Formation and Network Chain Control in Sparse Robot ad hoc Networks based on Potential Field

In this paper, we propose a scheme to maintain a communication link through the use of a communication relay chain in sparse mobile robot ad hoc networks. The scheme consists of three kinds of robots: a task robot, following robots and communication relay robots. The task robot performs predefined tasks; the following robots follow the task robot in a line formation; and the relay robots stop at given locations to form the relay chain. In addition traditional potential field, all robots are subject to an excess force caused by communication quality for formation and chain maintenance. If there appears a shortcut to previous relay, the unnecessary relay, subject to only forces created by the shortcut position and obstacles, will move by relay motion to the shortcut position. Our simulations show that the proposed scheme is very effective in sparse robot ad hoc network.