David J. Bruemmer, Donald D. Dudenhoeffer, and Julie L. Marble
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 multi-robot 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, once found. The system should be able to accomplish these objectives with human input varying from complete to none at all. We have developed a graphical user interface (GUI) that allows hierarchical tasking for groups of robots and have married this software to individual robot behaviors and a multi-modal communication architecture comprised of radio, infrared, and audible chirping. The ability for the robots to chirp and respond to chirps is the basis for our implementation of social potential fields -- attractive and repulsive forces that can promote grouping behaviors between adjacent entities such as might be seen in a flock of birds or a school of fish. Through coverage experiments in a test-bed environment, we have found that social potential fields provide a means to control a variety of emergent swarm effects including swarm size, swarm density, swarm translation. As this paper will discuss, social potential fields provide a unique means to accomplish deployment, convergence to the spill and to orchestrate perimeter formation.