Hydraulic Excavators Condition Monitoring And Fault Diagnosis System

Condition monitoring and fault diagnosis is one of key technologys of excavators' mechatronics.It can complete realtime monitoring of excavators' working condition,shorten off time for fault diagnosis and improve economy benefit of excavator.This paper found the structure of hydraulic excavator's condition monitoring and failure diagnosis system at first.That is a system composed of hypogynous SCM realizing on-line condition monitoring and epigynous PC realizing off-line failure diagnosis.Then the function and testing principle of hypogynous system is analyzed.The design of system hardware circuit and software formality are introduced.The characteristic of librating signal of engine's jar cover in frequent field is analyzed.The librating diagnosis mechanism to leaking gas fault of engine valve is investigated,and the distilling method of chatacter parameter Eh/Ew which is ratio of high frequency energy to chief energy is introduced. The librating diagnosis mechanism to clearance abnormity fault of engine valve is investigated,and the distilling method of chatacter parameter Eh which is high frequency energy is introduced.On the basis of analyzing and comparing to different methods of excavator's fault diagnosis, FDES of hydraulic excavator's condition monitoring and fault diagnosis system is founded.KA's method is introduced,including summarizing to experts' experiential knowledge and KA baesd on ANN technology.And a BP network of three lays is founded,which complete the function of abtaining knowledge from samples.Then the consequent mechanism of system is investigated.Consequent a method based on incertitude knowledge is brought forward.The choices of probability modulus,fuzzy modulus and difficult modulus are discussed.Finally condition monitoring system is investigated by experiment,results indicate that the method using SCM to test and memory working parameter datas of hydraulic excavators is feasible.The emphases of paper is investigating amalgamation of ANN and expert system fault diagnosis technology,as well as disposal technology toincertitude knowledge.The paper emphasizes self-adapted ability and self-study ability of system.It provides theoretics basic and new thought for the diagnosis and orientation after the event to hydraulic excavator's faults.