Avoiding Collision Logjams through Cooperation and Conflict Propagation

A methodology for resolving collision conflicts of many moving robots involving distributed cooperative behavior is proposed in this work. Robots are unaware of the goals and plans of other robots. Each robot is however assumed to be in knowledge of the current states of other robots within a given range of vision. The current state of a robot is represented by its current and target velocities and its heading direction. A conflict between two robots is a detection of an upcoming collision. The resolution of the conflicts occurs at three levels. At the first level the robots attempt to resolve the conflict individually. If individual attempts to resolve fail the robots enter into a cooperative phase of resolving the conflict at the second level. At the third level conflicts are propagated to robots not directly involved in any conflicts at that instant and their assistance sought for possible resolution. At all the three levels conflict resolution is attempted by velocity control of the robots through an algorithm that is distributed across all the robots in the system. Simulation results are shown to validate the efficacy of this methodology. Conflict resolution through cooperation and conflict propagation is pertinent to all those applications that entail a number of robots to crisscross each other in quick succession or in situations where robots find themselves coming together to get across an intersection from various directions which would otherwise result in a logjam.