大口径空间反射镜轻量化设计及其柔性支撑

Lightweight design and flexible support of large diameter mirror in space camera

设计了空间相机1.5 m口径反射镜组件的结构系统。首先,根据反射镜材料选取原则,选用Si C作为反射镜镜坯材料。初步确定了反射镜支撑方式、镜体结构参数,并对反射镜进行轻量化设计。通过对反射镜结构参数进行优化,得到重为152.4 kg的反射镜结构,轻量化率达到83%。然后,设计了一种双轴柔性铰链结构,并找出了在装调方向柔性铰链安装位置对面形精度的影响规律,利用有限元法对反射镜组件进行了动、静态特性及热特性分析,结果表明,反射镜组件一阶固有频率为100.6 Hz,在1 g重力及4℃均匀温升工况下反射镜面形精度RMS值分别为7.7 nm和8.4 nm。最后,对反射镜组件进行动力学试验及面形精度检测,结果表明反射镜组件完全满足设计指标要求。

The structure system of a 1.5 m diameter mirror subassembly in space camera was designed. Firstly, accord-ing to the selection principle of the mirror material, SiC was chosen as the material of the mirror blank. The support ofmirror and the structural parameters of mirror were preliminarily designed and lightweight design of the mirror was car-ried out. Through the optimization of structure parameters, the weight of the mirror is 152.4 kg, and lightweight ratioreaches to 83 %. Then, a flexure hinge structure with double -axis was designed, and the effects of the flexible hingeinstallation location on surface shape accuracy were found out in adjustable direction, the dynamic, static stiffness andthermal characteristics of the mirror subassembly were analyzed by finite element method. The results indicate that thefundamental frequency of the mirror subassembly is 100. 6 Hz ,and RMS of the surface figure accuracy are 7.7 nm and8.4 nm under load of 1 g gravity and a uniform temperature rise of 4℃ respectively. In the end, the dynamic test andthe surface figure accuracy measurement were performed in the laboratory. The experimental results show that mirrorsubassembly can meet the optical design requirements completely.