A MODULAR APPROACH FOR THE MODELING OF A CLASS OF ZONE-CONTROL CONVEYOR SYSTEM USING TIMED PETRI NETS

In this paper, modeling of a programmable-control conveyor system or a 'pallet handling system' is described. The concept of zone control is introduced as traffic control for this type of conveyor. Timed Petri net (TPN) modules are presented as basic building blocks to model and analyse operational performance of the system. This modular approach facilitates an easy model construction, and provides an easy way to create or revise TPN models. Moreover, P-invariants are used to analyse the logical properties of the TPN model, i.e. boundedness, conservativeness, and liveness. T-invariants are used to find all possible pallet routeings. Finally, straightforward application of the modular approach is demonstrated in a case study.