An algorithm of deadlock prevention for flexible manufacturing systems

This paper present a new class of Petri nets called extended S³PR (ES³PR) for modeling manufacturing systems where only parts can interact with resources, and resources alone cannot interactive with one another. ES³PR properly includes S³PR, augmented marked graphs and sub-classes of RCN merged nets where firing a transition may only generate parallel process for parts. As a result, ES³PR can model far more complex manufacturing process flows and resource sharing than these nets. In this paper, we also present an algorithm of deadlock prevention for the class Petri nets. This method is an iterative approach by adding two kinds of control places called ordinary control place and weighted control place to the original model to prevent siphons from being unmarked. We have obtained the relation of the algorithm and the liveness and reversibility of the controlled net. Finally, a flexible manufacturing example is presented for illustrating the method.