Research On Rotating Machinery Condition Monitoring Method And Its System Realization

Rotating machinery are widely applied in industries such as petroleum, chemistry, metallurgy etc., for many of them is the key equipment for production, and also the main target of machinery condition monitoring. It’s significantly important to strengthen rotating machinery condition monitoring for rotating machinery to ensure long-term safe operation, improve production and product quality, and improve enterprise economic. The main researches include:1. Design a condition monitoring system for rotating machinery based on dual processor system architecture.On the basis of comparison and optimization of the traditional design of rotating machinery condition monitoring system, a rotating machinery condition monitoring system is designed based on DSP+MCU architecture with the utilization of the wireless way for field data transmission, which not only enables to monitor frequency, phase, speed, shaft displacement and other related state parameters, but also can complete the analysis of the vibration signal spectrum and the marginal spectrum.2. Improved EMD algorithm is proposed to effectively improve the performance of marginal spectral analysis of the vibration signals.In rotating machinery vibration signal based on wavelet denoising, according to the characteristics of the non-stationary vibration signals, EMD method is proposed based on the combination of the time series and window function which is using ARMA model to have a waveform extension, then after inner product operation of the extension signal and cosine window function, the end effect can be effectively suppressed and Hilbert marginal spectrum will be accurately obtained.3. Design a hardware circuit module of the rotating machinery condition monitoring system, and complete the acquisition and transmission of state parameters.According to the functional requirements of condition monitoring system, a data acquisition circuit is designed with DSP and the AD7656as the core processor, and a sensor signal conditioning circuit is designed to filter and amplified the multi-state signal, at the same time, the nRF905wireless RF module interface circuit is also designed to have the digital signal modulation, demodulation and wireless transmission of the state signal..4. DSP program was developed with the PC software platform that enables real-time display and functional analysis of state parameters.The thesis develops functional modules such as AD program, system communication protocol, PC displays, data storage procedures, and the access from PC to the database. Software system complete the functions of the data processing, real-time display, historical data storage and management, spectrum analysis and Hilbert marginal spectrum analysis.5. Conduct a field test, complete the testing and analysis of mechanical vibration signal device status parameters.The system is debugged with the test object of the high-power motor and the gas compressors, and the test results is also analyzed. The system completes simultaneously collecting signals from5channels, the maximum speed that can be measured up to3000rpm, the relative error is less than1.3%. The amplitude value measurement range of the vibration signal is1～10mm(p-p), Meanwhile, with contrast of the spectral analysis and the marginal spectrum analysis of vibration signals, the paper sums up the shortcomings and areas for improvement of the system.Rotating machinery condition monitoring system based on double CPU has characteristics of low cost, short update cycle of the system software, and good compatibility. It is of great significance to reduce the cost of system development, improve the system analysis function and system accuracy of fault diagnosis.