【作者】 张吉志；

【导师】 刘振娟；

【作者基本信息】 北京化工大学 ， 控制理论与控制工程， 2008， 硕士

【摘要】 故障诊断技术大致分为基于模型的方法和基于历史的方法,其中符号有向图SDG模型是一种深层知识模型,能够揭示复杂系统的变量间内在因果关系及影响,是定性仿真的一个重要分支,是一种重要的故障诊断方法。本文在总结前人有关SDG故障诊断研究的基础上,对基于SDG的故障诊断方法进行了系统而深入的研究,着重研究了SDG建模和推理机制,对复杂系统SDG故障传播规律进行了详细的研究,发展并完善了基于图论的故障诊断方法。为了克服SDG模型的固有缺陷,提高诊断分辨率和诊断速度,阐述了将SDG方法和专家系统方法相结合的思想,对基于SDG的故障诊断专家系统进行了详细研究,摒弃了传统由SDG模型推导产生式规则的浅层知识库设计方法,提出直接以SDG图模型深层知识作为所开发专家系统的深层知识库,同时将专家的知识和经验作为浅层知识库。最后对该专家系统的推理机算法进行了详细研究并且给出算法。本文的SDGExpert专家系统是基于Visual Prolog语言实现的,SDGExpert专家系统采用了用户层、中间层、存储层的三层架构设计,完全应用了面向对象程序设计方法,应用了良好的软件设计模式,不仅实现了专家系统应有的功能,还最大程度的实现了SDGExpert专家系统的可复用和可扩展性,以应付以后的进一步开发。文章最后在多功能仿真平台的液位离心泵仿真系统进行了SDGExpert专家系统案例仿真。结果证明该SDGExpert能够发现系统的故障根源,而且软件的友好的用户界面可以直观的对故障模式进行观察。更多还原

【Abstract】 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.更多还原