Path Tracking Simulation of a Wheeled Mobile Robot with Three Mecanum Wheels

Abstract

This paper presents a study of wheeled mobile robot WMR path tracking by presenting the kinematic model of holonomic wheeled mobile robot with three mecanum controlled wheels. The advantage of mecanum wheels usage is to make the mobile robot movement in lateral and longitudinal directions smooth and to improve the tracking ability to travel in every direction under any orientation. This proposed type of WMR has three actuated input coordinates (angular velocities of the mecanum wheels) and three generalized output coordinates (robot linear translation along x, y axes and the robot orientation). The kinematic models of the WMR are based on a functional relation among configuration variables and their derivatives. It is a known fact that the WMR poses can be achieved in the configuration space but the path to reach these poses has complex step in the consideration. The mobility capability in the proposed design of WMR makes it suitable for different types of applications. The contribution in this work is the initiative to obtain the mathematical models of inverse and forward kinematics in order to analyze a new design of WMR with three mecanum wheels to simplify the task implementation of the robot by obtaining the suitable path to reach the mobile robot target. It has been taken in consideration that, the WMR motion is assumed as a pure rolling without any slipping. Simulation example results presented in this work show the proposed control algorithm applied on two different cases of path tracking (circular path, infinity path) and the effect of WMR wheels angular velocities on the robot body velocities and robot position errors. The results show a good performance in minimizing the positioning errors during the implementation of its task.