Swarm based enclosure model for unspecified number of targets

Target enclosure by autonomous robots is useful for many practical applications, for example, surveillance of disaster sites. Scalability is important for autonomous robots because a larger group is more robust against breakdown, accidents, and failure. However, traditional models only discussed cases in which minimum number of robots enclose a single target so that there is no way to utilize the redundant number of robots. In this paper, to achieve a highly scalable target enclosure model about the number of target to enclose, we introduce swarm based task assignment capability to Takayama et al.´s enclosure model. The original model discussed only single target environment but it has good nature for applying it into multiple targets environments. We show the robots can enclose without predefined position assignment by analytic discussion based on switched systems and a series of computer simulations. As a consequence of this property, the proposed robots can change its target according to criterion about robot density while they enclose multiple targets.