Guo Peng, Zhang Jingxu, Yang Fei, Hu Haifei, Jiang Haibo
Appl Opt. 2021 Apr 1;60(10):2861-2869. doi: 10.1364/AO.405638.
For passive support of large aperture telescopes, geometric layout optimization of the support structure is one of the most critical tasks because it determines the deformation of the mirror under gravity, which affects the wavefront aberration and image quality of the system. Due to a lack of symmetry, the optimization of an elliptical mirror support can be much more complex compared with circular mirrors. We optimize the geometric layout of axial and lateral support for the tertiary mirror of the Thirty Meter Telescope (TMT). Based on a theoretical analysis of the whiffletree principle, a parametric model of axial support is established based on the multi-point constraint equation. The mirror deformation SlopeRMS of the tertiary mirror under vertical gravity is used as the optimization target of the support points. The axial support point position is optimized by means of a simulated annealing algorithm and a mirror-deformed post-processing script written in Python. The TMT tertiary mirror lateral support also uses the whiffletree structure, and its in-plane layout affects the system's resonant modal frequency and the maximum load at each point. According to the dynamic equation and the static principle, the lateral support optimization model is established. The first-order resonant frequency and maximum load of the support point are the objective function. Through optimization of the axial and lateral support, the overall mirror distortion of the system is improved.
对于大口径望远镜的被动支撑，支撑结构的几何布局优化是最关键的任务之一，因为它决定了镜面在重力作用下的变形，进而影响系统的波前像差和图像质量。由于缺乏对称性，椭圆镜支撑的优化相比圆形镜要复杂得多。我们对三十米望远镜（TMT）的三镜轴向和横向支撑的几何布局进行了优化。基于对摇臂原理的理论分析，根据多点约束方程建立了轴向支撑的参数化模型。将三镜在垂直重力作用下的镜面变形斜率均方根（SlopeRMS）作为支撑点的优化目标。通过模拟退火算法和用Python编写的镜面变形后处理脚本对轴向支撑点位置进行了优化。TMT三镜横向支撑也采用摇臂结构，其平面内布局影响系统的共振模态频率和各点的最大载荷。根据动力学方程和静力原理，建立了横向支撑优化模型。支撑点的一阶共振频率和最大载荷为目标函数。通过对轴向和横向支撑的优化，改善了系统镜面的整体畸变。
