Swerve Drive vs Mecanum Wheel drive?

[Ben Wolsieffer]

Originally Posted by efoote868

2010 a large segment of the teams automatically ruled them out ("can't traverse the bump!"), similarly with 2012 ("can't balance on the bridge!").

As a mecanum lover, it really annoys me when people automatically rule out mecanums when the really don't know what they are capable of. Our robots in 2010 (http://youtu.be/rdAKiuimaY4?t=58s) and 2012 (http://youtu.be/tdAncHeHOEQ?t=1m36s) had mecanums and they could traverse the bump and balance on the bridge.

Originally Posted by RoboChair

Mecanum if done well, geared for agility, and absolutely programmed FIELD CENTRIC and then practice the hell out of it can be a very competitive drive train. Anyone that does not put in the effort to code and set up a mecanum drive for field centric is wasting their time. I have seen many teams drive mecanum like a tank drive with only the occasional strafe/rotation and this is a waste of time. You can dance across the field dodging defense all day if you can just move the stick and your robot moves that way on the field no matter where it is pointed. But if defense catches up to you that's it, you must be faster! Mecanum shouldn't really even have a tank style drive mode.

I especially agree with this. In past years we have driven our mecanums mostly as arcade drive and with crabbing at the press of a button. You can see the ineffectiveness of this in our video from 2012. This year though, I implemented a really cool (in my and the judges' opinions [we won the Innovation in Control Award for it at two districts]) field oriented drive mode that we use exclusively. I read about the idea on CD and decided to implement it early in the build season, so we had a lot of time to practice with it. Even though we aren't extremely powerful, we are agile.

Originally Posted by Chadfrom308

On each wheel, we have a toughbiox mini with 1 big CIM and 1 min CIM. (Yes technically we have an 8 CIM drive)

This allows us to accelerate crazy fast, which helps with all the defense,

Programming wise, we have 5 PID loops on our drivetrain. I'm not a programmer, but how I think we set up the PIDs is the based on rpm from each wheel, us telling the PID how fast it should be going. We have 1 PID on each wheel, and one for rotation. It's cool because you can push our robot and it will push back with independent power on each wheel. And speaking of pushing, that's how we play defense (sometimes). We sit in front of a robot and step away from the controls and it does the work (mostly) by itself.

That sounds really cool. I was thinking of using PID loops and encoders this year but I decided it was just easier to use a gyro to maintain our orientation if we were pushed and to correct for traction or weight imbalance problems, mostly because we have had bad experiences with encoders failing in the past. I might try that along with extra miniCIMs in the offseason.