This year for the 1st time in our team's history we have designed and built a butterfly drivetrain, and luckily one of the CAD team members decided to design a butterfly mechanism during the summer so he could help.
With our design (2 8" pneumatics wheels & 2 4" omni wheels) one of the major goals was to lower the omni wheels to the ground (their default position was higher than the 8" wheel), this was achieved using 2 cylinders for each module:
-1 "weak&long" cylinder to lower the wheels
-1 "strong&short" cylinder push the omni wheel below the pneumatic wheel.
Later on I will look for some pictures of the module it self
Reveal video
https://www.youtube.com/watch?v=ZwHWlINEuo8
OffSeason projects thread
http://www.chiefdelphi.com/forums/sh...highlight=3316