Resource-Oriented Petri Net-Based Approach to Deadlock Prevention of AMSs

Based on the systems of simple sequential processes with resources (S3PR) model, the existing methods involve prohibitive computation to synthesize a deadlock prevention controller for automated manufacturing systems (AMS). To reduce the computation, this work studies this problem by using a resource-oriented Petri net (ROPN) model. By revealing the relationship between bad markings and structural properties of an ROPN, it presents a method such that a deadlock prevention controller can be obtained by simple calculation. By such a controller, for each strongly connected subnet in an ROPN, only one control place is needed such that it is structurally very simple. Furthermore, a condition is given under which a maximally permissive controller can be efficiently obtained, which was never seen before. Examples are used to show the application and performance of the proposed method.