VariLeg exoskeleton at Cybathlon 2016
This week, the world’s first Cybathlon will take place in Zurich, Switzerland and today we present to you the third of the NCCR Robotics teams to be taking part in the competition, VariLeg. The Cybathlon is the brainchild of NCCR Robotics co-director and ETH Zurich professor Robert Riener, and is designed to facilitate discussion between academics, industry and end users of assistive aids, to promote the position of people with disabilities within society and to push development of assistive technology towards solutions that are suitable for use all-day, every day.
In our privileged position as presenting sponsor we are also proud to have NCCR Robotics represented by three teams: In the Powered Arm Prosthesis Race, by the team Le Mano; in the Brain Computer Interface (BCI) race, by the team EPFL Brain Tweakers; and in the Powered Exoskeleton race, by the team VariLeg.
VariLeg is a project that comes out of ETH Zurich, and is supervised by NCCR Robotics member Stefan Schrade (Gassert Lab).
The VariLeg is an experimental prototype of a new type of exoskeleton: the VariLeg uses actuated joints in two locations (hip and knee). The novelty of the device is a variable stiffness actuator in the knee providing variable impedance control. When a person without a disability takes a step, their knee automatically softens and stiffens as required, making small adjustments with muscles in the trunk and legs to compensate for unevenness in the ground and allowing for natural walking. One common problem encountered by exoskeleton users, and something that prevents exoskeletons from becoming more commonly used in everyday life, is that when joints cannot soften and stiffen. As a consequence, the leg cannot adapt to its environment causing discomfort, injury and risk of falling. This means that walking over anything but the smoothest of surfaces is not possible or at least very strenuous.
It is this issue that the VariLeg is hoping to provide a solution for. Varileg has been designed to navigate the tasks of everyday life featured in the Cybathlon. The team have been training with their pilots Philipp Wipfli and Werner Witschi two to three times a week over the summer.
(All photographs: ETH Zurich / Alessandro Della Bella)