【作者】 胡巧利；

【导师】 谷立臣；

【作者基本信息】 长安大学 ， 机械电子工程， 2008， 硕士

【摘要】 随着液压技术在各个领域的广泛应用,用户对液压系统的稳定性和可靠性的要求越来越高,若液压系统在运行过程中一旦发生意外故障,不能及时诊断维修将会给用户造成重大经济损失。传统的测试方法和故障诊断方法需要花费大量的人力和财力,而基于虚拟仪器的智能诊断方法由于利用领域专家丰富的经验和知识,在液压系统的故障诊断中充分显示出其优越性。本文首先介绍了虚拟仪器技术、专家系统和故障树分析法等技术,并阐述了各项技术在机械故障诊断中的应用现状;针对液压动力系统故障诊断的特殊性,提出了基于虚拟仪器的故障诊断专家系统的设计方案。根据液压动力系统对信号采集的特殊需求,选择了基于数据采集卡的硬件和LabVIEW软件作为液压动力系统虚拟仪器开发平台。该平台可以方便地采集液压动力系统的流量、压力、温度、电压、电流等多路动态信号,可以利用虚拟仪器开发平台在信号滤波、时域和频域分析方面的强大功能实现液压动力系统多源诊断信息的获取。本文主要研究了液压动力系统故障形成机理及其故障树的建立,在此基础上提出了基于故障树的液压动力系统故障诊断专家系统;利用故障树生成专家系统知识库后,实现了诊断知识的获取并确保了知识的一致性和完备性;最后利用C语言、Access、LabVIEW来实现专家系统的程序设计。更多还原

【Abstract】 With the wide application of hydraulic technology in various fields,users have increasingly high demands on stability and reliability of hydraulic systems.Once unexpected faults occurred in running of the hydraulic system and the system can not diagnose and repair in time,it will bring great economic losses to users.The traditional testing and fault diagnosis methods usually spend a lot of human and financial resources.The intelligent diagnostic methods which based on virtual instrument using a wealth of experience and knowledge of the experts demonstrate its superiority in the hydraulic system fault diagnosis.This paper introduced the virtual instrument technology, expert system ,and fault tree analysis techniques firstly,and the current statement of application in mechanical fault diagnosis has been described.According to the particularity of the hydraulic power system,the design of fault diagnosis expert system which based on virtual instrument is presented.According to the special requirements of signal acquisition from hydraulic power system,the hardware which based on the date acquisition card and the LabVIEW are selected as a development platform of virtual instrument of hydraulic power system .The platform can conveniently collect multi-channel dynamic signals,such as the flow,pressure,temperature,voltage and electric current.The virtual instrument development platform can be used in the signal filtering,time and frequency domain analysis in order to achieve the multi-source information of hydraulic power system.On the basis of the mechanism of fault and the establishment of the fault tree of hydraulic power system, generated expert system knowledge system by using fault tree,to achieve accessing to and to ensure the consistency and completeness of the diagnosis knowledge.The expert system is built using C language,Access and LabVIEW finally.更多还原