The first football kicked at the FIFA World Cup in Brazil later today will be made by a paralysed teenager thanks to a brain-controlled robotic exoskeleton.
The exoskeleton, which relies on numerous sensing technologies, was developed through the Walk Again Project involving more than 100 scientists worldwide. It could not only allow paralysed people to walk again, but help engineer safer, smarter industrial robots with rapid setup times.
The Walk Again Project is led by Professor Miguel Nicolelis of Duke University in the USA and the International Institute for Neurosciences of Natal, Brazil, and Professor Gordon Cheng, head of the Institute for Cognitive Systems at the Technical University of Munich (TUM) in Germany.
The team developed CellulARSkin − a cellular artificial skin capable of detecting and imitating the human response to pre-touch proximity, pressure, vibration and temperature. It consists of hexagonal sensor cells each containing a low-power-consumption microprocessor.
‘On each cell you have a particular force sensor, configured in a triangular manner, so that you can triangulate any sense of force,’ explained Cheng. ‘You have proximity sensing, which gives you an approximation of the distance before touching. And you have a temperature sensor on board. And one other important thing is that we have an accelerometer on board, which helps us detect the actual configuration in physical space.’
The cells are networked together in a honeycomb pattern and are integrated into a 3D micro-structured elastomer layer for protection (see figure 1).
Figure1: The individual sensor cells can be networked together in a honeycomb pattern. A Heddergott / TUM
Cooperation among the networked cells, and between a network consisting of self-organisation algorithms, allows the artificial skin to recognise the specific body part that it is attached to and recover automatically from certain kinds of damage.
‘You have the distributed intelligent sensors, which help the actual configuration, and also the central system, which helps to manage the whole system. But everything can be distributed very nicely, and you have that aspect of sensor redundancy,’ said Cheng. ‘If one cell is broken the whole system is reconfigured to accommodate the whole network.’
To retrieve information from the brain, non-invasive electrodes are inserted onto the surface of the brain. ‘What we're decoding is mainly the intention: “Do I want to move forward, do I want to stop, do I want to turn?” So those are the intentions that we are trying to extract from the brain in doing so, and that's what we're using to control the exoskeleton,’ Cheng added.
Tactile displays are also used to provide feedback to the user – the artificial skin sends signals to tiny motors that vibrate against the the neck – so that the person can associate the type of sensation they feel with different actions, such as taking a step or hitting an obstacle, for example. The patient can then learn to incorporate the robotic legs and feet into their daily movements.
Cheng believes that the World Cup opening will be a public demonstration of what science can do for people. Cheng said: ‘We should be able to learn from biology in building better machines. I think that building a human-like machine would help us scientifically understand humans better. And also vice versa.’
And, this could not only benefit the medical field, but could also enable the rapid setup of industrial robots – a research aim of the EU-sponsored ‘Factory in a Day’ project. ‘It’s surprising because some of this technology that we created for other arenas is completely, directly applicable to even such things as a factory. We are putting the skin into a factory robot, enabling them [robots] to have a sense of touch in a factory,’ said Cheng. He added that it would improve safety within factories and make robots easier to configure.
The fact that CellulARSkin can be implemented using standard off-the-shelf hardware means it will be easy to miniaturise and produce at a low cost. However, Cheng feels that there is a lot more work to be done to reach that point: ‘We should be able to make the exoskeleton cheaper, more diverse, more agile − for the subject, for the patient. And I think we are willing to invest another ten years in this, and it's a worthy effort, giving somebody the ability to be mobile again. I think some people see the World Cup opening as the end. But it's really just the beginning − we still have a lot to do.'
Professor Gordon Cheng with Exoskeleton. G Cheng / TUM