Relaxed stability criteria for linear neutral systems with constant delays

This paper revisits the problem of asymptotic stability analysis for linear neutral systems with commensurate constant delays. The purpose is to obtain delay-dependent stability conditions that are less conservative than the existing ones in the literature. First, a novel Lyapunov-Krasovskii functional that contains integrals related to the difference operator Dx_t is employed. Combining this Lyapunov-Krasovskii functional and the delay-decomposition technique yields a new delay-dependent stability criterion for the considered neutral system. Next, with the help of Jensen´s integral inequality and Wirtinger-based inequality, the obtained result is further improved by relaxing the positive-definiteness restrictions on the Lyapunov matrices involved in the single integral. Finally, two numerical examples are provided to show the improvement of the present delay-dependent stability criteria over the recent ones in the literature.