Identification of Continuous-Time Systems with Time Delay Based on Wavelet Analysis and Its Application to Bioler Process

Abstract

The wavelet analysis is superior to the Fourier analysis in the detectability of temporal (or spatial) information of signals. Therefore, the use of the analyzing wavelet which exists locally in the frequency domain makes it possible to estimate the time delay and the frequency response of the process transfer function in a specific time domain. First, we present a time-delay identification method by using the wavelet transform of the cross-correlation of input/output (I/O) data. Secondly, we present a method for obtaining the frequency response of the process to be considered as a time-varying system by directly using the wavelet transform of the auto-/cross-correlations of the I/O data. Thirdly, we determine the parameters in the transfer function by using the curve-fitting technique. Finally, we demonstrate the feasibility and validity of our identification procedure through some simulations and experiments for an actual boiler process.