Using Kevin's PWM outputs for a quieter drive system.

[Kevin Sevcik]

I'm going to say it's not related to your ADC oversampling. Blaming it on the ADC oversampling implies that the ADC code is taking a moving average of the analog input and thus damping the current feedback signal, but this simply isn't how the ADC code works. I think you're just seeing the mechanical dynamics of the system coupled with a slow control loop and delayed response from the Vics. I'd say you can compensate by increasing the PWM loop rate like we've been talking about and very carefully bumping up your gains. IR compensation is a little tricky since the electrical dynamics of the system are an few orders of magnitude faster than the mechanical dynamics. If you increase your gain too much, the IR compensation starts overshooting and you get chatter in your motor and it sounds even worse than they usually do. So I'd say speed up the loop and tweak up your gains till things start sounding off, then back them down a little and just assume that's the best you're going to do.