Torque and Position control to Create a Reel, vibration issues

Support ODrive S1 Support
1

Hi all,

I am using two motors in combination connected by a reel of plastic (think cassette player). The goal is to create a positional controlled piece of tape that is always under tension.
To achieve this I have one motor set in position control and the other in tension control.
This works great!

My only issue is that due to the torque control pulling on the positional control there is a noticeable vibration due to the feedback loops constantly playing off each other. Ideally I want to remove this vibration and allow the motors to be effectively static whilst still under tension.

Any tips/advice?
I have removed a lot of the positional control feedback vibration whilst not under tension by increasing the refresh rate to the 5000ms. But this is lost when the torque control is reintroduced (on val of 0.1).

I think there could be some tuning possible? I have not tuned the motors as I wasn’t sure if this was achievable under tension and thus would react differently when acting in tension.

Any advice or ideas appreciated!
Thanks.

2

Hi! What encoder are you using on both motors? And what motors are they in the first place?

3

both motors are using the 16384 cpr absolute rs485 encoder, along with dual shaft motor - D5312S 330KV. These are both them in combination with the S1 boards. I’m powering the motors from a bench top power supply to give it the smoothest power source too.