针对超薄反射镜径厚比大,自身刚度小,更易受环境变化影响面形精度的问题,本文对一块口径500mm超薄实验镜的主动支撑方案进行了有限元分析,并提出了主动支撑方案。本文包括以下内容:1)利用有限元软件系统建立了500mm超薄镜面的有限元模型;2)利用Zernike多项式几个低阶像差来模拟镜面的制造误差和工作环境变化引起的镜面形变,得到超薄镜面上各点的误差值;3)在分别计算出各个致动器响应函数的基础上,给出了该超薄镜具有最佳主动校正能力的致动器分布的优化方案;4)通过对比不同厚度的超薄镜的主动校正能力,给出了500mm口径超薄镜的最佳厚度。

Ultra thin mirror has a large diameter-thickness rate, so it will be more deformable because of the change of work surroundings. In this paper, some analysis and computing simulation for active ultra thin mirror surface by using Finite Element Method (FEM) were introduced. An ultra thin mirror with a large ratio was simulated by software "patran". The aberrations gotten with the Zernike polynomials several low-orders were used to simulate the surface error after ultra thin mirror fabrication and the deformation because of change of work surroundings. After getting the response function of single actuator, the optimum scheme of actuator array for an ultra thin active mirror with maximum corrective capability was achieved. At last, the optimal thickness of the mirror was determined.