多轴悬浮式低频振动传感器的理论研究

设计了一种新型结构的磁悬浮式低频振动传感器，用于航空航天微振动的多轴测量。该传感器采用电磁、永磁混合结构以及微弹簧作为支承元件，通过轴向位移检测电路和光电位移传感器对磁悬浮质量块与壳体间的相对位移进行检测，实现低频振动信号的多轴测量。动态测量时，磁悬浮质量块在电磁力、重力和弹力的共同作用下可回到平衡位置并实现稳定悬浮，通过调整传感器的控制电流，可主动控制系统等效刚度和等效阻尼，从而有效地降低了系统的固有频率，扩展了传感器的频率响应范围。理论分析得到该传感器的下限截止频率为0.6 Hz，实验结果表明该传感器具有良好的低频响应，本文方法为多轴低频振动传感器设计提供了新思路。

Theoretical research on multi-axis maglev low-frequency vibration sensor

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.