Robust gain & phase margin of minimum phase MIMO interval systems

This paper calculates exact stability margins of MIMO linear time-invariant interval systems based on the frequency domain theorem. After regarding each eigenvalue function of the MIMO linear system as a single SISO linear time-invariant system, two methods are studied in this paper. The one is a new analytical method which is proposed to give the worst-case gain margin and phase margin, The other is a graphical method which is also presented to analyze stability margin of the MIMO linear interval systems based on the definition of stability margin from Nyquist theorem. At last the simulation examples are presented to validate the effectiveness and the correctness of the two proposed methods.