Performance prediction of the TMT tertiary mirror support system

Cho, Myung K.

doi:10.1117/12.789292

Cited by 10 publications

(7 citation statements)

References 2 publications

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“…The set of optimal clamps and the temperature related to the minimal deformation are obtained by X opt arg minmax X∈Ω FX: (12) In this paper, we use the branch-and-bound optimization method [40] to solve the optimal problem [Eq. (11)], as it is a general algorithm for finding global optimal solutions of optimization problems.…”

Section: Optimization Of the Optical Deformationmentioning

confidence: 99%

“…Through careful treatment of the nodal displacement predictions from FEA and the use of polynomial fitting, the deformations of grazing incidence optical surfaces may be characterized for subsequent optical analysis. In Cho's work [11], FEA and optomechanical calculations were performed to optimize the Thirty Meter Telescope tertiary mirror, in which iterative parametric analyses were utilized to achieve the minimum global RMS surface error. Martin et al [12] described the optimization of support forces for a 6.5 m primary mirror of the Multiple Mirror Telescope Conversion, in which the fixturing functions were determined by FEA, and then the optimization was performed by singular value decomposition of the fixturing functions into normal modes.…”

Section: Related Workmentioning

confidence: 99%

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Optimization of fixture layouts of glass laser optics using multiple kernel regression

Cao

Qiao

2014

Appl. Opt.

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We aim to build an integrated fixturing model to describe the structural properties and thermal properties of the support frame of glass laser optics. Therefore, (a) a near global optimal set of clamps can be computed to minimize the surface shape error of the glass laser optic based on the proposed model, and (b) a desired surface shape error can be obtained by adjusting the clamping forces under various environmental temperatures based on the model. To construct the model, we develop a new multiple kernel learning method and call it multiple kernel support vector functional regression. The proposed method uses two layer regressions to group and order the data sources by the weights of the kernels and the factors of the layers. Because of that, the influences of the clamps and the temperature can be evaluated by grouping them into different layers.

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Section: Optimization Of the Optical Deformationmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Optimization of fixture layouts of glass laser optics using multiple kernel regression

Cao

Qiao

2014

Appl. Opt.

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“…According to the three potential plans, the TMT tertiary mirror FE model is built, three different lateral support structures are analysed [7]. lateral support rods.…”

Section: Application Of the Whiffletree Lateral Support Structurementioning

confidence: 99%

Kinematic evaluation of the whiffletree lateral support setup and its application for the mirror support of the TMT tertiary mirror

Wang

Linmin

Jin

2015

J. Eur. Opt. Soc.-Rapid Publ.

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With increasing size of the reflecting mirror apertures in telescopes, the lateral support is becoming more and more important. In order to find a setup satisfying the requirements for the TMT tertiary mirror, based on the classic three-point flexure support setup, a twelve-point lateral support setup was investigated its basic internal relations and properties were investigated. The virtual equivalent circle concept is then proposed to evaluate different potential setups. By studying the relationship between the virtual equivalent circle radius and the thermal deformation and resonant frequency, it can be concluded that a larger virtual equivalent circle radius results in a smaller the thermal deformation and a higher resonant frequency. Preliminary research results suggested that the TMT tertiary mirror surface figure error and thermal deformation requirements can easily be met. However, it was more difficult to obtain resonant frequencies higher than 15 Hz. Based on the virtual equivalent circle concept, the TMT tertiary mirror support setup was optimized, resulting in a resonant frequency of 17.7 Hz, which satisfies the requirements. The whiffletree lateral support setup can be applied to similar reflecting mirror support structures.

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“…Active support systems should have the ability to correct these basic low spatial frequency errors. For the purpose of making a performance comparison between the two active support schemes, several low-order Zernike modes (up to 10 FRINGE Zernike modes) [17,18] are modeled for each scheme. Each of the first 10 modes (excluding piston, tilts and focus) is scaled to a reference surface RMS error of 100 nm.…”

Section: Performance Of Active Support Systemmentioning

confidence: 99%

Performance comparison between two axial active support schemes for 1-m thin meniscus primary mirror

Niu

Wang

et al. 2013

J. Inst.

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Active support scheme may decide the deformation of the optical surface figure of the primary mirror. Two main active axial support schemes are often adopted to the thin meniscus primary mirror, one scheme is that the axial supports normal to the mirror bottom surface, and the other is that the active forces parallel to the optical axis. In order to compare the performance of the two support schemes, 1-m thin meniscus primary mirror is conducted. Finite element analysis (FEA) is employed to analyze the optical surface figures of the primary mirror, and optimizations are carried out by using ANSYS for each support scheme to obtain the locations and active forces. The axial support force sensitivities are calculated for the two support schemes in a case that a single axial support has a force error of 0.5 N. The correction ability of the active support system for both of the support schemes are analyzed when an arbitrary axial support is failure. Several low order Zernike modes are modeled with MATLAB procedure, and active optics corrections are applied to these modes for the two active supports. The extra mirror surface error due to thermal deformation is also corrected with the two support schemes.

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Performance prediction of the TMT tertiary mirror support system

Cited by 10 publications

References 2 publications

Optimization of fixture layouts of glass laser optics using multiple kernel regression

Optimization of fixture layouts of glass laser optics using multiple kernel regression

Kinematic evaluation of the whiffletree lateral support setup and its application for the mirror support of the TMT tertiary mirror

Performance comparison between two axial active support schemes for 1-m thin meniscus primary mirror

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