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Blanco TCS Upgrade Final Configuration, and Integration Test Results Nov-2011Thru Feb-2012 M.Warner E.Mondaca R.Cantarutti G.Schumacher. 1 - Motor and Tachometer Vendor Specifications: ftp://ftp.ctio.noao.edu/pub/warner/blanco/Blanco_motor&tach.pdf 2- Current Driver Data Sheet:

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  1. Blanco TCS UpgradeFinal Configuration, and Integration Test ResultsNov-2011Thru Feb-2012M.WarnerE.MondacaR.CantaruttiG.Schumacher

  2. 1 - Motor and Tachometer Vendor Specifications: ftp://ftp.ctio.noao.edu/pub/warner/blanco/Blanco_motor&tach.pdf 2- Current Driver Data Sheet: ftp://ftp.ctio.noao.edu/pub/warner/blanco/az40a8.pdf 3 – Original 4m Telescope Servo Analysis: ftp://ftp.ctio.noao.edu/pub/warner/blanco/blanco_4m_analysis.pdf 4 – TCS CDR (Telescope Lumped Mass Model): ftp://ftp.ctio.noao.edu/pub/warner/blanco/tcs_cdr_warner.pdf 5 - Blanco TCS Upgrade Project Report ftp://ftp.ctio.noao.edu/pub/warner/blanco/B4Upgrade.pptx 6 – TCS Upgrade Test Results ftp://ftp.ctio.noao.edu/pub/warner/blanco/TCSUpgrade_test_results.pdf References

  3. General Telescope and Drive Specifications • The Dynamic Telescope requirements for both axes, needed to meet DECAM mission (2deg in 17sec): • Maximum Jerk = 0.05[deg/s^3] • Maximum Acceleration = 0.05[deg/s^2] • Maximum Velocity = 0.5[deg/s] Note: This limits where used for all test trajectories presented in this repot. • Tracking Requirements: • Jitter : 0.1”rms maximum on both axes • Settling Time: 5sec • Error band: 0.1”, 1 Second Mean • Drift: 1” per min

  4. Final System Configuration • Hardware Overview • Manual Console Signals • Main Driver Chassis • Telemetry • cRIO-V and cRIO-P Hardware • Safety Interlocks • Web-browser based Engineering Panels • TSC Kernel • Pointing Kernel Model • Pointing Tests Results • Trajectory Generation using algorithms developed for robotic control.

  5. System Overview Computer Rack Main Chassis Telescope Mount Kernel PC HA Absolute Encoder DEC (South) Current Driver DEC (North) Current Driver HA (West) Current Driver HA (East) Current Driver Tach1 M1 HA Inc. Encoder Ethernet (20 Hz) HA Tape Encoder Tach2 M2 Torpedo (1KHz) cRIO-P cRIO-V DEC Tape Encoder M3 Tach3 HA Inc. Encoder Tach4 M4 DEC Absolute Encoder.

  6. CONSOLE SIGNALS Current Monitor Manual Slew Control OLD CONSOLE Guide Set Search West East North South Hand Paddle PLC cRIO -V

  7. Main Chassis Power Supply (2) Braker and Contactors Current Amplifiers (4) Filters (4) Fuses (8)

  8. cRIO-V Telemetry Configuration To Brakes Main Chassis Power Supply Enable Logic Brakes Voltage Power Supply (2) Brakes Power Supply Box Power Supply Voltage Telemetry (2) Current Amplifier Status (4) Current Amplifier (4) Current Amplifier Voltage Output (4) cRIO-V Current Amplifier Current Output (4) Current Transducers (4) To Motors Fuses

  9. Hardware Interlocks Main Power Supply (3 phases, 480V) Main POWER Interrupt Main Brakes ON/OFF Buttons Panic Stop Power Supplies (2) PLC Enable Software Enable To Motors Current Amplifiers (4) 25[A] Fuses

  10. cRIO-V Box: Front Panel

  11. cRIO-V Box: Rear Panel

  12. cRIO-P Box: During Assembly

  13. cRIO-V Safety Interlock System

  14. cRIO-V Engineering Web Browser Based Display Real time graphic display of all motor current, tachometer, and demand signals. Facilitate telescope balance adjustments, by monitoring motor current graph Status of all safety interlocks

