Anonymous Multi-Agent Path Finding with Individual Deadlines

Anonymous Multi-Agent Path Finding (AMAPF) is the problem of planning conflict-free paths to a set of target locations for a group of agents, where each agent is not associated with a specific target. This paper studies AMAPF with Individual Deadlines (AMAPFwID), where each target must be reached before a specific deadline, and the agent stays there to perform some long-term mission, for instance securing an asset, responding to an emergency, or performing a maintenance job. We examine three types of behavior of agents when reaching a target: (a) disappear on target, (b) stay on target, and (c) move after the deadline. The latter is only possible if the agent is replaced by another agent. We refer to this replacement as hot swapping. We propose a solution to AMAPFwID with each type of such behavior, based on a reduction to Network Flow. We test all solutions experimentally and show cases where hot swapping is beneficial. Finally, we also provide a solution to the case where agents disappear on targets that maximizes the number of targets reached and discuss other aspects of the problem.