Decentralized Cooperative Object Transportation by Multiple Mobile Robots with a Pushing Leader

Abstract

We address a decentralized control method for object transportation in coordination by a leader-follower type multiple robot system. The proposed system consists of a pushing leader, a 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 stop the object. Finally, a robot system including three omnidirectional mobile robots is presented and an experiment result is shown to illustrate the concept of the proposed control algorithm.