高精度次镜支撑结构设计及其稳定性验证

Design and Test of High Precision and Stability Support Structure for Secondary Mirror

在同轴三反射镜消像散(TMA)大口径长焦距相机中,次镜支撑为大质量悬臂结构,该相机系统对次镜的位置精度有较高要求,为提高次镜支撑的动力学特性,保证结构尺寸稳定性,采用理论研究和有限元分析相结合的方法设计了一种轻质高刚度高稳定支撑结构,组件质量为4.5 kg。分析及试验结果表明,组件一阶频率较高达到104 Hz,动力学特性较好。同时设计了结构稳定性试验装置及测试方法,结果表明:经过多次振动,结构尺寸稳定在3μm以内,组件具有较高抗振稳定性;热真空循环试验前后,结构尺寸亦未发生改变,支撑结构具有较高稳定性,满足空间应用要求。目前该支撑结构已应用于某些高分辨率空间相机中,并为高分辨率、轻质、敏捷空间相机设计提供参考。

For on-axis three mirror astigmatism(TMA) space camera with large aperture and long focus,the secondary mirror support is a big mass cantilever.In order to improve the dynamic characteristics and ensure support structure stability,a lightweight support structure with high stiffness and stability is designed by theory and finite element analysis.The assemble weighs less than 4.5 kg.The analysis and test results show that the frequency of the first mode is 104 Hz and the dynamic characteristic is good.The dimension stability is less than 3 μm through dynamic vibration and thermal vacuum circle by self-designed method and device,and the structure size does not change.Stability test results show that the barrel design is reasonable and has high stability.At present,the support structure is adopted in some high resolution space camera,which would be referenced by high resolution,lightweight,and agile camera design.