Inventor James Bruton built a mechanically stable monowheel robot that won’t fall over when it really gets going. How so? It uses a monowheel design combined with a Pedrail, or mechanical device consisting of small pivoting feet that can move in or out.
There are two wheels placed close together with the sliding legs keeping some of the feet in contact with the ground at all times. This enables the wheel can remain in a stationary position without any forward or backward movement. Nearly all of the parts were 3D-printed, except for the electronics, fasteners and bearings. A pair of DC motors connected to a Teensy 3.2 development board allow the wheels to spin and be controlled.