针对空间光学遥感器对大口径主反射镜质量轻、面形精度高的要求, 设计了一种超轻量化SiC反射镜。首先确定反射镜的轻量化方案, 之后采用集成优化方法, 在ISight软件平台上集成几何建模、有限元分析和面形拟合等设计流程并自动化运行。反射镜结构参数为优化变量, 镜体质量和面形精度RMS值为目标函数。采用第二代非劣排序遗传算法(NSGA-II)对集成优化模型进行多目标、全局性的优化求解。最后结合制造工艺调整优化结果, 得到反射镜的最终设计方案并仿真分析。结果表明, 反射镜的质量为11.4 kg, 面密度为37 kg/m2, 光轴水平工况下面形RMS值为1 nm, 一阶自由模态频率为1100 Hz。结果验证了所提出的集成优化方法的有效性。

Considering that the large aperture primary mirror of space optical remote sensor should have light weight and high surface quality,we designed an ultra-lightweight silicon carbide mirror.Firstly,the lightweight structure of the mirror was defined.Then,based on integrated optimization method,ISight software was used for implementing such design processes as geometric modeling,finite element analysis and surface fitting,and automatic operation was realized.The structure parameters of the mirror were all optimization variables,and both the mass and the RMS surface figure error of the mirror were taken as objective functions.The multi-objective,global optimization was achieved by using Non-dominated Sorting Genetic Algorithm II (NSGA-II).Finally,the optimal design was modified considering cast constraints and a verification model was constructed to evaluate the optimal design.The mass of the optimal mirror is 11.4 kg and the surface density is 37 kg/m2.Under the load of gravity vertical to the optical axis,the RMS surface figure error is 1 nm,and the first natural frequency reaches 1100 Hz.The result demonstrates the availability of the proposed approach.