基于磁悬浮效应的三维振动测量

Three-dimensional vibration measurement based on magnetic levitation effect

设计了磁悬浮球系统模型,测量一定电流下磁悬浮球位移与受力得到磁悬浮球的电磁力表达式,推导了磁悬浮球运动的动力学方程。实测中磁悬浮球模型壳体与被测振动体刚性连接,通过光电传感器测出磁悬浮球与壳体的相对位移得到三维被测振动信号。通过标准振动台实测验证,小于120 Hz的最大绝对误差为±0.3 Hz,相对误差为±1.5%～±0.25%,120 Hz～5 kHz的最大绝对误差为±1 Hz,相对误差为±0.83%～±0.02%。由于磁悬浮球悬浮于空中,灵敏度高,具有良好的频率响应特性,磁悬浮球运动各向同性,不存在因粘贴传感元件带来的极间耦合问题,与传统多维振动测量方法相比较该方法具有独特的优势。

A magnetic levitation ball system model was designed.The magnetic force that magnetic levitation ball bears was measured under fixed current and changing displacement.The dynamic equation of magnetic levitation ball movement is deduced.The shell of magnetic levitation ball system model joins up with the vibrating object under test rigidly in the test experiment.A photo-electric sensor is used to measure the relative displacement between the shell of the system model and the magnetic levitation ball,and three-dimensional vibration signals are obtained.Standard vibrator test verifies that the maximum absolute error is ±0.3 Hz and relative error is between ±1.5% and ±0.25% for frequency below 120 Hz,the maximum absolute error is ±1 Hz and relative error is between ±0.83% and ±0.02% for frequency between 120 Hz～5 kHz.Because magnetic levitation ball suspends in the air and the system does not have any pasted sensor,the effects from other directions do not exist.The system has excellent frequency feature and the features at different directions are the same.The system sensitivity is high.This method has better characteristics than traditional vibration measurement methods.