面向快速成像的全碳相机热设计研究

	面向快速成像的全碳相机热设计研究
	孔林
学位类型	博士
导师	金光
	2014-07
学位授予单位	中国科学院大学
学位专业	光学工程
摘要	随着航天技术的发展，“快速响应空间”的概念得到了广泛的关注，新理念对航天器各分系统及有效载荷的设计带来新的挑战，空间光学遥感器是一类重要的有效载荷，是获取地面图像信息的主要来源，为提高对突发事件、自然灾害等的响应速度以及适应“快速响应空间”技术，实现面向快速成像的应用需求，空间相机面临着巨大的挑战，这包括：快速入轨或变轨，在任务到达后，即刻具备发射条件或在轨卫星能够通过变轨实现对特定地区成像，这就要求空间相机能够和其他单机一样具备货架产品特性，因此，空间相机在设计时必须考虑多任务的适应性；入轨后快速获取图像，相机入轨后，通过调焦等手段，快速确定焦面位置，具备成像条件，这要求必须建立相机的温度-焦面特性以及确定相机入轨后温度变化规律；支持固体运载，控制发射成本，这要求相机具有较高的轻量化率，因此，必然要大量使用高比刚度碳纤维材料，因此需要实现全碳相机的轻型热设计。纵观空间相机的研制过程，热控分系统作为重要的保障条件，不仅贯穿整个周期，也是相机成像质量的重要影响因素，同时相机在轨的温度环境是制约相机快速成像能力的决定因素之一，本文以实际工程项目为背景，围绕快速成像相机的热控的关键技术问题，结合国内外“快速响应空间”的热控理念及新技术，从不同层次保证了空间相机快速成像的应用需求。针对上述内容，本文主要开展了以下几方面的研究工作：1. 介绍了“快速响应空间”的概念以及国内外发展现状，介绍了国内外碳纤材料在空间相机中的应用，在此基础上，综合了国内外关于“快速响应空间”的热设计及空间相机热设计，提出了面向快速响应的空间相机热设计的解决途径。2. 研究了空间外热流和轨道参数的关系，提出以轨道参数组合，相机热控功耗为评价的极端工况设计方法，对300km~900km的近地轨道外热流进行了研究，分析得到特定相机的极端工况轨道参数，研究了相机拍照过程主镜外热流变化对主镜温度的影响，在此基础上考虑了星上资源有限情况下，通过降低相机温度水平的方法，建立了相机温度水平与热控功耗的关系。3. 建立了空间相机支撑桁架温度梯度数学模型，分析了温度梯度与外热流、加热器布局的关系，为实现碳纤结构的等温化鲁棒设计，提出一种使用高导热率柔性石墨薄膜的轻型热控方案，分析并验证了热控效果。在此基础上，完成了相机的热设计，分析了相机极端工况条件下的温度分布，同时研究了相机初始入轨温度变化规律，建立了相机具备拍照温度条件与初始入轨温度的关系。4. 介绍了温度对光学系统及焦面位置的影响，介绍了光机热集成分析方法，使用集成分析的方法建立了相机温度-焦面关系，研究了相机极端工况、对地拍照过程及初始入轨后，焦面变化规律，分析了相机不同组件温度变化对焦面位置的影响，在此基础上，提出基于主敏感因子温度-焦面敏感矩阵，实现相机在轨温度调焦的方法，并给出了相机调焦量和主敏感因子温度的调焦矩阵。5. 介绍了空间相机空间环境模拟方法，在此基础上制定了详细的试验流程，并开展了相机热平衡及热光学试验，同时开展了相机初始入轨热试验以及非稳态热光学试验，热平衡及初始入轨热试验验证了热设计及热分析的正确性，相机稳态热光学试验调焦量和本文的分析结果十分吻合，验证了本文的集成分析方法和温度调焦策略，相机非稳态热光学试验调焦量和分析结果趋势一致，但存在较大差异，分析了可能的原因，并设想了一种拟合方式，拟合公式和试验结果十分吻合。
其他摘要	With the development of space technology, the concept of Operationally Responsive Space (ORS) has gained much attention, and the new concept of spacecraft presents new challenges for the design of all the subsystems and payloads. Space optical remote sensing is an important class of the payloads, which is one of the main resources for the acquisition of ground information. To improve the response to emergencies, natural disasters and so on, the realization of responsive imaging was demanded while many challenges were in the exploring of this topic. The enormous challenges for the design of space camera including: fast orbiting, rapid imaging and deliverability. Fast orbiting requires instant launching for arrived tasks such that the space camera should compatible to muliti-tasks. Rapid imaging was based on fast focusing which requires establishing temperature-defocusing formula in advances to determine the position of focal plane. Deliverability, namely, the camera should be light enough by using carbon fiber reinforced plastics (CFRP) which lead to difficulties in heat transfer. Throughout the development process of space camera, thermal control subsystem (TCS) secures the safety and is also the key that determine the image quality and rapid imaging capability of camera. This work, with actual project as background, focuses on thermal control of responsive imaging space camera whit new technologies and ORS thermal control concepts to develop a methodology from different levels to meet the demand for responsive imaging. The guideline of this work is following:1. First, the concept of ORS and its development was introduced, and CFRP materials were discussed, based on which the solutions to design of responsive imaging camera were put forward.2. Study of the correlation of heat flux and orbital parameters was conducted. A single hot- and cold-case design orbits was found. Further, the effect of heat flux to the primary mirror in the imaging process was studied. Considering the limited resources on the spacecraft, the relation between power and camera temperature was built.3. Mathematical model of heat transfer of the supporting truss was established. Analysis of temperature gradient caused by space environment and heaters layout was explored. To achieve robust isothermal design of CFRP structure, this work presents a high thermal conductivity, lightweight and flexible graphite film as thermal control solutions. On this basis, the thermal design of the camera was done, and the relationship between the first imaging time and the camera’s temperature after on orbit was established.4. This work also describes the effect of temperature on optical system especially on defocusing. By introducing the integrated structure-thermal-optical performance (STOP) analysis methods, relations between temperatures and defocusing was established. Based on it, sensitivity matrix of temperature-defocusing was proposed which leads to achieving of focusing on orbit.5. Last but not least, presented work introduces space environment simulation of camera. Both of thermal balance test and thermal optical test were carried out and the test validation was conducted to testify the analysis, and the test results match what proposed theories predict.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41421
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	孔林. 面向快速成像的全碳相机热设计研究[D]. 中国科学院大学,2014.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
孔林.pdf（5892KB）			开放获取	CC BY-NC-SA	请求全文