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Students build robot that solves the Rubiks Cube puzzle
Article Type: Mini features From: Industrial Robot: An International Journal, Volume 38, Issue 5
Rowan University students in the College of Engineering have designed and built a robot that quickly solves the Rubik’s Cube puzzle. A toy puzzle developed in 1974, the Rubik’s Cube is now even recognized by the Guinness Book of World Records in several categories of speed solving.
The Rubik’s Cube is a 3×3×3 stack of cubes, different colors on different sides of the cubes. The goal is to take a random arrangement of cubes and quickly align the cubes so each 3×3 face has only one color. One Rubik’s Cube expert claims there are 43,252,003,274,489,856,000 possible starting positions.
Two Rowan engineering students, Zachary Grady and Joe Ridgeway, took up the challenge to build a robot that might set a new world record for solving this puzzle. Heart of their development is an S7-1200 programmable logic controller (PLC) donated by Siemens to the effort. The team was assisted by Philip Mease, an Electrical and Computer Engineering Technician and Advisor, Professor Dr Shreekanth Mandayam and Mechanical Engineering student, Karl Dyer.
The robot consists of two-stepper motor-powered rotary axes and three pneumatic-powered rams or linear axes (Figure 1). One rotary axis is the cube holder. The cube stands on one corner and is held in place by thin shims that slide between the layers to firmly grip the one bottom corner cube. The cube is rotated to present different sides to the layer turning robot head as directed by the PLC.
A second rotary axis is an acrylic sleeve that rotates one or two layers of blocks on the cube. The PLC directs a ram to position the sleeve to grip one or two layers. A second ram is activated when only one layer is to be rotated and grips the middle layer to hold firm and prevent unintended rotation. A third ram is used to limit the travel of the sleeve ram when only one layer rotation is desired. The sleeve rotation can be directed as CW 90°, CCW 90° or 180° in either direction.
The solution is created by “looking” at the initial cube arrangement with a digital camera located to one side of the cube. The camera image is sent to the PLC. The PLC program then figures out the correct 18-step program that is needed to quickly align the color panels correctly. The robot has solved the Rubik’s Cube puzzle in as little as 15 s. This is not yet a Guinness Record but work continues in hopes of besting the 6.77 s record held by Australian Feliks Zemdegs, a human puzzle solver.
For more information about Rowan University, please visit: www.rowan.edu. For more information on the Rubik’s Cube-solving robot, please e-mail: firstname.lastname@example.org. To watch a video of the robot in action solving the Rubik’s Cube, go to: www.youtube.com/watch?v=goTn0-20BAE