Automatic Petri net simulation model generation for a continuous flow transfer line with unreliable machines

Abstract

A production line is studied with several machines in series. The machines are separated with finite buffers. They can break down and have to be repaired. Production is assumed to be continuous, i.e. no individual products can be identified. Analytical models for the performance evaluation of such a system are scarce. Analytical results for the throughput can be obtained only under very restrictive assumptions. The performance study of longer transfer lines requires either approximation or simulation. A Petri net model is developed for an n-machine (n - 1)-buffer system. The rules to design the Petri net transitions are given. The automatic generation of a discrete-event simulation model from the Petri net model is explained. Finally, some potential applications of the Petri net are illustrated. These applications include the simulation of transfer lines with complex stochastic behaviour, the optimization of buffer size and allocation and the evaluation of approximation models for long transfer lines. Using the simulation model described in this paper, quality and reliability engineers can simulate the performance of a given continuous flow transfer line and evaluate the effect of performance-increasing measures such as the insertion of extra buffer space or the use of more reliable machines. Copyright (C) 2004 John Wiley Sons, Ltd.