Research On Acoustic Emission Monitoring System Of Rotating Machinery

With the progress and development of modern industrial technology,rotating machinery is widely used and plays a key role in traffic construction,industrial manufacturing,energy exploitation,and national defense consolidation.As an important part of rotating machinery,the performance and working state of rolling bearing will directly affect the working state of the whole mechanical equipment.According to statistics,30% of the faults of rotating machinery are caused by rolling bearings.Therefore,this thesis takes rolling bearing as the research object,based on the principle of acoustic emission detection,with Microsoft Foundation Classes(MFC)application development framework and C++ programming language as tools,designed and developed a set of acoustic emission monitoring system for rotating machinery bearing fault.In this thesis,MFC is used as the application development framework and combined with the characteristics of rolling bearing acoustic emission signal,the overall development scheme of rotating machinery acoustic emission monitoring system was designed,including hardware system and software system.The hardware system is composed of high-precision acoustic emission sensor,front-end amplifier,PCI-2 data acquisition card and industrial computer;the software system is mainly developed based on PCI-2 acoustic emission data acquisition card in C++ language.The on-line acoustic emission monitoring of rotating machinery requires high real-time performance of the system.The problems of large amount of data acquisition and transmission,and many analysis parameters are the major problems in developing the real-time acoustic emission monitoring system.In order to solve this problem,the system developed in this thesis adopted the method of multithreading parallel computing to design the core framework.The main functions of the system and its development plan are established,and the feasibility of the related plan is proved.Based on the analysis of the requirements of acoustic emission monitoring for bearing fault in the industrial field,this thesis designs five modules: hardware parameter setting module,acquisition and display module,alarm module,tool module and replay module,then developed the specific functions of each module,and finally completed the overall development of the system.By analyzing the principle of the rolling bearing acoustic emission signal and the characteristic parameters of the rolling bearing acoustic emission signal,and comparing the actual collection of the rolling bearing acoustic emission data characteristics,the framework system and data processing method of the rolling bearing acoustic emission monitoring system were designed.Based on the parameter analysis method of acoustic emission signal,this thesis proposed a more efficient method of parameter feature extraction of acoustic emission signal based on C++ language.In view of the problem that kurtosis value is greatly affected by the interference signal,this thesis proposed the equal time difference kurtosis analysis algorithm based on the kurtosis analysis algorithm after the acoustic emission signal is denoised by the wavelet transform method.This algorithm greatly suppresses the interference signal and effectively realizes the qualitative analysis of the fault degree of rolling bearing.Finally,the system is tested on the spot by the actual fault bearing to improve the function and stability of the system.The results showed that the system had good performance in collecting and analyzing the acoustic emission signal of rolling bearing.The algorithm of equal time difference kurtosis analysis could analyze the fault degree of rolling bearing qualitatively.It is easy to operate,easy to maintain and has good engineering application value.