Study of fault diagnosis approach based on rules of deep knowledge representation of signed directed graph

The fault diagnosis method using a signed directed graph (SDG) based on qualitative model as a model of the system is useful to real-time diagnosis of failures that occur in process. First, it establishes the SDG of the systems and components, simplifies these SDG corresponding to the fault modes needing to be diagnosed, at the same time SDG are described the many rules forms for shortening the calculating time of making use of SDG, then expands the diagnosing rule with expert knowledge to construct the diagnosing rule bank of the system. Second, the fault modes can be primary diagnosed by using the constructed rules. And then the modes that can not be distinguished are diagnosed by adding adequate quantitative information. The case studies show that the problem of misoperation autodiagnosis during computer simulation training can be solved effectively, and the SDG diagnosis method has good completeness, fine resolution and detailed explanation in actual industrial process