谐波信号的通用频谱校正算法在回转机械监测中的应用

分析了常规FFT谱由于能量泄漏和栅栏效应,不能获得简谐振动信号精确幅值、频率和相位的原因。针对现有校正频谱方法的不足,提出了基于黄金分割的通用频谱校正算法。经仿真实例验证,该方法具有计算量小、校正精度高、适应面广的特性。经过回转机械启动实例分析,该方法能得到准确的临界转速、升速曲线和幅频响应曲线,为回转机械的瞬态行为分析提供了新的手段。

Harmonic Vibration Monitoring of Rotating Machinery Using General Corrected FFT Spectrum

Fourier spectrum is one of powerful tools to diagnose the faults of rotating machinery. However, leakage effects appear in the FFT spectrum despite the use of all kinds of window functions. In addition, an FFT spectrum is the result of continuous spectrum sampled with specified frequency interval and the corresponding spectrum line of harmonic is not located in the center of the main-lobe. Consequently, the calculated frequency, amplitude and phase of the vibration component are not accurate. A general corrected spectrum based on golden section is proposed. All types of simulation signals show that the method possesses the merit of higher precision, lower calculation complexity and broader adaptability in comparison with other techniques. Furthermore, the analytical results of test rig proved by this novel approach can obtain the accurate critical speed, acceleration curve and amplitude-frequency response in start-up stage and provide an effective tool to character the transient behavior of rotating machinery.