Engineering Minute

Engineering Minute – Designing An Ergonomic Wheelchair

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A group of researchers at Vienna University of Technology have developed a new drive system for wheelchairs, offering an ergonomic alternative to traditional wheelchair designs. In the new design, the wheelchair moves via hand gears instead of the wheel's handrim and mimics the natural movement patterns of the upper body. Best of all, the new drive mechanism allows for the wheelchair to reach the same speeds but uses significantly less effort. The researchers hope the new design will greatly decrease the occurrence of joint pain and injuries suffered by wheelchair users. 

 

ergonomic wheelchair design
The new wheelchair, developed at TU Wien Credit: Vienna University of Technology

“The motion sequence when using a wheelchair is usually quite unnatural, says Margit Gföhler Professor at the Institute of Engineering Design and Product Development at Vienna University of Technology. "Moving a wheelchair using a conventional handrim puts your joints into extreme positions, which our bodies are simply not made for,”

 

From the Vienna University of Technology article: "To change this, Margit Gföhler and her research team developed a biomechanical computer model to analyse various motion sequences of the upper body. 'We considered the following questions: What would be the optimal motion sequence? What movements are best suited to the way in which the shoulders and arms work?' says Gföhler.

The motion sequence determined to be best suited in the biomechanical simulations was then implemented in a mechanical drive system. The result is a wheelchair driven by two hand gears. During each revolution, the levers change their length, creating an egg-shaped movement rather than a circular movement. The hand gears are mounted on the wheelchair’s armrests and drive the rear wheels via a toothed belt. As a result, the wheels can be made smaller than usual. Thanks to its compact dimensions, the hand gear does not make the wheelchair wider or larger, so the drive is suitable for everyday indoor use."

 

Read more about designing an ergonomic wheelchair at Vienna University of Technology.