两米环形太阳望远镜的副镜姿态校正

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	两米环形太阳望远镜的副镜姿态校正
其他题名	Attitude alignment of 2m Ring Solar Telescope secondary mirror
	王昆延
学位类型	硕士
导师	季凯帆
	2022-07-01
学位授予单位	中国科学院大学
学位授予地点	北京
培养单位	中国科学院云南天文台
学位专业	天文技术与方法
关键词	太阳望远镜副镜校正像差探测并联机构动态仿真
摘要	两米环形太阳望远镜（2mRST）是我国正在建设的最大口径环形太阳望远镜，由于它直接面对太阳进行观测，在运行过程中更容易受到热等因素的影响，重力和温度作用会引起主副镜位置关系发生变化，导致时变像差。2mRST 的焦比较小，其像质对主副镜位置关系变化更为敏感，因此需要在运行过程中对望远镜副镜姿态进行实时校正，从而对像质进行严格控制。围绕 2mRST 副镜姿态校正系统的三个重要环节：波前探测和重构、失调量计算和 Hexapod 的调节量计算，建立了系统的准静态模型并分析了其性质，对系统进行了动态仿真分析。对于失调量计算环节，由于副镜的偏心和倾斜存在耦合，且 2mRST 的视场较小，无法通过多视场的波前像差探测实现解耦。为了减小耦合对求解精度的影响，分析了“采用正则因子约束低灵敏度失调量”和“直接约束低灵敏度失调量”两种方法的校正效果。提出了正则因子对失调量约束的两种实施方案：“基于稳定 0 点位置的失调量调整”和“相对位置的失调量调整”。利用 PID 控制算法从控制带宽、系统稳定性和调节时间等方面为控制系统设计了合适的控制器。结果表明，波前探测和重构以及 Hexapod 调节量计算两个环节的求解较为稳定，实验结果表明，离焦的探测精度可以达到 10.51nm。以一定的正则因子对失调量基于稳定 0 点位置进行整体约束的校正方案能够将波面均方根误差从 0.4959λ(λ@632.8nm) 改善到 0.0062λ，且不会在连续的调整过程中累积误差，该方案更适用于 2mRST 副镜姿态校正系统。系统加入积分控制器后，2mRST 副镜姿态校正系统能在 2 分钟以内完成一次校正，且稳定性和控制带宽等性能均能达到控制系统的设计要求。
其他摘要	2m Ring Solar Telescope is the largest ring solar telescope under construction in my country. Because it directly faces the sun for observation, it is more susceptible to heat and other factors during operation. The effect of gravity and temperature will cause the position of the primary mirror and secondary mirror，resulting in time-varying aberrations. The focal ratio of 2mRST is small, and its image quality is more sensitive to changes in the positional relationship of the primary mirror and secondary mirror. Therefore, it is necessary to perform real-time attitude alignment of secondary mirror during operation, so as to strictly control the image quality. Focusing on three important links of the 2mRST secondary mirror attitude alignment system: wavefront detection and reconstruction, misalignment calculation and Hexapod adjustment calculation, the quasi-static model of the system is established and its properties are analyzed, and the dynamic simulation analysis of the system is carried out. The misalignment calculation link, due to the coupling of the decenter and tilt of the secondary mirror, and the small field of view of the 2mRST, cannot be decoupled through the detection of wavefront aberrations in multiple fields of view. In order to reduce the influence of coupling on the solution accuracy, the method of “using the regular factor to constrain the low-sensitivity misalignment”and“directly constraining the low-sensitivity misalignment”are analyzed. Two implementations of regular factor constraints on misalignment are proposed: ”alignment based on stable 0-point position” and ”alignment based on relative position”. The PID control algorithm is used to design a suitable controller for the control system from the aspects of control bandwidth, system stability and adjustment time. The results show that the solution of the two links of wavefront detection and reconstruction and Hexapod adjustment amount calculation is relatively stable. The experimental results show that the value of the defocus detection accuracy can reach 10.51nm. The correction scheme in which the misalignment is constrained based on the stable 0- point position with a certain regularity factor can improve the RMSE of the wavefront from 0.4959λ(λ@632.8nm) to 0.0062λ without accumulating errors in the continuous adjustment process. This scheme is more suitable for 2mRST secondary mirror attitude alignment system. After adding the integral controller to the system, the 2mRST secondary mirror attitude alignment system can complete a alignment within 2 minutes, and the performance of stability and control bandwidth can meet the design requirements of the control system.
学科领域	天文学 ; 太阳与太阳系 ; 太阳与太阳系其他学科 ; 机械工程 ; 仪器仪表技术
学科门类	理学 ; 理学::天文学 ; 工学 ; 工学::光学工程 ; 工学::仪器科学与技术
页数	0
语种	中文
文献类型	学位论文
条目标识符	http://ir.ynao.ac.cn/handle/114a53/25768
专题	天文技术实验室
推荐引用方式 GB/T 7714	王昆延. 两米环形太阳望远镜的副镜姿态校正[D]. 北京. 中国科学院大学,2022.

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