Research On Transmission Case Of Machine Tool Condition Monitoring And Diagnosis System Using Virtual Instrument

With the rapid development of modern manufacturing, manufacturing equipment is developing towards large-scale, complication, automatization and integration. As a result, manufacturing systems in production technology become more and more complicated and they are more prone to failure in the course of operation. Hence, equipment condition monitoring and fault diagnosis are often employed in maintenance to prevent operational failure of services and the fatal breakdown of manufacturing equipment. Vibration-based machine condition monitoring is popular in industry, particularly in manufacturing and public utilities. Conventional machine condition monitoring systems always require the use of expensive hardware type instrumentation to perform signal analysis and fault diagnosis. With help from PCs, software type virtual instruments (VIs) can be created to perform tasks similar to those undertaken by the expensive hardware type instruments. Obviously, the cost of the VIs is lower than the hardware instruments. They are also more easily modified and are expandable in the future. Therefore, VIs have become popular in modern industries. In the research, mechanical equipments condition monitoring and diagnosis system is developed applied virtual instrument technology, and the system can carry on real-time monitoring and the fault symptom is discovered early.In this paper, research background, significance and worldwide development and present state were introduced firstly for equipments condition monitoring, then the concept, characteristics and the development application of virtual instrument were expatiated and the virtual instrument system of mechanical equipments condition monitoring and diagnosis was researched and developed applied software LabVIEW that produced by NI corporation with the corresponding sensor, signal regulator and data acquisition card. The software system can control data acquisition, signal processing and display the result. The system interface was designed using the menu mode. When the system was needed to add the new function, only the content of new function was added in the main menu program, and then the program can be executed. The system was divided into certain independent function modules and each independent sub-â…¥was established to each function module. When the function module was needed to execute and realize, the corresponding sub-â…¥was transferred by the higher authorityâ…¥. The modularization programming thought was used in the software including data pretreatment module, time-domain analysis module, the frequency-domain analysis module and joint time-frequency analysis, in which the data pretreatment module is mainly signal filter processing; the time-domain analysis module include amplitude domain parameter analysis, the signal autocorrelation and cross correlation analysis; the frequency-domain analysis module include FFT, the power spectrum analysis, the cepstrum analysis and autoregressive analysis; and joint time-frequency analysis include Short Time Fourier Transform and wavelet analysis.The functions of the system were tested on the experiment table of simple beam and the bear box of a machine tool. The results show that the interface of software system is friendly, and the operation is simple. It greatly improves the equipments online monitoring diagnosis level, moreover, it will provide advanced analysis tool for monitoring diagnosis in the future.