Professor Hugh Herr, head of the Biomechatronics Research Group at the Massachusetts Institute of Technology, bounds onto the stage full of energy. His is an inspirational story, and the room full of engineers is enraptured by his tale of technological triumph against adversity.
Both of Herr's legs were amputated below the knee in 1982 because of frostbite incurred during a mountain-climbing accident. Today he is able to bound on stage thanks to the bionic legs, he developed after decades of research, that give him a range of movement almost indistinguishable from fully limbed people.
Opportunity in adversity
A passionate climber, Herr says that after the accident in 1982 he refused to accept the doctor's diagnosis that his body was broken and he would never climb again. Instead he started to “hack” his own body so that he could not only climb, but climb tougher ascents than his fellow climbers.
He began to develop and test prosthetics for his legs. Each design iteration improved his climbing ability in one way or another - one design was the size of a baby's foot, another a wedge shape. He welded crampons onto them and developed height adjustable prosthetics that made him up to 5 ft tall. “What it meant for me was the integration was enabling me to do things that I couldn't do before,” he says. “Other climbers would get jealous and say they wanted to cut their legs off and use mine.”
Herr realised that viewing his double amputation as an opportunity was a profoundly different approach to the area of bionics, which he defines as the “interface between biology and design”, and furthermore that it was ripe for improvement. This desire to advance bionics has driven him through three decades of engineering R&D at MIT, resulting in several major breakthroughs in the emerging field of biomechatronics and the launch of his own company Bionx.
Herr’s Research Group has developed gait-adaptive knee prostheses for trans femoral amputees and variable impedance ankle-foot exoskeletons for patients suffering from drop foot, a gait pathology caused by stroke, cerebral palsy, and multiple sclerosis. As well as his own bionic legs, he also designed the world’s first bionic foot and calf system called the Biom.
Bionics, Herr claims, will have a “profound” impact on people who are not normal – have conditions that mean that their bodies or minds are abnormal. “I believe bionics will eliminate disability and also lay the foundation for us all to enhance our activities.”
Engineering bionics
Amongst the areas Herr's lab is looking at much of the focus is on understanding how the brain inputs and outputs information to control limbs. He says: “What makes the brain so remarkably complex is that there are tens of thousands of different types of cells. If we are going to interact and engineer with the brain at that scale we have to have a technology that can interact with cells at an individual scale.”
One approach is optogenetics, he says, where researchers use light to target and change the cell electrically, causing them to express protein. Herr says early promising applications include in the eyesand he cites Alan Horsager's research from 2011, which inserted genes from algae into the retinas of blind mice to reinstate their vision. The research is being continued by firm Eos Neuroscience. “The approach will lead to many engineered solutions to help a range of problems,” he says.
Lots of research is also being conducted on connecting the input / output of the body to the brain. Herr doubts that wireless technology will yield progress here. Instead the focus is on improving 'wired' connections and melding them with biological ones.
The biom ankle provides force feedback to improve the prosthetic's performance
Existing solutions use surface electrodes on a limb to trigger a mechanical limb and are not not practical, says Herr. One of the MIT Biomechatronics Lab's research projects is developing a bi-directional interface to nerves and muscles that uses slivers of muscle to stimulate the growth of nerves into electrodes inside of the limb. Another approach being developed is osseointegration, a titanium implant into the bone of the limb. Researchers are trying to run wires through the shaft and get a direct link to the bodies nervous system.
Another key part of research is describing and modelling how the body moves, so it can be recreated in biomechatronic body parts. Herr says: “Here science drives design. We model how humans walk and and how the muscles work. A lot of the processing required to walk happens not in the brain but in the spinal cord. We are working to understand that spinal circuitry.”
Feedback controls
Herr founded the Bionx prosthetics company in 2007. It's main product, the Biom ankle, has so far been fitted on to more than 1,000 people.
The prosthetic works by using sensors to measure the speed of the ankle joint. That data is fed into a model of a muscle programmed on a chip to simulate as if the muscle was present. “The greater the force interpreted, the greater the force activated. It responds to the force by activating the limb,” says Herr.
Researchers at Bionx are now working on linking the Biom's data to neural signals, and also extending the knowledge to exoskeletons to be used by people who are not disabled. Early prototypes show the effect on people wearing the exoskeletons is impressive. “The augmentation is so profound that when you take the exoskeleton off, your own legs feel stupid and heavy,” he says.
“Bionics is giving us a glimpse into a new age of human machine interaction. We are great users of tools, this is a glimpse of interaction that goes beyond tools. It's an integration of the design built wourld with out physiology. That integration has deep meaning and emotion and can extend human physiology and pyschology beyond normal human experiences.”
Innovation lessons
A career dedicated to improving prosthetics has also taught Herr a lot about how to enable innovation. One of the key factors, he says, is to ignore the disciplinary boundaries of engineers as much as possible. “You have electrical engineers, mechanical engineers, software engineers and tissue engineers. They all talk different languages, but once you have them all pulling towards the same goal, it's amazing what you can achieve. You also have to be fearless. All the great innovators have been fearless. It's not about failure, it's about exploration.”
He draws a distinction between invention, which he calls simple and real innovation, which he calls more difficult. Furthermore most of the enabling aspects of innovation are personal and emotional. A resilience to failure and a willingness to take risks are needed, as is a “childlike drive for exploration”.
“You have to be an unstoppable force of nature. You can't give up, you have to really believe in something that doesn't exist yet. You need emotional faith in your ideas.”
“I spend months talking to students about what they think is significant and helping them change the world. What we do in our work is such a large part of our life, it needs to be something you are passionate about.”
Herr's story is well-known, moreso in the US, where he's featured in Time magazine, a National Geographic film and a biography, as well as being covered by numerous other publications. This does not diminish the power of his story and the importance of his approach to innovation.
As the field of engineering he has helped to pioneer yields more results and products his fame will only continue to grow and help to fuel the valuable work he and his colleagues do, which makes such a massive difference to people. Equally his approach to innovation holds a lesson for many.