Bounded-Function-Based Schemes for Finite-Time Control of a NWMR With Input Constraints

This paper investigates the problem of finite-time stabilization and trajectory tracking control of a nonholonomic wheeled mobile robot (NWMR) under input constraints. Based on the hyperbolic tangent function <roman xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">tanh</roman>(⋅), a bounded finite-time stabilization controller and a bounded finite-time tracking controller are proposed. Specifically, for the stabilization controller, a switching strategy is used and an explicit upper-bound estimate for the closed-loop settling time is provided. For the tracking controller, a finite-time control scheme consisting of a bounded angular velocity controller and a bounded linear velocity controller is developed. For both the stabilization controller and the tracking controller, the saturation level of the control input can be predefined based on the actuator’s capacity. Comprehensive finite-time stability analyses are provided by selecting appropriate Lyapunov functions. Finally, simulation and experimental results addressing the stabilization and trajectory tracking problem for NWMR demonstrate the effectiveness of the proposed controllers.