Robotic textiles for everything from breathing recovery to feeling surfaces in Space
9 november 2021
Imagine an artificial fibre that can be programmed to contract and stretch just like human muscle fibres. Thin and flexible enough to be woven into a portable, robotic textile muscle, OmniFiber is the result of a collaboration between researchers at KTH, MIT Media Lab and Uppsala University.
The Uppsala researchers, led by Professor Klas Hjort at the Department of Materials Science and Engineering, has mainly concentrated on how to most effectively mediate contact with sensors and artificial muscles, such as a pat on the shoulder or a hug.
“The problem is that the artificial muscles that exist today require considerable amounts of energy and quickly run out of batteries or require that you do not move from a fixed facility. I want it to be a technology that you can have anywhere, and that can be used at any time”, says Klas Hjort.
In this first study, the challenge has been to integrate sensors in the artificial muscles and to make the muscles with such small tubes that they can be knitted or woven in ordinary knitting and weaving machinery, he explains.
Many possible applications
Portability is also one of the driving forces behind the main author behind the project, the KTH doctoral student Özgun Kilic Afsar, who is also affiliated with MIT. The idea is that the artificial muscle fibre should be able to be integrated and used in many different contexts.
“For example, the fibre must be able to be integrated in textiles we use every day, such as in clothes or interiors for cars. Furthermore, it also has the potential to be used in astronaut equipment. Today, their clothes are bulky and prevent them from actually feeling what they are touching during extravehicular activity. A more straightforward application is medical technology garments intended for rehabilitation or patient care at a distance”, says Özgun Kilic Afsar.
The researchers have contributed to a modular “breath-regulating undergarment” worn on the upper body. Through haptic feedback, the undergarment can support the teaching of respiratory activities in singing. One garment is worn by the teacher and the other one by the student. The test subject and collaborator in the research study has been an opera singer.
“The garment can sense the singer's breathing movements and transmit them directly to the novice singer. These nuanced breathing movements are otherwise difficult to articulate, so we believe that adding haptic communication is better than only using words, symbols and images when teaching. This is only one of many haptics-mediated skill applications that the artificial muscle fibre could be used for in pedagogic purposes”, says Özgun Kilic Afsar.
“Since breathing is a vital body function, the purpose of the undergarment technology can be extended to respiratory aid after surgical operations, or for a respiratory recovery for long COVID survivors or patients with sleep apnea”, says Klas Hjort.
The technology behind it – this is how it works
So how does the technology behind it work? The fibre itself consists of a woven casing that can be mechanically programmed, and inside it, there is a hollow liquid-filled elastomeric channel. When compressed air is sent through the hollow core, mechanical energy is generated from the compressed air. The pressure and flow of air is controlled by the FlowIO, a miniature platform developed by Ali Shtarbanov, a co-author in the paper, from MIT Media Lab.
Another prototype is based on the same fibre technology, in a knitted form factor, which is placed on the finger and intended to function as a stiffness-changing plaster. It is a simple tubular mesh made of OmniFiber, and inside is a liquid metal, Gallium, that melts at 30 degrees centigrade and is solid at room temperature. The fibre thus functions as an armour that holds the finger in position but can soften on-demand while the healing process is in progress.
Watch this video produced by MIT to learn more about the innovation and how this technology works.
Hoping to contribute to the internet of the senses
The project is a meeting between several different scientific disciplines and universities, and is also linked to a joint project within the framework of the Foundation for Strategic Research framework, which deals with energy-efficient BodyNETS.
The interdisciplinary environment between computer scientists, experts in human-computer interaction and microsystems technology, has been - and is - a very exciting and challenging process, according to both Özgun Kilic Afsar and Klas Hjort.
In the next step, both automation of the manufacturing process to be able to create longer fibre threads and further investigations for future commercialization await.
“Since the beginning, my passion has been to realize the idea of microfluidic textile muscles and to integrate them into our everyday textile interfaces in order to achieve a seamless technology for the internet of the senses”, says Özgun Kilic Afsar.
Klas Hjort looks forward to continuing to contribute to the project, especially when it comes to streamlining the development of the "muscles" themselves and refining their properties.
“We will use pneumatics and hydraulics for the most powerful muscles but other energy efficient and miniaturized electrostatic servomotors to control the muscles with high resolution”, he says and adds:
“The goal is to contribute to the "internet of the senses" of the future, where touch is one of the most important ways to convey information between people - but in the long run also between man and machine”.