Prescribed-time practical tracking control via switching for a lass of uncertain nonlinear systems with unknown control directions

This paper investigates prescribed-time practical tracking control for a class of uncertain nonlinear systems. Despite the distinguish characteristic of the investigated system which is reflected by the unknown control directions, prescribed regulation time of the tracking error is considered. These two aspects lead to the ineffectiveness of the traditional methods on this topic. For this, a novel switching control scheme is proposed in the paper. Specifically, a pivotal switching mechanism is first designed for the tuning of controller parameters, joint which a state-feedback controller is designed explicitly. Then, much efforts are taken to show that the switching of controller parameters under the designed switching mechanism just happens a finite-number of times, and moreover, all the signals of the resulting closed-loop system are bounded while the system output practically tracking the reference with arbitrary prescribed time. Finally, a simulation example is provided to validate the effectiveness of the proposed theoretical results.