Study Of System Of Engineering Machinery's Parameters On-line Monitoring And Fault-diagnosing Based On Technology Of WiFi And Virtual Instruments

After decades of development of the monitoring and fault diagnosis technology of construction machinery,the functions of vehicle monitoring and fault diagnosis has been achieved.However,it is limited by the factors such as complicated operation and strong specialization.The parameter monitoring and fault diagnosis of traditional construction machinery in China is mostly based on instrument inspection and manual failure maintenance.There is still a gap relative to foreign countries in performance of flexibility and accuracy.Based on WiFi and virtual instrument,the design of parameter monitoring and fault diagnosis system for construction machinery is proposed.It can carry out online parameter monitoring and fault diagnosis under the condition of excavator without stopping.It is of great significance to improve the mechanical efficiency,shorten the time of failure and ensure the construction progress.This paper takes Carter 320 C excavator as an object and puts forward the overall design plan of parameter monitoring and fault diagnosis.The structure,working principle and failure mechanism of excavator cooling system,electrical system,hydraulic system and rotational speed system are analyzed.Fault eigenvalue parameters are extracted and the fault solution is given.The working principle of engine cylinder head and valve mechanism is analyzed.Based on the principle of vibration signal analysis of EEMD(Ensemble Empirical Mode Decomposition),the extraction method of valve fault feature is studied by way of vibration signal of engine cylinder head.Using SVM(Support Vector Machine)discriminant mode,the fault diagnosis of engine valve mechanism is carried out.The hardware system is designed and the related components are selected.The sensor interface and signal conditioning printed circuit board is designed by Protel99 se software,which ensures the normal signal transmission.Taking Labview software as the man-machine dialogue platform,the system parameter monitoring and fault diagnosis of excavator is designed.The program block diagram,using computer and virtual instrument combination,is given.The signal data processing and analysis function parameter monitoring and fault diagnosis of excavator is accomplished.Each parameter sensor,data collector(NI CDAQ-91844)and WiFi wireless transmission device(AWK-3121)are integrated and installed on the excavator.In the place covered by WiFi at the construction site,the monitors run the corresponding software through the notebook computer.The functions of parameter monitoring,fault diagnosis,state alarm,data storage and report generation can be realized for several excavators without stopping.The experimental system is built,and the experiment,debugging and optimization are carried out in the laboratory,and the prototype is made.Relevant experiments on pickup trucks are carried out,and the experimental result of Carter 320 C excavator show that the system is reliable,simple to operate,easy to diagnose,and effective,which can be applied to construction machinery with broad market prospects.