This Unicycle-Like Robot Can Autonomously Right Itself Upright with One Wheel
The Wheelbot is a reaction wheel unicycle robot that can jump onto its wheels from any initial position.
Engineers from RWTH Aachen University and the Max Planck Institute for Intelligent Systems (MPI-IS) have developed a robotic unicycle capable of autonomously jumping onto its wheels from any position. The team states the new robot is intended for use as a research and teaching tool and is easy to replicate with 3D-printed parts. Known as the Wheelbot, the robot stands 22 cm tall and features a pair of wheels that are arranged vertically and offset by 900. This allows it to roll on one wheel while the other acts as a balancing mechanism.
“Previous unicycle robots were only designed to balance in their upright position, which severely limits the capabilities of these systems,” explains Rene Geist, project lead at RWTH Aachen University. “To maximize the utility of a unicycle robot with responsive wheels, we decided that the Wheelbot should be able to recover from fairly large perturbations, have an integrated power supply to prevent cables from limiting its maneuverability, and be able to right itself after a rollover.”
The Wheelbot employs the reaction wheel technique to maintain balance instead of a gyroscope and uses “reaction moments” to position itself upright from any position. It uses data garnered from four internal IMUs and wheel encoders to estimate roll and pitch angles to stand upright and maintain balance while stationary and in motion. The engineers are looking at ways to make the Wheelbot more accessible and simpler to build in future revisions, along with a better control algorithm that will enable the robot to travel a predefined path.