pic: Grasshopper Drive

[TheMadCADer]

I've seen a few drivetrains like this, notably in 2011 when 33 and 1477 each used some type of it (and just so happened to form an alliance at Championships that year). I'm sure there are more out there, plus you can also look at Butterfly drive designs since the principle is fairly similar.

For info on 33's version, check out their white paper as well as their CAD and code. It's hard to notice in their build video, but it's there if you look.

For 1477, I don't think there is much more available than what I could see in their build video (but there are plenty of shots of it in there). James Tonthat would be the person to ask for more information on it.