Complete CAD file can be downloaded here.
https://drive.google.com/open?id=0B6...Qzg&authuser=0
After our successful 1st year using our "In wheel" swerve we learned a few things and applied those lessons to our 2nd swerve design.
-Swerves can usually out maneuver other robots when there is an open field
-A single speed swerve is not good in a scrum with multiple defending robots
-Slip rings add weight, complexity, point of failure and the legality of the best Mercotac slip rings is being debated currently
-Colson tires get good traction and have a low rolling resistance but are more traction limited than Nitrile treaded tires
Therefore we developed a 2-speed coaxial swerve so we have speed and the ability to get out of a jam. We switched from Colson wheels to custom aluminum nitrile treaded wheels to gain added traction. We reduced the weight per module by 1lb each and the area is 33% of the "In Wheel" swerve.