In the near future, it may be possible to produce and deploy large numbers of inexpensive, disposable, meso-scale robots. Although limited in individual capability, such robots deployed in large numbers can represent a strong cumulative force similar to a colony of ants or swarm of bees. Using a team of small, sensor-rich robots and a larger, parent robot, we have explored the problem of how to enable flexible, adjustable autonomy control for a remote characterization task. To accomplish the task, the robot team must autonomously deploy into a building, efficiently search through corridors and rooms to locate a spill, and then cooperatively form a perimeter around a chemical spill. The system should be able to accomplish these objectives with human input varying from complete to none at all.
The problem of creating coordinated social behavior from simple, reactive behavior sets is not easily solved. One means insect societies use to impose order and structure onto the otherwise erratic behavior of individuals is group formation behavior, whereby a spatial relationship is maintained implicitly between adjacent entities as in a flock of birds, a school of fish, or a swarm of gnats. Likewise, using audible chirping, we have implemented social potential fields – attractive and repulsive forces that can promote grouping behaviors between adjacent entities. Our work with a collective of 12 small robots shows that social potential fields, although wrought entirely through local interactions and reactive behaviors, can provide a means for coordination and control of a collective as it performs searches in various environments. By modulating these fields through online adaptation or in response to high-level user commands, it is possible to spur dramatic performance improvements in the behavior of the collective as it deploys, searches, and converges to a spill and forms a perimeter around it.