On analysis of performance for digitally controlled and time-varying delayed systems

Systems, which are digitally controlled via a network, present necessarily time-varying delays. This main difficulty is a problem to design control laws. Besides their stabilization, this paper makes a study of performance degradation of networked control systems, in the presence of time-varying delays. An optimization problem using a Lyapunov-Krasovskii type approach yields to design, in one hand a stabilizing control law and in other hand an upper bound guaranteeing a performance level for all sequence of time-varying delays. An analysis of relevance for such an upper bound is provided.