Robotics - Half A Second To Solve A Rubik’s Cube

29 Aug 2018

A multi-generation toy, the Rubik’s cube, has been repurposed to create one of the fastest robot to date. The new robot that can solve the Rubik’s cube faster. (Image and video from builditsinprogress.blogspot.com)

Created in 1974, the Rubik’s cube was not meant to be the toy it is today. Erno Rubik, a Hungarian professor, built the cube to teach his students three-dimensional problems. Erno first named his cube the Magic Cube, and it wasn’t till the very first toy store decided to promote the cube that they renamed it “The Rubik’s Cube,” back in 1980. Since then, 400 million cubes were sold. Erno believed that the cube’s colors might attract the curious, but only the very determined people can solve it. And even then, the cube has a way to keep people interested: once someone solves the cube for the first time, the challenge now becomes to solve it faster and faster. Ironically, the creator of the cube took an entire month to solve it himself, the first time around. What does it say about the common man? The truth is that the cube can be rearranged in 43 quintillion different ways. And, although a lot of people have attempted to solve the cube, and many accomplished it in an astounding time frame, nobody has solved it in less than a 1 second. It is the feat of a robot invented by 2 students from MIT.

Using 6 ServoDisc U-9 Series motors in addition to 6 motor drivers and 2 playstations eye-webcams, Jared Di Carlo and Ben Katz build their robot with a Rubik’s cube at the center; almost as if in the hands of the robot. It was not the first engineers build a robot that could solve a Rubik’s cube; all prior models were from different companies and was not as fast as Di Carlo and Katz’s robot. This new robot has solved the cube in 0.38 second. Basically, to see this machine’s prowess, one should not blink the eyes. Out of fear that the system might explode if all the motors act at the same time, Katz and Di Carlo used a special AND board that allows some motors to shut independently when necessary. The robot is equipped with an algorithm, the Min2phase, that enables the robot’s solving skills. According to the 2 engineers, a few adjustments could make the robot even faster. However, there is a risk of losing the cube if the process is sped up. Katz explained in a blog post that the cube loosens up when the robot or a human starts to turn the various rings of tiles, and the faster the rings are turned, the looser the cube gets. Therefore, speeding up the process of solving the cube tends to make it explode into pieces. It probably won’t stop the team of engineers from finding ways to improve the robot.

A robot that can solve an equation with as many variables as the Rubik’s cube is certainly going to serve in the future. From a business standpoint, the robot might contribute to the boost in Rubik’s cube sales. Those humans who hold the record for quickly solving the cube might also want to compete with it. In any case, the Rubik’s cube might just survive a few more generations.