Monitoring System Design Of Machine Operating Condition Based On Noise

As the inevitable product in the industrial processing, noise contains a large amount of information of the industrial processes. These significant advantages make noise testing techniques being widely used in the field of industrial production. The implement of the noise acquisition and analysis can certainly improve the efficiency of the production and the safety of the equipment during working time. As the tremendous evolution of computer testing technology, the digital noise signal processing technology, based on the computer platform, is rapidly developing in this decade. Unlike other vibration signal or force signal, noise signal acquisition obtains unparalleled advantages. The microphone naturally eliminates the obstacle of sensor installation which is commonly occurred in vibration signal testing. However, the evaluation criterion of the sound is different as the vibration signal such as velocity and acceleration. Its magnitude is mainly described by the sound pressure level, which is more likely to be a relative value. In addition, the frequency of the noise signal takes a great influence on the distinction of the noise. As a consequence, the study on the frequency of the noise should be primarily considered compares to the characteristics of the time domain. According to the description of the above, it is utterly necessary and considerably valuable to design a monitoring system based on the noise of machine operating condition.In this paper, a noise monitoring system of machine operating condition is introduced. Based on USB serial communication protocol, the noise signal acquisition and analysis platform is built. The noise testing and monitoring system is developed under Visual Studio environment. The system contains multiply functions such as sensor calibration, time analysis, frequency analysis, filtering, wavelets transform etc. it accomplish the evaluation of the noise by embellishing sound level pressure function. It can monitor the process of different conditions and is flexible for different testing requirements. A test experiment on milling machine noise is illustrated in this paper in order to verify the functions of the software. Another experiment connecting force and noise during machine operating condition is displayed to show the distinction of characteristics under different condition. The result displays that the acquisition and analysis system is suitable for operating condition monitoring and screening of different machines.