Improved robust stability criteria for uncertain systems with time-varying delay

This paper is concerned with the delay-dependent stability and robust stability for uncertain systems with time-varying delay. Through constructing an appropriate type of Lyapunov-Krasovskii functional and proving its positive definiteness, using slack matrices and a convex combination condition, the delay-dependent stability criteria, which are less conservative, are derived in terms of linear matrix inequalities. Numerical examples are also given to illustrate the improvement on the conservatism of the delay bound over some existing results.