ASO-S/FMG稳像系统的柔性支撑摆镜设计与仿真

全日面矢量磁像仪(Full-disk vector MagnetoGraph, FMG)是先进天基太阳天文台(Advanced Space-based Solar Observatory, ASO-S)的主载荷之一,摆镜作为FMG稳像系统的重要组成部分,其力学性能是决定载荷观测指标的重要一环,需要对其进行仿真.设计了一种侧面固定的柔性支撑镜体结构,通过调整垫片厚度,可以得到由弹性压片提供的不同大小支持力.为了确定合理的支持力范围,建立3种不同参数模型,使用有限元软件对摆镜模型进行了在轨无重力环境的静力学仿真以及摆镜摆动频率为100 Hz、摆幅为±0.1 mrad时的动力学仿真,并进一步分析了地面有重力试验环境对面形的影响.仿真结果表明所设计的摆镜机构模型均满足通光口径内静态和动态的面形波峰波谷差(PeakValley, PV)小于1/10波长,面形均方根误差(Root Mean Square, RMS)小于1/40波长的光学系统要求,地面有重力环境不会对面形产生显著影响.在仿真结果的基础上,对其中一种模型进行加工装配和实际测试,测试结果表明摆镜结构设计合理,仿真计算结果有效.

Design and Simulation of a Flexible-support Tip/tilt Mirror in the ASO-S/FMG Image Stabilization System

The Full-disc vector MagnetoGraph (FMG) is one of the payloads deployed in the Advanced Space-based Solar Observatory (ASO-S). As an important part of the FMG image stabilization system, the tip/tilt mirror will determine the observational performance of the payload. Therefore, it is necessary to analyze the mechanical performance of the tip/tilt mirror. In this paper, we design a side-fixed flexible supporting mirror structure, of which the supporting force is provided by elastic presser, and the force can be changed by adjusting the thickness of mirror shims. In order to determine the appropriate thickness setting, we construct 3 models with different parameters. For each model, we simulate static analysis and transient dynamic analysis at 100Hz and pm0.1mrad in zero gravity field by finite element software. The effect of gravity on the surface is also considered. Simulation results show that the designed tip/tilt mirror meets the performance requirements of the optical systems, PV (Peak-Valley) $<$ 1/10 wavelength, RMS (Root Mean Square) $<$ 1/40 wavelength, and gravity has no significant effect on the surface. Based on the simulation results, we further process, assemble, and test one of the models. Test results verify that the design of the tip/tilt mirror structure is satisfactory, and the simulation results are valid.