What Exoskeletons Learned From One Relentless User

What Exoskeletons Learned From One Relentless User. For 15 years, this test pilot has helped shape exoskeleton tech. It’s easy to assume that Robert Woo was defined by the accident that took away his ability to walk. Certainly, the day of his accident—14 December 2007—was a turning point. Woo, an architect working on the new Goldman Sachs headquarters in New York City, hadn’t attended his company’s holiday party the night before, and that morning he was the only one in the trailer that served as the construction-site office. He was bent over his laptop when, 30 floors above, a crane’s nylon sling gave way, sending about six tonnes of steel plummeting toward the trailer. The roof collapsed, folding Woo in half and smashing his face into his laptop, which smashed through his desk. “I was conscious throughout the whole ordeal,” Woo remembers. “It was an out-of-body experience. I could hear myself screaming in pain. I could hear the voices of the rescue workers. I heard one firefighter say, ‘Don’t worry, we’re getting to you.’” The rescue workers hauled him out of the rubble and got him to the emergency room in 18 minutes flat; with one lung crushed and the other punctured, he wouldn’t have lasted much longer. In those frantic early moments, a doctor told him that he might be paralyzed from the neck down for the rest of his life. He remembers asking the doctors to let him die. Woo simply couldn’t imagine how a paralyzed version of himself could continue living his life. Then 39 years old, he worked long hours and jetted around the world to supervise the construction of skyscrapers. More important, he had two young boys, ages six months and two years. “I couldn’t see having a life while being paralyzed from the neck down, not being able to teach my boys how to play ball,” he recalls. “What kind of life would that be?”

After the surgeries and the early trauma, Woo found himself confronting a life he could not imagine living, and yet slowly he found the habits and instincts that would later make him an unusually effective test pilot for exoskeletons. As soon as he had regained use of his hands, he began searching for anything that could restore upright mobility. He tried rehab equipment such as harnessed treadmills, which required multiple therapists and still left the user exhausted, and he longed for independent walking. Several years after the accident he learned about experimental exoskeleton suits with motorized hips and knees, and he persuaded his Mount Sinai clinicians to bring prototypes into the clinic for trials. Those early sessions were physically and mentally demanding, and standing for the first time in an exoskeleton felt like floating because he could not feel his feet. An Ekso prototype initially required therapists to trigger steps from a remote, and users stabilized themselves with walkers or crutches, but simply standing upright proved a profound psychological and physiological benefit. Mount Sinai clinicians saw improvements in morale and in physical measures such as circulation and spasticity. Woo then joined a Department of Veterans Affairs clinical trial of the ReWalk device, where he logged dozens of walking sessions over many months, and he began to see tangible health benefits such as reduced medication for pain and muscle spasms, improved muscle mass, lower cholesterol, and better healing and digestion. Those measurable gains reinforced his commitment to testing and pushing the technology forward, and they convinced researchers and companies that everyday walking—even assisted and slow—had real value for people with spinal cord injuries. Over time, Woo became a frequent trial participant, an early adopter, and a passionate advocate willing to take prototypes into real-world settings to see how they held up under everyday use.

As a tester and designer of his own life, Woo treated exoskeletons like projects to be debugged, and his feedback helped shape engineering choices. He approached the machines the way he had once approached complex building sites, looking inside structures to identify weak points, and then suggesting fixes. Where straps rubbed and caused abrasions in early models, he recommended better padding and different load distribution. When battery and computer backpacks proved awkward, he reconfigured carrying systems and sent photos and sketches back to companies; on more than one occasion his improvised solutions influenced subsequent designs. When prototype motors overheated, he suggested improved cooling or shielding; when a device paused midstride, he pushed manufacturers to refine software and sensors to make gait detection more reliable. Because he combined practical user experience with an architect’s eye for structure, he could propose changes that were both ergonomic and manufacturable, and companies listened. His collaboration ranged from minor tweaks such as fanny-pack battery carriers to more forward-looking ideas, such as adding powered ankles to free users from crutches by enabling self-balancing legs. At first some firms resisted redesigning core platforms, but the industry gradually moved toward hands-free designs, and companies such as Wandercraft built self-balancing systems that take on both propulsion and balance. Engineers and clinicians valued Woo’s reports on comfort, battery life, control interfaces, and failure modes because real users reveal problems that bench tests do not, and his candid, meticulous nine-page critiques and annotated photos became part of development cycles. By testing in clinics and homes and by documenting edge cases and long-session wear effects, he accelerated improvements that made exoskeletons more practical and safer for a wider set of users.

The progression from clinic to home use changed what the machines needed to be, and it changed Woo’s life and routines in important ways. When ReWalk won regulatory clearance for personal, at-home use, Woo became the first person to buy a unit for daily living, paying tens of thousands of dollars when insurance would not cover it. The home model required a trained companion to assist with donning, balancing, and emergency recovery, and his partner, Vivian, learned how to suit him up and work the safety procedures. He practiced in hotel corridors and condo parking garages, logged thousands of steps, and improvised practical solutions for everyday tasks such as carrying a baseball and pitching to his sons by rigging holsters and attachments to the suit. Those domestic triumphs carried an emotional weight: they meant playing ball with his boys and being present for ordinary family life. But living with an exoskeleton also exposed limits. The equipment could glitch and require reboots, and a midstride freeze could leave a user collapsed on the floor if a companion was not nearby. Tasks as simple as cooking revealed trade-offs; moving reliably between counter, sink, and cupboards while balancing on crutches or using the suit consumed time and demanded careful planning. Over time, the early ReWalk in his home spent more time idle as the cumulative friction of everyday life and occasional failures outweighed the convenience for certain activities. Then, in 2024, Vivian was diagnosed with aggressive breast cancer and died that November, and for a while Woo stepped back from clinical work and questioned whether he could continue. He returned to trials because he felt Vivian’s presence in his resolve, and he found a community of clinicians and fellow test users who supported him through grief and work alike. Through those personal trials he continued to contribute to the technology, both by trying new hands-free systems such as Wandercraft’s self-balancing exoskeleton and by documenting issues like strap abrasion and battery range with photos and detailed notes to manufacturers.

Looking ahead, the technology is farther along than a decade ago but still faces significant technical and practical barriers before it becomes an everyday substitute for wheelchairs. Companies such as ReWalk, Ekso, and Wandercraft have sold thousands of devices to clinics and personal users, and the VA and Medicare reimbursement moves have begun to open broader access. Nevertheless, researchers point to remaining challenges such as battery life, reliability across varied terrain, dexterity for everyday tasks, and safe failure modes. Self-balancing systems promise to free users from crutches by incorporating powered ankles and more advanced balance control, and users like Woo test those capabilities in kitchens, on sidewalks, and in mock homes to push the designs toward real utility. Engineers say that human bodies and environments present far more variability than lab tests can capture, so collaborative development with experienced users is essential; seasoned testers find the edge cases and failure modes that matter most in daily life. For Woo, a truly wearable, all-day exoskeleton that replaces a wheelchair remains a long-term prospect, perhaps a decade away, and it may arrive for the next generation more than for him. But he has already helped shape the path toward that future, and his work has practical and emotional consequences for newly injured people lying in hospital beds who need a reason to hope. He imagines a moment when someone newly paralyzed will see a hands-free device in a clinic or on the street and be able to picture a rich life ahead; that imagined change, he says, is reason enough to keep testing, reporting, and pushing the machines to improve.