H∞ tracking control for a class of uncertain nonlinear systems using multi-model switching

This paper studies the design of H_infin tracking control for a class of uncertain nonlinear systems using multi-model switching in the presence of uncertainty and disturbance. First of all, T-S models are employed to model the uncertain nonlinear system. The input space is divided into multiple regions, in which the local T-S models are given and the corresponding controllers are designed Thereupon, the approach precision improves as the fuzzy domain decreases under constant fuzzy rules. Then, a sufficient condition, which satisfies the closed-loop stability and the performance of H_infin tracking, is presented for the existence of the controller on the condition that the uncertainty is gain bounded. By solving a family of linear matrix inequalities, the H_infin tracking control law is obtained. Based on Lyapunov theory, it is proven that the closed-loop system is exponential stability. Finally, a region controller, which is chosen according to the selected variables by the multiple-model switching control, is switched to the whole controller and that other controllers do not operate, the approach and control of the entire nonlinear system is therefore established. The effectiveness of the proposed method is demonstrated by the simulation results.