【作者】 陈新东；

【导师】 张学军；

【作者基本信息】 中国科学院研究生院（长春光学精密机械与物理研究所） ， 光学工程， 2012， 博士

【摘要】 空间相机在军事侦察与预警、气象观测、资源调查与环境监测、海洋探测、测绘、空间天文等领域发挥着不可替代的重要作用,然而发射过程中的巨大冲击和在轨运行状态时恶劣的空间环境可能造空间相机成像质量的下降,如何控制由温度场和力学冲击造成的波前畸变是保证系统成像质量的重要问题。目前采用的技术手段,如热控措施和离焦补偿装置等,结构复杂,达到的效果有限。为了增强空间相机的环境适应性和提升像质,论文研究在空间相机中采用主动变形镜的新技术,通过变形镜校正相机光学系统的像差,使空间相机在轨时保持较高的成像质量,并且降低热控等技术的难度。论文的主要内容包括以下四部分：1、变形镜的参数设计以某空间相机为例分析了重力释放和热耦合作用下空间相机出现的波前变化,验证其主要形式为离焦、像散和彗差,以此确定了变形镜的校正目标；分析了空间相机中应用变形镜的环境适应性需求。论文将校正目标、环境适应需求与变形镜的基本参数设计方法结合,分析了空间相机中应用的变形镜的设计原则。研究两种促动器排布方式,提出创新的孔径外排布的设计方法,并对模态法中的多项式拟合问题进行了研究。2、变形镜的有限元仿真首先介绍了有限单元法的基本原理和有限元建模技术的原则和流程；通过数值转换算法解决了有限元结果的处理和传递问题；通过仿真研究了变形镜校像差精度随促动器孔径外排布位置的变化规律,确定了优化的方案；对比了两种排布方式对像差校正精度的比较,设计方案实现了对彗差校正能力的提升。3、主动变形镜的结构设计与检测主要论述了主动变形镜实验镜的设计、分析、制造和性能检测。变形镜的采用步进电机结合联轴节作为促动器,有效了提高了促动力精度,且具备良好的线性度；采用MPC单元等关键建模技术对变形镜进行了工程分析,验证实验镜的空间环境适应性；通过磁介质辅助抛光方法完成了大径厚比反射镜面的高精度加工,面形达到RMS0.023λ;采用具备空间适应性的milbond胶实现变形镜的集成,并通过数值算法证明了粘胶仅引起镜面微量变化；利用4D干涉仪进行了静态、动态性能检测和像差校正能力测试,测试结果表明变形镜具有良好的静态和动态特性,响应频率达到28HZ,能够高精度的产生离焦、像散和彗差、精度优于λ/30。与OKO公司的37单元变形镜的对比表明,论文设计的9点促动变形镜提高了彗差的校正精度。4、主动变形镜在离轴三反系统中的应用研究开展变形镜在离轴三反系统中应用的仿真与实验研究。采用仿真方法探讨了变形镜在离轴三反系统中的应用,验证了次镜作为变形镜校正离轴三反系统像差的可行性。将设计的实验镜作为折叠镜融入到某空间相机中进行像差校正实验,该研究在国内外还未见报道。实验结果表明变形镜能够有效的降低系统像差,相机的MTF由0.364提升至0.428。本论文的研究工作围绕着应用在空间相机的变形镜技术,从分析空间相机中像差变化的特点、确定研究的变形镜类型开始,开展了主动变形镜的参数设计方法、集成仿真与优化、结构设计与分析等研究,针对彗差这种难于于校正的像差,提出了孔径外排布方式,提升了校正精度；通过工程分析验证了变形镜的环境适应性；采用干涉仪对变形镜的静态、动态特性和像差校正能力进行了检测；最后结合某空间相机的实验平台开展实验研究,实现了空间相机波前像差的有效校正。更多还原

【Abstract】 It is important to maintain the high image quality of space-borne cameras in orbit, though the environments of space are very risking and the image quality may be degraded because of force and heat reasons. Traditional thermal and misfocus control techniques are very complex with large source reqirements and limited effect.In order to improve the environment adaptive ability of space cameras, an active deformable mirror technique is proposed to be applied to space optical systems in this dissertation. The wavefront error can be corrected and the difficulties of thermal control may be reduced through applying the active deformable mirror.There are mainly four contents in this dissertation:1. Parameter design of active deformable mirrorThe wavefront variation of a space camaera under gravity release and heat is analysed. The analysis results shows that defocus, astigmatism and coma are the main wavefront error. So defocus, astigmatism and coma are the wavefront errors should be corrected by the designed deformable mirror. Some requests of deformable mirror are analysed in order to apply in space and the basic design principle are determined. Two different support topologies are compared and analysed, and a new topology based on outer effective apteure supporting is proposed. The polynomial fit methods used in modal control are investigated. 2. Simulation and design of deformable mirror using finite element methodThe main content is how to simulate the deformable mirror by finite element method(FEM). First the finite element principle and basic rules of modeling are introduced; the method of transferring the results of FEM are discussed and programmed; the law of correction accuracy vary with the postions of actuators is studied by simulation, and the scheme of actuator pattern is determined which the coma correction ablity is improved.3. Structure design and test of active deformable mirrorThe design, analysis, manufacture and test are discussed. Step motor with spring is used as the actuator. The actuators have high force accuracy and linearity. The MPC elements are used to model the jointing of structure and the deoformable mirror is analysed by FEM. The surface of deformable mirror is processed by magnetortheological polishing mehod, and the RMS of surface error is0.023A. The milbond glue is used to bond the actuator to the mirror, and it is proved that the surface quality error because of bonding is neglectable. The static, dymatic characters of deformable mirror is tested by4D interfereomter, and the response frequency is up to28HZ. Astigmatism, defocus and coma can be generated by the deformable mirror with the accuracy of λ/30. The results of comparison with OKO37channel deformable mirror shows that the designed deformable mirror improved the accuracy of coma.4. Research on application of active deformable mirror in off-axis TMA systemThe feasibility of deformable mirror in off-axis TMA system is simulated and discussed, and the system aberration can be corrected by the secondary mirror is proved. The designed mirror is inserted to the TMA system as a folded mirror, and the experiments shows that the deformable mirror can correct the wave front error of system, and the MTF is advanced to0.428from0.364The dissertation focuses on the deformable mirror techniques applying to space-borne cameras. The type of deformable mirror is initially determined according to aberration characters of space optical system, and the parameter design method, integrated modeling and optimization, structure design and analysis are developed. The correction ability of coma is improved by a new outer effective aperture actuator pattern. The charaters and application to TMA systems of deformable mirror are experimentally studied, which shows the aberration correction ablity of the deformable mirror.更多还原