Tech Teams of the Cybathlon: Varileg
Team leader Marius Stüchli talks to us about his preparations for Cybathlon 2016.
How / when did you fist hear about Cybathlon?
At the beginning of 2014 some professors at ETH Zurich discussed that it would be great if our university not only hosted Cybathlon but would also set up teams to participate. I was then soon involved in the planning by RELab (Prof. Roger Gassert) and pd|z (Prof. Mirko Meboldt) which lead to a student project to develop an exoskeleton with adjustable impedance from scratch.
What is your part of the team? Which race are you entered for?
Our system for the Powered Exoskeleton Race is being developed by two consecutive student projects. As the main coach of the first student team I’m also the “team leader” for Cybathlon participation, while the development project its self is managed by the students.
What concerns could this particular race / discipline involve?
Walking on two legs is a very complex process. Good coordination of the movements of the lower limb through the robot and the upper body movement of the pilot is very challenging from both an engineering and an athletic training point of view. Another challenge is that for the development of the device extensive testing is desired while for safety reasons we have to be very cautious about when a prototype is safe enough to let a human wear it.
What is your motivation for joining in the Cybathlon? What was your motivation for following this line of research career?
Our focus is on future users: We want to contribute to an exoskeleton putting paraplegic people back on their feet, throughout their everyday life. This is what drives me and, I think, everyone in the VariLeg team.
From a technical perspective, both labs supervising the project have a strong belief that adjustable impedance is a key feature in robust and dynamic walking. With this project we hope to develop a system capable of demonstrating the benefits of such a compliant system.
What did you get out of attending the rehearsal event?
We weren’t ready to use our system in active mode, but walking the system through the course gave us many insights into critical movement aspects and some limitations of our first mechanical design. Additionally we got a lot of motivation from this event. The atmosphere was fantastic and the discussions with other teams were encouraging.
Are you using a commercially available device or developing your own? What makes yours unique?
We develop an exoskeleton from scratch, which is not as rigid as an industrial robot, but has compliant joints, much like our own legs.
What level of development is your technology at? When do you expect to have first trials?
Our first student team already tested level walking and standing up from a chair on the first prototype after only eight months of development. The second team is currently defining how the first prototype shall be improved before the Cybathlon, so it can carry a paraplegic person over the race course and be intuitive to control.
How did you find your pilot?
We’re closely collaborating with the Swiss Paraplegic Centre. Thus, we have contact with many paraplegics who are really enthusiastic about the project and interested in piloting our exoskeleton at Cybathlon, but we haven’t selected the pilot yet.
What are the challenges you face?
Safety is our primary requirement. Therefore we haven’t started testing with paraplegic users, yet – and time to Cybathlon is short.
What scientific question do you hope you can solve during development and training? What are your future hopes for the technology being displayed at Cybathlon?
We hope to demonstrate that compliant exoskeletons are easier to walk with and more versatile. As well we hope to present a solution for how such a compliant system can be implemented.