedure: model structure selection and model parameter optimization. In this context, the first step is to parameterize the TFM in some special forms. Two such forms are introduced in the following: the matrix fraction (MF) parameterization and the polynomial matrix (PM) parameterization. After outlining a general modeling procedure, the two major computation steps, frequency domain curve-fitting and state-space system realization, are illustrated with detailed numerical routines. The algorithms employ transfer function matrix models in the form of matrix fraction or polynomial matrix and require respectively linear or nonlinear parameter optimizations. The proposed identification schemes are validated through the modeling of two experimental test structures. ©2005 Copyright ©2005 Elsevier Inc. All rights reserved.