An object-oriented methodology for the design of control software for flexible manufacturing systems

We describe here a systematic method for the design and modeling of flexible manufacturing systems, using object-oriented concepts and Petri nets. We first define the system components in terms of an object model consisting of hierarchical sets of classes and associations. Then, we model the dynamic aspects of the system using statecharts, including exceptions and abnormal behavior. As a third step, we derive Petri nets from those statecharts to realize the concurrency present in the system. Finally we develop a hierarchy of controllers, corresponding to the layers of the object model, for the independent components of the system based on the Petri nets obtained in the previous step. The approach is systematic and relatively easy to apply. It is illustrated through a realistic example