Adaptive Predefined‐Time Control for High‐Order Nonlinear Systems With Unmodeled Dynamics

In this paper, the adaptive fuzzy backstepping predefined‐time control problem is considered for a class of uncertain high‐order nonlinear systems in nonstrict‐feedback form with unmodeled dynamics and dynamic disturbances. Fuzzy logic systems (FLSs) are used to identify the uncertain nonlinear system and an innovative predefined‐time dynamic signal is proposed to tackle unmodeled dynamics. Based on the backstepping recursive technique and the power‐based Lyapunov function approach, an adaptive fuzzy predefined‐time tracking controller is developed. It is shown that the presented control method ensures that the controlled system is practically predefined‐time stable, and the tracking errors can be regulated to a small neighborhood around the origin through the appropriate selection of design parameters. In the end, several comparative simulations are provided to show the effectiveness of the proposed control strategy.