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?Knitted Muscles? May Power Exoskeletons

Photograph of textile actuators manufacturing, courtesy of the study authors and Science Advances.

Researchers at Linköping University and the University of Borås, both in Sweden, have coated fabric with an electroactive material, giving it the ability to actuate in the same way as muscle fibers. A low voltage applied to the fabric causes the electroactive material to change volume, causing the fibers to increase in length. The properties of the textile are controlled by its woven or knitted structure. Researchers can exploit this principle, depending on how the textile is to be used. The technology opens new opportunities to design textile muscles that could be incorporated into exoskeletons or clothes, making it easier for people with disabilities to move. The study was published January 25 in Science Advances.

“If we weave the fabric, for example, we can design it to produce a high force. In this case, the extension of the fabric is the same as that of the individual threads. But what happens is that the force developed is much higher when the threads are connected in parallel in the weave. This is the same as in our muscles. Alternatively, we can use an extremely stretchable knitted structure in order to increase the effective extension,” said Nils-Krister Persson, PhD, associate professor in the Smart Textiles Initiative at the Swedish School of Textiles, University of Borås.

The researchers show in the study that the textile muscles can be used in a simple robotic device to lift a small weight. They demonstrate that the technology enables new ways to design and manufacture devices known as actuators, which-like motors and biological muscles-can exert a force.

“It is our dream to create exoskeletons that are similar to items of clothing…that you can wear under your normal clothes. Such devices could make it easier for older persons and those with impaired mobility to walk,” said Edwin Jager, PhD, associate professor at the Division of Sensor and Actuator Systems, Linköping University.

Editor’s note: This story was adapted from materials provided by the University of Borås.