Trajectory planning to improve the motion performance for a nonholonomic wheeled mobile robot

Wheeled mobile robots suitable for a variety of applications in a wide field have been studied for many years. In any application, it is necessary to ensure the motion performance of a wheeled mobile robot to guarantee its reliability and security. However, it is difficult to control the motion of wheeled mobile robot because it is a three-dimensional two-input nonholonomic system. In this paper, we address the problem of motion under nonholonomic constraints for the wheeled mobile robot based on the fact that one can direct a nonholonomic automobile to track any path in a wide space by adjusting its velocity and orientation angle on-line. First, an on-line trajectory planning method is proposed to generate the reference velocity and the orientation angle according to the target position and the robot's current position. Then, the feedback velocity and orientation control law are designed based on the dynamic model. Finally, experiments are conducted to demonstrate the effectiveness of the proposed controller.