A pushing leader based decentralized control method for cooperative object transportation

In this paper, we address a decentralized control method for object transportation in coordination by using a leader-follower type multiple robot system, which consist of a pushing leader, a leader robot without grasping mechanisms, and multiple follower robots. During the object transportation, a desired trajectory is given to the leader robot only, and follower robots estimate the trajectory of the leader based on force/moment from the object. In the proposed system, a variable internal force is introduced to each robot\´s controller in decentralized style to let the follower\´s estimator work on not only the pushing but also the "pulling" case that the leader needs to slow down or move back the object. Finally, a multiple robot system including three omni-directional mobile robots is presented and experiment results are shown to illustrate the concept of the proposed control algorithm.