Optimal Polynomial Complexity Deadlock Avoidance Policies for Manufacturing Systems with Flexible Routings

This paper addresses the deadlock avoidance problems in automated manufacturing systems with flexible routings. A deadlock in the systems is characterized as a saturated perfect resource-transition circuit in the system Petri net models. For a large subclass of automated manufacturing systems with flexible routings and without center resources, the optimal deadlock avoidance policies with real-time polynomial complexity are obtained. Then, with a result on the design of optimal deadlock avoidance policies for automated manufacturing systems, a method for synthesizing a suboptimal polynomial time complexity deadlock avoidance policy for general automated manufacturing systems is presented.