A Modeling Strategy of Shop-Floor Interlocking and Controlling using Virtual Petri Nets and Production Simulation

The modeling of factories shop-floors has been studied to cope with the interlocking and control problems. Petri Nets have been applied to model these systems because they provide graphical resources to represent the system behavior. When the system is too large or complex, the modeling task is difficult and the elements in the model are too many for a simple understanding and analyzing task. Moreover, some important characteristics, like time, when considered can contribute for a difficult understanding. This work proposes an approach for modeling these systems in order to minimize the difficulties mentioned. The proposed approach uses Petri nets (PN) and some PN extensions with simulation as a way of analyzing. These extensions are colored PN, modular PN, timed PN and virtual PN (VPN). The system modeled by this approach is an experimental flexible manufacturing transfer line (FMTL) that consists of three machines and a conveyor. There are five types of products that can be produced. The whole production is controlled by a supervisory system.