Adaptive control for switched nonlinear systems with coupled input nonlinearities and state constraints

This paper focuses on the trajectory tracking problem for switched non-strict feedback nonlinear systems with arbitrary switching. Difficulties exist because coupled input nonlinearities and full state time-varying constraints. To solve this problem, we propose a new adaptive backstepping control strategy. This strategy has three distinguishing features: (1) Based on the concept of novelF-class functions, the proposed adaptive control strategy can deal with many input nonlinearities, including coupled unknown time-varying and state-dependent input nonlinearities. (2) By using a newsystem transformation technique, the proposed adaptive control method is suitable for very general systems, i.e., non-strict feedback nonlinear systems with arbitrary switching and time-varying state constraints. (3) The “explosion of complexity” problem in traditional backstepping design is avoided by using the approximation capability of fuzzy logic. It turns out that the proposed controller contains only one adaptive parameter. Practical examples are provided to illustrate the effectiveness of the proposed method.