Dynamical compensation for time-delay systems An LMI approach

This paper presents simple and explicit formulae of an `observer-based H∞ controller' for linear time-delay systems. Based on the LMI approach, we design a dynamical controller which guarantees the asymptotic stability of the closed-loop system and reduces the effect of the perturbation to a prescribed level. The main contribution of the paper is to provide closed-loop stability analysis when the system time delay is unknown. We give delay-dependent and delay-independent stability results. The proposed method is illustrated by examples. The paper completes the work of the same authors