A new approach to robust H_∞ filtering for uncertain systems with both discrete and distributed delays

This paper is concerned with robust H_∞ filter design for a class of linear distributed delay systems with norm-bounded time-varying parameter uncertainties. The distributed delays are assumed to appear in both state and measurement equations. A new design method is proposed by introducing some relaxation matrices and tuning parameters, which can be chosen properly to lead to a less conservative result. Asufficient condition is obtained to guarantee the existence of desired H_∞ filters, which can be constructed by solving a convex optimization problem. A numerical example is included to illustrate the effectiveness and the reduced conservatism of the proposed design technique.