A Petri-net based hierarchical structure for dynamic scheduler of an FMS: rescheduling and deadlock avoidance

Flexible manufacturing systems (FMSs) have received considerable attention and evolve to be one of the fastest growing industrial fields in the last decade. In these systems, much higher efficiency of manufacturing can be achieved (owning to their intrinsic flexibility) provided a good scheduling policy is adopted. In this paper, we propose a dynamic scheduler with a hierarchical structure to cope with the unavoidable disturbing events in such dynamic systems like an FMS. In particular, based on our earlier work (1991), we handle the rescheduling problem as well as the deadlock avoidance problem. The merit of this work is its completeness in considering all possible components in an FMS, including AGV transportation system