Layout-stiffness-correction force joint optimization of support system for ultra-large thin meniscus mirror

Xi Xinghua; Zhang Chaojie; Hu Haifei; Guan Yingjun

doi:10.12086/oee.2020.190551

Article navigation > Opto-Electronic Engineering > 2020 Vol. 47 > No. 8 > 190551

Next Article Previous Article

Xi X H, Zhang C J, Hu H F, et al. Layout-stiffness-correction force joint optimization of support system for ultra-large thin meniscus mirror[J]. Opto-Electron Eng, 2020, 47(8): 190551. doi: 10.12086/oee.2020.190551

Citation:

Xi X H, Zhang C J, Hu H F, et al. Layout-stiffness-correction force joint optimization of support system for ultra-large thin meniscus mirror[J]. Opto-Electron Eng, 2020, 47(8): 190551. doi: 10.12086/oee.2020.190551

Layout-stiffness-correction force joint optimization of support system for ultra-large thin meniscus mirror

1.
School of Mechanical and Electrical Engineering, Changchun University of Technology, Changchun, Jilin 130012, China
2.
Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033, China
3.
School of Mechanical and Aerospace Engineering, Jilin University, Changchun, Jilin 130025, China

Fund Project: Supported by National Natural Science Foundation of China (11873007) and Central Guiding Local Science and Technology Development Fund (202002035JC)

More Information

Corresponding author: Guan Yingjun, E-mail:gyj5460@sohu.com

Received Date 19 September 2019

Revised Date 09 January 2020

Published Date 01 August 2020

Abstract

Abstract

Passive hydraulic support units (PHSUs) are frequently used in the in-situ fabrication and testing (in-situ support). However, the difference in PHSUs' stiffness will affect the mirror surface figure, especially for those thin meniscus mirrors. In order to solve this problem, the joint optimization method of layout, stiffness and active correction is studied. Firstly, for the difference of PHUS' stiffness, a hierarchical layout optimization method for support stiffness and support position is proposed to obtain the initial optimization solution of the support system. Then, the mode calibration method and the least square method is used for active correction of support system to obtain the final optimized solution of the mirror surface figure. Finally, the effectiveness of the method is verified by a numerical simulation experiment with specific cases. The results show that, for 4 m thin meniscus mirror, after layout optimization, with the hydraulic passive support system, the root mean square (RMS) of the mirror surface errors of 60 point axial support system is reduced from 150.6 nm to 32.9 nm, and the RMS value of the mirror surface errors of 78 point axial support system is reduced from 45.2 nm to 22.6 nm. The optimization effect is remarkable. After active correction, the RMS value of the mirror surface errors of 60 point axial support system is 14.6 nm, and it is 6.9 nm for 78 point axial support system. The requirement of the RMS value of the mirror surface error is less than λ/40 (λ=632.8 nm). The support systems meet the requirement. Finally, the 60 point axial support system was selected. Through the joint optimization of layout, stiffness and active correction for supporting points, it can greatly increase the applicability, flexibility and reduce the difficulty of implementation for the in-situ support system.
- layout optimization /
- active optics /
- hydraulic Whiffletree /
- stiffness difference /
- in-situ support

FullText(HTML)

