用于主动光学系统中的特种精密位移传感器的研究

Along with the development of extremely large astronomical telescope, a light mass special displacement sensor (which is immune to the gap, tip-tilt between the adjacent segments, and is only sensitive to the piston of them) is necessary in active optics, especially in the technology of application of segmenting and thin mirror at the same. Studying to a new type area-sensing capacitive displacement sensor is proffered in this project to keep the requirements of current active optics. Difference method is used in this study to be immune to the gap between the adjacent segments, and to reduce the errors remarkably caused by environment such as the temperature; the sensing area is divided smartly that the reference sensor been made to cancel the errors caused by tip-tilt; the dual-frequency reversed-phase exciting in dual-end method is used in circuit to get high SNR and deep noise suppression; the high accuracy AD and DSP is designed to get high speed data acquisition. The displacement sensor used in astronomical telescope now cannot meet all the requirements (such as mass, dimension and accuracy) simultaneously，which is the need of the technology combined thin mirror with segmenting mirror. According to the description above, this study will offer the research basis for the active optics in Chinese future extremely large telescope, and offer the technology for China to take part in the international cooperation.

随着大口径和超大口径天文望远镜新技术的发展，主动光学中拼接镜面与薄镜面相结合的技术要求超轻型，不受间距、倾斜和旋转影响的精度达到纳米级精度的位移传感器。因此提出研究一种新型的电容式位移传感器，以达到现代主动光学技术的要求。传感器的工作原理采用变面积型，利用差分的方案，消除间距的影响并在很大程度上减小诸如温度、气流等环境因素对测量精度的影响；合理划分极板产生参考传感器用于基本消除倾斜与旋转的影响；在电路处理中，拟采用双端双频反相激励方式，以提高系统的信噪比和深度抑制噪声；设计高位高精度的模数转换和数字信号处理电路，从算法上实现快速的信号提取与输出。目前国际上用于天文望远镜中的位移传感器在重量、体积和精度上不能同时满足拼接镜面与薄镜面技术相结合的要求，本传感器的研究为我国未来极大望远镜设计中主动光学提供研究基础，同时为我国国际极大望远镜的合作提供技术储备。

随着大口径和超大口径天文望远镜新技术的发展，主动光学中拼接镜面与薄镜面相结合的技术要求超轻型，不受间距、倾斜和旋转影响的精度达到纳米级精度的位移传感器。因此提出研究一种新型的电容式位移传感器，以达到现代主动光学技术的要求。主要研究内容为研究设计了传感器的驱动、信号调制解调、信号前置放大、数字信号滤波、基于FPGA的信号处理及软件编程、AD转换及数字数据传输电路；对位移传感器的极板尺寸、材料进行分析设计和选材测试，最终以微晶玻璃镀金作为电容极板；对激励电源、传输线缆进行了研究测试，经测试后选用了线性电源，电缆选择内屏蔽层与线芯具有相同相位的材料，并设计相应的驱动电路；在洁净实验室内设计了高精度的位移驱动机构，利用高精度双频激光干涉仪的测量，将其数据与位移传感器的数据进行对比，取得了在大量程内的线性吻合。共发表了5篇论文，4篇被EI检索。培养研究生4名, 已毕业3名。