Distributed Grasp Synthesis for Swarm Manipulation with Applications to Autonomous Tugboats

Assume a swarm of mobile robots is in the act of transporting a large object in the plane, by applying unilateral forces to the perimeter of that object. We address the question of where a new robot, joining the group, should establish contact with the object to maximally improve the manipulation capabilities of the swarm. Inspired by the literature on multi-fingered hands, we synthesize a grasp by incrementally optimizing a grasp quality function. We adapt the quality function in several important ways to accommodate the distributed nature of the swarm problem. We show that the objective function is quasi-concave which has important implications for uniqueness and scalability of the solution and present a solution methodology. We apply the resulting framework to the example of a large swarm of autonomous tug boats towing a barge, taken from our larger research program.