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HMI Mechanisms

HMI Mechanisms. Dave Akin, Lockheed Martin AKIN@LMSAL.COM 650-424-3989. Revision K. HMI Mechanisms. Hollow-Core Motors (7 motors) Each motor rotates an optical element Shutters (2 motors) One for each CCD Control exposure to CCD Focus Wheels (2 motors)

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HMI Mechanisms

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  1. HMI Mechanisms Dave Akin, Lockheed Martin AKIN@LMSAL.COM 650-424-3989 Revision K

  2. HMI Mechanisms • Hollow-Core Motors (7 motors) • Each motor rotates an optical element • Shutters (2 motors) • One for each CCD • Control exposure to CCD • Focus Wheels (2 motors) • Adjust focus by placing various thickness glass into optical path • Calibration mode places 2 lenses into optical path • Front Door (2 motors) • Open and close aperture door • Alignment Mechanism (2 motors) • Move (point) instrument with respect to spacecraft

  3. HMI Mechanism Locations

  4. Hollow-Core Motor Requirements • Design Life (5-year mission): 80 M operations • Repeatability: 20 arc-seconds (1 sigma) • Absolute Stopping Accuracy: ±8 arc-minutes • Clear Aperture: > 1.340 inches (34 mm) • Operating Temperature: 15 to 35 C • Survival Temperature: -10 to 50 C • Time to Move: 180 degree move in 1 second

  5. Similar Motor from Program D

  6. Hollow-Core Motor Section RED = ROTATING PARTS

  7. Hollow-Core Motor Design • Motor: H.Magnetics Brushless DC Motor • Bearing: MPB Size S2532 Lubrication: Nye 2001B (vacuum impregnated) Retainer: Phenolic, one-piece Preload: Back-to-back matched pair; 10 – 15 lb. • Mass: < 500 g • Energy dissipated by Hollow-Core Motors (Joules): Windings: 0.0037 + 0.0015 * degrees moved Encoder: 0.0010 + 0.0001 * degrees moved Total: 0.0047 + 0.0016 * degrees moved (results of computer simulation) • Torque • 34 oz-in available (stall) • Bearing Friction: < 2 oz-in • Magnetic Detent: TBD (1 to 6 oz-in, based on prototype testing) • Hysteresis Drag Torque: < 1 oz-in

  8. Hollow-Core Motor Testing Prototype • Operate with 2 different rotors • Skewed magnets Like Program D motor Minimal magnetic detent • Straight magnets Unknown magnetic detent Reduced eddy current losses • Pick design with best repeatability • Operate motors in thermal chamber (-20 to 60 C) • Repeatability test with external encoder (all positions) • Repeatability test with theodolite (fewer positions, higher resolution than encoder) • Torque margin verification (operate with reduced voltage) • Friction & Cogging (measure with torque watch) • Measure disturbance torque vs. time • Measure Resistance, BEMF (Back ElectroMotive Force) , Damping and Friction Coefficients • IRED (Infrared Emitting Diode) intensity margin

  9. Hollow-Core Motor Testing Flight Motors • Repeatability test with external encoder (all positions) • Torque margin verification (operate with reduced voltage) • Friction & Cogging (measure with torque watch) • Measure Resistance, BEMF, Damping and Friction Coefficients • IRED intensity margin

  10. Hollow-Core Motor Life Test • 5-year expected use is 80 M operations • Vacuum life test 2 identical motors to minimum 160 M operations each • Life Test Motors: • Assembled using detailed assembly procedures (same as used for flight motors) • Functional Tests (same as flight motors) • Vibration (GEVS level) (GEVS = GENERAL ENVIRONMENTAL VERIFICATION SPECIFICATION FOR STS & ELV PAYLOADS, SUBSYSTEMS, AND COMPONENTS) • Thermal (-10 to 50 C in air) • Vacuum Life Test • Temperature held at 30 C with heaters • Mechanism health is trended throughout the test • Disassemble & Inspect • Refurbish to become Flight Spares (new bearings)

  11. Hollow-Core Motor - Heritage • MDI Michelson Tuning Motors • Single, Magnetically Preloaded Bearing • TRACE Guide Telescope Motors • Identical to MDI Tuning Motors • Program D Polarization Modulator • Similar Bearing Design (slight size difference) • Same Lubricant, Same Retainer • Program F Hollow-Core Motor • Similar Bearing Design (slight size difference) • Braycote 600, Teflon Toroids

  12. Focus Wheel Requirements • Design Life (5-year mission): 2 M Operations • Operating Temperature: 15 to 25 C • Survival Temperature: -10 to 50 C • Optical Beam Diameter: 1.004” (25.5 mm) • Optical Elements: Wheel 1 Wheel 2 Blank Position Blank Position 10.2 mm thick focus block 2.55 mm thick focus block 6.8 mm thick focus block 1.7 mm thick focus block 3.4 mm thick focus block 0.85 mm thick focus block 6.8 mm thick lens 5 mm thick lens

