H∞ control of networked control system with long time delay

In this paper we study the effect of networks with long time delay in the feedback loop of a control system. A new model of the NCSs with long time delay was proposed using buffering method and the uncertain long time delay can be converted to switch in some certain time delays. Thus the networked control system with long time delay is modelled as a discrete-time Markov jumping linear system (MJLS). Based on the results for MJLS, system performance is measured via an H_infin norm from disturbance to error and an output feedback controller is computed by a necessary and sufficient linear matrix inequality condition. A numerical example is given to illustrate the proposed results.