Virtual Petri nets as a modular modeling method for planning and control tasks of FMS

The modelling of automated manufacturing systems has been explored to offer solutions to production planning and control problems. Petri nets (PN) have used to model these systems because they provide resources for the representation of systems behaviour. When the systems are too large or complex, the modelling task becomes difficult and the elements in the model are too numerous for a simple understanding and analysis. This paper proposes a method of modelling these systems that minimizes the difficulties mentioned. The proposed method introduces the virtual Petri net (VPN) and a modular strategy considering the shared resources and the alternative process planning. Using this method, a system has been modelled, initially considering the systems elements necessary to the model the task, and then a modular linking method can be used in order to build the complete model.