Adaptive Predefined-Time Fuzzy Tracking Control for Output Constrained Non-strict Feedback Nonlinear Systems with Input Saturation

Abstract

An adaptive predefined-time fuzzy tracking control problem for non-strict feedback systems is investigated in this paper. Compared with some previous findings on adaptive control for the output constrained systems with input saturation, the most significant feature of this research is that the system convergence time only depends on one design parameter. To approximate the unknown nonlinearity, fuzzy logic systems as a powerful method is introduced. Additionally, by integrating the auxiliary control signal and the barrier Lyapunov function method into the backstepping deduce procedure, a predefined-time adaptive fuzzy control scheme is proposed for such a system. Theoretical analysis proves that all of the system variables are bounded, and the system output converges to a small region near the given signal within a predefined time. Finally, a practical example of the single-link rigid robot system and a numerical example are conducted to verify the effectiveness of the proposed control approach.