Parameterized ACD Modeling of Flexible Manufacturing Systems

Activity cycle diagram (ACD), which is essentially a timed Petri net, is one of the oldest formal modeling tools for discrete-event systems, and a flexible manufacturing system (FMS) is a highly automated job shop that is used widely in mechanical and electronics industries. Previous FMS modeling studies have indicated that formal modeling of real-life (or industrial) FMSs with classical ACDs (or Petri nets) is almost impossible. This paper presents an incremental modeling procedure for building a formal simulation model of a real-life FMS with parameterized ACD (P-ACD) that was proposed recently. The incremental modeling procedure consists of job flow modeling, job routing modeling, dispatching rule modeling, and refixture operation modeling. In this paper, a P-ACD model of a real-life FMS was constructed and an FMS simulator was implemented from the proposed P-ACD model. A simulation experiment was conducted in order to demonstrate the usefulness of the FMS simulator.