Interview to the Walk Again project

"Robots help us understand people better"

Walk Again researcher Gordon Cheng in his office © Astrid Eckert / TUM
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His goal is to advance the recovery of paralyzed people with state-of-the-art technology: Gordon Cheng from the Technical University of Munich is one of the researchers of the Walk Again Project. He and his colleagues use human-machine interfaces and robotic exoskeletons to restore more muscle control and sensation to patients with paralysis. In the interview, Cheng reports on goals and approaches of his work.

At the opening ceremony of the 2014 FIFA World Cup Brazil, a paraplegic Brazilian fired the first ball with a shot. The young man wore an exoskeleton, which he steered with the power of his thoughts. Now, researchers at the Walk Again project have reported the latest results and achievements: after one year of training, eight paraplegics have regained control of their leg muscles, at least in part, and are feeling something again - a great success.

What makes you so enthusiastic about robots?

I was fascinated by robots in my childhood. The animated creations I grew up with were always about robots helping people. So I always had a very positive attitude towards them. This fascination as well as the technical and scientific interest in robots have remained until today.

Do you have a favorite robot? display

All robots from Star Wars, especially R2D2 of course. And Astro Boy is one of my favorites. This is a robot that is constantly helping people, which I really like.

Also in the project Walk Again, the technology should support people. What was your approach here?

Walk Again was launched in 2008. Research Director is my good friend Prof. Miguel Nicolelis. He is one of the top experts in neuroscience, especially in the field of human-machine interface. Our goal was to develop a robotic system that can help paralyzed people to feel and walk again.

How would you describe the moment when the young man kicked the ball in the stadium in Brazil?

That was a wonderful moment, a milestone. We spent many months training patients to handle the exoskeleton. We wanted to see if it was possible for them to go and feel with their help. Many scientists from different disciplines have worked together to achieve this. It was a very important moment for all of us.

Now there are new results from the project. Could you summarize these briefly?

Over the past two years, the medical team has continued clinical studies on the patient. It turned out that her physiological and mental condition has improved. They regained some control over the movement of their legs. That surprised us a lot.

What possible explanation could there be?

The so-called neuronal plasticity plays a role. The brain can reorganize itself through training over a period of time. There are a lot of theories about the body schema, a representation of our body in the brain, with which we can associate sensations and movements. However, with the appropriate training, we can create new brain networks that allow us to reorganize the body schema and integrate a new element, such as the exoskeleton.

How could the patients actually perceive the leg movements of the exoskeleton?

A key element was tactile feedback, which allows patients to feel touchdown at every step. For this we developed an artificial skin here at the TU Munich. Their sensors can measure vibration, temperature, pressure and proximity. The artificial skin is placed under the feet of the robot. The sensors allow the exoskeleton to detect each step.

This information is relayed and patients receive tactile feedback via small motors on the arms. After a while, the brain connects this feedback with the steps. At the time, we did not know if that would work. But after six months of intense exercise, patients reported that they actually perceived movement of the exoskeleton as steps.

What's so special about the artificial skin?

We have developed a new generation of artificial skin that can detect approach and touch. With their help, for example, it is possible to make a robot safe. A standard industrial robotic arm would normally not notice if you approach it. We have developed an artificial skin that is very sensitive. You can then control the arm with very light touches.

One of the most important features of this artificial skin is that it can organize its own body pattern. The robot automatically knows where the skin is and where it is being touched. The concept of the body schema, which represents our body in our brain, we have transferred to the robot.

Can we learn from robots?

Working on humanoid robots helps us construct better robots for humans. At the same time, it enables us to understand people better. Building a humanoid robot that can walk like a human will help us develop a better exoskeleton. The algorithm we program for the run robot can also be applied directly to the exoskeleton, which can help a person get mobile again.

Will it be normal in the future for humans and robots to live together?

I hope so. There will be a similar evolution to the microwave and the cellphone, and they will become part of our lives. And I bet a positive part.

What are the plans for the future of the Walk Again project?

I hope that all the technology that we develop, such as the next generation of the exoskeleton or the artificial skin, can help the people in the future even more directly in their everyday lives.

(TU Munich, 12.08.2016 - NPO)