‘Bionic Olympics’ inspires future assistive technologies

The Cybathlon is an international Olympics-style event for bionic athletes. Think the Paralympics complete with cyborgs, AI and robotics. Last year saw 51 teams worldwide compete against one another in the second ever event organised by the Swiss Federal Institute of Technology in Zurich (ETHZ). The competition’s goal is to fuel the development of technologies to improve the day-to-day lives of those living with disabilities.

Teams can enter in six disciplines: powered leg prosthetics, powered arm prosthetics, powered exoskeletons, powered wheelchairs, bicycles for the paralysed that use their paraplegic pilot’s own electrically stimulated muscles, and a brain-computer interface race where competitors must control avatars in a software game by brain power alone.

Competing teams range from large companies to university labs, and one-man bands, fielding cutting-edge prototypes and commercially available products. The winners receive two medals – one for the technologists, the other for the human pilots who have been integral to the development of the devices, and have trained long and hard to learn new skills.

The event was originally due to be held in May 2020 in Zurich, but was postponed until November 2020 with teams competing virtually, on identical courses around the world, due to Covid-19 restrictions on travel.

Aldo Faisal, professor of artificial intelligence and neuroscience at the Brain and Behaviour Lab, Imperial College London, has been the Imperial team captain since 2014. The neurotechnologist says: “Working with assistive technologies, the students are forced from the outset to keep the end user at the heart of their designs. If they do not, they will fail. This year our teams are all embracing AI to enable or restore people’s ability to interact with their environment, and to change those lives for the better. It’s a real opportunity for them to learn that AI has more to offer than analysing and processing data streams to serve the needs of huge corporations.”

In 2020, Imperial fielded teams in three disciplines: cycling for paralysed cyclists, the robotic arm and the powered wheelchair. In each event, the teams have to accomplish a set of everyday tasks that are hard for the differently disabled people and then challenge what is possible with today’s technology.

London-based Canadian Conrad Bona was born without a left hand in the 1960s. “Ever since I can remember I’ve had a prosthesis; I had my first mechanical hand at 16. I’m now 51, and the pilot of the prosthetic hand challenge in the 2020 Cybathlon for Team Imperial.” Bona loves being a part of the development team at Imperial College led by Irene Mendez Guerra, a PhD student and bioengineer working in the Neuromechanics and Rehabilitation Technology lab. “Our prosthesis is unique,” she explains. “It is designed to tackle everyday, but difficult, real-world tasks like using a pair of scissors, and to significantly improve the quality of life for our users.”

Missing a limb, especially an arm, can have a devastating effect on the quality of a person’s life. Twenty thousand upper-limb-different people are under care and rehabilitation in the NHS but many of the current prostheses on the market are non-intuitive, rudimentary and require lengthy training to use effectively. From the beginning of the project, the Imperial team aimed to design a robotic prosthesis that the wearer could quickly and easily learn how to use.

The action of the team’s prosthetic hand and wrist is controlled by muscle activity in the remaining muscles in Bona’s upper arm. When muscles contract they generate a difference in voltage that can be detected by sensors on the surface of the skin. Irene’s team uses signal processing and machine learning to decode the muscle signals generated by Bona’s brain when he thinks about moving his missing hand. Those decoded signals, in turn generate corresponding commands for the motors in the prosthesis. In reverse, signals travel back from the robotic hand to Bona’s brain from sensors in the fingertips, giving him a haptic feedback or a crude sense of touch, allowing him to distinguish between objects of differing hardness and shape. The haptic feedback mechanism also helps to improve the quality of the bionic hand’s grasp. The prosthesis has been built from the ground up at Imperial – all of the robotics, sensors and electronics. “The tight integration of every element makes it compact and stable, and at each iteration Conrad has been there to give real user feedback,” says Guerra.

Without fine control and lacking intuitive interfaces, the operation of many prosthetics is an exercise in frustration for the user. As many as 40 per cent of disabled people issued with prosthetic devices abandon them within six months. According to Professor Faisal, this high rate of adoption failure may be the result of a design process that builds shiny robotics in a lab divorced from the real needs of the user base. “The Cybathlon competition seeks to right this by involving disabled pilots at all stages of development,” he adds.

Bona confirms: “It’s all about the user interface: if it’s not intuitive, then people won’t use it. Given that the competition hand is a one-off prototype and not commercially available, its significantly better than what I use on a daily basis. I aspire to have a perfectly functioning robotic hand. With this, the level of control is pretty phenomenal. Picking up fine objects like a key or a credit card and inserting them into a lock or a slot, that’s something I’d always do with my natural hand, but with this I can use the prosthesis. It’s hard to leave behind when I leave the lab!”

In the Cybathlon event, Bona with his robotic hand had to attempt everyday challenges like hanging up washing on a line with clothes pegs, cutting a baguette and picking up and screwing in a light bulb. Fifteen minutes before the start of their competition, the Imperial ARM thumb articulation broke, and the team had to compete using an earlier prototype, which did not perform well enough to land a medal place. 

