Robust Stability of Uncertain Discrete Systems with Time-Varying

Authors:	Fridman Emilia, Tel Aviv University, Israel Shaked Uri, Tel Aviv University, Israel
Topic:	2.5 Robust Control
Session:	Robustness Analysis II
Keywords:	time-varying delay, discrete systems,Lyapunov-Krasovskii method, norm-bounded uncertainties

Abstract

Robust stability is considered for uncertain discrete-time systemswith time-varying delays from given intervals. A new constructionof Lyapunov-Krasovskii functions (LKFs), which has been recentlyintroduced in the continuous case, is applied: to a nominal LKF, which is appropriate to the systemwith nominal delays, terms are added that correspond to the systemwith the perturbed delays and that vanish when the delayperturbations approach 0. The nominal LKF is chosen in twoforms: the descriptor type and the 'exact' one. The delay-independent result is derivedvia Razumikhin approach.The advantage of the new tests is demonstrated via illustrativeexamples.