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Self balancing unicycle

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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.

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Control theory of the self-balancing unicycle

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 self-balancing ridable unicycles

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.

True two-axis self-balancing ridable unicycles

A two-axis self-balancing unicycle balances itself side to side, in addition to the forward and backward axis.

  • In 2003, Bombardier announced a conceptual design for such a device used as a sport vehicle, the Embrio. It is unclear whether Bombardier ever intends to create a working prototype of this vehicle.
  • Aleksander Polutnik's Enicycle (2006) is probably the first two-axis balancing human-ridable unicycle.

    • Similar vehicles

    A number of vehicles share characteristics of self-balancing unicycles:

  • The Segway is a vehicle which is capable of automatically balancing itself in the forwards-and-backwards direction, but is a dicycle with two parallel wheels, similar to the later self-balancing two-wheeled board rather than being capable of balancing from side to side.
  • In 2006, researchers at Carnegie Mellon University developed a 2-dimensional inverted pendulum that balances on a ball rather than a wheel.
  • Two-wheeled self-balancing (mobile) robots
  • The Uno, a vehicle that superficially resembles a self-balancing unicycle but is actually a dicycle with its two wheels very close together
  • The Honda U3-X looks like a self-balancing unicycle, but balances on a powered Omni wheeI rather than on a single wheel

    • Fictional self-balancing unicycles

  • A self-balancing unicycle was described in 1969 in The Man From R.O.B.O.T., a short story by science fiction author Harry Harrison.
  • Fenton Crackshell, a Disney character, is depicted wearing a robotic unicycle suit as Gizmoduck.
  • Demolishor, a Decepticon from the 2009 Transformers sequel, whose robot mode is a gigantic robotic unicycle.
  • The "tumblebugs" in The Roads Must Roll
  • The protagonist in the Flash browser game, Little Wheel.
  • Thor, fictional inventor of the wheel and the comb, of the comic strip B.C..
  • Securitrons from Fallout: New Vegas.

    • OpenSource technology

    The community developed some OpenSource technology for electric unicycles:

  • Android app
  • Shell to be 3D printed
  • Firmware

    • Please see more information on the EGG Electric Unicycle project page.

    The community gathers on the online forum Electric Unicycle.

    References

    Self-balancing unicycle Wikipedia
    (Text) CC BY-SA