Adaptive Sliding Mode Control for Omnidirectional Mobile Robot Based on a New Friction Modeling

Abstract

Due to the special structure of omni-directional wheels, friction forces among hubs, wheels and ground have a great influence on the motion accuracy of four-wheeled omnidirectional mobile robot. In order to reduce the effect of friction on motion control system, this paper proposes an adaptive sliding mode controller (ASMC) based on the dynamic model considering the friction on omni-directional wheels. The research on the omni-directional wheels friction force is described in detail, which lays a foundation for the accurate control of omnidirectional mobile robot. Firstly, the paper analyzes the Coulomb's friction on the driving wheel and the driven wheel respectively which is introduced to the friction model of the omni-directional wheel. Secondly, a new adaptive sliding mode control method is proposed to address the friction problem. Finally, the validity and performance of the control method are verified by simulations.