An iterative deadlock prevention approach for automated manufacturing systems

This paper considers an iterative deadlock prevention policy in the context of the automated manufacturing systems (AMS) that constitute one of the major production technologies in modern industry. Owing to the specialty of an AMS, the reachability graph (RG) of its given Petri net model shows powerful analysis and control capability to crack such a hard nut. However, the fact that the number of nodes involved in an RG grows exponentially with the size of a Petri net model makes all the RG-based policies infeasible. The approach conducted in this paper illustrates that the bad nodes in an RG can be extracted iteratively by a set of mixed integer programming formulations so that the explicit enumeration of all nodes of the RG is avoided. The proposed approach promises a computationally efficient policy that guarantees a nearly optimal liveness-enforcing supervisor.