Abstract
Deadlock problems of zone-control uni-directional automated guided vehicle systems (AGVS) are discussed in this paper. A directed graph is defined to model the vehicle flows, to identify distinct vehicle flows, to represent states easily and to capture concurrent behaviour of zone-control AGVS. The motivation of this research was to propose a dynamic approach to enable prediction in real time and to avoid deadlocks that are caused by sharing guidepath zones for a class of AGVS so that both utilization of resource and overall throughput can be improved. The proposed algorithmic procedure, in accordance with the states gained and generated from the obtained model, can serve as a functional module for the operation of a zone-control AGVS without the need to revise the original vehicle control extensively.