Robust Stability Evaluation of Sampled-Data Control Systems with a Sector Nonlinearity

Abstract This paper describes a robust stability evaluation of sampled-data control systems containing a sector nonlinearity in the forward path. The result of this paper is derived from the norm condition in the frequency domain by extending the Popov's criterion theory. Some lemmas are presented, a theorem for l 2 -stability is proved, and the stability margin (allowable sector) of a nonlinear element is explicitly exhibited. This theorem is valid only for classes of nonlinear sampled-data control systems that satisfy some of assumptions. A theorem for the validity of extended Aizerman's conjecture is also presented. Some numerical examples are given to illustrate these results.