Improved robust absolute stability criteria for uncertain time-delay systems

Improved delay-dependent robust absolute stability conditions for a class of uncertain time-delay systems with nonlinearities subject to sector-bounded constraints are proposed. These conditions are in terms of linear matrix inequalities, which are obtained by choosing new Lyapunov-Krasovskii functionals. Both the cases with time-varying and time-invariant nonlinearities are considered. Numerical examples are provided to show that the robust absolute stability conditions are less conservative than some existing ones in the literature.