正六边形反射镜支撑结构设计

Support Structure Design of a Hexagonal Reflect Mirror

研究了正六边形主镜的支撑结构组件,对主镜组件进行了材料选择、结构形式与尺寸参数设计、仿真分析和试验验证。首先,针对使用要求,对主镜进行了材料选择,确定主镜材料为微晶玻璃,并进行了轻量化设计,对边320 mm的正六边形主镜最终重量约为7 kg,轻量化率为57%;其次,确定主镜支撑采取背部三点的支撑方式,支撑点分布圆为ϕ184 mm,对支撑组件中的镶嵌件、柔节和支撑背板进行了材料选择,并给出了组件的装配工艺,采取正交试验和有限元仿真相结合的研究方法对支撑组件中的柔节进行了优化设计,给出了柔节优化后的尺寸参数,分析结果表明:在1 g、-2℃工况及1 g、2℃工况下因结构支撑引入的面形误差分别为3.9 nm RMS和5.2 nm RMS,能够满足光学指标要求;最后,对组件进行了实物试验,试验结果表明:在室温18℃下检测其面形精度RMS为0.0189λ(λ=632.8 nm),在室温20℃下检测其面形精度RMS为0.0196λ,获得了比较好的面形精度,验证了结构设计的合理性,具备良好的性能,满足系统使用要求。

The supporting structure of regular hexagonal primary mirror are studied.The material selection,structural form and dimension parameter design,simulation analysis and experimental verification of the primary mirror components are carried out.Firstly,according to the requirements,the material selection of the primary mirror is made,the material of the primary mirror is ZERODUR,and the light-weight scheme is carried out.The final weight of primary mirror with 320 mm opposite side is about 7 kg,and the lightweight rate is 57%.Secondly,the support of the primary mirror is determined to adopt a three-point support mode on the back,with the support points distributed in a circle of 184mm,and material selection of the bushing,flexible joint and A-frame are given.Optimum design of flexible joint is carried out by combining theoretical analysis with finite element simulation.Optimum dimension parameters are given for flexible joint.The analysis results show that the surface figure accuracy(RMS)of the primary mirror reaches 3.9 nm and 5.2 nm on the working conditions of 1 g,-2℃and 1 g,2℃,which can meet the requirements of optical indicators.Finally,the results of the test of the components show that the surface shape accuracy is 0.0189λunder gravity and 18℃,the surface shape accuracy is 0.0196λunder gravity and 20℃.the better surface precision is obtained,which verifies the rationality of the structure design with having good performance and meeting the requirements of the system.