Moving-target tracking and obstacle avoidance control algorithm for unicycle mobile robots

A moving-target tracking and obstacle avoidance control system for unicycle mobile robots is proposed in this paper. The control system consists of two nested loops. Tracking law in the inner loop controls the robot to track the target via reducing the posture error to zero and its stability is analyzed using Lyapunov function method. The law also takes into account of the velocity limit of the robot. When any obstacle is detected, the external loop provides a modification on the target position based on the impedance control concept and the obstacle's distance measured by eight ultrasonic sensors. Simulation study and experiment show that the tracking law is correct and the control system can prevent the robot from obstacle collision.