Using Mobile Relays in Multi-Robot Exploration∗

Many robotics tasks require autonomous exploration by teams of robots. In difficult or large environments, communication drop-out complicates this task. Several approaches exist that aim to keep the team connected, but even so there is an inherent limit to the range that can be explored. In this paper we describe and examine Role-Based Exploration, an approach that uses mobile relays to ferry information back and forth within the team, and compare it to methods that do not. There are significant advantages in the use of such relays, such as improved coordination and responsiveness, and adaptability to unexpected communication dropout. The approaches are implemented and validated on a team of real robots.