Constraint programming with object-oriented Petri nets

This paper presents an object-oriented Petri net model with aspects of a constraint programming language, and describes a software implementation of this model. The ability of individual steps in a high-level Petri net model to represent the solutions to constraint satisfaction problems is well known, however practical techniques for the efficient evaluation of transition bindings are essential if Petri nets are to be used for the analysis, simulation and even direct control of complex industrial systems. A constraint model for binding evaluation is presented and it is shown how AI search techniques can be applied to reduce the search problem. The use of constraints within Petri nets is then extended to the object-oriented model. The use of Petri nets allows a declarative specification style and well defined analysis techniques for constraint programming, while the software tool produces fast executable code representations.