My co-workers fought in the heavyweight division at this weekend's RoboGames. Their robot, Counter Revolution, wields giant, counter-rotating blades made out of tool steel to deliver punishing blows. The blades aren't sharp, but that much tool steel can deliver quite a whack. The damage it was doing to the arena was definitely disconcerting to the organizers.
The design still needs some tweaks -- due to the inherent danger in running the robot, the only 'debugging' they've been able to do is at a filming of Battlebots as well as at RoboGames. What got them this time around were the holes they made in the base plate to lighten the robot. I'm looking forward to the next design iteration. There's too many boring combat robots out there, so I always enjoy a robot that puts even the announcer on edge with the potential for havoc.
You can see more video of them fighting on YouTube. Here's one from Friday where they managed to rip off the top of the other robot (about 2 minutes in):




