Patient or pilot

If your legs are paralysed, everyday activities like getting up off a deep sofa, walking over rough terrain or going upstairs are impossible. Or are they?

TU Delft students are working on a robot suit for paraplegics. The group of students in the March team are the latest addition to the Dreamhall, the workplace in the faculty of Civil Engineering and Geosciences where student teams work on a range of projects, including the Nuna solar car and the human-powered Wasub submarine. In October, they intend to compete using their exoskeleton at the Cybathlon in Zürich, the world’s first bionic Paralympics.

They still have a prototype that was the result of a previous collaborative project between TU Delft and the University of Twente – the Mindwalker. It is a bulky suit with large buttons. “It was originally hoped that patients would be able to control the suit with their brain, using EEG signals”, explains March’s PR man, Sjoerd Butter. “But that was asking too much of the technology.”

Instead, the students came up with an alternative approach. They have equipped the robot suit with numerous sensors, so that it feels natural to control. As a result, the exoskeleton senses what the patient wants based on only minimal movement. They themselves prefer the term ‘pilot’ to that of ‘patient’.

At the base and back of the suit are sensors that register when the wearer bends slightly. The robot will then realise that the pilot wishes to stand up and provide assistance. The patient – or pilot – will also have to use a remote control.

The suit itself needs to fit much more closely to the body. The students aim to achieve this by means of 3D scanning and printing technology. “Another new aspect of the design is that the robot will have five degrees of freedom in each leg, two of which will be in the hip, in order to enable natural walking movements”, chief engineer Nick Tsutsunava explains. “The question is: will the exoskeleton walk with you, as is currently the case since they make pre-programmed movements, or will you walk with the exoskeleton? Of course, we are making the latter happen.”

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