4m望远镜三镜系统研究设计

发布时间：2018-05-30 07:08

本文选题：望远镜 + 三镜　；参考：《中国科学院研究生院(长春光学精密机械与物理研究所)》2015年硕士论文

【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?rad,镜面面形的RMS误差值为1.96nm。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。
[Abstract]:With the increasing demand for observation of dark and weak targets, the need for telescope aperture is increasing. Three-mirror is an important component directly involved in the imaging of telescope optical system, and its surface accuracy is one of the key factors that affect the imaging quality of telescope. In this paper, for the 4m telescope project, the three-mirror module. 4m telescope is the largest aperture telescope undertaken by the department. The size of the three-mirror long axis will reach 500mm. The goal of the research and design is to ensure that the three mirrors maintain good surface shape accuracy, positioning and orientation error, system stiffness and efficiency when the focus is changed. This paper investigates and summarizes the large caliber ground-based telescope and its three-mirror system, and studies the basic theory of mirror support and the evaluation method of surface shape. The position of the support point is optimized by using the Slope RMS value and RMS value of the mirror shape error as objective functions, respectively. The Slope RMS error value of the optimal mirror shape is 4.05 radals, and the RMS error value of the mirror shape is 1.96 nm. According to the results of the preliminary analysis and calculation of the three mirrors of the 4m telescope, the base support scheme is composed of 6 points whiffletree structure, the side support scheme adopts the central diaphragm structure, and then the finite element software HyperMesh and Ansys are used to carry out the joint simulation analysis. The diameter of the base support rod and the thickness of the lateral support diaphragm in the flexible bracing are optimized. The optimum supporting rod is 2 mm straight and the optimum diaphragm thickness is 1 mm. The dynamic analysis of the supporting structure is carried out, and based on the LMS modal analyzer, the experimental results are carried out under the existing conditions in the laboratory. According to the requirements of the main system for the motion and adjustment of the three mirrors, the two dimensional adjusting components and the turntable of the three mirrors are designed. The function of the two-dimensional adjustment module is to facilitate the late-stage adjustment. The flexure hinge is chosen as the center of rotation for pitch adjustment. The function of the turntable is to meet the focus switching ability of the telescope system, and the torque motor is selected as the driving element. The angle sloshing of the three mirror turntable is analyzed by harmonic analysis method, which is within the allowable range of design.
【学位授予单位】：中国科学院研究生院(长春光学精密机械与物理研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH743

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