Hybrid modeling and simulation of manufacturing systems

In this paper, a new methodology for modeling and simulation of hybrid manufacturing systems is presented. This methodology which is based on an extension of Petri nets can be used to model, simulate and analyze systems with both time and event-driven parts. This new extension is called GPN (global Petri net). Here we show how it is used to model a jobshop at two abstraction levels. At the higher level the jobshop is modeled as a discrete-event system by a conventional PN. When more details about its behavior is required, we have modeled it as a hybrid system by a GPN. The modeling approach is very general and can be used for any type of hybrid systems. A simulation package developed based on the GPN modeling methodology is used for the simulation of the resulting nets. Various hybrid system properties such as boundedness stability, controllability and liveness can be investigated by the analysis methods developed for GPNs.