Verified positioners in theta reverse hardstop by hand. Moved phi to intermediate position

Ran several images without motion in between to measure joint angle stability in MSIM. Looked repeatable. D:\PfsTests\15_09_09_14_17_55_msimCenters\Log

Case Study on PID 9:

1639.010909, 1494.950314, 9.512194, 83.546917
1639.015469, 1494.949618, 9.507678, 83.541114
1639.026299, 1494.966767, 9.462858, 83.582771
1638.989696, 1494.927909, 9.579703, 83.498373
1638.978009, 1494.924961, 9.599850, 83.499336
1639.018310, 1494.927580, 9.544032, 83.473836
1639.007960, 1494.922499, 9.566369, 83.467384
1638.971294, 1494.946626, 9.569028, 83.568717
1638.999337, 1494.947836, 9.531346, 83.549141
1638.984517, 1494.939704, 9.564862, 83.537397

Commanded phi all the way out and repeated pictures. Found theta to stay at ~10deg

1612.001134, 1495.254202, 10.307388, 149.973990
1611.968848, 1495.261306, 10.204726, 150.227769
1612.017472, 1495.252043, 10.353620, 149.854833
1612.040316, 1495.239580, 10.452690, 149.633752
1612.016971, 1495.225077, 10.452127, 149.699773
1612.055621, 1495.222419, 10.550961, 149.435291
1612.038438, 1495.207727, 10.565453, 149.460212
1611.999091, 1495.222729, 10.419239, 149.801907

Commanded phi all the way in and repeated pictures. Now theta is totally different...

1639.735283, 1455.454917, 147.170602, 24.861867
1639.704160, 1455.516264, 146.826288, 24.822980
1639.717375, 1455.515868, 146.875580, 24.799836
1639.642199, 1455.472841, 146.766662, 25.001201
1639.711187, 1455.516682, 146.850111, 24.809704
1639.700574, 1455.509256, 146.839862, 24.840208
1639.696118, 1455.518971, 146.786981, 24.833281
1639.689207, 1455.512950, 146.784832, 24.854969
1639.710706, 1455.510546, 146.871615, 24.820013
1639.688442, 1455.509084, 146.796698, 24.862288

Commanded phi out 300 steps and repeated pictures. Theta back to ~10deg. Obviously error in inverse kinematics.

Overheating theta stages

Checking general health of Theta stage on PID 9 visually Script does the following in a loop
  1. Run 4000 steps fwd
  2. Wait 10 seconds
  3. Run 4000 steps rev
  4. Wait 5 seconds

In first loop iteration, Observed theta stage moving fwd correctly and back to hardstop with some overdrive. But all subsequent fwd moves fail to get out of hardstop. The motor can be heard, but no motion visible. Several full loops observed with this behavior in succession.

Reran the script and the first fwd motion is successful, but the next again fails as do the following fwd motions. Reverse can't be talked to since the motor never makes it off the rev hardstop after the first loop iteration.

Thinking this could be an issue with motor overheating, changed wait after reverse motions to 30sec. The fwd motions now succeed everytime.

Repeated the overheat experiment with PID 31 and same results. After moving back to hardstop 4000 steps with slight overdrive into hardstop, after waiting 5 sec, the motor does not move when given a fwd command of 4000 steps. After increasing the wait between moves to 30sec, the fwd motion is successful.

Confirmed the same behavior on older positioners 15, 21 and 37 using the same script.

Inverse kinematics debug continued...

  • Adjusted fiber arm on PID9 coupler to provide a certain positive offset when in home position.
  • Ran the following commands and watched by eye what was going on:
cmd_moveMotor_Steps_all 2,2000,1

{ Move to home position and out slightly on phi }
cmd_moveMotor_Steps_all 1,6000,1
cmd_moveMotor_Steps_all 1,-12000,1

{ Take reference image}
cmd_getImageStart_NoWait
cmd_getImageDone_Wait
cmd_findCentroids
cmd_LogCentroids
cmd_setCurrentPos_all
cmd_getCentroidsArmInverseKin  
cmd_clearOpenCV_Images
  • The first move on phi goes as planned
  • The second move of 6000 fwd on theta begins, but before I notice an end to the motor noise the next command kicks off and then completed immediately and proceeds to the camera command which I hear the camera click for while the motors are still moving!! This explains why the angles we were measuring here did not correspond to the hardstop, the camera took the image mid-motion.

* confirmed now that all of the positioners are in their theta rev hardstops

  1. take images, no motion
  2. Move in phi -2000 steps, take image
  3. Move in phi -2000 steps, take image
  4. 10 iterations of: Move phi 200 steps, take image * PID 9 Results
1649.220964, 1473.403612, 10.006204, 24.517356
1648.831170, 1469.729178, 9.077270, 15.773651
1648.696660, 1479.761686, 10.246687, 39.614717
1644.348054, 1489.283520, 10.342301, 64.512966
1637.307440, 1495.646859, 10.254036, 87.145947
1628.207385, 1498.704456, 10.488848, 109.705394
1618.723872, 1497.899769, 11.133845, 131.328195
1612.428443, 1495.146727, 11.622437, 146.725051
1607.913950, 1491.322876, 13.454309, 157.127254
1603.966002, 1485.883795, 17.938911, 163.915913
1602.232599, 1481.051764, 26.867528, 157.646242
1602.237929, 1481.058267, 26.872470, 157.616623
  • Positioner 21 appears to have something very wrong. Ignoring for now
  • All positioners seem to go past 180deg and then their phi angles decrease again with corresponding jump in theta angle

-- ChazMorantz - 09 Sep 2015

Topic revision: r1 - 2015-09-09 - ChazMorantz
 
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