Tuesday, December 20, 2011

Wheels. That Rotate. On Wheels.

Every so often you see or read about a technology that is intriguing, if for no other reason than a novelty.  Then, you happen across it again and realize the subtle details of engineering required to make the novelty function.  And then, you see it in action and you realize it deserves more attention than you originally paid.
Image courtesy of Grabcad.
The Omni-Directional Wheel
The omni-directional wheel was first conceived by Swedish engineer Bengt Erland Ilon in 1972.  (SHHHH. Don't tell any Norwegians a Swede invented something first.)  The patent traded hands a few times before the technology finally developed into something product-worthy that first shipped around 2005.  It was a material handling truck (aka forklift or lift truck) called the Sidewinder, produced by Airtrax.
Image from Airtrax website.

At first glance, this wheel looks like it would provide for a very bumpy ride as the load is transferred from roller to roller.  But, as shown in the embedded video, the wheel provides a startling smooth ride. 
The control is a combination of MOSFET, sensor technology, closed-loop feedback, regenerative breaking, speed control, onboard diagnostics, and traction control.  I remember as a tool designer making a moving assembly line with A.N.T's (Adaptable kNeel-down Transporter) that had standard casters on them.  It was very difficult to move that platform through the factory.  What I wouldn't give to be able to redesign that system using wheels and controls from Airtrax.

Most people say that there is no value in reinventing the wheel, but thanks to Bengt and the team at Airtrax, it appears that a reinvented wheel has great potential in the material handling, robotics, and assembly line industries.


  1. I remember seeing this a couple of years ago. I can't believe these wheels are more widespread in use by now, and haven't been developed for use in more robust applications. Imagine them on farm and construction equipment. How much better would an omni-wheeled airplane maneuver at an airport? I'm not sure if we want them on the highway, but in low speed settings, any wheeled vehicle becomes more functional with these.

  2. 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.

  3. Omnidirectional wheels have become popular and choose to develop for
    mobile robots, because they allow them to drive on a straight path from
    a given location on the floor to other places without having to rotate
    first. Moreover, the movement of translational along any desired path
    can be combined with a rotation, so the robot arrives to its
    destination at the correct angle.