Mixed H2/H∞ control of networked control systems with random delays modeled by Markov chains

This paper considers the mixed H₂/H_infin control of networked control systems where random time delays existing in sensor-to-controller (S-C) and controller-to-actuator (C-A) links are modeled by Markov chains. The designed output feedback controller is two-mode-dependent, which depends on the available S-C and C-A delay information. The closed-loop system is formulated as a special jump linear system. The definitions of the H₂ and H_infin norms are further proposed to reflect the special characteristics of the system. The H₂ and mixed H₂/H_infin control problems are solved via the linear matrix inequality (LMI) optimization approaches. Simulation examples illustrate the effectiveness of the proposed methods.