Active Target Tracking with Self-Triggered Communications in Multi-Robot Teams

We study the problem of reducing the amount of communication in decentralized target tracking. We focus on the scenario where a team of robots are allowed to move on the boundary of the environment. Their goal is to seek a formation so as to best track a target moving in the interior of the environment. The robots are capable of measuring distances to the target. Decentralized control strategies have been proposed in the past that guarantee that the robots asymptotically converge to the optimal formation. However, existing methods require that the robots exchange information with their neighbors at all time steps. Instead, we focus on decentralized strategies to reduce the amount of communication among robots. We propose a self-triggered communication strategy that decides when a particular robot should seek up-to-date information from its neighbors and when it is safe to operate with possibly outdated information. We prove that this strategy converges asymptotically to a desired formation when the target is stationary. For the case of a mobile target, we propose an extension whereby each robot decides its optimal partner to share its measurements with using observability as a criterion. We evaluate all the approaches (constant communication and self-triggered communication with centralized and decentralized sensor fusion) through simulations.