Deadlock Resolution in Networked Automated Manufacturing Systems With Communication Delays and Losses Using Petri Nets

This study tackles the issue of deadlock resolution in networked automated manufacturing systems (AMSs) with communication delays and losses in the framework of Petri nets (PNs). First, we refer to the transitions in which communication losses may occur as loss transitions and mathematically model the communication delays and losses. Second, we derive a necessary and sufficient condition for determining whether deadlock can be resolved in networked PNs, referred to as the networked deadlock resolution controllability theorem (NDRCT), within the framework of the observed reachability graph (ORG). Through the ORG, the networked supervisor can intuitively obtain the estimated marking set for a specific observation in the presence of communication delays and losses. Based on NDRCT, one can determine whether deadlock can be resolved and how to design the controller to avoid deadlock in networked PNs with communication delays and losses.