The Paralyzed Can Walk Again With This Super-Light Robotic Exoskeleton

This (nearly) affordable suit could be a replacement for wheelchairs.

When a BMX bike accident broke Steve Sanchez’s back a decade ago, he was paralyzed instantly. He has needed a wheelchair ever since. But now he can have more mobility than he ever hoped. With a new powered robotic suit that supports his body and allows him to take slow, controlled steps, Sanchez can walk again.


Sanchez is one of the earliest testers of Phoenix, a super-lightweight, modular exoskeleton developed at the Human Engineering and Robotics Laboratory at the University of California, Berkeley, over the last five years. A spin-off company called SuitX, created by Berkeley researcher Homayoon Kazerooni, plans to offer the product on sale for adults in the United States as soon as March. It is also developing a version for children with cerebral palsy and several spinal cord-related diseases, which could give them better mobility skills for life during a critical young time period when training is possible.

Wearable exoskeletons have become a popular area of innovation for roboticists in recent years. Research teams and companies are working on all kinds of applications, which range from assisting the disabled to helping workers avoid job-related injuries and soldiers operate better in the field. In the U.S. alone, there are an estimated 200,000 spinal cord injury patients and millions of wheelchair users.

Companies like Ekso Bionics and Rewalk Robotics have already brought devices to market that are aimed at people with spinal cord injuries (Kazerooni was also a co-founder of Ekso Bionics, which went public in 2013.) What’s different about Phoenix, says Kazerooni, is two factors: it is the lightest (at 27 pounds) and cheapest of these efforts so far.

The SuitX team shaved both cost and weight from the Phoenix through careful engineering. “Our design has more emphasis on software intelligence rather than elaborate hardware,” says Kazerooni. For example, they removed as many sensors as possible and instead wrote algorithms that could infer more information from fewer measurements. They also removed the actuators and a power source at the knee, and instead only have two actuators at the hip. “We strove to mimic biological systems rather than copying industrial robots that have actuators and motors at every joint,” he says. The system is also modular, with a pair of knees, ankles, and a hip piece that can be used separately, depending on need.

Low-cost is relative. The ReWalk, which became the first exoskeleton device for spinal cord injury patients in 2014, costs about $70,000, and others cost upwards of $100,000. The Phoenix, which doesn’t have the FDA’s clearance yet, will be available for $40,000.

That’s still expensive, especially compared to the fanciest powered wheelchairs, which are in the $10,000 range. But it puts the device closer in reach for extensive at-home patient use–Kazerooni’s ultimate goal. More expensive exoskeleton devices are generally in use in rehabilitation clinics, supervised by health professionals. If a device can be used at home, it can help paraplegics improve bone density and avoid the secondary medical problems that often come with long-term wheelchair confinement. As units are manufactured, Kazerooni expects to further reduce costs. Of course, what’s less clear is whether and when insurance companies will cover the expense.


Despite their potential to improve the lives of the mobility-impaired, exoskeletons have been slow to come into use. Ekso, a company founded in 2005, has sold or rented 155 units for medical applications so far. Clinical studies on randomized patient populations have also yet to be completed to show the extent of their benefits. Still, they eventually have a huge potential to improve the lives of the many people who are very limited in their motion today and they will continue to improve in effectiveness and cost. Right now, SuitX is a semi-finalist in the international Robotics for Good competition with its proposal for a kids suit.

“Once these devices will come out, other people will also get inspired. It’s not about creating a technology–it’s also about sustaining a technology,” says Kazerooni.

About the author

Jessica Leber is a staff editor and writer for Fast Company's Co.Exist. Previously, she was a business reporter for MIT’s Technology Review and an environmental reporter at ClimateWire.