Controlling an exoskeleton with your brain

Since each of the LEDs flickers at a different frequency, the EEG readout reflects this when the user focuses their attention on a specific LED. This signal is identified and used to control the exoskeleton.

One of the major issue the scientists tackled was separating these precise brain signals from those associated with other brain activity, as well as the highly artificial signals generated by the exoskeleton itself. Klaus Muller, an author on the paper, explained: “Exoskeletons create lots of electrical 'noise'. The EEG signal gets buried under all this noise - but our system is able to separate not only the EEG signal, but the frequency of the flickering LED within this signal.”

Published today in the Journal of Neural Engineering, the paper reports tests on healthy individuals but there is potential for the system to aid sick or disabled people.

“People with amyotrophic lateral sclerosis (motor neuron disease) or high spinal cord injuries face difficulties communicating or using their limbs,” continues Muller. “Decoding what they intend from their brain signals could offer means to communicate and walk again.”

The control system could serve as a technically simple and feasible add-on to other devices, with EEG caps and hardware now emerging on the consumer market.

It only took volunteers a few minutes training to operate the system. Because of the flickering LEDs they were carefully screened for epilepsy prior to taking part in the research. The researchers are now working to reduce the ‘visual fatigue’ associated with longer-term users of such systems.

“We were driven to assist disabled people and our study shows that this brain control interface can easily and intuitively control an exoskeleton system - despite the highly challenging artefacts from the exoskeleton itself,” concludes Muller.