H∞ Output Tracking Control for Networked Control Systems with Long Time Delays

This paper focuses on the problem of H-infinity output tracking control for networked control systems (NCSs) with network-induced long time delays. First, by combining the controlled plant and the reference model, the augmented closed-loop system is established. On the basis of the robust control method and time delay nominal point technique, the exponential uncertainty terms in the sampled system model caused by network-induced long time delays are transformed into sums of nominal terms and norm-bounded uncertainties. Then, by employing the Lyapunov-Krasovskii method, linear matrix inequalities (LMIs) technique and discrete Jensen inequality, sufficient conditions for the existence of the H-infinity state feedback controller are derived, which guarantee that the augmented closed-loop system is stable and satisfies the prescribed H-infinity tracking performance. Finally, the effectiveness of the proposed method is verified by a numerical example.