Synthesis of Place Transition Nets for Simulation and Control of Manufacturing Systems

Abstract This paper presents a methodology for constructing a class of place/transition nets for modeling, simulation and control of discrete manufacturing processes. We consider batch production processes which can be decomposed into a set of discrete operations. For each operation, required resources and associated discrete resource states are identified. To model the discrete-event evolution of the system we define a class of modified Petri nets and present a procedure for synthesizing the net model from simple activity cycles for each resource. New results in Petri net theory are presented which guarantee the absence of system deadlocks and proper resource allocation for the MPN models. Synthesis of the net constitutes a design of viable discrete contro logic including error recovery loops and other real-time decision structures. As an example, the proposed methodology is applied to the high-level discrete control of a two-arm robotic assembly cell.