关键词: 振动传感器, 低频, 多轴测量, 磁悬浮, 稳定性

Abstract: A new maglev low-frequency vibration sensor was proposed, which was used for multi-axis measurement of aerospace micro-vibration. It used micro-spring and the hybrid structure with electromagnets and permanent magnets as the supporting element. The axial displacement detection circuit and the photoelectric displacement sensors were used to measure the relative displacement between the maglev mass block and the shell and realize the multi-axis measurement of low-frequency vibration signals. When the sensor was used for dynamic measurement, the maglev mass block could return to the equilibrium position and keep stable levitation under the combined action of electromagnetic attractive force, gravity and spring force. The equivalent bearing stiffness coefficient and the equivalent damping coefficient of the system could be controlled by adjusting the control current of the electromagnetic coil, which can reduce the natural frequency effectively and extend application range of the sensor. Theoretical analyses show that the lower-cut-off frequency of the sensor is 0.6 Hz and it has better low-frequency characteristics. The proposed method provides new thought for designing multi-axis low-frequency vibration sensor.

Key words: vibration sensor, low-frequency, multi-axis measurement, magnetic levitation, stability