视频空间相机Φ330mm口径主镜组件设计

Design of the Φ330mm Primary Mirror Assembly of Spaceborne Video Camera

为满足视频空间相机中反射镜组件的轻量化、高刚度、高稳定性和短加工周期的要求,采用基于ZERODUR微晶玻璃的背部单拱形镜体轻量化方案,设计了一种外圆芯轴粘接的柔性支撑结构.通过有限元工程分析与基于响应面优化设计,确定了支撑结构的最优尺寸.对反射镜组件进行了模态试验,并完成了镜面的非球面光学加工与检测.试验结果表明:主镜组件的一阶自然频率为332.5 Hz,与分析结果之间的相对误差为2.5%;主镜组件在绕光轴分别旋转0°、120°与240°方向进行光学检测时,面形精度均方根值均优于λ/40,实现了地面重力对反射镜面形检测零影响,组件满足设计要求.

Crucial requirements were proposed on the Primary Mirror Assembly （PMA）, such as high lightweighting, high stiffness, high stability and short manufacturing cycle. In order to satisfy those, a meniscus-like mirror lightweighting scheme based on ZERODUR was designed, and the flexural support structure bonded to the outer ring of the mirror shaft was optimized. Through a finite element analysis and design approach, the optimal dimensions of the flexural support were obtained. In order to verify the finite element analysis results, a modal test was performed on the PMA, and the required aspherical optical surface was polished and tested. Test results show that, the first natural frequency of PMA is 332.5 Hz, the relative deviation is only 2.5% to compare with the analysis result; the surface figure of PMA maintains a constain RMS of λ/40 while rotating at 0°, 120° and 240° around the horizontal optical axis respectively; the influence of zero-gravity state is achieved on surface figure of PMA. The PMA satisfies the design requirements.