Improved H∞ filtering for continuous-time singular systems with time-varying delay

This paper presents an improved H_∞ filter design for continuous-time singular systems with time-varying delay. A delay-dependent H_∞ performance analysis result is first established for error systems via a novel estimation method. By combining a well known inequality with a delay partition technique, the upper bound of the derivative of the Lyapunov functional is estimated more tightly and expressed as a convex combination with respect to the reciprocal of the delay rather than the delay. Based on the derived H_∞ performance analysis results, the H_∞ filter is designed in terms of linear matrix in-equalities (LMIs). A numerical example is given to demonstrate the merits of the proposed method.