Adaptive fuzzy reliable control for switched uncertain nonlinear systems based on closed-loop reference model

Abstract

This paper investigates an input-to-state practical stability (ISpS) problem for a class of switched strict-feedback nonlinear systems with closed-loop reference model. The considered systems are with unmodeled dynamics, dynamic disturbances and actuator failures. Fuzzy logical systems (FLSs) are utilized to approximate the unknown functions. Different from the open-loop model reference adaptive control, a feedback gain term is introduced into the reference model to improve the transient performance of the considered systems especially when actuator failures occur and switchings take place. By combining the small-gain approach and backstepping technique, an adaptive fuzzy control method is proposed. It is shown that under the developed control scheme, the tracking error converges to a small neighborhood of the origin, while all the signals of the closed-loop system are semi-globally uniformly ultimately bounded (SGUUB). Simulation study is given to illustrate the effectiveness of our results.