A new kind of fiber developed by researchers at MIT and in Sweden can be made into clothing that senses how much it is being stretched or compressed, and then provides immediate tactile feedback in the form of pressure, lateral stretch, or vibration. Such fabrics, the team suggests, could be used in garments that help train singers or athletes to better control their breathing, or that help patients recovering from disease or surgery to recover their breathing patterns.
The multilayered fibers contain a fluid channel in the center, which can be activated by a fluidic system. This system controls the fibers’ geometry by pressurizing and releasing a fluid medium, such as compressed air or water, into the channel, allowing the fiber to act as an artificial muscle. The fibers also contain stretchable sensors that can detect and measure the degree of stretching of the fibers. The resulting composite fibers are thin and flexible enough to be sewn, woven, or knitted using standard commercial machines.
The fibers are dubbed OmniFibers.
The new fiber architecture has a number of key features. Its extremely narrow size and use of inexpensive material make it relatively easy to structure the fibers into a variety of fabric forms. It’s also compatible with human skin, since its outer layer is based on a material similar to common polyester. And, its fast response time and the strength and variety of the forces it can impart allow for a rapid feedback system for training or remote communications using haptics (based on the sense of touch).
The researcher says that the shortcomings of most existing artificial muscle fibers are that they are either thermally activated, which can cause overheating when used in contact with human skin, or they have low-power efficiency or difficult training processes. These systems often have slow response and recovery times, limiting their immediate usability in applications that require rapid feedback.
As an initial test application of the material, the team made a type of undergarment that singers can wear to monitor and play back the movement of respiratory muscles, to later provide kinesthetic feedback through the same garment to encourage optimal posture and breathing patterns for the desired vocal performance. .
Though this initial testing is in the context of vocal pedagogy, the same approach could be used to help athletes to learn how best to control their breathing in a given situation, based on monitoring accomplished athletes as they carry out various activities and stimulating the muscle groups that are in action. Eventually, the hope is that such garments could also be used to help patients regain healthy breathing patterns after major surgery or a respiratory disease such as Covid-19, or even as an alternative treatment for sleep apnea.
The soft fiber composite, which resembles a strand of yarn, has five layers: the innermost fluid channel, a silicone-based elastomeric tube to contain the working fluid, a soft stretchable sensor that detects strain as a change in electrical resistance, a braided polymer stretchable outer mesh that controls the outer dimensions of the fiber, and a nonstretchy filament that provides a mechanical constraint on the overall extensibility.
News source: MIT
