A General Method for Robustness Analysis of Multivariable Systems in the Frequency Domain

Based on the argument principle and multivariable Nyquist criterion,a general method is proposed for the analysis of multivariable systems in the frequency domain.This method combines organically both the main thinkings and methods ofrobust stability analysis in the past.Several new robustness criteria are obtained andthe stability criteria are readily derived by the method.At last,a thorough analysisis made for diagonal dominance systems.