Trajectory tracking for a wheeled mobile robot with an omnidirectional wheel on uneven ground

摘要

In this study, trajectory tracking control is investigated based on a double closed‐loop strategy for a wheeled mobile robot with an omnidirectional wheel on uneven ground. The omnidirectional wheel is used to make the wheeled mobile robot turn smoothly, however, external disturbances are caused when the wheeled mobile robot goes straight. Moreover, the external disturbances also come from uneven ground for the wheeled mobile robot. An extended state observer with a time‐varying gain is designed to estimate the external disturbances in an inner loop of the double closed‐loop strategy. Then a torque control law for integral sliding mode control is given to track desired velocities. In an outer loop, a kinematic controller is designed to generate the desired velocities. Experimental results are given to show the effectiveness and superiority of the double closed‐loop strategy for the wheeled mobile robot.