Behavior relations in synthesis process of Petri net models

System synthesis is one of the most important issues in automatic control. In a synthesis process, local system properties must be preserved in the gl obal system. Most of the previous researches focuses on such properties as liveness, reachability, reversibility, and so forth. However, little has be en done on system behaviors, that is, the language of firing sequences. In this paper, we study the behavior of systems using the Petri net model synt hesis, with self-loop inhibitor, as well as synchronization operations. A n ew system behavior property, behavior invariance, is defined. Self-loop and inhibitor operations are transformed into synchronization operations, unde r which a set of preservation conditions for behavior invariance are obtain ed. The theoretical foundation for the preservation of system behavior prop erties is presented and proved, and the applicability of the theory to real -world automation systems demonstrated. An example for modeling a super-ele vated conveyor is discussed, illustrating the usefulness of the proposed th eory in modeling and analyzing the behavior invariance of such a conveyor.