Omni wheel

A simple omni wheel. The free rotating rollers (dark gray) allow the wheel to slide laterally

A molded plastic omni wheel

Omni wheels or poly wheels, similar to Mecanum wheels, are wheels with small discs around the circumference which are perpendicular to the rolling direction. The effect is that the wheel will roll with full force, but will also slide laterally with great ease. These wheels are often employed in holonomic drive systems.

A platform employing three omni wheels in a triangular configuration is generally called Kiwi Drive. The Killough platform is similar; so named after Stephen Killough's work with omnidirectional platforms at Oak Ridge National Laboratory. Killough's 1994 design used pairs of wheels mounted in cages at right angles to each other and thereby achieved holonomic movement without using true omni wheels.^[1]

They are often used in small robots. In leagues such as Robocup, many robots use these wheels to have the ability to move in all directions. Omni wheels are also sometimes employed as powered casters for differential drive robots to make turning faster. However, this design is not commonly used as it leads to fishtailing.^{[citation needed]}

Omniwheels combined with conventional wheels provide interesting performance properties, such as on a six wheel vehicle employing two conventional wheels on a center axle and four omniwheels on front and rear axles [1].

Although omniwheels are capable of movement in many directions, they are not true omni-directional wheels, a classification reserved for spherical wheels such as ball transfer units.

See also

• Ball transfer unit

References

1. ^ "1997 Discover Awards". Discover Magazine. http://discovermagazine.com/1997/jul/1997discoverawar1170. Retrieved 22 September 2011. 

External links

Media related to Omni wheels at Wikimedia Commons

• PPRK - A commercial holonomic drive system developed by Carnegie Mellon University utilizing poly wheels.
• Airtrax^{[dead link]} - A series of commercial vehicles utilizing Mecanum wheels with poly wheels to provide omni-directional vehicle motion.