Research On Expert System To Fault Diagnosis Of Hydraulic Power System Based On Virtual Instrument

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.