Title of Paper:
Estimation of multi-order spectra for nonlinear closed-loop systems
Summary:
In this paper, a multi-order spectra estimation method is proposed for nonlinear closed-loop system based on Volterra series. Due to the correlation between the noise and the input, the estimation accuracy is poor when the nonlinear spectra of the plant are obtained using the traditional estimation method. In order to overcome this problem, a two-step scheme is used to estimate multi-order spectrum of nonlinear system operating in closed-loop. Firstly, the generalized frequency response functions (GFRFs) from the reference signal to the input of the plant are estimated, and they are used to simulate the noise-free input spectra of the plant. Secondly, the GFRFs of the controlled plant are estimated using the noise-free input spectra and the output spectra. Because the GFRFs are multidimensional functions, the required amount of calculation for estimation is very large. To reduce computational complexity, a simplified GFRF model is adopted to estimate multi-order nonlinear spectrum of the plant. In this model, the GFRF is transformed to one-dimensional function. Two simulation experiments are provided to illustrate the proposed approach.
Co-author:
Zhang Jialiang, Cao Jianfu
Papers
