Mitsubishi Robot Sets Guinness Record for Solving Rubik’s Cube

Talk about gleaming the cube.

Mitsubishi Electric Corp.’s TOKUFASTbot recently secured the Guinness World Records title as the fastest robot to solve a Rubik's Cube, shaving 0.075 of a second off the previous record to finish the puzzle in 0.305 second — not quite eye-blink territory, but close.   

By comparison, the Guinness record for a human solving a Rubik’s cube is a relatively sluggish 3.47 seconds, set by “speedcuber” Yusheng Du in 2018.

In a real-time video of the solve, a scrambled cube is held by six robot appendages, a blur of motion and a brief clatter ensue, and voila, a satisfyingly solved cube appears. To allow a human to observe the process, Mitsubishi slowed the playback 42x. Even then, it only takes nine seconds.

This latest feat of speedcubing was accomplished by a team of young engineers from Mitsubishi’s Component Production Engineering Center in Hyogo, Japan. The engineers built the TOKUFASTbot (TOKUI Fast Accurate Synchronized Motion Testing Robot) in their free time using the company’s high-speed, high-precision factory automation equipment and control technology, which is typically deployed in the manufacturing sector. 

"Shaving off time as much as possible was difficult, but it was fun at the same time,” the team leader told Guinness. “I never had issues with motivation through the project."

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The robot uses a newly developed AI-based color-recognition algorithm for instant color identification. According to the company, this is accomplished in the face of challenges like changing block positions, the shadows cast by the robot “hands” and differentiating between red and orange, which have similar hues. The computer program used to solve the puzzle in the shortest number of moves is run on an industrial PC and has been optimized to accelerate and enhance computational processing.

TOKUFASTbot also uses a proprietary, high-speed, high-precision positioning technology that is commercially used to accurately position electric wires in winding equipment used to make motor coils. Its rotation mechanism can rotate the cube 90 degrees in just 0.009 of a second using a compact, high-power and signal-responsive servomotor. 

In fact, one of the main limitations on the robot’s solving speed was the cube itself. In the team’s first official attempt, the cube jammed. The second attempt was successful and even topped times achieved during practice, Guinness said.

Other components include six-axis servo motors, programmable controllers, motion modules, servo amplifiers, cameras and a touch-panel display. 

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