Cyclists have been enjoying the benefits of gears for over a hundred years now but the wheelchair-bound have been stuck with the single 1:1 speed ratio on manual wheelchairs come flat ground or hilly since their invention centuries ago. Now Scott Daigle, a graduate engineering student at the University of Illinois, is addressing this oversight with IntelliWheels AGS (Automatic Gear-Shift), an automated system that detects how the wheelchair is being pushed and changes gears accordingly.

The IntelliWheels AGS system comes as a set of two wheelchair wheels that are compatible with any manual wheelchair. The wheels weigh about five pounds (2.2 kg) each and can be quick-released for loading into a car. Sensors on the bottom of the wheelchair analyze torque, speed and tilt to detect how hard the wheelchair user is pushing, how fast they are going and what kind of slope they are on to select the best gear for the job.

The wheels are designed to make climbing hills less of a strain and provide relief to the 73 percent of wheelchair users Daigle says develop shoulder pain. And because the system is automatic, the users don't need to change their behavior or think about which gear to employ.

With partners Marissa Siebel and Jean Samson, Daigle has started a company, IntelliWheels, to commercialize the wheels but they are not yet available to buy as they are still undergoing usability testing. The wheels will then be run on a special testing rig for 40 days and 40 nights to simulate three years of use.

Daigle says he expects the current testing phase and the construction of a third, ready for use prototype will take until around September 2012, so the IntelliWheels AGS system will hopefully be commercially available shortly after that.

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