Predefined-time path-following control of four-Mecanum-wheel omnidirectional vehicle with actuator saturation

Predefined-time control theory finds wide applications in practice due to its capability to achieve a user-assignable, in-advance finite settling time irrespective of initial conditions. However, despite recent advancements in trajectory tracking for omnidirectional autonomous vehicles, most existing finite-time and fixed-time control strategies are prone to severe performance degradation when physical actuator saturation exists. This paper investigates the predefined-time path-following control problem of a four-Mecanum-wheel omnidirectional vehicle (FMWOV) with actuator saturation. First, the tracking error system is established through analyzing the kinematic and dynamic modeling. Second, a nonsingular fast terminal sliding manifold is built, based on which a novel predefined-time controller is designed to enhance system robustness, accelerate convergence speed, and actively compensate for saturation nonlinearities. It is rigorously proved mathematically that the tracking error system is predefined-time stable, which indicates that the actual path tracks the desired reference path in a finite time while eliminating the effect of actuator saturation. Finally, an application example of the FMWOV is given to validate the effectiveness and superior robustness of the proposed predefined-time control scheme against existing approaches.