This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
The fictional Iron Man exoskeleton debuted in Tales of Suspense #39 in 1963 and was conceived, designed, created, and piloted by “world’s greatest engineer” Tony Stark. Stan Lee, the creator of Tony Stark, wrote about the origin in his blurb for “Inventing Iron Man”: ‘Back in the sixties, when I first dreamed up the concept of Iron Man, I thought, 'What if a man had a suit of armor, like the knights of old -- but modern armor that housed all sorts of miniaturized, technical weaponry? Such a man would seem to be the ultimate superhero.'
Although literally conceived as a motorized suit of armor reminiscent of medieval knights, it has come to represent a true technological-biological fusion as the most complicated neuroprosthetic ever imagined. And there are many versions of the Iron Man exoskeleton, in Tony Stark’s ‘Hall of Armor”.
The breadth and scope of sci-fi exoskeletal armor is nicely captured in the sweeping and grand scene near the end of the 2013 Marvel Studios production “Iron Man 3”. Tony Stark summons essentially his entire armory to fly over and provide assistance during the final battle. This scene is a pretty remarkable and visually stunning because it illustrates the many versions of the Iron Man exoskeleton dreamt up since 1963.
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To me this scene from Iron Man 3 really screamed “the exoskeletons are here!” In my book “Inventing Iron Man—The Possibility of a Human Machine” I use Iron Man as a metaphor for amplifying the potential of our human biology through the use of technology. I envision the seamless application of exoskeleton technology fully integrated with the human nervous system. To go beyond just the concept of a wearable armor to an armor fully integrated with—and controlled directly by—the human nervous system. As with the Extremis armor described by Warren Ellis in his take on Iron Man.
While we are a considerable way away from creating and controlling an Iron Man exoskeleton, I continue to keep a keen eye on what science and engineer produce to bring us towards this future biotech fusion. I remain staggered by the pace and scope of advances. Here I summarize 2 recent “commercial grade” applications of “wearable” exoskeletons and neuroprosthetics that I think are particularly important. They are striking in terms of how they could really be used now to help real people with mobility challenges, even if they are not yet up to the challenge of saving the world from evil on an Avengers mission.
A marathon example of exoskeletons in action
While the image of Iron Man rocketing across the sky is immediately compelling, that kind of integrated flying exoskeleton remains a long way off. Until recently even an exoskeleton you could even get around in with a slow walk was a thing only imagined on the horizon. Now, companies like Japan’s Cyberdyne Inc. (producer of the Hybrid Assistive Limb (HAL)) and Israel’s Argo Medical Technologies (producer of ReWalk) have begun to translate this science fiction concept to real life.
Last summer, an English woman named Claire Lomas used the Argo’s “ReWalk” device to become the first person to use a robotic exoskeleton to finish a marathon. The ReWalk lower limb exoskeleton provided movement of her legs and allowed her, in conjunction with forearm crutches, to walk the entire 26.2 miles of the London Marathon route.
This was a grueling effort and it took 16 days but it represents a fantastic example of the power of fusing science, engineering, and the human spirit. Using a technique successfully applied in many powered prosthetics, the leg movements produced by the ReWalk device are controlled by cues triggered by movement from the upper body. To move closer to the integrated neuroprosthetic design that I feel would be truly necessary to use an exoskeleton that could fully replicate and enhance human movement, it remains for future developments to include commands triggered directly from the nervous system (brain and spinal cord).
Using nervous system commands to control prosthetics
When we decide to produce a movement, complex commands related to motor planning and organization send signals to the motor output areas of the brain. These commands then travel down the spinal cord to the appropriate level. That is, higher up for arm movements and lower down for legs. At the spinal cord level the cells controlling the muscles that need to be activated are found. From the spinal cord the commands go to the muscles needed to produce the movement. All of this relaying takes time and introduces control delays that would make armored superhero fights difficult.
Because of these delays, I argued in Inventing Iron Man that the ultimate objective should be to create neuroprosthetics controlled by brain commands. This reduces all the transmission delays found in using commands “downstream” in the spinal cord or at the muscle level. But it also currently requires inserting electrodes into the nervous system. Instead, a good starting point for now is to use the commands from the brain that are relayed and detected as electrical activity (electromyography, EMG) in muscle.
These EMG signals can be detected quite readily with electrodes placed on the skin over the muscles of interest. The EMG activity is a pretty faithful proxy for what your nervous system is trying to get your muscles to do. It’s kind of like a biological form of “wire tapping” to ‘listen’ in to the commands sent to muscle. Many different neuroprosthetics have been developed to use EMG control signals in order to guide the activity of the motors in the prosthetic itself.
An extreme example of using this kind of control for prosthetics came up last year. Zac Vawter, an above-knee amputee, used a powered lower leg neuroprosthetic that used EMG control to climb 103 flights of stairs in the Willis Tower in Chicago. Zac’s climb was part of a fundraiser for the Center for Bionic Medicine at the Rehabilitation Institute of Chicago and was a very public demonstration of the state of the art for neuroprosthetics.
While the idea of replacing a limb and its function with a prosthetic is not exactly the same thing as that of an Iron Man exoskeleton restoring or enhancing function, the basic principles for control are very similar. In fact, Cyberdyne’s “Robot Suit HAL” uses EMG signals to control the arm and leg portions of the full body exoskeleton.
At the time of this writing, “Robot Suit HAL” can only be accessed and used in Japan via rentals at certain rehabilitation centers. It seems certain that overseas applications and opportunities are just around the bend. ReWalk is available for purchase in Europe but is undergoing FDA approval for offer in America. It’s clear that future solutions to mobility challenges and the enhancement of human abilities are presently addressed by scientists and engineers working around the world.
These real-life advances are being incorporated into products that will shortly be commercially available worldwide. They represent staggering advances in science and engineering application of concepts that were simply science fiction a decade ago. These advances also highlight the potential for future developments that continue to be driven by human ingenuity. To paraphrase John F. Kennedy’s inspirational words from 1963 “some people see things as they are and ask why? I dream things that never were and ask, why not?”
I suggest that if we can dream it, we can imagine it. If we can imagine it, we can invent it. If we can invent it, we can put it to good use.