A deadlock control policy for a subclass of Petri nets G–system

Since deadlock problems in flexible manufacturing systems(FMSs) modeled with Petri nets are closely related to the siphons in Petri nets, how to accurately and quickly solve such problems is important for designing the control policies for siphon-based controllable deadlock. This paper proposes an iterative deadlock control policy to solve and control smart siphons(SSs) in a subclass of Petri nets, i.e., G–system. Comparing with the existing partial siphon enumeration methods for solving the siphons associated with deadlocks, the proposed method avoids the process of finding the maximal deadly marked siphons in the Petri net and then extracting from which the minimal siphons, thus improving the solution efficiency. Meanwhile, by adding the proper control places(CPs) to make the obtained smart siphons max0-controlled, we further increase the number of permissive behaviors of the corresponding live controlled Petri net system with liveness. Theoretical analysis and examples validate the efficiency of the proposed policy.