A hierarchical multi robotic collision avoidance scheme through robot formations

This paper depicts the utility of having robot formations to aid in collision avoidance amongst multiple robots in a multi agent/multi robotic setting. A set of robots satisfying certain proximal constraints reach a formation that enables considering that set of robots as a single robot cluster. Such a robot cluster is characterized by a cluster velocity computed from the individual robot velocities that comprise that cluster. The multi robotic collision avoidance problem can then be posed as collision avoidance between such robot clusters than between individual robots. Clusters could include single robot clusters. The robots within a cluster move such that they are guaranteed not to collide with each other. This is accomplished in this paper by ensuring that robots within a cluster reach a configuration where their velocities are equal and they move in a parallel formation. The underlying collision avoidance scheme thus needs to search for cluster velocities that provides collision free motion between clusters; this search at the cluster level than at an individual robot level greatly reduces the search space, thus providing for a hierarchical collision avoidance strategy. The strategy has been tested and verified in simulations and their results presented vindicating its efficacy.