Study On Large-scale Rotary Machinery Intelligent Diagnosis Multi-Agent System

Large rotating machinery are extensively used in key equipments such as steam turbine generator set, hydraulic generator set, turbojet engine, compressor, fan, water pump and so on. In order to ensure the equipments working safely, it is of urgent demand to build large rotating machinery intelligent diagnosis system.With the large rotating machinery in industries development oriented to be distributing, open, complicate and intensive, multi-algorithm'dynamic fusion'intelligent diagnosis with distributing intelligence and self-adjusting function is the urgent problem to be solved in theoretical research and engineering application.Multi-Agent System, abbreviated to MAS, as a branch of distributed artificial intelligence, will divide the problem domain into multiple autonomous or half-autonomous Agents. These Agents interact, negotiate and collaborate with environment around, human and individuals, which will perform the collectivity intelligence for solving the complicted problems. So Multi-Agent System is well applied in areas such as robot intelligent decision-making, web search engine and so on.The work in this thesis was supported by National Science & Technology Development Program'Plant fault internet-based intelligent diagnosis system'and relative horizontal projects. Based on the basic theory of Multi-Agent System and the characteristics of large rotating machinery, the knowledge system of large rotating machinery, Multi-Agent System general design, single Agent, Multi-Agent System model and policy were studied, large rotating machinery intelligence diagnosis Multi-Agent System with strong applicability were built and then was examined primarily in some relative engineering projects.Main research objectives in this thesis are listed as follows:(1) Study on knowledge system of large rotating machinery intelligent diagnosis. Based on investigations of many relative large companies, ISO 18436 International Standard and characteristics of large rotating machinery intelligent diagnosis, the concept and research methods of knowledge system in Education were introduced into large rotating machinery intelligent diagnosis system for the first time. The structure, contents and system implementation method were systemically studied. Using Authorware software as the platform, a new style, systemic, open and modular knowledge system and software of large rotating machinery intelligent diagnosis were built in this thesis.(2) General design of large rotating machinery intelligent diagnosis Multi-Agent System. Based on the knowledge system of large rotating machinery intelligent diagnosis, task decomposition method of large rotating machinery intelligent diagnosis system was studied. The structure of Multi-Agent System and single Agent model were built at the same time. In the process of designing the structure of Multi-Agent system, the components, the function of each part and system working mechanism of Multi-Agent System were studied. Large rotating machinery intelligent diagnosis Multi-Agent System was built, which completed the diagnosis task by'dynamic fusion'which is the result of coordination multiple function Agents negotiation with principal Agent. During designing the single Agent model, based on the traditional BDI model, introducing the mental model which is based on interest index and confidence index to the thinker model was first proposed. The two layer single Agent structure composed of thinker and behavior was built and the function and the structure was analysed.(3) Study on large rotating machinery intelligent diagnosis single Agent. Based on the BDI model, the thinking state specific structure and behavior flow of single Agent were proposed. The affecting factors of mentation in single Agent mental were studied. The confidence index algorithm based on two dimensional fuzzy membership grade and the interest index algorithm based on CBR were built, which made the single Agent simulate the human expert in the process of solving diagnosis problem and autonomously select the appropriate diagnosis action and complete the diagnosis by the specific task.(4) Study on the Multi-Agent System model and policy of large rotating machinery intelligent diagnosis. The specific structure and relative althorithm of the negotiation policy, diagnosis flow, communication protocol, the tingker of principal Agent in Multi-Agent System were studied. The communication mode which integrates the partitioned blackboard and information transporting mode, and the communication protocol of shared ontology were proposed, which make the Multi-Agent System simulate the collectivity diagnosis mode of human expert so that interaction, negotiation and collaboration to solve the diagnosis problems were realized.(5) Study on application of large rotating machinery intelligent diagnosis Multi-Agent System. Based on the current network of one large steel industry, for the two stream turbine fan set, from the views of the structure design, diagnosis policy of the system and software developing and so on, the on-line diagnosis system of stream turbine fan set which based on large rotating machinery intelligent diagnosis multi-Agent system was built. Finally, the feasibility and validity of the large rotating machinery Multi-Agent System were primarily examined.