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FITTING ERROR ANALYSIS FOR THE VLT DSM

FITTING ERROR ANALYSIS FOR THE VLT DSM. A. Riccardi, M. Xompero, L. Busoni (INAF-Osservatorio di Arcetri). OUTLINE. Fitting error and force analysis starting from FEA influence functions Full and partial correction results (wrt number of corrected modes)

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FITTING ERROR ANALYSIS FOR THE VLT DSM

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  1. FITTING ERROR ANALYSIS FOR THE VLT DSM VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 A. Riccardi, M. Xompero, L. Busoni(INAF-Osservatorio di Arcetri)

  2. VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 OUTLINE • Fitting error and force analysis starting from FEA influence functions • Full and partial correction results (wrt number of corrected modes) • Preliminary comparison of FEA result with P45 measurements • Preliminary step response and chopping results with P45

  3. VLT DSM VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  4. FEA MAIN PARAMETERS VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  5. /1mm /1mm DEFINITIONS VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 mm j-th influence function: shelldeformation [mm] setting act position actuator force pattern to producej-th influence func. [N] Z a-dimensional [mm/mm]z,p [mm]K [N/mm]; f [N]

  6. MIRROR MODES VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 First 64 least stiff mirror modes First 64 least stiff mirror modes

  7. Modal stiffness (mirror modes) VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 Max Act Force: 1N Force Thresh.:0.1N Stiffest mode: 0.1N/(6.6N/mm)= 15nm PtV (surface) Astig mode: 0.1N/(10-5N/mm)= ~100mm PtV (!!!)

  8. Envelope of Zernike decomposition for manufacturing error VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 Max flattening force: 0.1N Zern coeff at 0.1N peak Kolm turb(0.2arcsec seeing) Mirror fitting residual

  9. Hp 1: Same thin shellHp 2: Same Actuator-to-shell interfaceHp 3: Same shell constrains on edgeHp 4: All dof are used (no slave acts) w = F1 v p = M1 v 1 g1 g1 00100 0 0 0 0 = M1-1 V1 V1 V2 V2 V3 V3 V4 V4 V5 V5 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 g1 1 g2 g1 0 0 0 0 V1 V2 V3 V4 V5 w = F2 v g2 p = M2 v V1 V2 V3 V4 V5 00100 V1 V2 V3 V4 V5 w2 = (F2 M2-1) p = M2-1 V1 V2 V3 V4 V5 ACTUATOR COUPLING VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 v = M1-1 p w1 = (F1 M1-1) p g1<g2 w1=w2 -> (F1 M1-1) = (F2 M2-1)

  10. ACTUATOR COUPLING VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  11. MAIN PARAMETERS OF THE SIMULATION VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  12. WF GENERATION VALIDATION VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 10’000 phase screens 13.3% wrt Zern rms (in agreement with Dai et al.)

  13. Actuator position Structure Function VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 Actuator SF Kolm SF VonKar. SF

  14. MEDIAN SEEING FULL CORRECTION VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  15. l l/l l/l MEDIAN SEEING: V/K WF AND PSF CORRECTION VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  16. MEDIAN SEEING: V/K STREHL RATIO DISTRIBUTION VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  17. AIRY RINGS VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  18. FULL CORRECTION: MEDIAN AND BAD SEEING COMPARISON VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  19. Inter-actuator stroke. Bad Seeing VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 10000 layers

  20. BAD SEEING: PERFORMANCES CORRECTING 738 MODES VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  21. Mirror and Zernike modes vs KL VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 Zern/KL Mirror/KL

  22. Measured 19% extra stiff.(requires 6.3% thinner shell) - measured - simulated 2.0mm -> 1.88mm ===Not yet calibrated actuators=== PRELIMINARY FEA COMPARISON WITH MEASUREMENTS (P45) VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  23. Low stiffness mode Mid stiffness mode High stiffness mode NEW ELECTRONICS:PRELIMINARY STEP RESPONCES (P45) VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 Modal settling time: ~0.57[ms] to ~0.67[ms]

  24. Settling Time ~10ms PRELIMINARY CHOPPING RESULTS (P45) VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  25. Rms ~3.2 [mas] PRELIMINARY CHOPPING RESULTS (P45) VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005 K Band d.l. size: ~53[mas]

  26. P45 MODAL PLANT TRANSFER FUNCTIONS VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

  27. P45 ACTUATOR PLANT TRANSFER FUNCTION VLT DSM – JRA1 meeting 2 Firenze – 7th-8th July, 2005

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