Deadlock Recovery for Flexible Manufacturing Systems with Exhaustive Exploration of the Reachability Graph

In the article a novel deadlock recovery policy for flexible m a nufacturing s y stems, m o delled b y t h e P e tri n e ts, is proposed. Deadlocks in manufacturing systems are costly, as then the system gets stuck in one of its states and does not evolve. The proposed policy is based on full reachability graph analysis and considers the paths from deadlock markings to preceding legal markings. As a result, the system may recover from all deadlock markings and continue its operation, and - at the same time - the number of recovery transitions added to the basic Petri net is minimal and the existing state space is not modified. T h e i n troduced p o licy i s i l lustrated w i th s o me wellknown examples from the literature and confronted with the different approaches. The preliminary results indicate that the proposed deadlock recovery policy achieves good results in the respect of added recovery transitions.