Design and optimization of integrated flexure mounts for unloading lateral gravity of a lightweight mirror for space application

Zhang, Liu; Wang, Tailei; Zhang, Fan; Zhao, Huanyu; Zhao, Yu; Zheng, Xiaohui

doi:10.1364/ao.414054

Cited by 14 publications

(6 citation statements)

References 23 publications

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“…The modal frequency and mass are negatively correlated as follows:

where

is the modal angular frequency,

is the rigidity coefficient, and

is the mass. Thus, the masses of the two mirrors were adjusted to be equal to compare the mechanical properties accurately [ 24 ]. Since the closed-back scheme has a back plate, the mass is heavier under the same conditions.…”

Section: Structural Design and Finite Element Analysismentioning

confidence: 99%

Design and Fabrication of an Additively Manufactured Aluminum Mirror with Compound Surfaces

et al. 2022

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Microsatellites have a great attraction to researchers due to their high reliability, resource utilization, low cost, and compact size. As the core component of the optical payload, the mirror directly affects the system package size. Therefore, the structural design of mirrors is critical in the compact internal space of microsatellites. This study proposes a closed-back mirror with composite surfaces based on additive manufacturing (AM). Compared with the open-back mirror, it provides excellent optomechanical performance. In addition, AM significantly reduces the intricate mechanical parts’ manufacturing difficulty. Finally, the roughness was better than 2 nm. The surface shape of the AM aluminum mirror reached RMS 1/10λ (λ = 632.8 nm) with the aid of ultra-precision machining technologies such as single-point diamond turning (SPDT), surface modification, and polishing, and the maximum deviation of the surface shape was about RMS 1/42λ (λ = 632.8 nm) after the thermal cycle test, which verified the optical grade application of AM.

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“…The modal frequency and mass are negatively correlated as follows:

where

is the modal angular frequency,

is the rigidity coefficient, and

Section: Structural Design and Finite Element Analysismentioning

confidence: 99%

Design and Fabrication of an Additively Manufactured Aluminum Mirror with Compound Surfaces

et al. 2022

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“…This inconsistency between alignment status and usage status will inevitably, more or less, lead to a decline in the performance of the optical system. Namely, the supporting structure of the primary mirror needs to have sufficient rigidity to resist gravity deformation or deformation caused by external acceleration [ 15 ]. Furthermore, the working temperature of the optical system inside the aerial optoelectronic sensor in this paper can usually be maintained within a wide range of temperature change (−10~+50 °C) with an active-passive combined thermal control measures.…”

Section: Performance Requirementsmentioning

confidence: 99%

Design and Optimization for Mounting Primary Mirror with Reduced Sensitivity to Temperature Change in an Aerial Optoelectronic Sensor

Zhang

Qi-peng

Tian

et al. 2021

Sensors

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In order to improve the image quality of the aerial optoelectronic sensor over a wide range of temperature changes, high thermal adaptability of the primary mirror as the critical components is considered. Integrated optomechanical analysis and optimization for mounting primary mirrors are carried out. The mirror surface shape error caused by uniform temperature decrease was treated as the objective function, and the fundamental frequency of the mirror assembly and the surface shape error caused by gravity parallel or vertical to the optical axis are taken as the constraints. A detailed size optimization is conducted to optimize its dimension parameters. Sensitivities of the optical system performance with respect to the size parameters are further evaluated. The configuration of the primary mirror and the flexure are obtained. The simulated optimization results show that the size parameters differently affect the optical performance and which factors are the key. The mirror surface shape error under 30 °C uniform temperature decrease effectively decreased from 26.5 nm to 11.6 nm, despite the weight of the primary mirror assembly increases by 0.3 kg. Compared to the initial design, the value of the system’s modulation transfer function (0° field angle) is improved from 0.15 to 0.21. Namely, the optical performance of the camera under thermal load has been enhanced and thermal adaptability of the primary mirror has been obviously reinforced after optimization. Based on the optimized results, a prototype of the primary mirror assembly is manufactured and assembled. A ground thermal test was conducted to verify difference in imaging quality at room and low temperature, respectively. The image quality of the camera meets the requirements of the index despite degrading.

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“…In the literature, a tangential flexure strap has been employed on a three-point side-supported circular mirror to reduce the surface thermal sensitivity. Since then, three-point support systems that employ various flexures have been widely used [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. This group of mirror mount systems mainly uses radial flexure to reduce the TCML sensitivity due to CTE mismatch across the interface [ 15 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Contributions of Support Point Number to Mirror Assembly Thermal Sensitivity Control

Zhang

Ding

et al. 2023

Sensors

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Due to the extreme environmental temperature variations, solutions that enable ultra-low thermal sensitivity in a mirror assembly are crucial for high-performance aerial optical imaging sensors (AOIS). Strategies such as the elimination of the coefficient of thermal expansion (CTE) mismatch and the employment of a flexure connection at the interface cannot be simply duplicated for the application involved, demanding specific design constraints. The contributions of support point number to the surface thermal sensitivity reduction and support stiffness improvement have been studied. A synthetic six-point support system that integrates equally spaced multiple ultra-low radial stiffness mirror flexure units and assembly external interface flexure units has been demonstrated on a 260 mm apertured annular mirror that involves significant CTE mismatch and demanding support stiffness constraint. The surface deformation RMS, due to the 35 °C temperature variation, is 16.7 nm.

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Design and optimization of integrated flexure mounts for unloading lateral gravity of a lightweight mirror for space application

Cited by 14 publications

References 23 publications

Design and Fabrication of an Additively Manufactured Aluminum Mirror with Compound Surfaces

Design and Fabrication of an Additively Manufactured Aluminum Mirror with Compound Surfaces

Design and Optimization for Mounting Primary Mirror with Reduced Sensitivity to Temperature Change in an Aerial Optoelectronic Sensor

Contributions of Support Point Number to Mirror Assembly Thermal Sensitivity Control

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