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题名	拼接望远镜主动控制中的光学测量
作者	袁沭
学位类别	博士
答辩日期	2012-11-23
授予单位	中国科学院研究生院（云南天文台）
授予地点	北京
导师	刘忠
关键词	主动光学 拼接望远镜主动控制 光学测量 局地大气环境
其他题名	Optical Measurement in Segmented Telescope Active Control
学位专业	天文技术与方法
中文摘要	8米环境拼接太阳望远镜是中国未来巨型太阳望远镜(Chinese Giant Solar Telescope, CGST)计划中的重要方案。在主动控制方面，环形拼接望远镜的问题在于自由度探测不足，因此需要附加光学倾斜测量才能实现主动控制的闭环。本文主要内容在于高精度光 学测量方法在拼接望远镜主动控制中的应用，面临的主要问题，以及解决方法。目的是为CGST计划的环形拼接望远镜方案提供一种可能的主动控制光学测量方法。 论文在开篇首先介绍了主动控制的基本概念，原理，过程，以及要求。着重说明了环形拼接望远镜主动控制的特点。 第二章介绍了用于拼接望远镜主动控制中的光学测量方法和传感器，并提出了三种实现环形拼接子镜倾斜控制的光学测量方案。基于在控制精度、带宽以及热敏感方面的考虑，最终选择了基于Shack-Hartmann波前探测器的内光源倾斜测量方法作为进一步讨论的对象。 第三章分别对该方法的探测器噪声、子镜热变形、大气湍流噪声、环境温度梯度引起的倾斜测量误差进行了分析。经过比较指出大气湍流引起的随机波前位相起伏是光学倾斜测量最重要的误差源。 论文在第四章计算了在局地大气湍流环境中各子镜间较差倾斜测量湍流误差。并提出使用快速短曝光时间积分抑制湍流噪声的测量方法。基于Taylor大气冻结假设，计算了不同子镜间，不同的风速风向下的测量误差随积分时间增加而下降的过程。结果表明，在一定的通风速度条件下， 高频面形误差能够实现更快的测量，而低频面形误差的测量要慢得多。 论文在第五章讨论了局地环境与主动控制光学测量的关系，并提出建立环境控制与主动控制结合的综合系统构想。同时介绍了近地湍流强度与高度、圆顶视宁度与地板热通量、镜面视宁度的半经验理论模型。最后是温度梯度场地测量的结果。 结论认为，通过合理的环境控制与望远镜热设计，环形拼接望远镜能够实现高精度的光学测量主动控制。关键在于主动控制要与环境控制建立良好的配合。
英文摘要	The 8m ring segmented telescope is an important candidate solution for the Chinese Giant Solar Telescope project in the future. Being different from these full aperture segmented telescope, the ring segmented telescope need an additional tip sensing for closing the active control loop. Optical measurement method is a good choose for tip sensing, as its inherent sensitivity for angle measurement. This thesis focus on the discussion about the application of high accuracy optical measurement method to the segmented telescope active control, and the primary problem for the application, and the solution for the problem. The goal of these discussions is to propose a real-time optical measurement method for active control of the ring segmented solar telescope. The basic concept, principle, process, and requirement of the active control are presented in the chapter 1. While, the characteristic of the ring segmented telescope active control is emphasized in this chapter. The optical measurement method and optical sensor for active control is reviewed, and three candidate solutions of tip sensing for the ring telescope are proposed in the chapter 2. Based on the consideration of accuracy, bandwidth, thermal sensitivity, an internal optical metro-logy developing from Shack-Hartmann wavefront sensor is chose for further discussion. The tip measurement error from detector noise, thermal distortion of segments, turbulence noise, and the temperature gradient of environment is analyzed in the chapter 3. To compare these errors, it's found that the phase fluctuation caused by the turbulence is the most serious error source in these three. The turbulence error of differential tip measurement among these segments is derived in the case of local turbulence environment. Then, a temporal integral measurement method is proposed for suppressing the turbulence noise. Based on the Taylor's atmosphere frozen hypothesis, the curve of the error falling with the increasing of integral time is calculated with different pair of segments, and different case of ventilation. The result show that the high frequency surface error on the ring primary mirror can be corrected more quick than the low frequency error in the case of ventilation, when the control accuracy of different error mode is same. The relationship between the local atmosphere environment and optical measurement of active control is discussed in the chapter 5. Then an idea of constructing a synthetic system composed of environment control and active control is proposed. Then, a semi-empirical theoretical model of local seeing is introduced for environment control. And a result of temperature gradient measurement in field is shown in the end. The conclusion is that a high accuracy active control with optical metrology can be achieved, by proper environment control and thermal control. The point is a good cooperation between active control system and environment control system.
语种	中文
学科主题	天文学
页码	81
内容类型	学位论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/4906]
专题	云南天文台_抚仙湖太阳观测站
推荐引用方式 GB/T 7714	袁沭. 拼接望远镜主动控制中的光学测量[D]. 北京. 中国科学院研究生院（云南天文台）. 2012.

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