PUSH AND PULL RULES FOR DISPATCHING AUTOMATED GUIDED VEHICLES IN A FLEXIBLE MANUFACTURING SYSTEM

Automated guided vehicle (AGV) systems are widely used in flexible manufacturing systems (FMSs) for material handling purposes. Although the AGV systems have provided high flexibility, the design issues on AGV dispatching rules are still to be resolved. The AGV-dispatching rules in an FMS are generally based either on a push or a pull concept. A Petri-net-based simulation was used to investigate the effect of different dispatching rules on the FMS performance. The developed simulation model consists of two modules: a Petri net model and an AGV dispatcher. The two modules are integrated so that the AGV dispatcher controls AGV tokens in the Petri net model. It was shown that there was no significant difference in output rate between push- and pull-based AGV-dispatching rules for a busy FMS.