五线摆扭转频率测量质心测量系统  

Mass center measurement system based on torsional frequency measurement of five-wire pendulum

作　　者：张晟 梁铭涛 王智 ZHANG Sheng;LIANG Mingtao;WANG Zhi(School of Fundamental Physics and Mathematical Sciences,Hangzhou Institute for Advanced Study,UCAS,Hangzhou 310024,China;University of Chinese Academy of Sciences,Beijing 100049,China;Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China)

机构地区：[1]国科大杭州高等研究院基础物理与数学科学学院,浙江杭州310024 [2]中国科学院大学,北京100049 [3]中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《中国测试》2024年第10期105-112,共8页China Measurement & Test

基　　金：国家重点研发计划(2020YFC2200600)。

摘　　要：测试质量是空间引力波探测仪器中惯性传感器关键组成部分,是边长46 mm、质量约为2 kg的正方体。为减小测试质量的质心偏离对惯性传感器精度的影响,需要对测试质量的质心偏离量精确测量。由于测试质量的质心偏离允差仅为3.75μm,以往的质心测量方法不能满足测量精度的要求,特提出通过高精度测量五线摆的扭转振动固有频率来间接测量测试质量质心偏差。该文首先通过对五线摆的动力学分析,给出物体质心偏离量与五线摆固有频率之间的函数关系,并据此分析固有频率测量精度需求。接着,介绍采用衍射光栅和四象限探测器测量五线摆扭振角位移的原理。然后通过建模和电磁仿真设计基于电磁螺线圈和永磁体的电磁驱动器。最后,给五线摆施加振幅可控的激励脉冲,根据记录的角位移数据拟合出五线摆的扭转振动固有频率。实验结果表明,在初始振幅为3×10^(-4) rad的扭转振动情况下,五线摆的固有频率测量精度为2.66×10^(-5) Hz,能够满足利用五线摆法测量测试质量质心偏移的需求。The test mass(TM) is a key component of the inertial sensor in the space gravitational wave detection instrument,which is a cube with a side length of 46 mm and a mass of about 2 kg.In order to reduce the influence of the mass center deviation on the accuracy of inertial sensor,it is necessary to measure the mass center deviation of the TM accurately.Because the deviation of mass center of TM is only 3.75μm,the former method of mass center measurement can't meet the requirement of measurement precision,it is proposed to measure the deviation of mass center indirectly by measuring the natural frequency of torsional vibration of five-wire pendulum with high precision.Firstly,through the dynamic analysis of the five-wire pendulum,the functional relationship between the offset of the mass center and the natural frequency of the five-wire pendulum is given.Based on this,the precision requirement of natural frequency measurement is analyzed.Then,the method of measuring torsional angular displacement of five wire pendulum with diffraction grating and quadrant detector was introduced.Then the electromagnetic driver based on electromagnetic coil and permanent magnet was designed by modeling and electromagnetic simulation.Finally,the torsional vibration natural frequency of the five-wire pendulum was fitted according to the recorded angular displacement data.The experimental results show that the measurement accuracy of the natural frequency of the five-wire pendulum is 2.66×10^(–5) Hz,under the torsional vibration with an initial amplitude of 3×10&(–4)rad.This system can meet the needs of measuring mass center by five-wire pendulum.

关 键 词：五线摆 固有频率 衍射光栅 四象限探测器 电磁驱动 

分 类 号：TB9[一般工业技术—计量学] TH825[机械工程—测试计量技术及仪器] O436.1[机械工程—光学工程]