We are using a 24 volt ODrive with this motor:
We were following this guide: https://docs.odriverobotics.com/hoverboard.html. After encoder calibration, we got an
encoder.offset_float of about 1.3 (should be 0.5?) Velocity control worked up to about 1000 (42 counts per revolution) before we got
ERROR_CURRENT_UNSTABLE. Position control couldn’t go more than a couple revolutions before failing with the same errors. Increasing the
current_limit_tolerance (to about 3), as suggested here: https:// discourse.odriverobotics .com/t/motor-failed-current-unstable/3194/2
did not seem to have an effect. (I added a space to the URL because I can’t post more than two links) Increasing the current limit did though, but the error would still occur at higher speeds. Sometimes we would get an over speed error too.
We tried another of the same motor and it produced the same
offset_float after calibration (1.3). We switched the sensor wires around and re-calibrated, this time getting an
offset_float of -0.3. We switched the sensor wires again and got 0.7. This is closer, but it didn’t seem to make a difference. We still got the errors around a velocity of 1000. We don’t have any other motors to test yet, and this is our first time using an ODrive.
https:// discourse.odriverobotics .com/t/motor-failed-current-unstable/3194/4
(Can’t have more than two links)
suggests that it may be related to encoder/hall sensor misalignment which could also be why we have a weird
offset_float. We opened up one of the motors to look, and here is a picture:
It’s easier to see in person, but the hall sensors are slightly offset from directly between two coils.
- What is
offset_floatand why should it be close to 0.5?
- Could the slight offset of the hall sensors seen in the picture be the reason for a bad
- Is the value of
offset_floatrelated to the errors we are seeing?
- If this is a result of the hall sensor offset, is there a way to fix it aside from physically adjusting it or using a different motor?
- If this isn’t a result of the hall sensor offset, what could be causing it?