Effortlessly efficient
© ETH Foundation / Valeriano Di Domenico
Effortlessly efficient
Pioneer Fellows Stefan Villiger and Reto Togni are convinced that much more can be done to improve the mechanics and design of wheelchairs. Taking part in their mission is former Excellence Scholar David Mzee – as test subject and sparring partner.
To what extent could Versive’s approach revolutionise manual wheelchairs?
STEFAN VILLIGER – At the core of our wheelchair is a new steering system: this functions intuitively via the upper body, thanks to a special backrest that’s connected to the front wheels. With our design, upper body movements are translated into steering motions: sitting upright means going straight, leaning to the right means turning right. Conventional manual wheelchairs with front castor wheels are usually designed to be steered by pushing and braking at the same time. This is extremely inefficient and also means wheelchair users constantly need to use both hands.
RETO TOGNI – As part of my doctorate, I asked participants to navigate a course with curves and cross slopes similar to most pavements. The exercise revealed that when they steered conventionally, they expended a third of their energy on braking alone! Even worse, controlling the wheelchair’s movements comes at a double cost: once when braking in order to steer, and then again to compensate for lost energy when reaccelerating. Because our prototype can be steered without braking, it’s much faster. At the same time, the user has one hand free, and they’re spared the heavy strain on their shoulders.
David, as a movement scientist, wheelchair user and early tester, how do you assess the innovation?
DAVID MZEE – When you’re out in a wheelchair every day, you notice that the most troublesome surfaces to navigate apart from stairs are pavements. Every pavement slopes sidewards, pulling the wheelchair toward the street, which you’re constantly having to fight against. Unfortunately, hardly anyone realises this. When using your wheelchair outdoors, it just makes you angry that you have to waste so much energy and strain your joints unnecessarily. When the street in my neighbourhood, the one I use the most, was up for repair I thought about asking the council if they could make it less sloped. But deep down, I knew “it’s never gonna happen.” So the solution has to come from the wheelchair itself. This chair solves one of the biggest challenges that wheelchair users face every day. The first tests showed me this quite clearly. Back then, the chair didn’t run as smoothly as it does now, and other issues were apparent. However, with my scientific background, technical expertise and personal experience, I’ve been able to provide inputs to advance the project. Even at its current stage, Versive offers a cool manoeuvrability experience and is fun to use.
© ETH Foundation / Valeriano Di Domenico
“This chair solves one of the biggest challenges that wheelchair users face every day.”
What was it that drove you to develop a better wheelchair?
RT – During my industrial design studies at Zurich University of the Arts, I had a fellow student who was a paraplegic. He made me aware of the pavement problem mentioned earlier. I also saw how challenging it was for him to transport a coffee from A to B without a free hand; he often had to wedge it between his legs. This inspired me to develop a novel wheelchair steering system while pursuing a Master’s in Innovation Design Engineering at the Royal College of Art and at Imperial College in London. The idea evolved into a research project at the Laboratory for Movement Biomechanics at ETH Zurich and became the subject of my doctorate.
Stefan, you’re a mechanical engineer. How did you come to join the project?
SV – I heard Reto give a presentation at ETH. When I was looking for a topic for my Master’s thesis, I approached him. I have a preference for elegant mechanical solutions that stand out with their simplicity. These solutions pay off both functionally and economically. What I appreciate about working with Reto is the way that we’re both committed to finding an ever better solution. We spur each other on like this.
Now that you’re ETH Pioneer Fellows aiming to bring the project to market, what other challenges do you face?
RT – At this stage, we need to persuade decision-makers to incorporate our wheelchair into the state-funded wheelchair provision system. But we’re encountering a lot of scepticism, with comments along the lines of: “These are people whose upper body muscles are impaired. How are they supposed to steer with them?”. However, our tests show that this steering system can work to a certain extent even for tetraplegics. One of our strongest supporters is paralysed from C5/6 level, which is relatively high up. Limiting factors exist, but they are more of a coordinative or psychological nature. One of our participants has been using this wheelchair for half a year now, even though it’s still just a prototype. She says she doesn’t touch her old wheelchair anymore. That’s quite a remarkable success for a first prototype. We’re very grateful that the Pioneer Fellowship gives us the time to both optimise the wheelchair before making it commercially available and to resolve key issues around market entry with entities like Disability Insurance.
How big is the market for this wheelchair?
SV – There are moments when we’re bold enough to believe this could become the new industry standard. In our view, it’s simply the superior product.
DM – What’s good is that you can convert this wheelchair back into a regular one. So, at the very least, the new steering system is a cool added feature that for certain people is of great help. On top of this, there are positive aspects like pressure relief for the buttocks resulting from weight shifts. The ultimate success of the chair will also depend on factors such as its final weight or price.
RT – The cost driver in wheelchair construction is configuring it to the individual. This is also something we want to explore digitally. 3D printing offers significant opportunities for savings.
David, you also like designing assistive devices yourself. What are you up to at the moment?
DM – After being one of the first tetraplegics in the world to find a way to wakeboard and kite, I’m now developing a seat to achieve another first: wakefoiling. I didn’t practise these sports before my accident, and there’s no one to show me how to do them today, as I may well be the first tetraplegic to attempt them. Once I find the time, I’m planning to share my journey with others who are interested on my Instagram channel.
