When Bob Radocy lost part of his left lower arm in a car accident in 1971, there was little that the prosthetics industry could offer him. Artificial limbs available commercially at the time were quite crude, bulky, and inconvenient, and didn't really allow people to perform most daily tasks.

Not content with the status quo, Radocy, a native of Boulder, Colorado, decided to research the topic, and started a company offering prosthetic upper limbs in 1979. Thirty-seven years later, on October 8, 2016, he won the powered-arm prosthesis race at the first Cybathlon competition in Zurich.

Radocy's arm, developed in a cooperation with Delft University of Technology in the Netherlands, was the most low-tech of all contestants. Unlike his competitors' battery-powered limbs, his team DIPO Power used upper body muscles to power the arm mechanically. Radocy's prosthesis was also the only one in the competition that didn't look like a human arm.

"It gives me the ability to be quicker, react spontaneously; I'm in control all the time," Radocy says. "It's very close to a human hand in the way it operates, even though it doesn't have four fingers and a thumb. The best way to explain body power is the way bicycle brakes work. If you squeeze a brake lever, you have a directly proportional relationship to the calipers. So if you imagine the arm as the calipers, my arm and body are a living lever, and I can control the tension of the cable."

The inaugural Cybathlon

The one-day Cybathlon was organised for the first time this year, and claims to be the first ever competition of its kind. A brainchild of Robert Riener, a professor from the Swiss science and technology university ETH Zurich, the event was held at a roofed stadium in the suburbs of Switzerland's largest city.

"Switzerland is the Silicon Valley of robotics," Riener tells Ars. "I think we have highest density of good robotics researchers and neuroscientists."

The main goal of the competition, Riener says, is to raise awareness of the challenges that people with disabilities are facing every day, as well as facilitate collaboration between assistive-tech researchers across the world. Scientists come together to help solve the single biggest challenge in the entire field, which, according to Riener, is finding the best way to connect human and machine.

"We need to bring technology together with the body mechanically, but also from a control point of view," he says. "The technology must not dominate the user. The user has to be the master controlling the device. This means, for example, that the device must understand the motion intention of the user.

"The main non-tech challenge for us is to find acceptance in the heads of the people, make them less afraid of hi-tech," he adds. "Some people—both disabled and not—are still very sceptical."

The Cybathlon challenges are designed to make the athletes—real humans with real disabilities—negotiate an obstacle course that consists of a number of daily tasks. These range from hanging clothes for contestants with prosthetic arms, to going up and down steps for powered wheelchair users. Unlike the Paralympics, Cybathlon participants are allowed—and encouraged—to use all sorts of tech to help them out.

The rules regarding the participants' health conditions remain quite strict though. In the powered exoskeleton race, for example, the audience was surprised to see a woman complete the course about 10 times faster than everyone else without even using crutches. She would later be disqualified, however, as her legs were more functional than the rules allowed.

Cyborgs on crutches

The powered exoskeleton race was arguably the most spectacular competition, but it also clearly demonstrated how far the industry is from making a device that can be used by people suffering from paraplegia on a daily basis. The nine teams' pilots were put through a course of obstacles that included a few slalom cones to walk around, as well as steps, doors, tilted surfaces, and a set of artificial stones they had to navigate.

Andrii Degeler

Andrii Degeler

Andrii Degeler

Andrii Degeler

The most surprising thing—at least for someone not actively involved in assistive tech—was the fact that all the competition participants had to use crutches. Exoskeletons weigh upwards of 14kg, but can't guarantee the pilot enough balance to stand, let alone walk, without additional support.

As they're obviously a technology at a very early stage of development, the exoskeletons shown at Cybathlon were also painfully slow. The time limit for the obstacle course—which could be completed by a non-disabled person in under a minute—was 10 minutes, and not everyone was able to finish it in time.

The main reason for the slowness, and seeming awkwardness, of the exoskeletons appears to be the fact that they have to be controlled manually. Participants used smartwatches or touchscreens mounted on their crutches to change modes to correspond with different obstacles.

The US-based team from the Institute of Human and Machine Cognition (IHMC), which took the second place in the finals, had brought a 34kg exoskeleton which is controlled by two separate computers. The first one, a Raspberry Pi with a touchscreen running Ubuntu, is mounted on the right crutch and is used for mode changing. The second, more powerful one controls the movement of the motors. Its software is written in Java.

"It carries me and itself, so I don't really feel its weight," says IHMC's pilot Mark Daniel. "I trained with it for about six weeks before the competition. The machine does make me feel stable, but my trust really comes from all the guys who worked on it."

The battery life of IMHC's exoskeleton is about two hours. The researchers have yet to experiment with reducing the cost and weight of their device, but mentioned ongoing talks with some commercial companies that might be interested in mass production further down the line.

Bulky and unresponsive hardware wasn't the only problem faced by the exoskeleton teams. Switzerland's Silke Pan, a former acrobat who fell from a trapeze in 2007 and became paraplegic, had the lightest exoskeleton at just 14kg, but came fourth due to a software bug.

Andrii Degeler

Andrii Degeler

Andrii Degeler

"Stairs were my best obstacle, but two times—in the qualifications and the finals—my software crashed," Pan says. "I was prepared to manage everything, I was really looking forward to completing the course. I also do a lot of hand cycling competitions and I used to be an acrobat, so I've been making progress fast because of my sense of balance and strong arms."

While slow and tiresome for the pilots to operate, the exoskeletons in the competition were quite impressive, since they can give people suffering from paraplegia the chance to stand and walk, when they normally can't control their leg muscles at all. The root of each of the problems faced by the technical teams is ultimately Riener's issue: the difficulty in making a machine that's a continuation of the human body, rather than a cumbersome external frame.

Listing image by ETH Zürich / Nicola Pitaro