Robotic researchers from ETH have created a one-wheel cube-shaped robot named One-Wheel Cubli that can balance using only a single reaction wheel.
The group, led by Professor Raffaello D’Andrea, previously created a cube-shaped robot, Cubli, 10 years ago which served as the predecessor of One-Wheel Cubli. Applying what they learned from Cubli, One-Wheel Cubli is now a simplified version of the cube-shaped robot wherein instead of additional wheels, is now equipped with a pole and single reaction wheel in order to balance.
For One-Wheel Cubli to stabilize in both directions, the group carefully designed the cube-shaped robot to have its inertia in each direction to be higher than the other. This was made possible by placing two masses on each side of the One-Wheel Cubli that would be far from the center. Such design also allowed it to move faster in the direction with the lower inertia and slower in the other.
Thus, the whole system enabled One-Wheel Cubli to balance and be stable in both directions despite having only a single reaction wheel. The entire design and system of this cube-shaped robot also allow it to have two main degrees of movement; tilting front to back or side to side. Regardless, if One-Wheel Cubli is pushed or disturbed, it is still able to stably recover and balance on its pivot.
The group continues to seek improvements on One-Wheel Cubli to see how its system can be potentially applied in the attitude control of satellites in space.