Event-based controller to avoid deadlock and collisions in zone-control AGVS

Automated Guided Vehicle Systems (AGVSs) are the most flexible means to transport pieces among workstations of an Automated Manufacturing System (AMS). The traffic control of such systems must be in charge of avoiding collisions and deadlock conditions. This paper formulates a zone-control scheme to face this problem in real time, based of the knowledge of the AGVS operative conditions. Starting from some theoretical results already stated in the context of deadlock avoidance in AMS, some algorithms are proposed to control, in real time, path assignments to the vehicles and their moves from zone to zone in the system. A final discussion compares the proposed approach with other methods offered by the recent literature.