Robust H∞ control of network control systems with state observer

The robust H_∞ control of a class of networked control systems with uncertain delay and unmeasured system states is studied. A general framework for networked control systems is given in this paper. Under this framework, the outputs from the plant are the only information we know, the controller and actuator of the NCS are event driven, the network induced delay is time-varying,uncertain and less than the sampling period. A sate observer here is designed to estimate the states; also, the observer can work as a compensator to compensate time-delay. Then the whole system is modeled as an uncertain linear discrete system, Based on Lyapunov function, a sufficient condition for NCS which is subject to the asymptotic stability and H_∞ performance is derived, and the output feedback controller design method is presented. Simulation example for the design is done in truetime simulation platform, compared with the method of state feedback, the results shows the validity of the proposed method.