气门磨损失效分析专家系统知识库的构建与推理研究

The Constructing of a Knowledge Base of Expert System for Wearing Failure Analysis of Valve in Engine and its Reasoning Study

在讨论气门磨损失效形式和影响因素的基础上,建立了发动机气门磨损失效分析专家系统的知识库,提出了气门磨损失效分析专家系统的知识库结构———树状结构、知识获取与表示方法,给出了采用数据库技术构造的知识库体系与推理机制。在气门磨损失效分析专家系统中,要提高产生式系统的可理解性,应当通过对规则的适当划分,将规则组织成易于管理的功能模块。将故障树分析法和基于产生式规则的失效诊断专家系统有机地结合起来,能很好的解决基于产生式规则的专家系统最突出的弱点,即知识获取难的问题。为了更快、更准寻找到气门磨损失效的影响因素,采用最好优先搜索法。

Based on discussing the wearing failure form of valve and the influence factors, the knowledge base of expert system for wearing failure analysis of valve in engine was established. The structure of knowledge base of expert system for wearing failure analysis of valve was put forward, including tree-structure, knowledge acquisition and representation method, the technology of date base was adopted to build the knowledge base system and reasoning mechanism in the expert system for wearing failure analysis of valve. The tactics of best-first search was used to quickly and precisely search influence factors of wearing failure of valve. In order to raise the comprehension of production system, rules should be properly divided and be organized to function model which is easily managed. Fault tree-analysis is combined with expert system for fault diagnosis based on production rules, which can well solve the prominent deficiency which is the problem of knowledge acquisition of expert system based on production rules.