I can't find this torque control error from this community

hello! i’m using odrive v3.6 with hall sensored motor with 1870 kV. There are several weird issues and i can’t figure out answer for it. my motor has 1 pole pairs and cpr value is 6.

  1. when i set torque constant to 1, it works really well in velocity control. but when i switch it to 8.27/1870 (manually), it doesn’t work well.
  2. i put my motor in torque control mode. and i started gradually increasing input_torque from 0.0001 to 0.005. there’s no any movement until it gets to a certain point(for example 0.02). and at this certain trigger point, it starts rotating at really fast constant speed(vel_estimate says 360). and i can’t control velocity at this point, i tried to lower input_torque but it doesn’t work, it keeps rotating so fast.

idk what’s wrong… i set current_control_bandwidth to 1000, but didn’t try anti_cogging. but i think anti cogging is not a problem in this case. hmm

Based on the information you provided, it seems like there could be a few potential issues causing the behavior you are observing with your motor.

First, it’s possible that your torque constant value of 8.27/1870 is not accurate. The torque constant represents the relationship between motor torque and current, and an incorrect value could lead to unexpected behavior. You may want to double-check your calculations and verify that the value you are using is correct for your specific motor.

Second, the fact that your motor only starts rotating at a certain input torque value suggests that there could be an issue with the current control loop. It’s possible that the current control bandwidth of 1000 is not sufficient for your motor and that increasing it could help. Additionally, enabling anti-cogging could potentially help smooth out the behavior and improve control.

Lastly, it’s possible that there could be some mechanical or electrical issues with the motor itself. If you have access to an oscilloscope, you could try measuring the current and voltage waveforms to see if there are any abnormalities.

I would recommend double-checking your torque constant value, experimenting with different current control loop parameters, and investigating the possibility of any mechanical or electrical issues with the motor. Hopefully, these steps will help you identify and address the issue.

in odrive docs, they say torque constant is 8.27 / motor kv. but i think i should measure it on my own. i’ll try what you said!! thanks!!

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