Development and testing of a high-precision high-stiffness linear actuator for the focus-center mechanism of the SOFIA secondary mirror

Zago, Lorenzo; Schwab, Philippe; Gallieni, Daniele

doi:10.1117/12.389116

Cited by 5 publications

(4 citation statements)

References 1 publication

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“…16,23,24 While these mechanisms belong in the first category since large separations are desired, similar techniques can be applied to designing optomechanical interfaces, which typically require high stiffnesses in order to control motion to a fraction of a wavelength. [25][26][27][28] Since flux pinning resists changes to the magnetic field distribution inside the superconductor, one design approach is to shape the magnetic field so that it is constant in directions where motion is desirable. For example, to allow only translation along a line, like a parallel-blade flexure, one mechanism design consists of a cubical superconductor pinned between two long cylindrical magnets [ Fig.…”

Section: Flux-pinning Mechanismsmentioning

confidence: 99%

Flux-pinning mechanisms for improving cryogenic segmented mirror performance

Gersh-Range

Arnold

Lehner

et al. 2014

J. Astron. Telesc. Instrum. Syst

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Although large cryogenic space telescopes may provide a means of answering compelling astrophysics questions, the required increase in the primary mirror diameter presents technical challenges. Larger primaries are more flexible, and cryogenic mirrors are typically very lightly damped-the material damping is negligible, and common damping methods break down. To address these challenges, we propose placing flux-pinning mechanisms along the edges of adjacent mirror segments. These mechanisms consist of a collection of magnets and superconductors, and like flexures, they preferentially allow motion in specific degrees of freedom. Motion in nonpreferred degrees of freedom is resisted by a force analogous to a damped spring force, and the stiffness and damping can be adjusted independently. As an example, we consider simple mechanisms consisting of an inexpensive magnet and a single superconductor. These mechanisms provide increasing resistance as the magnet and superconductor-or mirror segments attached to each-come closer to colliding. These mechanisms, with typical stiffness and damping values on the order of 5000 N∕m and 5 kg∕s, respectively, also provide modest improvements to the mirror performance. Greater gains can be achieved by using stronger magnets or smaller separations, or by placing nonmagnetic conductive materials near the mechanism.

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Section: Flux-pinning Mechanismsmentioning

confidence: 99%

Flux-pinning mechanisms for improving cryogenic segmented mirror performance

Gersh-Range

Arnold

Lehner

et al. 2014

J. Astron. Telesc. Instrum. Syst

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“…These measures cause a sacrifice in the optical performance and an increase in system weight. For large-aperture space telescopes, a six-degrees-of-freedom (DOF) mechanism was designed for correction [ 3 , 4 ]. However, there are few reports about the adjustment mechanism for TMA optical systems with a large aperture and super aspect ratios.…”

Section: Introductionmentioning

confidence: 99%

Design of a Focusing Mechanism Actuated by Piezoelectric Ceramics for TMA Telescope

Chen

Zhu

2023

Sensors

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With the development of space telescopes towards high-resolution and intelligent imaging, the scale and complexity of the focal plane components of large-aperture, off-axis, three-mirror anastigmatic (TMA) optical systems are increasing. Traditional focal plane focusing technology reduces the system reliability and increases the scale and complexity. This paper proposes a three-degrees-of-freedom focusing system based on a folding mirror reflector, with a piezoelectric ceramic actuator as the driver. An environment-resistant flexible support was designed for the piezoelectric ceramic actuator through an integrated optimization analysis. The fundamental frequency of the large-aspect-ratio rectangular folding mirror reflector focusing mechanism was around 121.5 Hz. After testing, it was found to meet the requirements of the space mechanics environment. This system shows promise for application to other optical systems as an open-shelf product in the future.

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“…It offers many advantages, such as high stiffness, six degrees of freedom of adjustment, and non-accumulation of position errors [12]. In addition to five DOFs of adjustment, the SOFIA sub-mirror has a fast chopper with frequencies up to 20 Hz [13,14]. This paper deals with the design of the secondary mirror adjustment in the context of a large vehicle-mounted telescope.…”

Section: Introductionmentioning

confidence: 99%

Design of a Dynamic Secondary Mirror Truss Adjustment Mechanism for Large Aperture Telescopes

Wang

Zhang

2023

Applied Sciences

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This study focuses on the dynamic secondary mirror truss adjustment mechanism for large aperture telescopes. The relative positions between the primary and secondary mirrors have stringent requirements for large aperture optical telescopes, with an aperture of more than 2 m. Due to the large mass of the primary mirror, the secondary mirror system is designed as an adjustable mechanism with multiple degrees of freedom, dramatically impacting telescope imaging. The kinematic modeling is followed by a detailed description of the designed adjustment mechanism, and then a static and modal analysis of the designed mechanism is performed. Subsequently, a kinematic performance test of the experimental prototype is conducted. The developed mechanism can travel up to ±5 mm in the z-direction with an accuracy of 16 µm and deflection of ±0.574° in the xy-direction. It provides accuracy better than 6.4 arcseconds.

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Development and testing of a high-precision high-stiffness linear actuator for the focus-center mechanism of the SOFIA secondary mirror

Cited by 5 publications

References 1 publication

Flux-pinning mechanisms for improving cryogenic segmented mirror performance

Flux-pinning mechanisms for improving cryogenic segmented mirror performance

Design of a Focusing Mechanism Actuated by Piezoelectric Ceramics for TMA Telescope

Design of a Dynamic Secondary Mirror Truss Adjustment Mechanism for Large Aperture Telescopes

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