A distributed approach to automated manufacturing systems with complex structures using Petri nets

One of the major challenges from both a theoretical and practical perspectives, for effectively establishing unattended operation of automated manufacturing systems (AMSs), is to resolve the deadlock. In the existing methods on deadlock problem, most of them are focused on the models with either flexible routes or assembly operations, whereas few method investigates them with both. Furthermore, applying these methods into large-scale systems is usually nontrivial, primarily because of the fact that they generally require the enumeration of all the states or siphons. The work presented in this paper proposes a Petri net-based model which can deal with both features and develops an innovative distributed strategy that provides an online and dynamic mechanism for deadlock resolution. Each step's execution depends on a search-based procedure that seeks to determine whether there exists a feasible event sequence bringing the currently-active process or sub-processes to the nearest global critical place when other processes stagnate. By taking our approach, system can benefit from minimal communication amount among different processes, better toleration to many contingencies like resource failure, and improved system performance like throughput.