AVOIDANCE OF DEADLOCKS IN FLEXIBLE MANUFACTURING SYSTEMS USING A CAPACITY-DESIGNATED DIRECTED GRAPH

Deadlocks in flexible manufacturing systems (FMSs) refer to the stop s tate of job flow that may often occur while operating the systems. Thi s state should be avoided to provide the efficient way of job flow and to achieve full utilization of high-capital resources. In this paper, we developed a capacity-designated directed graph (CDG) representing machine resources and job routeings in FMSs. Using the CDG, a deadlock -avoidance method is proposed to prevent the system from satisfying th e necessary condition for deadlocks. This deadlock-avoidance method is implemented into static and dynamic strategies. A simulation study de monstrates the applicability of the two strategies to an FMS.