A Token Passing Approach for Circle Formation by Multiple Mobile Robots

This paper proposes a weakly centralized distributed approach for positioning multiple mobile robots in a circular formation based on token passing. The problem of the circle formation with multiple robots which are arbitrarily placed on a 2D plane requires all robots to be uniformly positioned (i.e., at an equal angular distance of 2 pi/N, where N = number of robots) on the circle circumference. The suggested approach is a leader-follower approach wherein it is the leader robot which computes the uniform positions on the circle circumference for all the follower robots. The problem of circle formation is divided into two sub-problems (a) leader selection and (b) finding enviable positions for the follower robots from the set of uniform positions computed by the leader robot. Both these problems are solved by token passing so as to reduce communication load on both the leader and the follower robots. The introduction of token passing makes it a weakly centralized framework thereby reducing the burden on the leader robot.