Reactive collision avoidance of multiple moving agents by cooperation and conflict propagation

A strategy for collision avoidance between several moving robots that are not in possession of each other's plans is presented here. A robot's awareness of other robots is limited to the knowledge of their current states represented by their present and impending velocities and their motion direction. A robot is aware of the presence of other robots when they fall within its field of vision. Collision avoidance is attempted at three levels namely at individual, cooperative and propagation levels through velocity control. At individual level it suffices that one of the robots involved in a forthcoming collision modifies its velocity. The cooperative level is characterized by the requirement that all the robots involved in collision modify their velocities in a synchronized fashion. In the third level robots not involved in a collision are entailed to participate by altering their velocities in a manner that resolves collision conflicts between the robots involved. The third level is termed as the propagation level since the collision conflict is propagated to robots not a part of the conflict and their assistance sought in avoiding conflicts. The strategy is implemented in a distributed fashion across all robots in the system. Simulation results are presented to authenticate the efficacy of the proposed method.