A robust sliding mode control of mecanum wheel-chair for trajectory tracking

Abstract

This paper presents a brief study of a dynamic control system and explains a control approach for a mecanum wheel-based mobile robot, such as Mecanum Wheelchair (MWC). The MWC has 4 mecanum wheels which are operated by individual motors and is capable of agile movement in a limited space while maintaining omnidirectional ability. Due to the presence of many external disturbances and uncertainties, the MWC's dynamic and kinematic models are constructed, and different types of control techniques are being categorized. The trajectory tracking control of a parallel wheeled holonomic drive MWC is explained in this manuscript, in which the wheelchair must reach its goal/target by following a pre-determined trajectory under variousinitial states. The proposed robust velocity controller was built using the sliding mode control technique to control the trajectory of a three-degree-of-freedom MWC that was subjected to various external disturbances and uncertainties. The results show that the proposed controller has superior performance as compared to the other methods such as the Computed Torque Method (CTM) in presence of uncertainties.