How can I plot the waveform of vel_feedback?

as title.
I baught Odrive S1 and set it up already.
I use optical encoder of 4000 CPR and run closed loop velocity control with Odrive.
I use live plotter to plot the signal of vel_estimate and found it’s really noisy.
The signal of vel_estimate is used as vel_feedback?
Can I know if any LPF used to filter the vel_feedback? if yes, what the cuf-off frequency .
Many thanks.

Jack Yeh

Hi Jack,

We’d recommend using the new GUI for plotting - it’s going to be a lot easier in general.

That being said - vel_estimate is what’s used as feedback, yes. More accurately, pos_vel_mapper.vel is what you should be looking at. We don’t have a LPF, as this would introduce steady-state phase lag - instead, we use a second order estimator. So it provides filtering, but without lag at constant speed. The response time (in rad/s) can be modified with the encoder_bandwidth parameter. However, reducing this will affect the performance of the controller, so it’s not recommended - typically this is only lowered for low resolution encoders (such as hall sensors).

Can you elaborate more on the noise you’re seeing? Some amount of velocity noise is expected. Could you share more details as to the motor and any load you have? And is it possible to post a screenshot of your plot showing the noise?