Object Manipulation Using Cooperative Mobile Multi-Robot Systems

Transportation of large objects or their manipulation in hazardous environments are tasks where the utilization of groups of mobile robots working in a cooperative fashion can be of great advantage. To execute such tasks, a multirobot formation control framework is necessary in order to coordinate the motions of the robots in the group. In this article, a particular formation control approach called cluster space control is utilized to control a group of four non-holonomic wheeled robots. A single operator using a joystick input controls in run time the position of all the robots in the formation. We first present the application of the cluster space framework to a group of four robots and show how it is used in a closed loop controller that facilitates a pilot to appropriately control all the degrees of freedom of the formation. Then, the tasks of cooperatively manipulating and transporting an object are implemented and verified using a hardware experimental testbed.