Lego Robot Solves Any Rubik's Cube In 12 Seconds

kkleiner writes "Cube Stormer is the latest creation from Mike Dobson, aka Robotics Solutions, and not only is it made entirely out of Legos, it can solve any 3x3 Rubik's cube in less than twelve seconds. Often it can finish in less than five! This thing looks bad-ass and is incredible to watch."

Comments

That's fast

[TheVoxyn]

Think 99% of the world population can't do that :P

How they are doing it?

[JoshuaZ]

Unfortunately, the linked to post and video doesn't give much details. Naively, I expect that the computer program is first figuring out very quickly what the series of movements to solve the cube and then implementing those. There are around 4 * 10^19 possible configurations for a Rubik's cube, but the group theory allows one to work out what steps to take without having to do very exhaustive searches since the Rubik's group is very well-behaved. However, this assumes one is in an actually solvable configuration. I'd be curious to find out if they've debugged the device well enough to make sure it doesn't hang or get in some infinite loop if one gives it an unsolvable cube (not all possible permutations of squares are solvable. Most trivially, edges need to stay on edges, corners on corners and centers on centers. But some configurations are still not solvable. For example, if one swaps two center stickers it isn't hard to see that that lays outside the Rubik's group of reachable permutations).

Re:This Video is FAKE

[bondsbw]

The next to last solve (at 41s) takes 21 moves*, and is the only cube claimed to be random... thus, I don't see any dishonesty. It takes around 1.9 seconds to analyze, about 0.4 seconds to reset/process, and the remaining 8+ seconds to solve. Therefore, it makes on average between 2 and 3 turns per second.

Humans do not include inspection time in the speed calculation (at least, that's the case in the accompanying video of the world record). An apples-to-apples comparison, therefore, would be the human time at 7 seconds and the robot at a little over 8. I couldn't follow the world-record video, but I think I saw at least one mistake (a move followed by the opposite move) and a little hesitation. So, you're probably correct in the 3-5 moves per second for humans.

*21 includes twice that the computer simultaneously moves two faces, each counted as two separate moves. 180 degree moves are counted once.