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Undulator Motion ControlsFAC, June 2009 2
Outline
• Basics
• Performance
• calibration
•motion
• Stability
Undulator Motion ControlsFAC, June 2009 3
Degrees of Freedom
• Girder: x,y, (2X) and roll, control Q, BPM, BFW and undulator transverse positions.
• Undulator: girder motion plus 85 mm of horizontal translation
• 33x6 total degrees of freedom for mechanical motion
-5 to 80 mm
+/- 1 mm
UndulatorUndulator BPMBPMQQBFWBFW
Undulator Motion ControlsFAC, June 2009 4
Linear Potentiometers
• Six linear potentiometers provide indepenent on-line measurement of girder motion with about 5 micron resolution.
• Also used for calibration of cam angles and motion verification.
Undulator Motion ControlsFAC, June 2009 5
Kinematics
•Girder is treated as a rigid body.
•Unique, invertable geometrical relations between the cams and the objects.
• Roller bearings on cams determine Q or BPM, and BFW transverse positions independently.
Undulator Motion ControlsFAC, June 2009 6
Matlab Motion Control Programs
•CVS’d matlab routines for undulator motion control applications
• epics controls are also used
girderAngle2Axis girderCamSet girderAxis2Angle girderCamWaitgirderAxisFind girderAxisFromCamAngles girderGeo girderAxisMeasure girderLinearPot girderAxisMove girderLinearPotZero girderAxisSet girderLPOT2Axis girderBFWMove girderMotorStatusReadgirderBFWposition girderPositionPlotGui girder_bump girderPositionPlotGui girderCalReset girderQuadMovegirderCamAngleCalibrate girderQUADposition girderRangeCheckgirderCamMotorRead girderRotaryPot girderCamPot girderScoreField_Integral_GUi Field_Integral_GUI undulatorPositionPlotGuiundulatorPositionPlotGui moveUndulatorQuadrupole_guimoveUndulatorQuadrupole_gui scan_backlash segmentTranslatesegmentTranslateWait segmentTranslationStatus steer_undulator_guitaper_control und_quad_align UndKact UndKactMonitor UndulatorTaperControl
Undulator Motion ControlsFAC, June 2009 7
Motion Checking
• Accuracy check based on linear potentiometers which are good to about +/- 5 microns.
• During initial system checkout, we found gross distortion in the motion due to software irregularities. (fixed)
Undulator Motion ControlsFAC, June 2009 8
Calibration
• Linear potentiometer reading versus cam angle. Should be sinusoidal.
• Phase is determined by matlab software. Period is determined by ANL software.
Undulator Motion ControlsFAC, June 2009 9
Calibration of Many
• Calibrate up to 33 cams at once, but still takes at least a half and hour per cam - often much more.
•One Linear pot is wired backwards in this picture.
Undulator Motion ControlsFAC, June 2009 1
0
Calibration Irregularity
• This showed up a problem with the earthquake restraint bolts that were engaging the girder during the motion. (We fixed this problem)
Undulator Motion ControlsFAC, June 2009 1
1
BBA Motion Control
• BBA corrections motions are typically ~10 microns or less.
•Corrections are applied to all 33 girder simulateously through matlab software.
Undulator Motion ControlsFAC, June 2009 1
2
Undulator Pointing
• Can aim the x-rays by moving the entire undulaor line.
• Range is limited to about 1 mm (radius) at FEE.
Undulator Motion ControlsFAC, June 2009 1
3
Tolerance Zones
• Plan from 2004
Zone 1Zone 1 (non-invasive correction) (non-invasive correction)•• 120-Hz 120-Hz trajtraj-feedback (LTU -feedback (LTU BPMBPM’’ss))•• 0.1-Hz 0.1-Hz trajtraj-feedback (und. -feedback (und. BPMBPM’’ss))
Zone 2Zone 2 ( (ΔΔtt >> 1 , hr 1 , hr⟨⟨PP//PP00⟩⟩ > 90%, - )non invasive > 90%, - )non invasive•• ( 5) MICADO best steering within undulator ( 5) MICADO best steering within undulator 3Zone 3Zone ( (ΔΔtt >> 24 , hr 24 , hr⟨⟨PP//PP00⟩⟩ > 75%, )invasive > 75%, )invasive
•• Weighted steering of undulator Weighted steering of undulatortrajtraj. (1 .)min. (1 .)min•• ... - (10 .)or quadrupole gradient scans fast BBA min... - (10 .)or quadrupole gradient scans fast BBA min•• - ( .)Possible x ray pointing few min - ( .)Possible x ray pointing few min 4Zone 4Zone ( (ΔΔtt >> 1 , wk 1 , wk⟨⟨PP//PP00⟩⟩ < 50%, )machine time < 50%, )machine time
•• (<1 )One iteration of BBA hr (<1 )One iteration of BBA hr 5 (Zone 5 (Zone ΔΔtt >> 6 , - )mo shut down 6 , - )mo shut down
•• (1 )Reset movers set to zero and manual realignment wk (1 )Reset movers set to zero and manual realignment wk•• 3 (~3 )Full iterations of BBA hrs 3 (~3 )Full iterations of BBA hrs
*Worst Case - noreliance on
position monitoringsystem
Undulator Motion ControlsFAC, June 2009 1
4
Drift Rate
• < 1micron/day motion relative to neighboring BPMs
• Prediction (2004) +/- 0.5 microns/day from ground motion. (Weather also contributes a few-day time scales.)
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5
Girder Motion from ADS
•ADS (stretched wire) measurements of programmed girder motion
•>10 minutes per point
Undulator Motion ControlsFAC, June 2009 1
6
Hysteresis in Girder Motion
• Extremely sensitive beam-based measurements show up to 1 micron of hysteresis.
•We may implement a correction cycle, but further understanding is needed.
Undulator Motion ControlsFAC, June 2009 1
7
Summary
•Motion controls have been performing with accuracy and precision needed for BBA.
•New applications using motion controls are still being created.
• Preliminary indications of mechanical stability are favorable.