A deadlock prevention policy for flexible manufacturing systems using siphons

We present a new deadlock prevention algorithm for a class Petri nets. A new class of net that is extended from S³PR, called ES³PR, where deadlocks are related to unmarked siphons. This method is an iterative approach by adding two kinds of control places, called the ordinary control place and weighted control place, to the original model to prevent siphons from being unmarked. We obtained the relation of the algorithm, liveness and reversibility of the controlled net. Finally, a flexible manufacturing example is presented for illustrating the method.