经纬仪主镜在支撑系统下的面形变化

为研究在重力作用下主镜支撑系统对经纬仪主镜处于不同工作角度时面形误差的影响,以600 mm口径主镜为研究对象,利用Abaqus软件分别建立了600 mm主镜在加工状态下和工作状态下的有限元支撑模型,并进行了重力变形分析,然后借助4D干涉仪对在不同支撑系统下的主镜进行相关的面形检测。实验结果表明,在吊带支撑系统和主镜室支撑系统下,主镜的自身面形误差RMS为16.18 nm和16.90 nm。利用有限元分析了理想状态的主镜在不同仰角工况下的面形误差,结合主镜自身的面形误差,计算得到了主镜面形误差在光轴由水平变化到竖直的过程中逐渐变大,其RMS最大为19.58 nm,表明该主镜室支撑系统具有良好支撑效果,可满足工程要求,同时也验证了主镜室支撑系统有限元理论模型的准确性。

Surface deformation of theodolite primary mirror under the support system

In order to study the effect of support system on surface deformation error of theodolite primary mirror at different working angles under gravity, the 600 mm primary mirror finite element support models in processing state and working state are built using Abaqus software, and the gravity deformation analysis of the primary mirror is also carried out. Then, the related surface deformation tests of the primary mirror at different support systems are carried out using 4D interferometer. As a result, the surface deformation errors RMS of the primary mirror at strip support system and mirror room support system are 16.18 nm and 16.90 nm, respectively. The surface deformation errors of ideal primary mirror in varied elevation angles are analyzed by the finite element method. Combining with the surface deformation error in itself, it is found that the surface deformation error of the primary mirror increases gradually in the process of the optical axis changing from horizontal direction to vertical direction, and the maximum RMS is 19.58 nm. This shows the primary mirror chamber support system has an excellent supporting performance and can satisfy the engineering requirements. It is also verified that the finite element theoretical model of the primary mirror chamber support system is accurate.