光学精密工程2017，Vol.25Issue(10)：2607-2613,7.DOI:10.3788/OPE.20172510.2607
4m口径SiC反射镜原位检测用静压支撑系统
Hydrostatic support system for in-situ optical testing of a 4 maperture SiC mirror
摘要
Abstract
A set of hydrostatic support system for a 4 m SiC mirror in-situ testing was designed to re-duce the risk of ultra-large mirror off-line testing and to improve fabrication efficiency .Firstly ,the analytical formula for calculating support stiffness was derived ,and its main factor was found .Then , some support samples were tested ,and the support stiffness of a single support unit in different groups was predicted by combining the sample results and analytical formula .Finally ,the stability of the support system was evaluated by pressurization test and in-situ testing ,and the mirror surface precision with its gravity offloaded by the support system was calculated by finite element simulation . Results show that the average stiffness is about 1 .9 kN/mm with a relative difference among support units about 3％ w hen 5 units are linked together ,the stiffness for a single unit isolated is as high as 15 kN/mm ,and 3 kinds of unit stiffness in the support system are 1 .7 ,1 .1 and 0 .8 kN/mm respectively . Moreover ,pressurization test shows a slow pressure change ,which indicates that the system is well sealed .When the hydrostatic system was used for a 4 m mirror ,the height changes rise up and down within 50 μm in 11 days ,and the relative change is less than 20 μm .When the mirror is supported on 54 units with stiffness difference by 3％ randomly ,the surface RMS is less than 20 nm .The proposed system meets the requirement of in-situ optical testing for precision and stability .关键词
超大SiC反射镜/原位光学检测/静压支撑系统/刚度差异/面形精度Key words
ultra-large SiC mirror/in-situ optical testing/hydrostatic support system/stiffness differ-ence/figure accuracy分类
机械制造引用本文复制引用
胡海飞,赵宏伟,刘振宇,罗霄,张学军..4m口径SiC反射镜原位检测用静压支撑系统[J].光学精密工程,2017,25(10):2607-2613,7.基金项目
国家自然科学基金资助项目(No.61210015,No.61605202) （No.61210015,No.61605202）
