Design and Simulation of a Wheeled Mobile Robot Control System Based on Sliding-Mode Variable-Structure Algorithm

Abstract

This paper investigates trajectory-tracking control for a wheeled mobile robot under model uncertainty and bounded velocity disturbances. To improve tracking accuracy, robustness and chattering suppression, a kinematic model is established and a sliding-mode variablestructure controller with a saturation-type reaching law is designed. The controller switches the control input according to the sliding variable so that the closed-loop system approaches the sliding surface and the robot tracks the prescribed sinusoidal trajectory. A numerical simulation is conducted with a sampling period of 0.01 s and a 20 s reference trajectory. Quantitative results show that, after the initial convergence stage, the maximum position error under disturbance is 0.157 m, the average position error is 0.090 m, the root-mean-square position error is 0.230 m, the steady-state error remains below 0.0032 m, and the maximum disturbance recovery time is 0.78 s, which verifies that the proposed algorithm achieves accurate trajectory tracking and strong disturbance-rejection capability.