Abstract: Mechanical domain knowledge base is a central component of the domain diagnosis expert system, so its abnormity, such as redundancy, and conflict, can affect the reasoning result. The mechanical knowledge is taken as backgrounds, and the Petri net technology is introduced for the knowledge analysis and verification. The methods modeling the knowledge base with the colored Petri net are presented, which include the save of the facts, the control of using the same rules and so on. Based on the colored Petri net, the methods are presented for detecting the abnormity of the mechanical domain knowledge base.

Key words: Colored Petri net, Expert system, Mechanical exception, Model, Petri net, Verification