4m望远镜三镜系统研究设计

	4m望远镜三镜系统研究设计
其他题名	Study and design of 4m telescope tertiary mirror
	李明璇
学位类型	硕士
导师	张景旭
	2015-11
学位授予单位	中国科学院大学
学位专业	机械制造及其自动化
关键词	望远镜三镜面形评价支撑结构优化误差分析
摘要	随着人类对暗弱目标观测需求的提高，对望远镜口径的需求也越来越大。三镜是直接参与望远镜光学系统成像的重要元件，其面形精度是影响望远镜成像质量的关键因素之一。本论文针对4m级望远镜项目，研究设计了其中的三镜组件。4m望远镜是部门承担的最大口径的望远镜，三镜长轴的尺寸将达到500mm。研究设计的目标是保证三镜在工作时保持良好的面形精度、定位定向误差、系统刚度和焦点转换时的效率。对国外技术领先的大口径地基望远镜和其三镜系统进行了调研与总结；研究了镜子支撑的基础理论和面形评价方式，分别以镜面面形误差的Slope RMS值和RMS值为目标函数优化了支撑点的位置，计算得到了最优镜面面形的Slope RMS误差值为4.05，镜面面形的RMS误差值为1.96nm。 rad 依照对4m望远镜三镜初步分析和计算的结果，底支撑方案选用6点whiffletree结构，侧支撑方案选用中心膜片结构，然后利用有限元软件HyperMesh和Ansys进行联合仿真分析。对柔性支撑中的底支撑杆的直径和侧支撑膜片的厚度进行的优化，得到最优的支撑杆径直为2mm，最优膜片厚度为1mm。并对所设计的支撑结构进行了动力学分析，并以LMS模态分析仪为依托，以实验室现有的条件进行了实验。根据主系统对三镜运动和调整的要求，设计了三镜的二维调整组件和转台。二维调整组件的作用是方便后期的装调，选取柔性铰链作为俯仰调整的回转中心。转台的作用是满足望远镜系统的焦点切换能力，选取力矩电机作为驱动元件。利用谐波分析法分析了三镜转台的角晃动量，在设计允许范围之内。
其他摘要	With the advancing of human's observing requirement for the dark and faint target which is far from the earth, the aperture of telescope become larger and larger. Tertiary mirror is an important component in the optical system, and its figure error is one of the pivotal factors of the large telescope's imaging quality.For the Fou Meter telescope project, tertiary mirror system is developed and researched. 4m telescope is the largest telescope which the department has manufactured, the long axis of tertiary mirror will be 500mm. The goal of the design is to ensure the mirror figure error and pointing error meeting the requirement, and to ensure the focus conversion speed meets the design requirement. Following typical foreign large aperture telescope and its tertiary mirror are achieved. Study on the mirror supporting theory and surface evaluation methods, optimize the location of support point, optimization target is the value of Slope RMS and RMS. The result of the optimization is the mirror surface error RMS value is 1.96nm and the Slope RMS value is 4.05.According the workcase of tertiary mirror of 4m telescope, 6 point whiffletree structure is selected to use as the axial support, and the center diaphragm structure is selected as the lateral support. With tht help of the FEA software HyperMesh and Ansys, the analysis of the supporting structure is completed. The diameter of axis support link and the thickness of lateral support are optimized, and the optimal diameter is 2mm, with the optimal thickness rad of 1mm. Dynamic analysis is implemented for the support structure's FE model. Analogy experiment which make the other mirror supporting structure owned by department as the experiment object is done relying on the LMS modal analyzer. According to the requirements of the tertiary mirrorin the movement and the adjustment, the two dimensions adjustment mechanism and the turntable is designed. The function of the two-dimensions adjustment is convenient for the alignment and assemble, flexible hinge is selected as the center of tilt adjusting structure. The function of the turntable is to meet the requirement for the telescope which should switch the focus within 30 seconds. Torque motor is selected as the driving element. Utilizing the harmonic analysis method analyze the rotation error of the turntable, which is within the design allowable range.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49237
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	李明璇. 4m望远镜三镜系统研究设计[D]. 中国科学院大学,2015.

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