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Holonomic Wheelchair More details

The wheelbase wheels

The wheels used on the chair are 48mm Robot Omni wheels. Omni wheels or poly 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.

Whatis a Holonomic Robot

According to Wikipedia: A Holonomic Platform robot is defined as a system that has the same numbers of actuation and degrees of freedom. The degrees of freedom are the x axis, y axis, and rotation about the origin. In this space, a mobile base with three omnidirectional wheels in a triangular configuration would be considered holonomic, but a tricycle would not (due to the Parallel parking problem). See my Post: Holonomic Platforms: Doing the MATH!

What's different about my Wheelchair

A standard wheelchair is a chair with wheels, designed to be a replacement for walking. The device comes in variations where it is propelled by motors or by the seated occupant turning the rear wheels by hand. My wheelchair preforms best when powered by the three motors, one per omni-wheel. But because of the inherent design of omni-wheels, the chair can be easily pushed by an able body person as with standard wheelchair. By far the biggest difference is maneuverability. My wheelchair will turn on the spot requiring a turning circle the size of the wheelbase. The other advantage is the fact my wheelchair can be moved in any direction without the need of rotating the chair on its axis.

Let's wheel out the Holonomic Wheelchair

The Holonomic Wheelchair uses 3x Rotacaster Omni-wheels in a Holonomic Platform configuration, power by 3x Small Lego Power Function Motors. A Mindsensor PSP-Nx-v3: Sony PlayStation2 Controller interface for NXT is used for controlling the Wheelchair. A PlayStation2 Controller is used to control the wheelchair via the two Analogue Joysticks.

Conclusion

A Full-Size Version of the Holonomic Wheelchair would be great fun, but more importantly be of great benefit to those that require a wheelchair. They would appreciate the excellent maneuverability that the Holonomic Platform wheelbase offers them. It's ability to quickly rotate in it's own foot-print would be of great benefit in many non-wheelchair friendly environments. Having only three contact points with the grounding surfaces, also makes the platform extremely stable on many undulating surfaces. Add 3D Acceleration sensors to allow the wheelchair 's occupant to use the motion of their body to control it, and the possibilities become enormous for wheelchair sport, such as every Australian's favorite: "Murderball" or Wheelchar Rugby.