Collinear formation control of autonomous robots to move towards a target using artificial force fields

In this paper, we propose a novel approach to control autonomous robots to achieve a desired linear formation during movement towards the target position. Firstly, one robot, which has the closest distance to the target, is selected as the leader of the swarm. The desired formation is built based on the relative position between this leader and the target. Secondly, the trajectory of the remaining robots towards the optimal positions in the desired formation is driven by the artificial force fields. These force fields consist of the local and global attractive potential fields surrounding each virtual node in the desired formation. Furthermore, an orientation controller is added in order to guarantee that the desired formation is always headed in the invariant direction to the target position. In addition, the local repulsive force fields around each robot and obstacle are employed in order to avoid collisions during movement. The stability of a swarm following a desired collinear formation in invariant direction towards the target is verified in simulations and experiments.