The Development Of On-Line Detection And Fault Diagnosis System For Vehicle Wiper DC Motor

With the improvement of environmental protection requirements, vibration and noise of the vehicle motor has been used as an important indicator of motor performance evaluation. On-line detection of vibration and noise of the motor is an effective way to reduce failure rate. At present, vibration and noise on-line detection of the motor mainly rely on the way of human touching and ears.it is strict for workers,high work intensity, low efficiency, high rate of misdiagnosis, poor stability,difficult to adapt to the market in which competition is more Large. Therefore, it is necessary to develop a meeting production line, efficient and reliable system.This study is based on the urgent need of a domestic vehicle motor manufacturer for improving the accuracy and efficiency of on-line detection of woper motor to make.Firstly, in this paper the characteristics of motor vibration and noise, acoustic indicator of evaluation of noise measurement and the typical signal processing method of vibration and noise are introduced.Secondly, the typical failure mechanism of the motor were studied. For excessive machine vibration and electromagnetic vibration, mainly based on the characteristics of motor vibration signal and the structure, causes are received excessive; For the bearing and worm fault, artificial defecting is to gain access to the inherent structure Frequency and the various parts of bearing fault characteristic frequency, causes of the abnormal sound are received.Thirdly, starting from the signal processing,fault feature parameter extraction was studied. For the access of fundamental frequency, this paper presents a method which fundamental frequency can directly be extracedt from the cepstrum of vibration signal; compare with the results of short-time Fourier transform analysis and wavelet transform analysis bearing abnormal vibration signal; the method of Hilbert package and detailed spectral analysis for detail signal of wavelet transform is used to obtained the fault characteristic frequency of bearing components; based,fault feature parameters are extracted and thresholds are setted.Finally, to achieve the required measurement signal-noise ratio, vibration isolation system of hardware a is re-designed; By software platform of MATLAB, the the motor on-line detection and fault diagnosis system is developed. Main functions includ:counting A sound level meter, speed extraction, time-domain analysis, frequency-domain analysis, joint time-frequency analysis, etc. This system use user-friendly manual design to facilitate the production line, has the functions of on-line detection and off-line analysis, and the completed system is in the trial operation in production line. its practicality and reliability are verified. At present.the system has been in the production line runing.