Individual distinguishing pheromone in a multi-robot system for a Balanced Partitioned Surveillance task

A multi-robot system conceived for accomplishing surveillance tasks is designed. The surveillance task addressed differs from that usually considered in the sense that additional requirements must be satisfied, namely: the environment must be virtually partitioned into so many disjoint areas of equal task cost as the number of robots; and each robot must execute the surveillance task restricted to only one area. The strategy adopted to coordinate the robots is based on a stigmergic communication mechanism based on the following property: every robot releases its own pheromone (individual distinguishing pheromone), that is, every robot is able to distinguish the pheromone it releases from that pheromone any other robot does. The multi-robot system operates in a totally decentralized, reactive and on-line mode. Different environment structures and number of robots are considered to build experiments. The respective results confirm the capabilities of the multi-robot system proposed. Specifically, as the robots execute the task, it is possible to observe some behaviors emerge: firstly, dispersion; after that, navigation confinement. In the end, the system dynamics correspond to the task execution according to the desired requirements, at least, approximately: the environment is totally and unceasingly monitored and virtually partitioned into balanced disjoint areas each of which surveilled by only one robot.