One computationally improved deadlock prevention policy for flexible manufacturing systems using Petri nets

Petri nets have been recognized as one of the most powerful tools for modeling flexible manufacturing systems (FMSs). Deadlock prevention policies are used to solve the deadlock problems of FMSs. It is well known that theory of regions is the efficient method for obtaining maximally permissive controllers. All legal and live maximal behavior of Petri net models can be preserved by using marking/transition-separation instances (MTSIs) or event-state-separation-problem (ESSP) methods. However, computing all sets of inequalities are an extremely time consuming problem due to the reachability graph of the deadlocked system. In our previous works, we proposed CMTSI method to improve the computational cost. In this paper, the selective siphon method is merged in our new deadlock prevention policy. The merit of the proposed policy is that the number of two types CMTSIs can then be simplified. Experimental results indicate that it is the most efficient policy to obtain maximal permissive behavior of Petri net models.