Researchers at ETH Zurich and NVIDIA report that a four-legged ANYmal-D robot solved a giant Rubik’s Cube using only its feet. It completed three independent solutions on the physical machine, each requiring about 30 steps and eight to nine minutes.
The robot first walks around the cube and flips it to inspect every side with its camera. A puzzle-solving program calculates a solution, which another program converts into movements. Between moves, the camera updates the cube’s position so the robot can place its feet correctly.
Its skills include tipping the cube toward or away from its body and turning its layers. For one turning movement, the right foot holds the cube while the left turns the top two layers. The remaining layers must stay fixed, because an unwanted turn would disrupt the solution.
The team taught these skills in a computer simulation, rewarding accurate movements and balance. Tests included slippery floors, stone paving, a pull on the robot’s leg and a push that moved the cube. The robot recovered from these disturbances. According to the team, the results show how camera guidance and coordinated foot movements can support long physical tasks without additional arms or gripping tools.