  15. cRIO-P Engineering Web Browser Based Display Real Time graphic display of all positions and demand signals, including position error RMS value Status of all safety interlocks

  16. TCS Kernel • TCS Kernel main function is to generate the demands to the mount Servo system. • Demands are generated using software based on a pointing model. • The pointing model parameterize real behavior of the telescope structure. • The demands are computed at 20Hz and fed to a trajectory generator, before passing them to the Servo. • The Kernel transformation functions are also utilized to compute the guider (X,Y) position to acquire a guide star.

  17. Roll index error Pitch index error Vertical deflection OTA/pitch nonperp Roll/pitch nonperp Roll misalignment W Roll misalignment N IA IB VD CA NP AW AN Pointing Kernel Concepts(P.T. Wallace 2002) Offsets TARGET [α, δ] Equatorial Telescope: Roll ≡ -hour angle Pitch ≡ declination GENERIC MODEL Light deflection, aberration Precession-nutation POINTING MODEL Earth rotation [h, δ] Site location, UT1 Weather, color Refraction Mount orientation AW, AN AIM [xa, ya, za] Target position Pointing origin -ha roll IA A Roll/pitch non-perpendicularity NP dec pitch IB B Mount axes Pointing origin BORESIGHT [xb, yb, zb] guiding GA, GB [ξ, η] Rotator angle X, Y Target position Pointing origin TELESCOPE [xt, yt, zt] Vertical deflection VD OTA/pitch non-perpendicularity CA Mount axes [1, 0, 0]

  18. POINTING TESTS RESULTS A pointing test was performed utilizing the Mosaic instrument, in order to derive a new model utilizing the tape encoders. Based on that data the new model is: IH +669.0271 Hour Angle Index ID -153.5064 Declination Index NP -57.1753 Non-Perpendicularity between HA and DEC CH +60.1232 Collimation: non-parallel between optical and mechanical axis ME +167.3562 Polar axis error in elevation MA +25.9390 Polar axis error in azimuth HXSH -105.4795 Horseshoe flexure east-west (dynamic non-perpendicularity) HHSH2 +62.5299 Horseshoe flexure HA HDCH4 -22.8837 Horseshoe flexure DEC HDCH3 +51.5131 Declination gearbox Note the large value of the ME coefficient. Historically this value was in the range of 25-30. It means that the mount did sag sometime after 2001, when the previous pointing test was done. The new model was tested with the same instrument, by setting a star in the guider box and observing the drift. None was observed for about 10 minutes, an indication that on one side, the model produces the correct motion demand and on the other, the new servo control handles the mount correctly.

  19. DEC drift eliminated, with Pointing Model Correction. DEC Tracking Error=0.013”rms Pointing Model Correction

  20. Kernel Dataflow TCS Demanded Mount Position Demanded Guider Position Jerk/Accel/Velocity Limited Trajectory KERNEL COMPONENT Absolute Time Mount Demand TRAJECTORY GENERATOR A, B Environment Info (t, p, h) Astrometry. Pointing Model. Demand Computation. Internal State. Focal Plane Configuration X, Y POSITION VELOCITY Mirror Position Guider Demand Guider tracking errors 20 Hz Offset Requests TCS cRIO-P Pointing Coefficients

  21. Optimum Jerk/Acceleration/Velocity Limited Trajectory Profile This method generates the smoothest possible motion within the dynamic constraints imposed, allowing a seamless transition during track-slew -track motions.