  13. Focus Wheel Design • 5 positions per wheel • Order of optics in wheels selected for best balance • Wheels are not otherwise balanced • 1.190” Diameter Opening • Bearings • Timken MPB SR4FCHH7 • Lubricant: Braycote 600 Grease • Preload: 3 lb. • Mass: < 300 grams • Torque • 20 oz-in available (stall) • Bearing Friction: < 1 oz-in • Magnetic Detent: ~ 6 oz-in • Hysteresis Drag Torque: < 1 oz-in

  14. Filter Wheel

  15. Focus Wheel Layout

  16. Focus Wheel Testing • Prototype • Operate in thermal chamber (-20 to 60 C) • Repeatability (external encoder) • Torque margin verification (operate with reduced voltage) • Friction & Cogging (measure with torque watch) • Measure disturbance torque vs. time • Measure Resistance, BEMF, Damping and Friction Coefficients • IRED intensity margin • Flight • Repeatability (external encoder) • Torque margin verification (operate with reduced voltage) • Friction & Cogging (measure with torque watch) • Measure Resistance, BEMF, Damping and Friction Coefficients • IRED intensity margin

  17. Focus Wheel - Heritage • MDI • 68 M operation vacuum life test without failure • 3 wheels functioning without failure in the MDI instrument since 1995 • TRACE • 5 ½ years of on-orbit operations without failure • Program C • 32 M exposure vacuum life test without failure • 4 filter wheels are integrated to 2 flight SXI instruments • Program B • Prototype filter wheel has undergone thermal & vibration testing • 2 flight filter wheels are integrated to the flight instrument • Flight instrument has undergone environmental testing • Program E • 2 wheels are integrated to the flight instrument; testing is in-progress • Program D • 4 wheels are integrated to the flight instrument; testing is in-progress

  18. Shutter Requirements • Design Life: 40 M Exposures • Operating Temperature: 15 to 25 C • Survival Temperature: -10 to 50 C • Performance Requirements: • Minimum exposure: 50 ms • Nominal exposure: ~250 ms • Maximum exposure: 10 s (for LTC and darks) • Exposure Measurement Resolution: 2 μs • Repeatability: 10 μs standard deviation (one sigma) • Uniformity: 250 μs (across field of view)

  19. Shutter Design • Motor: Kollmorgen RB-00502-N02 • Bearing Design is TBD (based on outcome of life test) • Baseline Design: Nye 2001B lubricant Phenolic retainer 0.9 lb. spring preload • Mechanical design is similar to Program D shutters • Thicker encoder housing for radiation shielding • Energy: Joules per exposure = 0.043 + 0.045 * exposure in seconds (computer simulation) • Mass: ~125 grams (motor & blade) • Torque • 2.44 oz-in available (stall) • Bearing Friction: < 0.2 oz-in • Magnetic Detent: ~ 0.5 oz-in • Hysteresis Drag Torque: < 0.2 oz-in

  20. Shutter Section RED = ROTATING PARTS

  21. Shutter Motor Exploded View RED = ROTATING PARTS

  22. Shutter Operation • Clockwise Operation Shown • 2 Moves for each exposure • 120 degree move to open • 240 degrees to close

  23. Shutter Testing • Prototype • Operate in thermal chamber (-20 to 60 C) • Exposure repeatability test • Torque margin verification (operate with reduced voltage) • Friction & Cogging (measure with torque watch) • Measure disturbance torque vs. time • Measure Resistance, BEMF, Damping and Friction Coefficients • IRED intensity margin • Flight • Exposure repeatability test • Torque margin verification (operate with reduced voltage) • Friction & Cogging (measure with torque watch) • Measure Resistance, BEMF, Damping and Friction Coefficients • IRED intensity margin

  24. Shutter Performance Testing Prototype HMI Shutter • 1000 Consecutive Exposures • 100.352 ms Exposure Setting • Vary Voltage from 14.9 to 15.0 every 100 exposures 14.9 V 15 V

  25. Shutter Life Test • 5-year expected use is 40 M exposures • Life test 4 shutters: Lubricant Retainer Preload Bearing 1) Bray 815Z Crown 0.9 lb. SR3FCHH7P28LY303 2) Nye 2001B Phenolic 0.5 lb. N298-000 (custom) 3) Nye 2001B Phenolic 0.9 lb. N298-000 (custom) 4) Nye 2001B Minapore 0.9 lb. N298-800 (custom) • 80 M exposure (each shutter) life test: • Assemble using detailed assembly procedures (same as used for flight motors) • Functional Tests (same as flight motors) • Thermal (-10 to 50 C in air) • Vibration (GEVS level) • Vacuum Life Test • Temperature held at 30 C with heaters • Mechanism health is trended throughout the test • Disassemble & Inspect Bearings

