Motor Calibration Current not Working

1

Hi again guys,
I build a mobile vehicle and every time I start my system I need to find index of the encoder ( Im using incremental encoders. Every time the system is on the ground and I execute command to find the index my motors start vibrating. Only if i lift the system in the air , motors are able to move without vibrating,find index and then everything works OK. Im having a battery that can deliver 30 A , so I have set the calibration current to 25 A in order for the motors to be able to move on the ground while doing calibration functions. Today i noticed on the liveplotter that my motors dont draw enough current while searching the index and calibrating . They draw max 10 A . My current lim is 30 A. What else can cause this behaviour ?
Thanks

2

I had a similar situation and issue. I was able to resolve it by increasing calibration_lockin.current and general_lockin.currrent (I think the default is 10 amps).

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3

That’s not right either. It doesn’t matter what current the battery can do, since the ODrive acts like a power converter.

4

UPDATE: After I set the parameters calibration_lockin.current and general_lockin.currrent the system now moves when sending the command for full calibration sequence. Now i get the following error:
ENCODER_ERROR_CPR_POLEPAIRS_MISMATCH
If i calibrate in the air, i dont get it.
I use D6374 150kv and CUI AMT102-V
pole pairs is set to 7 and cpr is 8192

So you say the battery power is not enough during calibration ? But then if I calibrate in the air and put the odrive in closed loop and the system back on the floor i can send commands, they are executed and the odrive draws the 25A current and can move the mechanical parts without problem. My question here is:

  1. Is there a problem if I calibrate in the air (with less mechanical load) and then use the system with more mechanical load
  2. If 1) is ok then i neead to lift the system in the air on every startup witch would not be ideal

We decided to put another planetary gearbox between motor and mechanical system with bigger ratio, so that it is more easier for the motor to overcome the mechanical load when calibrating and searching index.

5

No, exactly the opposite. You can increase the current limit and calibration current on the odrive because at slow speed you will only pull small currents from the battery.

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