Track: Automation and Agility

Abstract

Various deadlock control policies for automated manufacturing systems with reliable and shared resources have been developed, based on Petri nets. In practical applications, a resource may be unreliable. Thus, the deadlock control policies proposed in previous studies are not applicable to such applications. The main disadvantage of the existing policies is that many control places, recoveries sub-nets, and associated arcs are added to the initially constructed Petri net model, which significantly increases the complexity of the supervisor of the Petri net model. Therefore, the aim of the paper is to propose a robust deadlock control strategy for systems with unreliable and shared resources. First, a live (deadlock-free) controlled system that does not consider the failure of resources is derived by using elementary siphon control. Second, all control places obtained in the first step are merged into a single control place based on the colored Petri net to mark all SMSs. Considering all resource failures, a common recovery subnet based on colored Petri nets is proposed for all resource failures in the Petri net model. The recovery subnet is added to the derived system at the second step to make the system reliable. Finally, the proposed method has been tested using an automated manufacturing system from the literature.