  26. Shutter Heritage • SXT • In orbit since 1991 • 8 M on-orbit exposures without failure • MDI • 68 M operations without failure (vacuum life test) • ~ 70 M on-orbit operations without failure • TRACE • 12.5 M on-orbit exposures without failure • Program C • 33 M operations without failure (vacuum life test) • 2 Shutters integrated to 2 flight SXI Instruments • Program B • Shutter integrated to flight instrument; undergone environmental testing • Program F • Life test in progress • Program E • Integrated to the flight instrument; testing in-progress • Program D • 2 Shutters integrated to the flight instrument; testing in-progress

  27. Door Requirements • Mechanism must open the door with any plausible single-point failure • Door Opens 170  5 Degrees • Design Life: 1000 Cycles • Operates in Any Orientation in 1G • Operating Temperature: 0 to 40 C • Survival Temperature: -20 to 65 C

  28. HMI Door

  29. Door Assembly

  30. Door Design • Spring to hold door shut: • SPEC T051-360-406R • 1.5 in-lb closed • 2.9 in-lb opened • Actuator: • Made by CDA Intercorp • Torque: 6 lb-in (50:1 gearhead, 100 pps) • 12 steps per motor revolution • 600 steps per worm revolution • 11,333 steps to open door (113 seconds @ 100 pps) • Lubricants: • Actuator Gearhead: Braycote 600 • Worm & Wheel: Pennzane Grease

  31. Door Operation • One motor is normally used to open/close the door. • Nothing prevents both motors from being used at once. • Each motor operates independently from the other. • Motor runs until either: a) Limit switch is activated b) Programmed maximum number of steps have been sent • Drive electronics stores the number of steps required to open or close the door. • There are override commands in case a limit switch fails closed. • Door can function with either a failed-open, or failed-closed limit switch. • Door may be opened to less than the nominal 170 degrees.

  32. Door Testing • Brassboard Mechanism • Various Functional Tests • Torque Margin Verification • Operate in Thermal Chamber (-20 to 70 C) • Vibration with Structural Model • Flight Mechanism • Various Functional Tests • Torque Margin Verification • Environmental Tests with Flight Instrument

  33. Door Heritage • Similar to MDI Door • Either Motor Can Open Door • Spring Holds Door Closed • Door is Balanced • Differences: • HMI uses Step Motors from CDA Intercorp • MDI used Brushless DC Motors from Inland Motor • HMI uses CDA Gearhead (integral with motor) • MDI used Gearhead from PIC

  34. Alignment Mechanism Requirements • On-Orbit Range: ± 200 arc-seconds • Range for Ground Testing: ± 600 arc-seconds • Step Size: 2 arc-seconds maximum • Design Life: 1 M steps • Operating Temperature: 0 to 40 C • Survival Temperature: -10 to 50 C

  35. Alignment Mechanism Design • Actuator: • Made by CDA Intercorp • Maximum Operating Force: 10 lb. • Maximum Non-Operating Force: 250 lb. • 12 steps per motor revolution • 25:1 Gearhead Ratio • Step Resolution: 0.00033 inches • Lubricants: • Actuator Gearhead: Braycote 600 • Leadscrew: Braycote 600 • Position Feedback: • Each lever has a 2-channel optical encoder • One channel indicates if the mechanism is within its operating range • Other channel indicates which half of the range the mechanism is in

  36. Alignment Mechanism

  37. Alignment Mechanism

  38. Alignment Mechanism

  39. Alignment Mechanism

  40. Alignment Mechanism Range

  41. Alignment Mechanism Testing • Brassboard Mechanism • Various Functional Tests • Torque Margin Verification • Vibration with Structural Model • Flight Mechanism • Various Functional Tests • Torque Margin Verification • Environmental Tests with Flight Instrument

  42. Alignment Mechanism Heritage • Similar to MDI Alignment Mechanism • Differences: • HMI uses step motors from CDA Intercorp • MDI used Kollmorgen motors • HMI has gearhead between leadscrew & motor • MDI had motor directly drive the leadscrew • HMI uses optical sensor for position feedback • MDI used microswitches & potentiometers • Optical limit switch • Same electronic parts as other encoders • Same design as: • TRACE Focus Mechanism • Program D Slit Scan Mechanism

  43. Disturbance Torque • Focus Wheel 40 oz-in (computer simulation) • Hollow-Core Motor 15 oz-in (computer simulation) • Shutter 3 oz-in (computer simulation) • Front Door Disturbance < 2 oz-in Mechanism is seldom used • Alignment Mechanism Disturbance < 2 oz-in Mechanism is seldom used

  44. Summary • Peer review held 9/17/2003 • Received comments from Ken Lee & John Van Blarcom (NASA) as well as from several Lockheed Martin participants • Hollow-Core Motors • Prototype motor on-order; expected 11/25/2003 • Life test planned to start spring 2004 • Shutters • One for each CCD • Life test planned to start January 2004 • Focus Wheels • Detailed drawings in-process • Front Door • Detailed drawings in-process • Alignment Mechanism • 2 actuators on-order (due 3/10/2004)

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