[alphastryk]

Our team (1002) has actually been looking into the hemispherical wheels thing since we figured it out over the summer, but we haven't figured out how to get the wheels to have enough friction to move the robot, but little enough that the ratio can change.

To make sure your ground clearance stays constant, you pivot the "wheels" around a diameter.

I think we decided on some sort of rubber-coated aluminum spheres.

Don't know if this helps anyone with figuring this out, but it will be a really neat innovation for whoever can get it working.