I wanted to give a plea to all teams:
Please have some ground clearance on your robots.
With up to 60 points in the balance based on robots climbing onto one another, it would be a smart design choice to give your self some clearance underneath your frame so that you can climb onto other 'ramp' type robots during the endgame.
In terms of numbers:
In the picture attached to this post 'a' is the ground clearance of the frame and 'b' is the distance from the front of the frame to the point where the wheel makes contact with the ground. For simplication, we can assume that 'b' is 1/2 of the wheel diameter.
Therefore, with only a 1" ground clearance with 6" wheels, you can climb onto a ramp that is roughly 19 degrees in grade (use arctan{a/b}).
So just to reiterate, please consider sacrificing at least one inch of ground clearance to make you more of a team playing robot that can climb onto ramps a bit easier!
Gabriel Goldman
PhD Candidate
RoMeLa: Robotics and Mechanisms Laboratory
Virginia Tech
http://www.me.vt.edu/romela
P.S. Feel free to contact me if you need any help with robot mechanisms (like cool four bar linkages!)