In the powered wheelchair race, Mahendran Subramanian, based at Imperial’s Brain and Behaviour lab, is the biomedical engineer behind an extraordinary wheelchair, almost as tooled up with sensors as a top-of-the-range Tesla.

A very new drive-by-eye system allows severely disabled people to navigate through their environment using a self- driving electrically powered wheelchair, with just a look. It’s as simple as staring at the intended destination, and confirming it with a wink. New users take mere minutes to learn how to direct the chair, which delivers safe independent mobility for people so severely disabled that they cannot use a conventional joystick or other navigation interfaces such as tablets and touchscreens. “We used AI and machine learning to decode the difference between a gaze with intent and a glance. You wouldn’t want to end up at a wall that you had glanced at rather than the kettle that you wanted to go to and make a cup of tea,” says Subramanian.

The pilot of the extraordinary wheelchair is paraplegic business owner Paul Moore, whose company Activelinx specialises in assistive technology for the disabled.

An infrared gaze-tracker tracks Moore’s eye movements to determine where in the physical world he wants to go. A simple RGB camera with a built-in depth sensor calculates the distance to his desired destination. Once he confirms his intention with a three-second wink, the software combines the ‘kettle in the kitchen’ destination with commands that are sent to the navigation software. One cup of tea coming up.

Borrowing technology from self-driving vehicles, a two-dimensional lidar sensor supplies data about the surrounding environment to a Simultaneous Localisation and Mapping (SLAM) algorithm on a laptop mounted on the back of the wheelchair. The SLAM creates a map and locates the wheelchair within it, in real time, allowing the wheelchair to detect obstacles or objects moving in the local area and for it to plan a route to the kettle to safely avoid them.

“We deliberately used cheap off-the-shelf sensors to keep the cost of our conversion kit down. That will make it more accessible to the people who really need it,” says Subramian. “Ultimately we plan to market it as a kit to adapt existing electrical wheelchairs, for much the same price as it costs to add a joystick.”

“This drive-by-eye technology will be revolutionary for those with a severe neurological condition,” Moore explains. “The Cybathlon is more than a competition; it’s a phenomenal showcase for coming technologies. We all feel very strongly that this should be within the reach of any disabled person. There’s no doubt that the drive-by-eye concept is amazing and could be transformative for some people in the future, but it’s still got a way to go before we will see it on the market.”

Subramian’s chair design does not have added tracks – so like any other ordinary chair it cannot climb stairs. This meant it could not have won the Cybathlon race, as the course included a set of stairs. “But our prototype is more practical than any tracked vehicle,” Moore comments. “It can fit in a car or travel on the Tube. Most wheelchair users are not after the equivalent of a four-wheel-drive car, or an all-terrain vehicle. We just want to be able to get about independently. Like anyone else.”

Because of Covid-19 travel restrictions, Subramian and Moore were to compete virtually at the Allia Business Centre in Peterborough, rather than Zurich, but sadly limited set-up time meant that the team had to withdraw at the last minute.

The third event that Imperial participated in is the Functional Electrical Stimulation (FES) bike race. FES is a technique that has been around for more than two decades. It allows paraplegic riders to use their paralysed legs to cycle by electrically stimulating the muscles to contract.

The team is using a modified BerkelBike recumbent tricycle as its platform, invented by Dutch chemist and exercise scientist Rik Berkelmans, who explains: “The combination of FES and cycling produces huge benefits in terms of life-expectancy improvements, reversal of muscle atrophication, and can help to avoid many of the other health problems associated with debilitating spinal injuries, such as obesity, and cardiovascular issues.”

Imperial’s pilot for this race is Johnny Beer, whose life changed at the age of 16 when a trampolining accident left him paralysed with a complete spinal cord injury. “I can’t move my legs, but the technology keeps me fit,” says the passionately determined and competitive cyclist who trains several times a week. Beer has been riding a BerkelBike since 2012. The event would normally be held on a cycle track, but Covid-19 forced the FES racing teams to set up their bikes on Wahoo V4 standardised training rollers used by cyclists the world over to train during bad weather. Each roller was checked and calibrated at Cybathlon HQ in Zurich before being sent out. The move indoors meant that any aerodynamic improvements made to the bikes were negated by the lack of wind resistance.

Adhesive electrodes stimulate Beer’s muscles and a computer monitors the pedal position so that the correct muscles can be stimulated during the 360-degree pedalling cycle. Thai national Nat Wannawas is Imperial’s robotic engineer behind the FES entry and his job was to fine-tune that process using AI and machine learning to deliver an optimal level of stimulation given Beer’s speed and fatigue levels. The combination of training and fine-tuning of the software resulted in Imperial’s only medal at the 2020 Cybathlon. Beer and Wannawas won the silver medal, losing out to Dutchman Sander Koomen.

The next Cybathlon will be held in 2024, once again stretching the possibilities in next-level prosthetics and showcasing life-​changing technologies for disabled people.