An efficient deadlock prevention policy for FMSs using reduction method and theory of regions

Petri nets have been recognized as one of the most powerful tools for modeling FMSs. The reason is that PNs are suited well to represent FMS characteristics such as present relations, concurrence, conflict and synchronization. On the other hand, it is well known that the marking/transition-separation instances (MTSIs) method with the theory of regions has been recognized as the best (i.e. maximally permissive) policy in deadlock problems. However, its major shortcoming is the state explosion and redundant inequalities problem since the reachability graph of a plant model has to be generated when one wants to find all MTSIs. For improving these drawbacks, this paper uses the reduction method and proposes a novel concept of the crucial marking/transition-separation instances (CMTSI) which is the key of MTSIs based on Petri nets and the theory of regions. According to our experimental results, our deadlock prevention policy is more efficient in existing literatures based on the theory of regions.