Robotic unicycle

The problem of creating a robotic unicycle, a self-powered unicycle that balances itself in three dimensions, is an interesting problem in robotics and control theory.

The theoretical work on the unicycle problem is complemented by work on the construction of actual mechanically ridden unicycles.

In 2003, Bombardier announced a conceptual design for such a device used as a sport vehicle, the EMBRIO. It is unclear whether Bombardier intends to create a working prototype of this vehicle.

Trivia

• Pixar's 1987 animated film "Red's Dream" depicts a computer-animated unicycle riding itself. It is unclear to what degree this provided motivation for the research described above.

See also

• inverted pendulum
• Lyapunov-Malkin theorem
• eunicycle

References

• S. V. Ulyanov et. al. Soft computing for the intelligent robust control of a robotic unicycle with a new physical measure for mechanical controllability. Soft Computing Volume 2 Issue 2 (1998) pp 73-88.
• Zenkov, DV, AM Bloch, and JE Marsden [1999] Stabilization of the Unicycle with Rider. Proc. CDC 38, 3470-3471 (pdf format available here)
• Zenkov, DV, AM Bloch, NE Leonard and JE Marsden, Matching and Stabilization of Low-dimensional Nonholonomic Systems. Proc. CDC, 39, (2000), 1289-1295. (pdf format available here)
• Sheng, Zaiquan; Yamafuji, Kazuo: Realization of a Human Riding a Unicycle by a Robot. Proceedings of the 1995 IEEE International Conference on Robotics and Automation, Vol. 2 (c1995), pp 1319 - 1326
• A. Schoonwinkel, "Design and test of a computer stabilized unicycle," Ph.D. dissertation, Stanford University, California, 1987.

External links

• Robot unicycle model (Japanese language text)
• http://www.ifr.mavt.ethz.ch/movic98/proceedings/78c.pdf another paper
• An interesting post from the Unicycling mailing list
• Mike Hinson's collection of unicyling, robotics, and physics links
• Bombardier Recreation Products EMBRIO one-wheeled recreational vehicle concept design
• The loonycycle, which superficially resembles a simple robotic unicycle, but uses side-thrusting fans for lateral balance
• Rosie the Robot - a Question of Balance Ken Perlin's page on robotic unicycles, with designs and java applet examples.
• Pixar - Red's Dream

Note: the term "unicycle" is also sometimes used in robotics to mean a generalised cart or car moving in a two-dimensional world. This is distict from the sense of "one wheeled robot bicycle" above.

A physically realisable unicycle, in this sense, is a nonholonomic system. This is a system in which a return to the original internal (wheel) configuration does not guarantee return to the original system (unicycle) position. In other words, the system outcome is path-dependent.