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提出一种基于激光多普勒技术和光学外差原理对高速回转机械进行扭振测量的新方法,分析了工作原理,推导出光路部分的数学模型,并通过实验分别验证了测量方法的可行性和准确性。高相干激光投射到转轴同一个截面上2点,反射光的多普勒频移正比于转轴转速,通过光学配置,使前后两个时刻的多普勒频移光信号在光探测器上发生光学混频,光电流拍差正比于转轴在两个时刻的速度差,控制两个时刻时间差很小,直接得到角加速度。与其他激光多普勒扭振测量方法相比,该方法直接测量转动角加速度,在保证测量精度的前提下,提高了扭转振动测量的实时性,极大地扩展了扭振测量的动态范围,对大型回转机械运行状态监测和故障诊断具有重要意义。
A new method based on laser Doppler and optical heterodyne is proposed to measure the torsional vibration of high-speed rotating machinery. The working principle is analyzed and the mathematical model of the optical path is deduced. The feasibility of the measuring method is verified through experiments And accuracy. High coherent laser beam projected onto the same section of the shaft 2:00, the Doppler shift of the reflected light is proportional to the rotational speed of the shaft, through the optical configuration, so that before and after the two time Doppler shift optical signal optical detector in the optical Mixing, photocurrent difference is proportional to the shaft speed difference between the two moments, control the time difference between the two very small, direct angular acceleration. Compared with other laser Doppler torsional vibration measurement methods, this method directly measures the acceleration of rotation angle, which improves the real-time performance of torsional vibration measurement and greatly expands the dynamic range of torsional vibration measurement under the premise of ensuring the measurement accuracy. Large rotating machinery operating condition monitoring and fault diagnosis is of great significance.