Design Of Simple Supervisors For Resource Allocation System Based On Generalized Mutual Exclusion Constraints

The competition for limited resources can produce deadlocks in flexible manufacturing systems (FMS). Petri nets are an effective tool to model, analyze, and control deadlocks in FMS. A variety of important Petri net-based methods to prevent deadlocks arising in FMS are to add some control places and related arcs to strict minimal siphons (SMS) such that no siphon can be emptied. But once the net's model becomes large, it is very time-consuming to calculate all the SMS, and the resulting net supervisor will be more complex than the original one.Some researchers have proposed some different deadlock avoidance policies. Resource upstream neighborhood (RUN) control policy provides a very useful method. It avoids solving all the siphons, strict minimal siphons and the mixed integer program (MIP), and facilitates our work in deadlock avoidance. This policy can be used not only in ordinary nets, but also in the general ones, so it has more widespreard application value. But sometimes this method need add some redundant control places, and makes the result net system more complex. In this thesis, a simplification of this method is introduced, and analytical formulations and efficient solution algorithms are developed for the case that the FMS is structurally controlled by a class of simplified control places.