Last year team 857 used the killough platform as the drivetrain for our robot. This design needs only three wheels to achieve perfect holonomic omni-directional motion. This means complete control over direction and orientation of travel. You can see pics of the design in the robot photo section of this website.......and if you're interested I'd gladly send you the existing cad files of how we achieved this momentus task. No luck on helping you control it though...that's proprietary.
keep up the good work.
Sincerely,
Anthony Lapp
Lead Design Engineer
Michigan Tech -- Superior Roboworks