How four-legged robots and smart belts help people overcome everyday barriers
In the international Cybathlon competition, people with physical disabilities undertake routine tasks with the aid of assistive technology that can be seamlessly integrated into everyday life. Below, we present three ETH teams that will be putting their innovative solutions to the test at this October’s event.
Help from a fourlegged friend
Developed by the Robotics Systems Lab at ETH Zurich, ALMA is a quadrupedal robot equipped with a range of sensors and a robotic arm. Unlike other entries in the Cybathlon discipline for assistive robots, all of which are attached to a wheelchair, ALMA moves autonomously on its own four legs, controlled by paraplegic pilot Sammy Kunz via a quadstick – a type of mouth-operated joystick. Deploying the robot as a separate system provides greater mobility, say team managers Carmen Scheidemann and Andrei Cramariuc. “But our biggest asset is also our biggest liability,” Scheidemann explains. “Because we have to ensure that ALMA moves safely without bumping into any objects.” In competition, the team has ten minutes to complete ten everyday tasks. For example, the pilot must use the robot to open a door and then close it behind them, or to pick up an apple and hold it in such a way that the pilot can take a bite. The quadstick used with ALMA features various tubes. By blowing or sucking, the pilot is able to control the different axes of the robot: either its quadrupedal platform or its gripping arm.
“At a preliminary event in February, we had eight minutes to complete four tasks,” says Scheidemann. “In the end, we needed just over six.” The team is therefore confident about achieving a good score at the upcoming championship. In preparation for October’s event, various refinements to ALMA have been made in close cooperation with Kunz. Most of these involved enhancing the controls so that Kunz can operate the robot with as little practice as possible. “We suggest an improvement, and Sammy gives us feedback on what works for him and what doesn’t,” explains Scheidemann. “Then we make the necessary modifications.” Whereas 15 hours of practice were required before the preliminary event in February, improvements to the control system have now drastically reduced preparation times.
Both managers have hugely enjoyed working with Kunz. “It’s really fulfilling to be working on a project that has the potential to bring about such a major improvement in the day-to-day lives of people with disabilities,” says Cramariuc. ANYmal robots, which provide the quadrupedal platform for ALMA, are already in use for a variety of industrial jobs, including the inspection of oil rigs. The current challenge is to deploy assistive robots not only in controlled environments but also in everyday situations. The team will continue to refine ALMA. “But it will be a good few years before the platform is ready for market,” Scheidemann cautions. “We’re still very much at the experimental stage.”
Cameras and a vibrating belt
Pressing the right doorbell, finding a free seat and navigating an area containing obstacles of various heights are just some of the challenges that blind pilot Lukas Hendry will face in the Vision Assistance Race at the Cybathlon. Technical support comes from the Sight Guide team, which will guide Hendry using data from two cameras strapped to his chest. Patrick Pfreundschuh, one of the team managers, describes how the technology works: “We use one camera for positioning – that is, to tell us where Lukas is and where he’s heading. The other is a depth camera that takes 3D measurements of the surrounding area.” There’s also a third camera which the pilot holds in his hand to assist with tasks that require objects to be examined in more detail. All three cameras transmit information to a small, lightweight computer that Hendry carries on his back. The computer crunches the data and sends Hendry corresponding instructions via an audio signal. Finding a system with enough computing power was surprisingly difficult, says Pfreundschuh: “When your pilot is in the race, you need to be processing the input as quickly as possible. Otherwise, he might collide with an obstacle, which is obviously something we want to avoid!” The Sight Guide team is hopeful about making further improvements before the Cybathlon, such as making the audio signals that convey the instructions more easily understandable. In addition to the computer and cameras, Hendry also wears a special vibrating belt that tells him in which direction to move. “We don’t want to say exactly how this belt works, because it’s what gives us our competitive edge!” says Pfreundschuh with a smile.
The Sight Guide team consists of doctoral candidates and students from the Autonomous Systems Lab at ETH Zurich, the Robotics and Perception Group at the University of Zurich and the Institute for Mechatronic Systems at Zurich University of Applied Sciences (ZHAW). For the doctoral students, the Cybathlon is both inspiring and enjoyable, which is why they are happy to work on the project in their spare time. Every month or two, they meet up with Hendry to perform mock-ups of the tasks they will face in the Cybathlon. Hendry then supplies feedback – for example, on how fast he receives the instructions – and many of the tweaks he suggests can be applied on the spot. Working with the pilot is one of the things that makes this project so special, says Pfreundschuh: “It’s great to see Lukas sailing through tasks that would be impossible for him without our technology. It makes me happy and proud to see the benefits we can provide for blind people simply by putting theory into practice.” The goal is to continue improving the technology once the Cybathlon is over – and Pfreundschuh hopes to find a new generation of students willing to take the reins.
Experience CYBATHLON 2024 live!
The third edition of the one-of-a-kind championship initiated by ETH Zurich takes place in the SWISS Arena in Kloten from 25 to 27 October 2024. Cybathlon is a competition in which people with disabilities compete to carry out everyday tasks with the aid of state-of-the-art assistive technology. You can look forward to watching teams from across the world compete in exciting competitions in eight disciplines – as well as an interactive supporting programme. Get your tickets external page here.
Sensing the ground while wearing prosthesis
A key drawback of a prosthetic leg is that wearers are unable to feel the ground beneath their foot. The absence of sensory feedback on where their foot is positioned and how firmly it is touching the floor makes it difficult to walk, especially on uneven terrain or when climbing stairs. This is the main reason many patients decide against a prosthesis. But it doesn’t have to be this way, as Stefan Poth has discovered since becoming a pilot in the Cybathlon. He is taking part in the competition with his own prosthetic leg, which has been fitted with a special insole in the shoe. Developed by the NeuroLegs team, this insole is equipped with sensors that gather information on what the researchers call the foot-ground interaction. This includes feedback on whether Poth’s weight is on the toe, middle part or heel of his prosthetic foot. Data on where he is stepping is sent to a microprocessor attached to his waist. The computer processes the data and converts it into electrical stimulation by activating electrodes on an elastic belt that Poth wears around his leg stump. “Depending on where Stefan is stepping, electrical stimulation is applied in real time to either the front, side or back of the stump to replicate the sensation that would normally be perceived in the foot,” says Noemi Gozzi, co-manager of the NeuroLegs team.
Poth’s team for the leg prosthesis race is made up of students from the Neuroengineering Lab at ETH Zurich. Affiliated with the Department of Health Sciences and Technology, the lab is headed by ETH professor Stanisa Raspopovic. This year’s team is building on the valuable experience gained in the previous Cybathlon four years ago. “Instead of starting from scratch, we’ve actually been able to improve our technology this year. For example, we’ve made it a lot more userfriendly,” says Valerio Aurucci, the second of the team’s two managers. The belt Poth wears around his leg stump was developed by this year’s team to avoid having to attach electrodes to his skin one by one, which has also made the system more reliable.
Gozzi emphasises how rewarding it is to see their research being put into practice: “We’re trying to develop systems that will make people’s day-to-day lives easier. Stefan’s reaction when he felt a sensation from his foot for the first time was something very special – and it certainly made up for all those hours in the lab!” The Neuroengineering Lab is one of the leading research groups working on peripheral nerve stimulation, and Aurucci sees
major benefits in the innovative solution they have developed: “The biggest advantage is that our system can be used with any prosthesis.” Getting to a market-ready product will require more development and additional safety features. The two team managers – both of whom are doing their doctorate at ETH – are therefore carefully considering their next step. Should they stick to research and hand over NeuroLegs to the next generation, or take the plunge into business by setting up a spin-off? The future is theirs to decide.