Improved analysis and H ∞ control for networked control systems with time-varying delays and packet dropout

This paper studies the improved analysis and H_∞ control for a class of networked control systems with time-varying delays and packet dropout via a quadratic convex combination approach. The newly proposed augmented Lyapunov–Krasovskii functional is constructed by using the quadratic terms multiplied by a third-degree scalar function. A sufficient condition for asymptotic stability of networked control system is derived in terms of linear matrix inequalities. The H_∞ state feedback controller is obtained with an iteration algorithm. Differently from previous results, our derivation applies the idea of a second-order convex combination and the estimation of cross items. This method gives a reduced conservatism without using Jensen’s inequality. Numerical examples show the validity and feasibility of the proposed theoretical results.