Adaptive predefined-time tracking control of nonlinear systems with unmodeled dynamics

Consider the problem of predefined-time adaptive tracking control in this paper for a class of strict-feedback nonlinear systems in the presence of unmodeled dynamics and dynamic disturbances. An improved predefined-time dynamic signal for the first time is proposed to address unmodeled dynamics. Via the practical predefined-time stability criterion and the adaptive backstepping control method, an adaptive predefined-time tracking controller is designed, which guarantees the tracking error converges to the small neighbourhood near zero within a predefined time. Simultaneously, all the signals in the closed-loop system are bounded. Finally, the developed scheme's feasibility is illustrated by simulation.