Undulator Motion Controls Jim Welch June 9, 2009 J. WELCH welch@slac.stanford.edu June 9, 2009 FAC, June 2009.

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  • Slide 1
  • Undulator Motion Controls Jim Welch June 9, 2009 J. WELCH welch@slac.stanford.edu June 9, 2009 FAC, June 2009
  • Slide 2
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 2 Outline Basics Performance calibration motion Stability
  • Slide 3
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, 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 Undulator BPM Q BFW
  • Slide 4
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, 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.
  • Slide 5
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, 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.
  • Slide 6
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 6 Matlab Motion Control Programs CVSd 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
  • Slide 7
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, 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)
  • Slide 8
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, 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.
  • Slide 9
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, 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.
  • Slide 10
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 10 Calibration Irregularity This showed up a problem with the earthquake restraint bolts that were engaging the girder during the motion. (We fixed this problem)
  • Slide 11
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 11 BBA Motion Control BBA corrections motions are typically ~10 microns or less. Corrections are applied to all 33 girder simulateously through matlab software.
  • Slide 12
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 12 Undulator Pointing Can aim the x- rays by moving the entire undulaor line. Range is limited to about 1 mm (radius) at FEE.
  • Slide 13
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 13 Tolerance Zones Plan from 2004
  • Slide 14
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 14 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.)
  • Slide 15
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 15 Girder Motion from ADS ADS (stretched wire) measurements of programmed girder motion >10 minutes per point
  • Slide 16
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 16 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.
  • Slide 17
  • J. WELCH welch@slac.stanford.edu Undulator Motion Controls FAC, June 2009 17 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.

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