[Image from Technische Universität Wien]
The biomechanics and rehabilitation engineering researchers at TU Wien developed a new drive system that is moved through a newly designed hand gear instead of the hand rim on the wheel. The researchers suggest that the hand gear is more ergonomic and better suited for the natural movement patterns of the upper body.
“The motion sequence when using a wheelchair is usually quite unnatural,” Margit Gföhler, a professor in the Institute of Engineering Design and Product Development at TU Wien, said in a press release. “Moving a wheelchair using a conventional hand rim puts your joints into extreme positions, which our bodies are simply not made for.
Using a biomechanical computer model, the researchers analyzed different motion sequences of the upper body. They looked at what the optimal motion sequence would be and what movements are best suited for the way that shoulders and arms naturally move.
The researchers found what the best motion sequence in the biomechanics simulations was and implemented that into a mechanical drive system. The resulting system was a wheelchair that was driven by two hand gears instead of the handrails. As the wheels turn, the levers change lengths to create a more egg-shaped movement instead of a circular motion.
The hand gears are mounted onto the wheelchair’s armrests and give the rear wheels motion through a toothed belt, which means the wheels can be made smaller as well. The hand gears are also compact, which means the wheelchair is still suitable for everyday, indoor use.
A rehabilitation center in Klosterneuburg, Austria tested the wheelchair technology. They tested the spirometries, which analyzes how strenuous the hand grips are. The tests showed that the new drive technology enabled the same speeds to be reached, but with less effort.
“The responses were very positive. People were pleased that the joints no longer have to move outside the natural angular range and that the wheelchair enables continuous movement without interruption,” Gföhler said. “Our new wheelchair concept could really improve many people’s quality of life. We hope to find a partner in the industry soon to develop our design into a commercial product.”
The wheelchair drive system was recently registered for a patent and the research team is now looking for industrial partners.
