A review of synthesis techniques for Petri nets with applications to automated manufacturing systems

Research results in both bottom-up and top-down synthesis techniques for Petri net modeling are reviewed. These methods can be adopted for representing parallel and distributed application environments such as automated manufacturing systems. Bottom-up techniques, consisting of the merging of places and sharing of simple elementary paths, have the advantage of ease of system description since the modeled subsystems usually have real-life correspondences. Nevertheless, with current bottom-up techniques, the synthesized system may not exhibit the same control properties as the subsystems. Top-down methods, including refinement of transitions and refinement of places, have the advantage of viewing the system globally, which may generate more structured designs. However, it is difficult to apply these methods to the environments with highly shared resources. Examples in the context of automated manufacturing systems are given to demonstrate application of these techniques. Petri net reduction techniques and their relationship to synthesis methods are discussed