How to use start_anticogging_calibration

1

Hi,

the search doesn´t help, there are only outdated posts and incomplete descriptions which all do not work.

I use a brand new odrive v3.6 24 V with originally installed dev firmware.

So please advice how to start/use e.g. odrv0.axis0.controller.start_anticogging_calibration()

At the time being, can anti_cogging be used in real-life applications or is it just for “playing” ?

2

Your command should work with no changes.

It works but it’s best at low-speed, constant velocity or to smooth out velocity control (rather than position control).

3

Thanks a lot !

  1. Aha, first I tried in position control and it did nothing. With vel_control it works (without changing gains in my case).

  2. Is the calibration data stored automatically? How do i save it ?

  3. A short description of how it works for me: (in case other people also have troubles)

  • run full calibration sequence if not calibrated

  • set controller mode to velocity control: odrv0.axis0.controller.config.control_mode = CTRL_MODE_VELOCITY_CONTROL

  • start closed-loop control: odrv0.axis0.requested_state = AXIS_STATE_CLOSED_LOOP_CONTROL

  • maybe you have to increase the gains a lot (i didn´t have to)

  • start anti_cogging_calibration with e.g. odrv0.axis0.controller.start_anticogging_calibration()

  • motor should spin slowly

  • wait until motor stops - or stop it if it does something weird

4
  1. Weird, all it does is switch back to position control mode before starting the calibration. It needs to be in closed_loop_control, however.
  2. It is not. It cannot be saved (this will be fixed eventually)
5

How long should that anticogging-calibration process take? I see pos_setpoint changing very little over time, but not constant. contoller.calib_anticogging = true but it already takes like 5 Minutes now. Am i doing something wrong?

6

if you don’t increase your gains dramatically, between 5 and 10 minutes. You’ll want to multiply your pos_gain and vel_integrator_gain by something like 10x

7

How does the anti-cogging calibration look like?

We have our motors already installed, and it is difficult to get the belts off from a few of them. Is it safe to run the calibration procedure on a live system? I’m concerned if the motors will have to spin for several minutes. A few revolutions would be ok for us. What about payload mass? Can the calibration be done with it or do we need to strip done everything?

8

The calibration just does one revolution, but no, you can’t do it with a payload mass. Needs to be done on a disconnected motor.

1 Like