Command filter-based adaptive predefined-time control for non-strict feedback nonlinear systems with unmodeled dynamics

In this paper, a predefined -time control strategy based on the command filtered technique is proposed for a class of non -strict feedback nonlinear systems with unmodeled dynamics. Compared with the fixed -time control, the convergence time of predefined -time control is a more accurate and user -designed positive constant. The command filtered backstepping technique is employed to overcome the ultrahigh computation in the traditional backstepping method. The proposed command filter -based predefined -time control scheme can guarantee that convergence of all signals in the closed -loop system reach a small neighborhood within the predefined time. The effectiveness of the developed scheme is demonstrated by two simulation examples.