Leader-Following Formation Navigation for Multiple Robots with Collision Avoidance

This paper deals with a collision avoidance problem in leader-following formation navigation for multiple mobile robots. Because followers should move along a leader’s trajectory, we first try to avoid collisions by adjusting their velocities on the trajectory. This strategy causes delays of the followers from the leader, which is often problematic because we cannot predict how late the followers will be from the leader. Moreover, there are situations that the robots cannot avoid collisions only with this strategy. If the leader goes straight and turns back toward the followers suddenly, the followers have to move back along the trajectory where the leader just moved. In this case, the followers would be better off moving around to the back of the leader and recover their delays even if they go away from the specified trajectory. From these viewpoints, this paper proposes a collision avoidance method for leader-following formation navigation taking into account both the tracking errors and the delays of the followers from the leader. This method adjusts the velocity of each follower, as well as modifies the shape of the trajectory if a delay becomes too large. The effectiveness of the proposed method is demonstrated by a simulation with three mobile robots.