Fei YANG, Qi-chang AN, Jing ZHANG, et al. System error modeling and analysis for GSSM of TMT[J]. Optics and precision engineering, 2017, 25(7): 1790-1795.
DOI:
Fei YANG, Qi-chang AN, Jing ZHANG, et al. System error modeling and analysis for GSSM of TMT[J]. Optics and precision engineering, 2017, 25(7): 1790-1795. DOI: 10.3788/OPE.20172507.1790.
System error modeling and analysis for GSSM of TMT
To fully analyze precision requirements of surface figure precision and pointing accuracy of plane mirror for the Giant Steerable Scientific Mirror (GSSM) system of this Thirty-Meter Telescope (TMT)
system error model of GSSM needed to be established. In this paper
up-to-down distribution mode of system error was adopted. Technological indexes were understood and analyzed and converted to precision requirements of surface figure precision and pointer accuracy of plane mirror
according to standardized Point Source Sensitivity (PSSn) with its good features of synthesis and degradation. On the other hand
disturbance factors affecting system performance were analyzed
and influence of gravity print-through and atmosphere disturbance on PSSn was compared by using analysis result of finite elements for static error. System performance evaluation was conducted with systematic transfer function for dynamic error. Finally
Index requirements of all key components were proposed
and system error model of GSSM was established to satisfy system requirements of TMT as basis for GSSM system development. The experiment results indicate that seeing condition is good (
r
0
<
0.1 m)
influence of seeing on PSSn was great; mirror print-through could only exert its functions on condition of good atmosphere seeing. With increase of vibration amplitude
system transfer function degenerated
and its PSSn would also reduce correspondingly from 0.996 to 0.992. It can be found that PSSn has special advantages as the next index of performance evaluation and error distribution of telescope
and its unique synthesis features and frequency domain calculation method can contribute greatly for telescope construction of the next generation.
WANG F G, AN Q CH. Evaluation of mirror surface figures for TMT based on Slope RMS.Opt. Precision Eng., 2014, 22(5):1171-1175.(in Chinese)
王孝坤.大口径离轴凸非球面系统拼接检验技术.中国光学, 2016, 9(1):130-136.
WANG X K. Measurement of large off-axis convex asphere by systemic stitching testing method. Opt. Precision Eng., 2016, 9(1):130-136.(IN Chinese)
MACMARTIN, D G, THOMPSON P, COLAVITA M M, et al.. Dynamic analysis of the active-controlled segmented mirror of the Thirty Meter Telescope[J]. IEEE Trans. Control Sys. Tech., 2013, 22:58-68.
CHEN L S, HU ZH W. The research on the application of normalized point source sensitivity in wide field optical spectrometer of the thirty Meter Telescope. ACTA ASTRONOMICA SINICA, 2016, 57(5):585-596.(in Chinese)
PAZDER J S, VOGIATZIS K, ANGELI G Z. Dome and mirror seeing estimates for the Thirty Meter Telescope[J]. Proc. SPIE 7017, Modeling, Systems Engineering, and Project Management for Astronomy Ⅲ, 70170R (July 09, 2008).
RUDOLER S, HADAR O, FISHER M, et al.. Image resolution limits resulting from mechanical vibrations. Opt. Eng., 1991, 30(5):577-589.
HADAR O, DROR I, KOPEIKA N S. Image resolution limits resulting from mechanical vibrations. Part Ⅳ:real-time numerical calculation of optical transfer functions and experimental verification[J]. Opt. Eng. 1994, 33(2):566-578.
DENG Y T, LI H W, WANG J L, et al.. Large telescope low speed control based on adaptive sliding mode control. Chinese Optics, 2016, 9(6):713-720.(in Chinese)
KOPEIKA N S, WULICH D. Image resolution limits resulting from mechanical vibrations[J]. Journal of Modern Optics, 2008, 55(3):401-407.