Trajectory tracking for groups of unicycles with convergence of the orientation angles

This paper presents a trajectory tracking control strategy for unicycles based on local potential functions and the leader-followers scheme. The leader robot must follow a prescribed trajectory and the rest of the robots follows the leader whereas achieves a desired formation at the same time. Every follower robot does not possess a global information about the leader path and the goals of the other followers. The control strategy does not influence directly the orientation angles, however a sufficient condition is established for their convergence to the same value. Finally, the performance of the proposed strategy is evaluated over an experimental set-up consisting of three unicycle-type robots and a computer vision system.