Self-balancing unicycle

A self-balancing unicycle is a unicycle electric vehicle that assists the rider in staying upright by using an electric motor and gyroscopes controlled by a computer that is fed data from accelerometers and other sensors. As of 2015, several models were commercially available. They are commonly referred to as Electric Unicycles and EUCs.

Creating a self-powered unicycle that balances itself in three dimensions is a robotics and control theory problem. A self-balancing unicycle can be considered as a non-linear control system similar to that of a two-dimensional inverted pendulum with a unicycle cart at its base. There are many higher-order effects involved in modelling the full system. Rotation of the drive wheel itself can provide control in only one dimension, forwards and backwards. Control in other dimensions generally requires other actuators, such as auxiliary pendulums, reaction wheels, or control moment gyroscopes attached to the main unicycle pendulum.

Laws in some places do not address powered unicycles, but there are some provisions regarding electric mobility devices for the disabled.

Single-axis unicycles are self-balancing only in the forwards-backwards direction, so a rider must balance them from side to side, such as Trevor Blackwell's Eunicycle or the RYNO Motors Micro-Cycle. In 2008, Focus Designs released the first commercially available self-balancing unicycle. In 2011, Inventist marketed an 11 kg stand-up, seatless version called the Solowheel that has a weight, size and carry handles that make it usable by last mile commuters. Late in 2015, the Ford Motor Company patented a "self-propelled unicycle engagable with vehicle", intended for last-mile commuters.

The RIOT wheel is a ridable single-axis self-balancing unicycle with an unusually low centre of gravity, with its rider in front of, rather than on top of its single wheel, balanced by a counterweight within the wheel.

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