Infrared and Laser Engineering, Volume. 52, Issue 1, 20220363(2023)
Structure design and verification of primary mirror assembly for large off-axis TMA camera
Figures & Tables(22)
Fig. 8. Relationship between flexure structure slot position and mirror deformation
Fig. 13. Flow chart of stress relieving for primary mirror assembly
Fig. 15. Interferogram of primary mirror during optical accuracy test
Table 1. Design requirements for primary mirror assembly
View tableView in ArticleTable 1. Design requirements for primary mirror assembly
Item Requirement Clear aperture 1250 mm×460 mm Mass ≤80 kg Tilt θ≤10″ Displacement δ≤20 μm Surface accuracy RMS≤1/50λ (any φ400 mm area) Working temperature (20±2) ℃ Frequency ≥110 Hz
Table 2. Properties of common materials for large mirror
View tableView in ArticleTable 2. Properties of common materials for large mirror
Property RB-SiC Be ULE Zerodur Density, ρ/kg·m−3 3050 1850 2210 2530 Elastic modulus, E/GPa 340 287 67 91 Poisson ratio, μ 0.2 0.08 0.17 0.24 Thermal conductivity, λ/W·K−1·m−1 155 216 1.31 1.64 Thermal expansion coefficient, α/10−6·K−1 2.50 11.4 0.03 0.05 Specific stiffness, E/ρ 111.5 155 30.3 36 Thermal stability, λ/α 62 18.9 43.7 32.8 Comprehensive performance, (E/ρ)·(λ/α) 6913 2939 1324 1180
Table 3. Variable ranges and optimization results (Unit: mm)
View tableView in ArticleTable 3. Variable ranges and optimization results (Unit: mm)
Parameter Limits Original Optimized Adjusted Face, F [ 5 ,10 ]6 5.63 5 Back, B [ 3 ,8 ]6 4.37 4 Perimeter, P [ 3 ,8 ]5 3.27 4 Cone, C [ 8 ,14 ]15 14.32 12 Central rib, R1 [ 3 ,8 ]5 3.28 4 Exposed rib, R2 [ 3 ,8 ]5 3.10 3 Side trimming, H1 - 100 - 116 Central trimming, H2 - 50 - 38
Table 4. Material properties of supporting structure
View tableView in ArticleTable 4. Material properties of supporting structure
Part Cone Flexure Base Material 4J36 TC4 SiC/Al Density, ρ/kg·m−3 8.1 4.4 3.0 Elastic modulus, E/GPa 141 114 180 Poisson ratio, μ 0.25 0.34 0.18 Thermal expansion coefficient, α/10−6K−1 2.5 9.1 8.0
Table 5. Simulation results under main conditions
View tableView in ArticleTable 5. Simulation results under main conditions
Temperature change, 4 ℃ Gravity, 1 g, -Y Unflatness, 0.01 mm RMS/nm 3.983 2.035 0.295 θX/(″) - 1.217 - δY/μm - 9.541 -
Table 6. Modal analysis results of primary mirror assembly
View tableView in ArticleTable 6. Modal analysis results of primary mirror assembly
Order Frequency/Hz Vibration mode description 1 126.7 Mirror rotation around Y axis 2 146.6 Mirror rotation around X axis 3 160.1 Mirror rotation around Z axis
Tools
Get Citation
Copy Citation Text
Jian Yuan, Lei Zhang. Structure design and verification of primary mirror assembly for large off-axis TMA camera[J]. Infrared and Laser Engineering, 2023, 52(1): 20220363
Paper Information
Category: Optical design
Received: May. 30, 2022
Accepted: --
Published Online: Feb. 9, 2023
The Author Email: Zhang Lei (18686344285@163.com)
© Copyright 2018-2021 | Chinese Laser Press.
All Rights Reserved 沪ICP备15018463号-20