Pitter Patter in the US uses cams to shuffle, as did Overhaul at last year's Battlebots (only in the whiteboards though)
They seem good but a little bit bumpy from what I can see, might be feasible to get rid of some of that with some tweaking...



Of course the massive detriment is that unlike some US events you don't get any weight increase so it's a bit more weight in a drive system for no real gain over a conventional wheeled setup (which is why overhaul swapped to wheels for the competition). That said, if the FRA were to honour the Robot Wars weight increases I can imagine it'd be a fair enough trade. I suppose in the wooden floor arenas you could also try small studs in the 'feet' to help increase traction?