基于几何负刚度弹簧结构的超低频有源垂直隔振系统研制  

Development of ultralow frequency active vertical vibration isolation system based on geometric anti-spring structure

作　　者：伍康[1,2] 徐子涵 周铁生 要佳敏 郭梅影 张嵘 WU Kang;XU ZiHan;ZHOU TieSheng;YAO JiaMin;GUO MeiYing;ZHANG Rong(Department of Precision Instrument,Tsinghua University,Beijing 100084,China;State Key Laboratory of Precision Space-time Information Sensing Technology,Beijing 100084,China)

机构地区：[1]清华大学精密仪器系,北京100084 [2]时空信息精密感知技术全国重点实验室,北京100084

出　　处：《地球物理学报》2024年第12期4515-4521,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金(61627824和41604151)资助。

摘　　要：绝对重力仪在地球物理、精密计量、资源勘探等科学研究和工程技术领域有广泛应用.地面振动噪声严重制约绝对重力测量精度.超低频垂直隔振系统可以显著提高绝对重力测量精度.本文研制的超低频有源垂直隔振系统,利用几何负刚度弹簧结构静刚度大、动刚度小的优点,以其替代经典垂直隔振系统中的负载支撑弹簧,通过精密位移检测和伺服反馈控制实现超长的谐振周期.本文详细介绍了该系统的等效物理模型和控制模型,推导了闭环系统的传递函数.所研制的样机闭环周期超过20 s,相关试验验证了系统可以支撑绝对重力仪实现微伽级高精度测量,并且可以在实验室环境下长期稳定工作.该系统的负载安装在结构顶部,适用于激光干涉和原子干涉两种体制的绝对重力仪.Absolute gravimeters have emerged as essential instruments for geophysics,metrology,and geological exploration.A significant constraint on their measurement accuracy is environmental vibration.This study introduces an ultralow frequency active vertical vibration isolator,specifically designed to improve measurement precision.This isolator employs geometric anti-springs instead of the traditional cylindrical spiral springs used in classical absolute gravimeters to support the proof mass.The geometric anti-spring structure offers high static stiffness and low dynamic stiffness,making it an optimal choice.The isolator is implemented with precision displacement detection and feedback control to achieve an extended period.This paper presents both the equivalent and control models,and derives the transfer function of the vibration isolator.Experimental results demonstrate that the system period surpasses 20 seconds,and the custom-built isolator fulfills the requirements for microgal level high precision absolute gravimetrical measurement.Furthermore,the isolator can maintain stable operation in a standard laboratory environment for several weeks.Considering that the load can be positioned at the top of the vibration structure,the isolator is applicable for both classical and atom absolute gravimeters.

关 键 词：垂直隔振 超低频 几何负刚度 绝对重力仪 

分 类 号：P631[天文地球—地质矿产勘探]