Multi Robotic Conflict Resolution by Cooperative Velocity and Direction Control

Abstract

A method by which the velocity and orientation axis of the robot can be dissected into various portions and these portions labeled as conflict free or conflicting with a particular set of robots, unreachable and reachable is presented. The conflict free intervals along the axis that are also represent the solution space for the robot. When the entire reachable space is conflicting with one or more robots it points to the need for cooperation between robots. For a pair of robots that are in conflict with one another and either of them unable to resolve the conflict individually plot of the joint solution space demarcates area where cooperative change of velocities or directions can result in collision freeness. For a pair of robots the entire solution space need not be searched, if a solution is not possible at the corners of the rectangular portions demarcated there is no possibility to resolve the conflict by mutual cooperation. Often a velocity or direction control strategy that solves a conflict with one robot results in conflict with others there by bringing in more robots into the resolution scheme. In such situations the space to be searched for finding a solution increases exponentially. However a method by which requests are passed between robots to resolve the conflicts drastically reduces the space to be searched. We call this as a three-tiered strategy of individual, mutual and tertiary levels. Simulation results confirm the efficacy of the method. Existential and inevitable nature of cooperation is also presented and analyzed in detail