Hi All, I’m looking for some feedback on suitability of ODrive components for a design I want to make.
The challenge is that I need 3Nm of torque at the handle of a force feedback knob to overcome friction and variable user input, and I need to position the knob with 0.005 revolution (1.8deg) precision.
I’ve done a first iteration with a Moteus BLDC motor and 4:1 pulley but it didn’t go well. The controller couldn’t overcome friction (high torque) and control very low velocity well at the same time (e.g. moving from 0.0 to 1.8 degrees). The flex in the pulley didn’t help either.
The ODrive motors have enough torque to directly drive without a pulley, have way lower kV (lower velocity) and the controllers appear to have a low speed mode (though I don’t understand it fully) so I’m considering making the investment.
Thanks in advance!
Andy
ODrive can do this particularly with anticogging enabled for that low speed precision.
Agreed with Paul on the feasibility. You can definitely try the S1+8325s start kit. The only concern I’d possibly have is with the S1’s onboard encoder’s noise and resolution limiting the fine grained force feedback you can get, but adding an external high-resolution incremental encoder would be quite easy. You could also use the S1 + 6374 + AMT21 (16384 CPR RS485 encoder), though that’ll take a bit of 3d printing to set up.
Hi All,
Thanks for the input!
I read about the anti-cogging and it looks straight forward to do. I’m curious to try doing that calibration and then running the motor with just FF to see just how smooth (cogless) the system is when turned by hand with no position control going on.
The D5065 motor with dual shafts for easy encoder mounting sure looks nice to use. It has lower torque but it might be ok to use its peak torque for haptic feedback since it will spend a lot of time just sitting and cooling off.
I’m going to order some goodies and see what happens!
Andy