  22. Optimum Jerk/Acceleration/Velocity LimitedTrajectory Generation(from Reflexes Type IV Motion Library) FROM KERNEL 0.5 0 deg/s 0.05 deg/s² 0.05 deg/s³ TO cRIO-P FROM cRIO-P

  23. HA Trajectory: Track+2 Deg Slew+Track Reflexxes Type IV Motion Library TorstenKröger Trajectory generation for 2 degrees + track to track motion: Max Vel: 0.5 deg/sec Max Acc: 0.05 deg/sec² Max Jerk: 0.05 deg/sec³ Track Slew Track

  24. Test Results Overview • Servo Models • Matlab Model and LabView Implementation • Open Loop Bode Plots • Velocity Loop Test • Velocity Loop Servo Model • Slew Trajectory and Model Verification • Slew Velocity Loop Step Response and Closed Loop Plots, Model Verification • Friction Loop Plots • Position Loop Tests. • Telescope Models for Tach->Tape Transfer Function • Position Loop Test Results for Slew Trajectory • Tracking jitter performance on the sky • Final Integration Tests. • Full Range Friction Plots, for establishing a baseline before DECam Integration. • Parametric study on Settling time v/s Trajectory Limit

  25. Servo Models • Servo Models are based on Lumped Mass model described on Ref. 3, and coded into Matlab. • DEC Velocity Slew Compensation is based on original analog compensation modified to have a larger DC gain. • HA Velocity Slew Compensation is based on modified original analog compensation. • Tachometer to Tape Transfer Function was derived from measured sine wave sweep data.

  26. HA Servo Model(Slew Baseline Model) Position Loop (cRIO-P) Velocity Loop (cRIO-V) Tachometer Tape Encoder s + 0.5 HPCOMP1 = ------- s 66.6 s^2 + 682.6 s + 16650 HVCOMP1 = -------------------------------- s^2 + 9.3 s + 8.3

  27. DEC Servo Model(Slew Baseline Model) Position Loop (cRIO-P) Velocity Loop (cRIO-V) Tachometer Tape Encoder s + 0.5 HPCOMP2= ------- s 60.37 s^2 + 9170 s + 84070 HVCOMP2 = ----------------------------------- s^2 + 53.12 s + 52.12

  28. Position Loop Implementation in LabView coderunning at 1Khz loop cycle cRIO-V Command Kernel Command HA Tape Encoder Inputs Servo Compensation Filters DEC

  29. Velocity Loop Implementation in LabView coderunning at 1Khz loop cycle cRIO-P Command Tach Inputs Motor Amplifier Current Command HA Servo Compensation Filters DEC

  30. Velocity Open Loop Bode Plot

  31. Position Open Loop Bode Plot(Combines Lumped Mass and Tape Measurements)

  32. Velocity Loop Tests • Velocity Loop Test • Baseline 2 Deg Slew Trajectory performance was compared against Model • Slew Velocity Loop Step Response and Closed Loop Plots, Model Verification.

  33. HA 2 Deg Baseline Trajectory Test (Position and Velocity)

  34. HA 2 Deg Baseline Trajectory Test (Velocity Error)

  35. DEC 2 Deg Baseline Trajectory Test (Position and Velocity) Tachometer Jitter

  36. DEC 2 Deg Baseline Trajectory Test (Velocity Error) Tachometer Jitter

  37. HA Slew Velocity Loop Step Response

  38. HA Slew Velocity Closed Loop Bode Plot

  39. DEC Slew Velocity Loop Step Response

  40. DEC Slew Velocity Closed Loop Bode Plot

  41. Position Loop Tests • Position Loop Test • Telescope Models for Tach->Tape Transfer Function based on actual measurements • Baseline Slew Trajectory performance was compared against Model • HA Tracking Jitter Measurements

  42. HA Tachometer to Tape Transfer Functionused on Position Loop Models

  43. DEC Tachometer to Tape Transfer Functionused on Position Loop Models

  44. HA 2 Deg Position Loop Trajectory Test(Comparison to Servo Model)

  45. DEC 2 Deg Position Loop Trajectory Test(Comparison to Servo Model)

  46. HA Track-2.25 deg Slew-Track Test using Kernel Generated Trajectory HA Position HA Position Error

  47. HA Track- 2.25deg Slew-Track Test using Kernel Generated Trajectory (Detail) HA Position Error +/- 0.2” 25sec +/- 0.4” 23sec

  48. DEC 2 deg Slew Test using Kernel Generated Trajectory DEC Position DEC Position Error

  49. DEC 2degTrack-Slew-Track Test using Kernel Generated Trajectory (Detail)Final Baseline Compensation DEC Position Error +/- 0.2” 24sec

  50. Long Term Track Jitter

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