Online Performance-Based Adaptive Fuzzy Dynamic Surface Control for Nonlinear Uncertain Systems Under Input Saturation

Abstract

As an extension of the conventional prescribed tracking performance constraint problem, this paper proposes a novel online tracking performance constrained control combined with the dynamic surface control (DSC) technique for a class of strict-feedback nonlinear systems with unmeasurable states and input saturation. Using fuzzy logic systems to approximate the unknown nonlinear functions, a high-gain fuzzy observer is designed for state estimation. In the development of DSC control, a serial-parallel estimation model is introduced to analyze the effect of input saturation, and a compensation term is added. To deal with the singularity problem of the prescribed performance constrained method, a novel online performance function is investigated to obtain a satisfactory tracking performance. Under the proposed control scheme, the stability and boundedness of all closed-loop signals are confirmed via Lyapunov synthesis. Finally, numerical simulation results illustrate the effectiveness of the proposed scheme.