针对空间相机快速反射镜的工作条件和工作要求, 提出了快速反射镜的结构轻量化设计方案。以100 mm口径圆形反射镜为研究对象, 设计了利用加强筋减重的反射镜轻量化结构, 并提出了基于镜面抗弯刚度等效的等效标准圆镜厚度的计算方法; 分别设计了基于镶嵌体结构的背部三点支撑方案和背部中心支撑方案, 有限元对比分析的结果表明, 采用背部中心支撑方案可以避免镜座与反射镜之间因温度变形不协调引起的多个支撑点相互干涉, 镜面面形精度较高, 并且由于结构简单, 其摆动组件的总质量更轻; 为了进一步提高快速反射镜结构的综合性能, 同时以摆动组件的总质量及镜面面形的均方根值为优化目标, 对背部中心支撑方案下快速反射镜的主要结构参数进行了多目标优化, 优化结果显示, 加强筋的高度和镶嵌体的壁厚对结构综合性能的贡献最大; 最终优化方案下快速反射镜的摆动组件总质量仅为95.75 g, 结构的一阶谐振频率为217 Hz, 在-8 ℃温度载荷的作用下, 镜面面形的RMS为7.26 nm, 满足设计要求的同时, 反射镜实现了40.4%的轻量化率。

Aiming at the working conditions and working requirements of the fast steering mirrors for space cameras, a lightweight scheme for fast steering mirrors was proposed. Taking the mirror with a diameter of 100 mm as the research object, the lightweight structure based on ribs was designed, and the calculation method of the equivalent thickness of standard circular mirror was proposed. Two supporting methods of the mirror, rear support with three points or rear support with a central point, were designed separately, and the results of the contrastive analysis indicate that mirror supported with a central point can avoid mutual interference between multiple support points, which is caused by inconsistent temperature deformation of the holder and the mirror. The accuracy of the mirror surface is higher, and because of its simple structure, the total mass of the wobble assembly is lighter. In order to achieve the best overall performance of the fast steering mirror structure, a multi-objective optimization of the main structural parameters was executed, the total mass of the wobble assembly and the RMS value of the mirror surface were simultaneously used as the optimization goals. The optimization results showed that the rib height and the adapter thickness contributed the most to the overall performance of the structure. The total mass of the wobble assembly under the optimized scheme is only 95.75 g, and the first-order resonant frequency of the structure is 217 Hz, the RMS of the mirror surface is 7.26 nm under the condition of -8 ℃ temperature load, which meets the design requirements while achieving a 40.4% reduction in the weight of the mirror.