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Proceedings Paper • Open Access

Parameter design and experimental study of a bifunctional isolator for optical payload protection and stabilization
Author(s): Guang-yuan Wang; Xin Guan; Dong-jing Cao; Shao-fan Tang; Xiang Chen; Lu Liang; Gang-tie Zheng

Paper Abstract

With the raise of resolution, optical payloads are becoming increasingly sensitive to satellite jitter. An approach where the entire spacecraft is pointed with great accuracy requires sophisticated and expensive bus design. In an effort to lower the overall cost of space missions that require highly stable line-of-sight pointing, a method of separating the bus and the payload with low frequency isolators is proposed. This isolation system can block the transmission of disturbance and allow relatively large bus motion. However, if the isolator is linear then there is a trade-off between isolation and static deflection as the launch and the on-orbit stage have difference requirements on the isolation frequency. Otherwise, an extra locking system should be appended to protect the payload before getting into orbit, as the STABLE isolation system[1] and the MIM isolation system[2] did.

To overcome this limitation, an alternative approach is to design a nonlinear isolator with high-static stiffness during launch and low dynamic stiffness on orbit. Several specially designed nonlinear isolators have achieved low dynamic stiffness with large static load capacity. Virgin[3] considered a structure made from a highly deformed elastic element to achieve a softening spring. Platus[4] exploited the buckling of beams under axial load in a specific configuration to achieve a negative stiffness in combination with a positive stiffness, and hence low-dynamic stiffness. Others have achieved the same by connecting linear springs with positive stiffness in parallel with elements of negative stiffness[5]~[7].

In the present study, a bifunctional isolator has been developed for optical payloads. The isolator have good performance both during launch and on orbit because of its specially designed nonlinear stiffness and damping. The isolator works in a linear part with low stiffness and small damping ratio under the micro-vibration and microgravity on orbit. The transmissibility requirement and the displacement restriction during launch are satisfied by tuning the nonlinear stiffness and damping parameters. A group of sample isolators are designed tested both statically and dynamically.

Paper Details

Date Published: 20 November 2017
PDF: 7 pages
Proc. SPIE 10565, International Conference on Space Optics — ICSO 2010, 105651P (20 November 2017); doi: 10.1117/12.2309098
Show Author Affiliations
Guang-yuan Wang, Tsinghua Univ. (China)
Xin Guan, Tsinghua Univ. (China)
Dong-jing Cao, Beijing Institute of Space Mechanics and Electricity (China)
Shao-fan Tang, Beijing Institute of Space Mechanics and Electricity (China)
Xiang Chen, Beijing Institute of Space Mechanics and Electricity (China)
Lu Liang, Tsinghua Univ. (China)
Gang-tie Zheng, Tsinghua Univ. (China)

Published in SPIE Proceedings Vol. 10565:
International Conference on Space Optics — ICSO 2010
Errico Armandillo; Bruno Cugny; Nikos Karafolas, Editor(s)

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