Robot Solves Rubik's Cube In Less Than a Second (livescience.com)

An anonymous reader quotes a report from LiveScience: In just over half of a second (0.637 seconds), the Sub1 Reloaded robot made each side of the Rubik's Cube show a single color. This breaks the previous record of 0.887 seconds achieved by an earlier version of the same machine using a different processor. German technology company Infineon staged the record attempt at the Electronica trade fair in Munich this week, as a way to highlight its self-driving-car technology. The company provided one of the Sub1 Reloaded robot's microchips. Infineon said more than 43 quintillion combinations of the Rubik's Cube's colored squares are possible. That same number of cubes would cover Earth in 275 layers, resulting in an approximately 65.6-foot-high (20 meters) layer of Rubik's Cubes, the company added. The record-breaking attempt began with the press of a button. Sensor cameras on the machine had their shutters removed, and the computer was then able to detect how the cube was scrambled. The computing chip, or the "brain" of the machine as Infineon called it, then determined the fastest solution. Commands to execute the solution were sent to six motor-controlled arms. "It takes tremendous computing power to solve such a highly complex puzzle with a machine," Infineon said in a statement. "In the case of 'Sub1 Reloaded,' the power for motor control was supplied by a microcontroller from Infineon's AURIX family, similar to the one used in driver assistance systems."

Comments

Human did it in 4.74 seconds 5 days ago

[JoeyRox]

Although that doesn't include the time he was allowed to examine it before starting. Here's the video:

https://www.youtube.com/watch?v=tLksISrKtO8

Re:Human did it in 4.74 seconds 5 days ago

[Anonymous Coward]

I don't see why a computer couldn't use a similar algorithm...

Because the people that programmed this thing have never read any of the books written on solving a rubik's cube. There is *ONE* solution; one sequence of moves that when repeated will eventually solve the puzzle. There's no need to think out a solution. Simply pick up the cube and start repeating the pattern until all the sides match. (btw, that's how real people do it.)

No such solution exists. The best you can do by repeating the same pattern is to cycle through 1,260 states, multiplied by the length of the permutation sequence: https://people.kth.se/~boij/ka...

There does exist at least one sequence of moves that is guaranteed to solve the cube, eventually (it forms a Hamiltonian circuit.) It's 43 quintillion moves long, and you can download a (200MB) specification describing how to construct the sequence here: http://bruce.cubing.net/ham333... Iterating a sequence that long is well beyond the capabilities of both human and robot, sadly.

Modern solvers use variations of the Kociemba algorithm, which can find near-optimal solutions very quickly: http://kociemba.org/cube.htm CPU power is important because more time spent searching can yield shorter move sequences - the slowest part of the solve (computer vision, solution search, twisting the cube) is the physical part. However, every millisecond spent searching for shorter sequences might be better spent actually executing a suboptimal solution.

Re:What does it mean to 'solve a rubiks cube'?

[ShanghaiBill]

Solves -which- permutation of a Rubik's cube in less than a second? Every single one? How can they prove that before the end of the universe?

It has been proven that 20 moves suffice to solve Rubik's Cube from any starting position.

If you restrict each move to a quarter turn, then 26 moves suffice.

The proof only took 35 years of CPU time.