MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW1 MARS 2 Mechanical Design Review

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 2 Topics Drive axes –Orientation, location, & travel range of axes –Typical axis drive configuration –Axis loads, drives, encoders, & bearings Optical mounts –Manual adjustments Beam splitter Collimator Lenslet/camera Knife edge CCAS mounting Current design status

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 3 Drive Axes

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 4 MARS 2 Remote Axes Top to bottom Wavescope camera SenSys camera focus Focus (Z) X Yaw (rotation about an axis parallel to Y) Pitch (rotation about an axis parallel to X) Y’ (combined with Focus to get Y)

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 5 Axis Travel Ranges

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 6 MARS 2 Axes from Model Y’ Pitch Yaw X Focus Camera SenSys

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 7 Common Axis Drive Components For all BUT the SenSys axis –Stepper motor –Ball screw with preloaded drive nut –Limit and home switches –Encoder (absolute, rotary) –Fail-safe brake (not on camera axis) SenSys camera axis –TS Products motor with internal encoder

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 8 Axis Drive Resolution Stepper motor –200 full steps per revolution –10  steps per full step  2,000  steps per revolution Lead Screw –2-mm per revolution lead screw –With  stepping results in 1  m per  step resolution will need ~1/2  m per  step for yaw and pitch resolution Absolute encoder –Parallel interface –Minimum encoder resolution of 2,000 counts per revolution will count each  step

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 9 Axis Drive Loads Worst case is “uphill” motion Loads consist of: –Inertia load –Gravity component along axis –Friction Encoder Bearings Drive screw Others

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 10 Axis Loads Axis Load [lbf] Torque [oz-in] Camera Focus X Yaw Pitch Y’

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 11 Linear Axis Mounting THK preloaded rails & bearings –Multiple rails with one block per rail –Slides mounted perpendicular to travel on one side will prevent binding due to misalignment & thermally induced dimensional changes similar to bearing arrangement on the tracker carriage

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 12 Yaw/Pitch Axis Mounting Yaw axis –THK radial cross roller bearing for the pivot –THK curved bearing rail for additional support similar to rho bearing on the carriage Pitch axis will use flex pivots for the pivot Yaw and Pitch axes will use flex pivots and small slides to accommodate  (±2°) &  L (~0.3 mm) at the drive nut Lead screw Stage  L

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 13 Optical Mounts and Adjustments

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 14 Optical Mounts Manual adjustments made with opposed adjusting screws where possible –Locks stage in position, does not rely on springs to hold stage against adjustment screw Combination of flex pivots, pins, adjusting and clamping screws for yaw/pitch adjustments X-Y-Z and X-Z cross roller stages for translation

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 15 Manual Adjustments Part 1 Lenslet –x, y, yaw, pitch: aligns lenslet to optical axis Lenslet/camera stage –focus: positions lenslet/camera wrt collimator Collimator –x, y, yaw, pitch: aligns collimator to optical axis –focus: positions collimator wrt beam splitter cube Beam splitter cube –x, y, focus, yaw, pitch: aligns cube to laser beam

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 16 Manual Adjustments Part 2 Reference mirror –x, y, yaw, pitch: aligns mirror to optical axis –focus: positions mirror wrt HET focus SenSys camera –x, y: positions camera wrt optical axis Light source –x, y, focus: positions fiber wrt pin hole Knife edge –focus: positions knife edge wrt beam splitter cube

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 17 Isometric View of MARS2 Reference Mirror Beam splitter Cube Collimator Lenslet Knife Edge

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 18 Mounting in CCAS Tower Remove everything down to 12-inch I-beams Install stiffeners to forward cross beams Install a layer of dampening material (plywood) Install base plate –Incorporates gross translation & tip/tilt adjustments Install base wedge with y’-axis Install pitch, yaw, & x-axis assembly Install assembled optical bench with focus axis Install electronics rack

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 19 CCAS Components Frame stiffener Dampening material Base plate 12-inch I-beam members Electronics rack

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 20 Current Design Status Most purchased components are identified Final layout work & mounting details need to be completed Drive configuration needs to be finalized Laser for component alignment needs to be added Drawing generation is the next big task

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 21 Unknowns Tolerance analysis Metal finishing-is it needed?

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 22 Top View of MARS2 Camera Lenslet Reference Mirror Knife Edge Collimator Pellicle Beam splitter Cube SenSys Camera Light Source

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 23 Relative Axis Locations Side View Y Focus Y’ Yaw Pitch Camera SenSys X

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 24 Axis Drive Loads in pictures and equations W cos(  ) W a F drive F fr Note that:   = 35° >> cos(35°) = 0.82  g c = in/sec 2 >> for small a’s, cos(  ) dominates  used a = 10 in/sec 2 in calculations  Not all axes have a W cos(  ) component  F = ma F drive -F fr -W*cos(  ) = m*a and with m = W/g c F drive -F fr -W*cos(  ) = W*a/g c F drive = F fr + W*[cos(  ) + a/g c ] rearranging +

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 25 Torque to Load Ball screw with xx lead (pitch) Motor produces torque Drive nut converts torque to force Drive coupling  = efficiency of ball screw, ~ *  *  Force * Lead Torque =

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 26 Axis Drive Specifics IMS stepper motor –two sizes to cover six axes –dual shaft Schneeberger ball screw –12-mm diameter for all but camera axis 3,400 N (770 lbf) static load  s. f. min = 4.2 2,500 N (565 lbf) dynamic load (L 10 )  s. f. min = 3.1 –preloaded drive nut –special order for length and end configuration Absolute rotary encoder –parallel output –multi turn (25 turns needed) –4,096 steps per revolution 2 encoder steps/1  m 1 encoder step /0.5  m Electroid fail-safe brake –engages with power off

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 27 Beam Splitter Mount

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 28 Collimator Mount

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 29 Lenslet/Camera Mount

MARS 2 Design Review-Optomechanical Review 07 Nov 2002 GLW 30 Knife Edge Mount