Robust mixed H2/H∞ control of networked control systems with random time delays in both forward and backward communication links

This paper is concerned with the two-mode-dependent robust control synthesis of networked control systems where random delays existing in both forward controller-to-actuator (C-A) and feedback sensor-to-controller (S-C) communication links are modeled as Markov chains. The output feedback controller is designed to depend on the current S-C delay and the previous C-A delay. Then, the closed-loop system is formulated as a special jump linear system. The generalized definitions of the H-2, and H-infinity, norms for such underlying special systems are proposed. Further, the two-mode-dependent robust H-2 and robust mixed H-2/H-infinity control design methods for NCSs are developed. The design examples illustrate the effectiveness of the proposed methods. (C) 2011 Elsevier Ltd. All rights reserved.