Looking at holonomics/omniwheels..

[kresty]

I've been trying to figure out if it's possible to get omniwheels that'd work on Lego for BB-8's head in a holonomic drive.  From what I've seen it looks really challenging.  Probably need about a 2" wheel with a big diameter roller.

Anyway, while hunting, I stumbled across this interesting type of omniwheel.  Apparently it's been used in a couple droids.  It has nested big/little rollers so that the outer provide is more circular.  Looks pretty cool.  Most of the wheels I've seen, especially in smaller diameters, have a bit of a "thumping" to them as the robot drives.  This would avoid a lot of that.  (I'd have enough thumping from the Lego studs.)  Of course making this small enough is probably not very feasible.

http://hackproj.blogspot.com/2012/10/rob...heels.html


Here's an exploded wheel from the rezero ball bot: