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UM7 accel drift

asked 2015-12-14 17:47:15 -0500

baronep gravatar image

I am experiencing some odd behavior with my CH Robotics UM7 IMU that I recently purhcased. When the unit is just sitting on the table, it reads 9.2 instead of 9.8 m/s/s for acceleration. I can find instructions on how to zero the rate gyros but nowhere does it mention calibrating the accelerometers. Has anyone run into something similar before with these IMUs or any other unit? I have included an example message

  seq: 3506
    secs: 1450136355
    nsecs: 252817294
  frame_id: imu_link
  x: -0.0238677723
  y: 0.0203094265
  z: -0.9840840295
  w: -0.1747282065
orientation_covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
  x: -0.000581685356641
  y: -0.000610669209776
  z: 7.07960511619e-05
angular_velocity_covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
  x: -0.0682945557769
  y: 0.22608049971
  z: 9.21032193719
linear_acceleration_covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
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Hey, did you ever end up figuring out how to fix this problem? I'm getting a similar error with my new UM7, where my z-acceleration is hovering at around 10 m/s^2 when resting. My UM7 is running firmware version U72A.

J-rizzy gravatar image J-rizzy  ( 2016-09-01 15:39:28 -0500 )edit

Yes I did. The UM7 (and all accelerometers) are very sensitive to mechanical strain, temperature and a variety of other factors. As such, you need to calibrate the accelerometer fairly frequently. I would suggest the CH Robotics utility to do this

baronep gravatar image baronep  ( 2016-09-01 17:15:26 -0500 )edit

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answered 2015-12-16 00:53:30 -0500

Akif gravatar image

AFAIK, UM7 has a Windows software for calibration and configuration. You can try it for calibration, after that return back to Linux.

Software is here.

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Asked: 2015-12-14 17:47:15 -0500

Seen: 282 times

Last updated: Dec 16 '15