.120-1 Air Brake Fault Diagnosis Expert System

120-1 air-brake is the core technology of the70-ton trucks under heavy vehicle braking, In order to protect the he safe operation of the new heavy goods vehicles, It must be equipped with sophisticated, intelligent and ef-ficient testing of the integrated test system.The reliability indicators of the 120-1 air-brake is the whole railway system to the safety, reliability, and bring huge economic impact, and the fault diagnosis is to ensure the elia-bility of an important part of the traditional ,But now fault diagnosis has been unable to meet the needing. This article researches and designes the key technology of the 120-1 air-brake system fault diagnosis expert in the construction.This article analysises 120-1 air brake's structure and the mechanism of operation first, summes up the fault reasons and types of equipment failure, according to experts and equipment maintenance experience, fault diagnosis and maintenance of equipment recommendations, with the fault tree analysis methods to design fault Diagnostic mode. According to the analysis of the system's mission and design requirements, Designes and plannes the overall structure and function modules of the 120-1 air brake fault diagnosis expertsystem,and gives the system workflow description.Following according to the three important aspects of the knowledge pr-ocessing, first of all, by means of knowledge's classification,with the model designed by the fault tree,summes up the knowledge acquisition of thepresent system; To ensure the availability and effectiveness of the knowledge base, According to the system of its characteristics, analyzes knowledge way of the system, uses the knowledge way of "production rules + object-oriented fra-mework ", and uses database to describe the kn-owledge base.Then this paper describes the expert system's forward, reverse and two-way structure of the reasoning and analysis and comparison of the depth and width of priority search priority search of two search strategy, the system ins-pired by the reasoning, imprecise reasoning, reasoning and interpretation are Reverse reasoning approach in the search strategy on the choice of depth-first search methods.When constructions the reasoning system,this system applies JESS technology, the inference engine development tools makes it reliable and sound, makes the process simple and clear.Against 120-1air brake system fault diagnosis expert's uncer-tainty in the reasoning, uses the credibility met-hod to deal with them.Finally in accordance with the life cycle of the systems design and dev-elops a Web-based fault diagnosis system, In this paper, the structure of the system is in compliance with the structural framework proposed, and uses the JSP + Servlet + JavaBean components of Web applications, embed JavaBean JESS JESS in the manner of integration with Java. Through the system to achieve the key technology and systems analysis of the normal operation of the system verify the validity and accuracy of diagnosis.