SDG Fault Diagnosis Expert System And Its Realization Based On Visual Prolog

The technology of fault diagnosis can be divided into the method based on model and the method based on process history. The SDG model is deep knowledge model, which can express the complex cause and effect relations, and has very large capacity of containing process potential information. The SDG based fault diagnosis method is one of important branch of qualitative simulation, as well as an important fault diagnosis method. Based on the past research of SDG, The thesis systematically and deeply studies the SDG method including the modelling method and reasoning mechanism of SDG, especially on the laws of fault propagation of complex system.To overcome the intrinsic defectiveness of SDG model and enhance the diagnosis resolution and speed, the thesis presents the method of combining the SDG method and expert system method. The thesis puts forward the method taking the SDG model directly as the deep knowledge base of the expert system, as well as expert knowledge and experience as shallow knowledge base. Finally the reasoning mechanism is studied and the algorithm is given. In this thesis the SDGExpert software is realized in Visual Prolog language. It employs the three-layer architechture including the user-interface-layer, middle-layer and memory-layer from top to bottom. The software completely applies the object-oriented programming method and nice software design patterns which not only realizes the basic function of the expert system, but also achieves the reusability and expansibility for further development.Finally, the diagnosis simulation of centrifuge pump system based on SDGExpert is carried out on the MPCE simulation platform. The result proved that the SDGExpert can find out the root fault with friendly user interface showing the fault.