Electric vehicle on one wheel

This paper presents an innovative unicycle which is powered by a fourquadrant DC-servo drive consisting of a permanent exited DC-motor and a 4q-chopper converter. The control of gravitation, speed and torque is done by an observer-based cascade structure which stabilizes the unicycle automatically and places the driver's position in such a way that the centre of gravity is always above the axle of the wheel. As electric drive systems are able to correct the tilt angle nearly one hundred times a second these electric one-wheelers can stand absolutely alone just like ghostly balanced.