Improved H∞ control for networked control systems with network-induced delay and packet dropout

The H-infinity performance analysis and controller design for linear networked control systems (NCSs) are presented. The NCSs are considered a linear continuous system with time-varying interval input delay by assuming that the sensor is time-driven and the logic Zero-order-holder (ZOH) and controller are event-driven. Based on this model, the delay interval is divided into two equal subintervals for H-infinity performance analysis. An improved H-infinity stabilization condition is obtained in linear matrix inequalities (LMIs) framework by adequately considering the information about the bounds of the input delay to construct novel Lyapunov-Krasovskii functionals (LKFs). For the purpose of reducing the conservatism of the proposed results, the bounds of the LKFs differential cross terms are properly estimated without introducing any slack matrix variables. Moreover, the H-infinity controller is reasonably designed to guarantee the robust asymptotic stability for the linear NCSs with an H-infinity performance level gamma. Numerical simulation examples are included to validate the reduced conservatism and effectiveness of our proposed method.