2m SiC反射镜柔性被动支撑系统

摘要

针对2m SiC反射镜在地基望远镜中的应用,结合SiC反射镜热膨胀系数大、重量轻的特点,设计了柔性被动支撑系统.该系统底支撑w hiffletree结构中的支撑杆采用柔性细杆,侧支撑杆采用柔性铰链结构,从而使底支撑系统和侧支撑系统分别起支撑作用,不但保证了主镜良好的位置误差和形状误差还很好地消除了装配应力和热应力.对在支撑系统作用下反射镜进行了静力学分析、热力学分析和模态分析,并通过面形检测和主镜倾斜与平移检测验证了分析结果.检测显示:反射镜面形(RMS)达到λ/40(光轴竖直)和λ/16(光轴水平),主镜指向不同俯仰角时最大倾斜变化量为8″,偏心为0.0707 mm,基本与分析结果吻合,达到了设计要求,表明这种柔性支撑系统具有很好的工程应用能力.%To apply SiC mirror in a ground-based telescope ,a flexible passive support system was de-signed on its high thermal expansion coefficient and high rigidity .In this system ,a thin and long flex-ible rod was used in the axial support whiffletree structure and a flexure joint rod wad used in the lat-eral support structure .By w hich ,the axial support structure and the lateral support structure could support the system respectively .This structure not only allows the primary mirror to be a good posi-tion and a shape but also easily eliminate assemble stress and thermal stress .The static analysis ,ther-mal analysis and modal analysis for the mirror were performed under the support system ,and then the analytical results were verified by a surface test ,mirror inclination test and a displacement test .The test result of the primary mirror shows that the surface error (RMS) is λ/40(the optical axis is verti-cal) and that (RMS ) isλ/16 (the optical axis is horizontal ) ,the maximum inclination change of the primary mirror at different pitch angles is 8 "and the displacement is 0 .0707 mm .The test results are basically consistent with the analysis results ,meeting the design requirements .It shows that this flexible passive support system has good engineering feasibility .