A transformation theory for Petri nets and their applications to manufacturing automation

Design methods for automated manufacturing systems are investigated using Petri net theory. The methods presented in this thesis are based on the analysis of interactions between sub-systems. Four types of the interactions are identified: (1) common Transition-Transition-Path, (2) common Place-Place-Path, (3) common place (resource sharing), and (4) common transitions.;Transformation methods for generalized Petri nets are presented by introducing and using the concept of a live and bounded circuit (LB-circuit). The concepts of an arc ratio and a remainder are introduced. Also, a partially overlapping relation between two common paths is introduced. Using these concepts, it is shown that LB-circuits can be fused into a live and bounded net while preserving liveness and boundedness. Also, two live and bounded nets can be fused by a DEP;Synthesis methods for colored Petri nets are presented. The synthesized net guarantees the liveness and boundedness. Some restrictions for incidence functions and color sets are given. All synthesis lemmas and theorems for synthesizing generalized Petri nets are extended for colored Petri nets. A complex colored Petri net can be constructed using the methods.;Some interactions between sub-systems in manufacturing environments cannot be described by common paths. The interactions described by common transitions and a special case of a common place (resource sharing) are studied using the deviation bound and the shared resource net (SRN). A weighted deviation bound is introduced to solve the shared resource problems in generalized Petri nets. It is proven that the combined net of an SRN and LB-circuits is live and bounded. It is shown that an LB-circuit can be fused into the combined net composed of an SRN and LB-circuits while maintaining liveness and boundedness if the given conditions are satisfied. The initial conditions for liveness and boundedness can be found using the theorem presented in this thesis.;Colored Petri net models of information flows in a CIM system are presented. Three important sub-systems of CIM are considered, which are an MRP, a Process Planning, and a Shop Floor Control system. The required functionality of each sub-system is modeled using IDEF0. From these IDEF0 models, colored Petri net models are designed for analysis and control of information flows in a CIM system.;All synthesis methods presented in this thesis are illustrated by Petri net models for manufacturing automation.