临近空间816mm口径望远镜复合支撑主镜组件设计

Design of primary mirror assembly with compound support forΦ816 mm near space telescope

针对某临近空间望远镜高面形精度和0°~65°观测角度的要求,设计了816 mm口径的SiC主镜组件。依据经验公式和拓扑优化方法,完成了主镜的设计,基于大口径反射镜复合支撑原理、功能分配和指标分配以及解耦标准设计了主镜支撑组件,最后根据支撑结构形式和装配公差要求设计了主镜组件装配工装并制定了装配工艺流程。对主镜组件进行了静力学和动力学仿真验证,然后对主镜组件进行振动、面形检测和倾角等试验验证。试验结果表明,主镜组件在光轴水平,1 g重力作用下面形精度RMS值为0.019λ(λ=632.8 nm),反射镜翻转180°后的面形RMS为0.02λ;总质量为102.7 kg,基频为171 Hz,振动前后RMS值基本不变,与分析结果吻合。证明该主镜组件的设计与装调工艺的合理性,满足临近空间望远镜的设计要求。

To meet the requirements of the near-surface telescope's high surface accuracy and 0°-65°obser⁃vation angle,aΦ816-mm SiC aperture primary mirror assembly was designed.The design of the primary mirror was completed according to the empirical formula and topology optimization method.Based on the principle of compound support of large-aperture mirrors and the methods of function allocation and index al⁃location,a primary mirror support assembly was designed,and decoupling standards were formulated.Ac⁃cording to the supporting structure and assembly tolerance design requirements for the primary mirror component assembly tooling and assembly process.Finite-element software was used to verify the statics and dynamics of the primary mirror assembly,and the primary mirror assembly was verified by performing ex⁃periments such as vibration,surface shape detection,and inclination.The test results show that the prima⁃ry mirror assembly is at the optical axis level,RMS value of the profiling accuracy under the action of 1 g gravity is 0.019λ(λ=632.8 nm),and RMS of the surface shape after the mirror is turned by 180°is 0.02λ.The total mass is 102.7 kg,fundamental frequency is 171 Hz,and RMS values before and after vi⁃bration are unchanged,which is consistent with the analysis results.The results proved that the design and installation process of the composite support are reasonable,and that they meet the design requirements of near-space telescopes.