Output tracking control for fuzzy delta operator systems with time-varying delays

This paper addresses the fuzzy output tracking control problem of Takagi-Sugeno (T-S) fuzzy delta operator systems with time-varying delays. For a new model transformation, the time-varying delay is approximated via an input-output approach. Based on the transformed model, a sufficient criterion of asymptotic stability with H_∞ tracking performance is derived for the closed-loop system by using scaled small gain theorem. Based on the criterion, a fuzzy H_∞ state-feedback controller is designed such that the output of the plant can track the output of a given reference model in H_∞ sense. The existence condition of the controller can be expressed by a convex optimization problem. Finally, simulation results are given to demonstrate the effectiveness and potential of the proposed new design technique.