[Qbranch]

My partner and I built a drive system extremely close to this for an AGV to transport materials throughout our factory. The only difference is, ours used a central turntable with driven 'casters' on all four sides linked by a timing belt.

Eventually we scrapped the idea since the robot drifted slightly off of square with the building and could not correct its body angle... the only thing it could do is move in different directions.

Have you prototyped this? Can it turn by some method i'm not seeing? If it works like I think it does, I have a suggestion that might let you turn...

-q