Articles
An international research project has developed a mind-controlled exoskeleton that works by decoding electrical signals from the brain
Researchers from Korea University and TU Berlin, Germany, used an electroencephalogram (EEG) cap as the brain-machine interface for the lower limb exoskeleton. The system enables users to move forwards, turn left and right, sit and stand by staring at one of five flickering light emitting diodes (LEDs).
Each of the five LEDs flickers at a different frequency, and when the user focusses their attention on a specific LED this frequency is reflected within the EEG readout. This signal is identified in real time and used to control the exoskeleton.
A key problem was separating these precise brain signals from those associated with other brain activity, and the highly artificial signals generated by the exoskeleton.
Klaus Muller, a researcher from TU Berlin, said: “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.”
Although the paper reports tests on healthy individuals, the system has the potential to aid sick or disabled people.
Muller said: “People with amyotrophic lateral sclerosis [motor neuron disease], or high spinal cord injuries face difficulties communicating or using their limbs. Decoding what they intend from their brain signals could offer means to communicate and walk again.”
EEG caps and hardware are now emerging on the consumer market an the researchers hope the system could provide a technically simple and affordable control system to other devices.
Training for the system is said to take just a few minutes. 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,” Muller added.