An Experimental Realization of Cooperative Behavior of Multi-Robot System

In this paper we deal with experimental study on the possibility of emergent behaviors of multi-robot system when the robot system consists of simple-functioned mobile robots and they move essentially in a random manner. We manufacture 10 hardware robots equipped with simple mechanical functions such as locomotion and detection of obstacle by touch-sensor as well as equipped with small intelligence such as obstacle avoidance based on the information from their touch-sensor. When these mobile robots make locomotion in a given space, the trajectories made by these robots are found to fill more densely the given space with increasing the population size of the multi-robot system. We evaluate the ability in terms of ‘Space Coverage Ratio’ and find that the space coverage ratio increases more effectively than that in population size. Secondarily, the following function and intelligence are implemented on each individual robot: A function of communication within a limited spatial range to transmit a signal message at regular interval, and the intelligence to cease the locomotion and to return a couple of steps toward a signal message transmitter and then to become a signal message transmitter when the robot has lost the signal message transmitted from other robots. The 10 robots are initiated to move freely and communicate each other and then we find experimentally the multi-robot system to create a communication network starting from the initial location area and expanding over the given space. We experimentally evaluate the reliability of the communication network. In these technical aspects of a multi-robot system, we have experimentally demonstrated the emergent cooperative behaviors by using 10 hardware robots.