Grammps Represents a Milestone in Demonstrated Coop- 10. References [1]alami, R, Et Al. " a General Framework for Multi-robot Cooperation and Its Implementation on a Set of Three 7. Live Results

erative robotic systems, as the first fully-integrated autonomous multi-robot system operated in natural terrain. The mission grammar supports a wide variety of missions, providing optimal execution of those missions by teams of robots, with graceful degradation of optimality for compu-tationally intractable missions. Furthermore, GRAMMPS supports heterogeneous robots as specified via the mission statement as well as by incorporation robot speed estimates into the planning process. Finally, GRAMMPS is general, capable of functioning with a general class of local navigation systems. It is the intent of future work to increase the capabilities of GRAMMPS by improving the robustness of the system against partial failures, and by extending the class of missions which can be executed. An alternative world representation for dynamic planning (a Framed-Quadtree) which has performed well in initial testing is likely to be fully integrated, providing significant memory savings. The mission planning component of GRAMMPS is centralized in nature, running only on one of the robots involved in the mission. It would be advantageous to enable decentralization of this component to improve system reliability and parallelize computational requirements. The mission grammar could be extended to support cooperative foraging, the meeting of robots at a central location , and the dependency of later parts of the mission on earlier choices. Finally, a randomized search algorithm could be utilized on the entire mission statement, rather than just on components thereof, permitting near-optimal execution of increasingly complex tasks. The authors would like to thank the CMU UGV group for their support of live-vehicle demonstrations and testing. In particular, Jim Frazier's tireless efforts at maintaining the vehicles and Dr. Martial Hebert's ongoing research in perception and local navigation have been critical to the success of this work. ule of GRAMMPS is responsible for the inter-vehicle aspects of execution, excluding the actual mission planning. Under its purview are map information compression and exchange, position sharing, steering vote-passing, and inter-robot collision avoidance. The intercom modules can be connected to each other either in a ring (each only talks to its neighbors) or in a fully-connected configuration. If the communication infrastructure supports multi-cast, then the latter is the preferable choice. If, however, all communications are point-to-point, then a ring structure may be more effective. For two robots, as used in these live tests, the choices are equivalent. Each local navigator generates updates to the map within its field of view. This raw obstacle/non-obstacle information is passed …