On the stability radius of control systems with interval plants and first-order controllers

This paper considers the stability radius problem of control systems with interval plants and first-order controllers. The nominal plant P-o(s) used for the controller design is the centre of the interval plant. Under the condition that a lead controller C(s) stabilizes P-o(s), the stability radius of the closed-loop system is determined in terms of the eigenvalues of four frequency-independent matrices of the form Hbeta,i-1Hgamma,i, where both H-beta,H-i and H-gamma,H-i are Hurwitz-like matrices. Copyright (C) 2000 John Wiley & Sons, Ltd.