References

[1]	张珑, 叶璐, 张金平, 等. 1.2m轻量化空间反射镜的重力支撑变形分离[J].光子学报, 2018, 47(7): 0722002. Google Scholar Zhang L, Ye L, Zhang J P, et al. Gravity and support error separation of 1.2 m lightweight space mirror[J]. Acta Photonica Sinica, 2018, 47(7): 0722002. Google Scholar
[2]	柳鸣, 张立中, 李响, 等.空间轻小型反射镜柔性支撑设计与动力学分析[J].光电工程, 2018, 45(5): 170686. doi: 10.12086/oee.2018.170686 CrossRef Google Scholar Liu M, Zhang L Z, Li X, et al. Design of flexure support of space compact reflector subassembly and dynamic analysis[J]. Opto-Electronic Engineering, 2018, 45(5): 170686. doi: 10.12086/oee.2018.170686 CrossRef Google Scholar
[3]	胡海飞, 罗霄, 辛宏伟, 等.超大口径光学制造均力支撑布局优化[J].光学学报, 2014, 34(4): 0422003. Google Scholar Hu H F, Luo X, Xin H W, et al. Layout optimization of equal-force supports for ultra-large optical fabrication[J]. Acta Optica Sinica, 2014, 34(4): 0422003. Google Scholar
[4]	郭鹏, 张景旭, 杨飞, 等. TMT三镜缩比系统支撑点位置优化[J].激光与光电子学进展, 2015, 52(11): 112205. Google Scholar Guo P, Zhang J X, Yang F, et al. Optimization of TMT M3 prototype's support points[J]. Laser & Optoelectronics Progress, 2015, 52(11): 112205. Google Scholar
[5]	戴晓霖.薄型主镜面形主动控制技术研究[D].北京: 中国科学院大学(中国科学院光电技术研究所), 2018. Google Scholar Dai X L. Study on the active control technology of a thin primary mirror[D]. Beijing: University of Chinese Academy of Sciences (Institute of Optics and Electronics, Chinese Academy of Sciences), 2018. Google Scholar
[6]	李宏壮, 张振铎, 王建立, 等.基于浮动支撑的620 mm薄反射镜面形主动校正[J].光学学报, 2013, 33(5): 0511001. Google Scholar Li H Z, Zhang Z D, Wang J L, et al. Active surface-profile correction of 620 mm thin-mirror based on flotation support[J]. Acta Optica Sinica, 2013, 33(5): 0511001. Google Scholar
[7]	朱熠, 陈涛, 王建立, 等. 1.23 m SiC主镜的本征模式主动光学校正[J].光学精密工程, 2017, 25(10): 2551-2563. Google Scholar Zhu Y, Chen T, Wang J L, et al. Active correction of 1.23 m SiC mirror using bending mode[J]. Optics and Precision Engineering, 2017, 25(10): 2551-2563. Google Scholar
[8]	Lan B, Wu X X, Li J F, et al. Influence of axial-force errors on the deformation of the 4 m lightweight mirror and its correction[J]. Applied Optics, 2017, 56(3): 611-619. doi: 10.1364/AO.56.000611 CrossRef Google Scholar
[9]	Hu H F, Luo X, Liu Z Y, et al. Designing a hydraulic support system for large monolithic mirror's precise in-situ testing-polishing iteration[J]. Optics Express, 2019, 27(3): 3746-3760. doi: 10.1364/OE.27.003746 CrossRef Google Scholar
[10]	陈夫林, 张景旭, 吴小霞, 等.模态振型拟合薄镜面变形分析[J].红外与激光工程, 2011, 40(11): 2238-2243. Google Scholar Chen F L, Zhang J X, Wu X X, et al. Deformation of thin primary mirror fitted with its vibration mode[J]. Infrared and Laser Engineering, 2011, 40(11): 2238-2243. Google Scholar
[11]	Noethe L. Use of minimum-energy modes for modal-active optics corrections of thin meniscus mirrors[J]. Journal of Modern Optics, 1991, 38(6): 1043-1066. doi: 10.1080/09500349114551091 CrossRef Google Scholar
[12]	范磊, 乔兵, 王富国.薄镜面力矩校正在自由谐振模式下的定标计算[J].长春理工大学学报(自然科学版), 2016, 39(3): 9-13. Google Scholar Fan L, Qiao B, Wang F G. Calibration of moment correction for thin mirror surface based on free harmonic vibration modal[J]. Journal of Changchun University of Science and Technology (Natural Science Edition), 2016, 39(3): 9-13. Google Scholar
[13]	Nelson J E, Lubliner J, Mast T S. Telescope mirror supports: plate deflections on point supports[J]. Proceedings of SPIE, 1982, 332(12): 212-228. Google Scholar
[14]	胡海飞, 赵宏伟, 刘振宇, 等. 4 m口径SiC反射镜原位检测用静压支撑系统[J].光学精密工程, 2017, 25(10): 2607-2613. Google Scholar Hu H F, Zhao H W, Liu Z Y, et al. Hydrostatic support system for in-situ optical testing of a 4 m aperture SiC mirror[J]. Optics and Precision Engineering, 2017, 25(10): 2607-2613. Google Scholar
[15]	王富国, 李宏壮, 杨飞.薄镜面主动光学对光学像差的校正能力分析[J].光子学报, 2010, 39(5): 871-875. Google Scholar Wang F G, Li H Z, Yang F. Ability of the thin mirror active optics to correct optical astigmatio[J]. Acta Photonica Sinica, 2010, 39(5): 871-875. Google Scholar

Overview

Overview

Overview: With the increasing requirements for the sensitivity, resolution and angle of view of space telescopes, the aperture of space mirror are getting bigger and bigger, which greatly increases the difficulty of mirror fabrication support. For the space mirror in the in-situ fabrication and testing, besides the influence of other factors such as temperature, the self-weight deformation has a great influence on mirror surface figure. And the larger the aperture and the higher the precision, the more difficult the support is. The self-weight deformation is mainly affected by factors such as the number of support points, the position of the support points and the stiffness of the support unit. Passive hydraulic support units (PHSUs) are frequently used in the in-situ fabrication and testing. However, some studies have found that the number of supporting units of large-aperture mirrors is too large, resulting in a large difference in the stiffness of each group of hydraulic support units, and has a great influence on mirror surface figure. It has become a hidden danger affecting the accuracy of in-situ fabrication and testing. In order to reduce the number of supporting units and increase the accuracy of the supporting surface, the joint optimization method of layout, stiffness and active correction is studied. Firstly, for the difference of PHUS' stiffness, a hierarchical layout optimization method for support stiffness and support position is proposed to obtain the initial optimization solution of the support system. Then, the mode calibration method and the least square method is used for active correction of support system to obtain the final optimized solution of the mirror surface figure. Finally, the effectiveness of the method is verified by a numerical simulation experiment with specific cases. The results show that, for 4 m thin meniscus mirror, after layout optimization, with the hydraulic passive support system, the root mean square (RMS) of the mirror surface errors of 60 point axial support system is reduced from 150.6 nm to 32.9 nm, and the RMS value of the mirror surface errors of 78 point axial support system is reduced from 45.2 nm to 22.6 nm. The optimization effect is remarkable. After active correction, the RMS value of the mirror surface errors of 60 point axial support system is 14.6 nm, and it is 6.9 nm for 78 point axial support system. The requirement of the RMS value of the mirror surface error is less than λ/40 (λ=632.8 nm). The support systems meet the requirement. Finally, the 60 point axial support system was selected. Through the joint optimization of layout, stiffness and active correction for supporting points, it can greatly increase the applicability, flexibility and reduce the difficulty of implementation for the in-situ support system.