Multi-robot routing under limited communication range

Teams of mobile robots have been recently proposed as effective means of completing complex missions involving multiple tasks spatially distributed over a large area. A central problem in such domains is multi-robot routing, namely the problem of coordinating a team of robots in terms of the locations they should visit and the routes they should follow in order to accomplish their common mission. A typical assumption made in prior work on multi-robot routing is that robots are able to communicate uninterruptedly at all times independently of their locations. In this paper, we investigate the multi-robot routing problem under communication constraints, reflecting on the fact that real mobile robots have a limited range of communication and the requirement that connectivity must remain intact (even through relaying) during the entire mission. We propose four algorithms for this problem, all based on the same reactive framework, ranging from greedy to deliberative approaches. All algorithms are tested in various scenarios implemented using the Player-Stage robot simulation environment. Our results demonstrate that effective multi-robot routing can be achieved even under limited communication range with moderate loss compared to the case of infinite communication range.