A new design of delay-dependent robust ℋ_∞ filtering for continuous-time polytopic systems with time-varying delay

This paper revisits the problem of delay-dependent robust ℋ_∞ filtering design for a class of continuous-time polytopic linear systems with a time-varying state delay. Based on a newly developed parameter-dependent Lyapunov-Krasovskii functional combined with Projection Lemma and an improved free-weighting matrix technique for delay-dependent criteria, a new sufficient condition for robust ℋ_∞ performance analysis is first derived and then the filter synthesis is developed by using a simple matrix inequality linearization technique. It is shown that the desired filters can be constructed by solving a set of linear matrix inequalities. Finally, two simulation examples are given to show the effectiveness and less conservatism of the proposed method in comparison with the existing approaches.