A recent paper by Xi Yu and M. Ani Hsieh from the University of Pennsylvania presents a distributed control and coordination strategy that allows a swarm of mobile robots to form an intermittently connected communication network as they monitor a given environment. The approach assumes robots are tasked to patrol a set of perimeters in a region of interest and are only able to communicate with one another when they move into each other’s communication range as they monitor their assigned perimeters. The work shows how intermittent connectivity can be achieved as each robot synchronizes its speed with other robots moving along neighboring perimeters. As robots synchronize with one another, they effectively ensure future pair-wise rendezvous with robots on neighboring perimeters.  This enables the team to form a time-varying communication network where information can be successfully transmitted between any pair of robots within some finite time period.  Additionally, the approach provides bounds on the time needed to propagate information throughout the network. The feasibility of the strategy and the validity of the approach is validated in simulation.

Fig. 1.  An overhead view of an urban environment (left) where robots are tasked to patrol perimeters around different buildings.  As robots move into each other’s communication range (robots on perimeters 7 and 8 and robots on perimeters 11 and 12 in the right figure), information can be exchanged.  In both figures, blue robots are robots who have obtained a new piece of information from a robot on a neighboring perimeter while red robots are robots who have not received the information.  As robots rendezvous with each other, the information will eventually propagate throughout the entire network.