Indirect adaptive fuzzy sliding mode control : Part I : Fuzzy switching

摘要

In this paper, by using the concept of sliding mode control design and Lyapunov synthesis approach, we propose an indirect adaptive fuzzy sliding mode control (IAFSMC) scheme for a class of nonlinear systems. In contrast to the existing sliding mode fuzzy control system designs, where the sliding mode control law is directly substituted by a fuzzy controller, in our approach both the equivalent control term and switching-type control term in the sliding mode control law are approximated by fuzzy systems, respectively. An on-line adaptive tuning algorithm for the consequent parameters in the fuzzy rules is also designed. The sliding mode-based design procedure ensures the stability and robustness of the proposed IAFSMC. We prove that the proposed adaptive scheme can achieve asymptotically stable tracking of a reference input with a guarantee of the bounded system signals. The chattering phenomena in the sliding mode control is attenuated and the steady error is also alleviated. Simulation studies have shown that the presented adaptive design of fuzzy sliding mode controller performs very well in the presence of an unknown disturbance.