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Proceedings Paper

A secondary mirror adjustment system with hexapod structure for optical telescope application
Author(s): Nan Zhou; Chuang Li; Wei Gao; ZongXi Song; Chao Zhao; GuoRui Ren; Nan Jing
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Paper Abstract

Benefiting from low cost, light weight and reduced volume in launch, deployable optical telescopes will be extensively applied in microsatellites. As a result of manufactured tolerance and external disturbance, the secondary mirror can’t arrive at designed position precisely after a deployable telescope is unfolded. We investigate an adjustment system with six degrees of freedom based on hexapod structure to solve this problem. There are mainly four parts in this paper. Firstly, the adjustment methods of deployable telescopes for microsatellites are introduced. Generally several kinds of optical components can be adjusted to align a deployed telescope: primary mirror, tip/tilt mirror and secondary mirror. Due to its high sensitivity and convenience, the secondary mirror is chosen to collimate the optical system of the telescope. Secondly, an adjustment system with hexapod structure is designed for a secondary mirror with 85 mm diameter. After comparing the characteristics of step motors, piezo actuators and voice coil motors (VCMs), VCMs are selected as the linear actuators. By using optical gratings as displacement sensors in the system, we can make closed-loop control come true. The hexapod structure mainly consists of 6 VCMs, 6 optical gratings and 6 oblique legs with flexible hinges. The secondary mirror adjustment system is 83 mm in diameter and 55 mm high. It has tip/tilt rotational ranges of ±2.205° with resolution of better than ±0.007°, and translational ranges of ±1.545 mm with resolution of better than ±0.966 μm. Thirdly, the maximum stress and the maximum deformation in the adjustment system are computed with finite element method. At last, the kinematics problems of the adjustment system are discussed.

Paper Details

Date Published: 2 September 2014
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Proc. SPIE 9280, 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, 92800N (2 September 2014); doi: 10.1117/12.2068311
Show Author Affiliations
Nan Zhou, Xi'an Institute of Optics and Precision Mechanics (China)
Univ. of Chinese Academy of Sciences (China)
Chuang Li, Xi'an Institute of Optics and Precision Mechanics (China)
Wei Gao, Xi'an Institute of Optics and Precision Mechanics (China)
ZongXi Song, Xi'an Institute of Optics and Precision Mechanics (China)
Chao Zhao, Xi'an Institute of Optics and Precision Mechanics (China)
Univ. of Chinese Academy of Sciences (China)
GuoRui Ren, Xi’an Institute of Optics and Precision Mechanics (China)
Univ. of Chinese Academy of Sciences (China)
Nan Jing, Xi'an Institute of Optics and Precision Mechanics (China)
Univ. of Chinese Academy of Sciences (China)


Published in SPIE Proceedings Vol. 9280:
7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes
Wenhan Jiang; Myung K. Cho; Fan Wu, Editor(s)

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