Reactive multi-agent based control of mobile robot chain formations

Abstract

A Multi-agent based coordination scheme for chain formations of mobile robots, employing geometric constraint satisfaction rules, is presented. Applying this architecture on mobile robot swarms, snake-like real-time motion and reactive obstacle avoidance is achieved. A “Master – Slave” relationship is used, where a controller agent's motion is propagated to its two neighbouring ones in the chain formation and progressively further on towards the two chain endpoints. At each propagation step, a constraint preservation mechanism enforces the respect of minimum and maximum (minmax) distance constraint between agent pairs, and of minmax angular constraint among triplets of consecutive chain agents. The emergent behaviour of this multi-agent system is as if a moving part of the chain pushes or pulls the two subparts it divides the chain into. To allow replaning in case a slave part can't adapt to its master's motion, being trapped in obstacles or malfunctioning, the notion of a “Vetoable slave” behaviour is used, where the slave part can object (veto) to the motion of its master part.