pic: Reverse Drive

[skimoose]

Originally Posted by Chris is me

That being said, I've been told many times before that CIMs have no significant motor bias whatsoever. I have no data, but my team has also never had this problem so I'm inclined to think for my purposes, it's not a big deal. Your team and setup could be completely different, particularly if you have a 2WD robot which has no turning scrub.

We ran tests in 2007 using victors to control the CIMs and there was some bias, and it was different for each motor tested, it was most apparent when ramping speed up or down. The response curves varied, not significantly but enough to be a problem occasionally, because they were not linear. We wrote code that year to flatten out the response curves to be more linear and that helped.

We haven't done the same testing with Jaguars yet, might be a good exercise for this season.

Drive line friction would probably cause greater issues with a robot driving straight, than motor bias which is fairly consistent throughout the motor's life. No matter what the source of driving error, I'd be looking to sensors and code to fix those issues if you want to achieve truly accurate autonomous navigation.