Note: the term "unicycle" is also sometimes used in robotics to mean a generalised cart or car moving in a two-dimensional world: this article is about normal one-wheeled cycless, albeit with robotic riders.

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.

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

The difficulty of this problem can be compared to that of constructing a one-wheeled Segway.

In 2003, Bombardier announced a conceptual design for just such a product, the EMBRIO, intended as a sports vehicle. It is unclear whether Bombardier intends to create a working prototype of this vehicle.

See also:

• Lyapunov-Malkin theorem
• Inverted pendulum

Table of contents

1 Trivia 2 References 3 External links

Trivia

• 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.