基于电容传感的二维复合摆地倾斜低频隔振系统研究

It is very important significance in science for direct detection of gravitational wave to validate general theory of relativity and to discriminate kinds of gravitational theories. Due to the introduction and application of horizontal and vertical vibration pre-isolation systems, ground tilt vibration has been one of key problems to improve the sensitivity of laser interference for gravitational wave detection, and ground tilt low-frequency vibration isolation system with high sensitivity needs to be studied urgently, but at present it is few. For the 0-2Hz band of the tilt vibration suppression to the order of nrad, a two-dimensional compound pendulum ground-tilt low frequency vibration isolation system is put forward in this project, where not only compound pendulum with long resonance period and capacitance detection technology are used to measure ground tilt vibrations in two directions but also piezoelectric ceramic transducer is used to regulate the tilt of frame. Owing to the application of two-dimensional cylindrical compound pendulum with relatively simple structure and capacitance mini-displacement detection technology, the vibration isolation system is easy to fabricate and miniaturize.. This project studies mainly the analysis and design of two-dimensional compound pendulum and its damping structure, displacement capacitance detection system, piezoelectric ceramic transducer control system, software design of multi-channel data acquisition, compound control algorithm, multi-channel analog-to-digital conversion and person-computer alternation interface, and testing experiments of key performances. Through these researches, a two-dimensional ground tilt vibration isolation system with the 0-2Hz band will be developed successfully.

引力波的直接探测对于验证广义相对论、甄别各种引力理论具有重要科学意义。水平和垂直预隔振系统的引入与成功应用，地倾斜振动已成为制约激光干涉仪引力波探测器灵敏度提高的关键性问题之一，迫切需要研究目前还不多见的高灵敏度地倾斜低频隔振系统。本项目提出利用长共振周期的复合摆和电容传感技术检测两个方向上的地倾斜信号，压电陶瓷驱动器调节框架倾斜，构建二维复合摆地倾斜低频隔振系统，将0-2Hz频段内的地倾斜振动抑制到nrad量级。由于采用结构相对简单的二维圆柱对称复合摆和电容微位移传感技术，隔振系统能同时抑制2个方向倾斜振动，装置制作简单且易于小型化。. 本项目开展二维复合摆及其阻尼系统的分析与设计，电容位移传感系统的分析与设计，压电陶瓷驱动控制系统的分析与设计，多通道数据采集、复合控制算法、多通道数模转换及人机交互界面等程序设计，关键性能指标测试等，研制成功0-2Hz频段的二维地倾斜隔振系统。

地倾斜低频隔振对于地面激光干涉式引力波探测等精密科学实验具有重要意义，本项目研究一种基于电容传感的二维复合摆地倾斜低频隔振系统。建立了复合摆对外界垂直振动、水平振动及倾斜振动响应特性的理论模型，数值分析了复合摆结构参数对其响应特性的影响，进行了复合摆结构设计。完成了电容传感器电场及电容微位移传感电路的理论分析，电容极板的结构设计与加工制作，电容微位移传感电路的设计与制作。.分析了复合摆的三个自由度转动时四个检测电容变化与摆体偏转角之间关系以及二维复合摆倾斜仪的交叉耦合效应。进行了压电陶瓷电压-位移特性测试，由测试数据建立了基于多项式模型的压电陶瓷多环迟滞模型。完成了一种压电陶瓷逆模型与数字PID控制器相结合的复合控制方案设计，建立了垂直摆倾斜仪的复合控制系统模型，完成了PID参数整定及阶跃响应仿真实验，分析了闭环系统的稳定性条件、PID和PD控制下的稳态误差。进行了基于遗传优化的PID控制器参数整定的仿真实验，分析了电容极板的椭圆率对检测电容的影响。.进行了直流放大式电路设计压电陶瓷驱动电路设计与制作，倾斜隔振系统的数据采集与数模转换电路的设计制作。完成了垂直摆倾斜仪的数据采集、复合控制算法、数模转换等程序设计，人机交互界面等应用程序设计；系统装置装配，软硬件集成与调试；关键性能指标的测试实验及结果分析。