SIMULATION STUDY OF FLEXIBLE MANUFACTURING CELL BASED ON TOKEN-ORIENTED PETRI NET MODEL

An initial manufacturing plan may not consider the particular implementation of flexible manufacturing cells (FMCs). Therefore, the FMC is subject to modelling and simulation to evaluate and correct the production plan using feedback. In the case of highly shared resource contention, deadlock and blocking present an inevitable, unavoidable problem, and corrections may be required for production plans. However, by using existing Petri net model theories and certain simulation software for model establishment, the structure and scale of the model may vary with changes in the parts, machines, and robots. This results in a cumbersome and complicated model building process. To address this practical problem, a token-oriented Petri net model theory is therefore proposed. The movable directions of a token are detected to determine if the firing conditions are satisfied. To avoid deadlock, the token first predicts the status of resource utilization prior to decision-making when entering the transporting-transition state. Accordingly, during the model run, events are triggered against the expected time, and transitions are thereby enabled and fired. An improved machine processing plan and robotic transporting plan may be obtained via path scenario deduction. In this study, classic case data were processed for simulation analysis of the manufacturing job, which verified the validity of the model algorithm.