精密测试中的振动相位零点漂移误差及其减小方法

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精密转子的功能需要通过严苛的动态运行精度来实现,这给振动测试的精度提出更高的要求。现有方法通过对快速傅里叶变换的改进,已经实现对振动幅值、相位等参数的精确提取,但对于振动相位零点漂移误差及其减小方法的研究还较少。通过对精密测试中振动相位零点漂移误差来源及其变化规律的深入分析,提出一种减小精密振动测试中相位零点漂移误差的方法。该方法依据相位序列变化步长搜索键相序列信号变化的周期数、以变化周期内信号的平均值估计相位零点漂移的中间值;在此基础上,结合信号的角度分辨率对初始相位序列的极值进行估计进而确定振动信号初始相位补偿量。该方法的有效性和可行性通过仿真试验和实际测试分析结果得到验证,为提高信号相位的测试精度提供一种可靠的解决方案。 Strict dynamic operating accuracy is the prerequisite of the realization of the function of a precision rotor,which demands much higher vibration measurement precision than that for traditional industry rotors.Although the accurate extraction of vibration parameters,such as amplitude,frequency and phase,has been realized with several modified FFT methods,the initial phase zero shift error and its reduction method still require further investigation.An in-depth study on the source and the change rule of this error is made and an error reduction method suitable for precision measurement is presented.The theory and the implementation of this method are discussed.The effectiveness and feasibility of this method has been testified by the result of a simulation experiment and a real test,respectively.The analytical conclusion shows that this method provides a reliable solution scheme to improve the phase measurement precision.