检验考虑宏观物体自旋效应的新型等效原理，对于完善现代引力理论具有重要意义。新型等效原理空间实验的检验精度预计达到10-15，需要研制专门的低噪声空间静电加速度计作为核心实验仪器。本文介绍了检验新型等效原理的无拖曳卫星实验方案，开展了空间实验差分静电加速度计设计与关键技术研究。研制了静电加速度计地面实验样机，采用薄壁圆筒形检验质量，利用同轴的内/外电极筒实现五自由度高压静电悬浮及绕敏感轴的静电加转驱动。针对地面1 g0实验环境需要大幅度提高静电支承力的需求，对实验样机的检验质量、电极间隙、支承电压、电极配置等进行了改进设计，并完成了一套敏感结构的精密加工、装配与测试。为了实现五自由度稳定悬浮，建立了包括位移检测灵敏度、静电执行器增益和负刚度的静电悬浮系统模型。设计并比较了基于PID、滞后-超前、H∞控制器的静电悬浮系统，仿真表明支承刚度等指标满足地面悬浮要求。研制了面向地面高压静电悬浮的位移检测电路及高压放大器；优化了隔离网络，大幅度降低了悬浮高压对位移检测信号的耦合干扰。开展了五自由度高压静电悬浮实验研究，测试了静电加速度计的量程、标度因数和带宽等性能。建立了圆筒形检验质量静电加速度计的轴间耦合模型。通过分析检验质量径向偏移对轴向电容的影响，建立了敏感轴电极电容的解析模型和数值模型，并推导了轴间耦合的近似线性模型和频率特性。设计径向激励实验，产生与理论预测相符的轴间耦合信号，验证了轴间耦合模型的有效性。研究了两种抑制轴间耦合误差的方法，经过校准径向悬浮零位后，轴间耦合减少了66.7%；采用基于扰动模型的补偿方法，去除了75.9%的轴间耦合干扰。为解决高真空下宏观尺度可变电容静电电机存在启动困难和失步的问题，提出了一种基于三相电容式齿极检测的静电电机同步驱动技术。利用该同步驱动技术，实验表明三相可变电容静电电机可实现可靠启动、运行和制动；结合恒速回路建模与设计，并实现了静电电机的恒速运行。为了评估静电加速度计的噪声水平，分析了仪器电路噪声及其对加速度测量噪声的影响。通过径向变预载实验、悬丝实验、地脉振动噪声互相关实验，评估了地面环境静电加速度计的电路噪声、轴间耦合噪声和地脉振动噪声的水平，在此基础上评估了面向空间实验差分静电加速度计的噪声水平。
Testing the New Equivalence Principle (NEP) which considers the rotation effect of extended bodies is significant for developing modern gravity theories. The expected test accuracy of the NEP space experiment is 10-15, and it needs to develop appropriative low-noise space electrostatic accelerometers as the core experiment instrument.An experiment scheme with a drag-free satellite for testing the NEP is proposed in the thesis, and the design and key technology research of the differential electrostatic accelerometer for the space experiment are carried out. An electrostatic accelerometer prototype for ground test is developed, which includes a thin-walled cylindrical proof mass, and achieves the five-DOFs high-voltage electrostatic suspension and electrostatic rotation driving along the sensitive axis with coaxial inner/outer electrodes cylinders. For the requirement of improving electrostatic support force in the experimental environment of 1 g0 on ground, the proof mass, electrode gap, support voltage and electrodes arrangement of the prototype are designed and improved. The precision machining, assembly and testing of a set of sensitive structure are completed.To achieve the stable five-DOFs suspension, the model of the electrostatic suspension system is built, which includes the displacement measurement sensitivity, electrostatic actuator gain and negative stiffness. The electrostatic suspension system with controllers, such as PID, lag-lead and H∞, are designed and compared, and the simulation shows the indexes such as the suspension stiffness fulfill the requirement of the suspension on ground. The displacement detection circuit and the high-voltage amplifier for the high-voltage electrostatic suspension on ground are developed. The isolated network is improved, which decreases the coupling interference on the displacement detection signal from the high voltage for suspension drastically. The experimental research of the five-DOFs high-voltage electrostatic suspension is performed, and the performances of the electrostatic accelerometer such as the range, scale factor and bandwidth are tested.The cross-axis coupling model of an electrostatic accelerometer with a cylindrical proof mass is established. The analytical model and the numerical model of the sensitive axis electrode capacitance are established by considering the radial motion of the proof mass affects the axial electrode capacitance, and the approximate linear model and frequency characteristics of the cross-axis coupling are derived. The radial excitation experiment is designed, which generates the cross-axis coupling signal that meets the theoretical prediction, and it verifies the effectiveness of the cross-coupling model. Two methods are used to decrease the cross-axis coupling error. After calibrating the radial suspension zero-position, 66.7% of the cross-coupling signal is decreased; with disturbance compensation method, 75.9% of the coupling signal is removed.To solve the problems of startup difficulty and out-of-step that the macro-scale variable capacitance electrostatic motor (VCM) in high vacuum has, a kind of synchronous driving technology of the electrostatic motor based on the three-phase capacitance tooth/pole detection is proposed. With the synchronous driving technology, reliable starting, spinning and braking of the three-phase VCM are realized in experiments, and with modeling and designing the constant-speed control loop, the constant-speed operation of the VCM is also achieved.To assess the noise level of the electrostatic accelerometer, the instrument circuit noises and their influences on the measured acceleration noise are analyzed. The circuit noise, cross-axis coupling noise and seismic noise of electrostatic accelerometer in ground environment are estimated through the radial preload voltage variation experiment, pendulum experiment and seismic noise cross-correlation experiment. On this foundation, the noises level of the differential electrostatic accelerometer for the space experiment is assessed.
