Unified Model for Synthesis and Optimization of Discrete Event and Hybrid Systems

A recently proposed generic discrete event model is further developed and exemplified in this paper. Since every transition is expressed as a predicate on the current and next values of a set of variables, the model is called Predicate Transition Model (PTM). It is briefly illustrated how a number of well known discrete-event models, including automata and Petri nets extended with shared variables, can be formulated and synthesized in the PTM framework. More specifically modular Petri nets with shared variables (PNSVs) are shown to be significantly more readable compared to ordinary Petri nets. PTMs are also naturally extended to hybrid systems, and finally it is shown how easy and efficiently PNSVs can be optimized concerning performance based on Constraint Programming. To summarize, the proposed modeling framework unifies and simplifies both synthesis, optimization and implementation of discrete event systems.