Fabrics of the Future
November 2020 YSM Article
For centuries, fabrics have been simple, yielding materials, but Professor Rebecca Kramer-Bottiglio and her research lab, the Yale Faboratory, seek to integrate robotics with fabric. Recently, Kramer-Bottiglio and lead author Trevor Buckner developed robotic fabrics that can be programmed to sense and change shape or stiffness. These fabrics have potential applications from smart deployable structures to assistive clothing.
The robotic fabrics consist of three main components. The first is a flattened wire made of shape memory alloy, allowing for control over bending. In one example, one ribbon in a set of fabric wings can be programmed to extend upon electrical heating (~100 oC). Another ribbon can be programmed to wrap the wing around the plane body for storage. Heating specific ribbons controls whether plane wings are extended or wrapped.
The second component is variable stiffness fibers created with Field’s metal mixed in epoxy. This material allows the fabric to hold its shape, becoming softer in warm temperatures (~65 oC) and stiffer in cool temperatures. Kramer-Bottiglio and Buckner demonstrated this through a flat fabric that transforms into a table-like conformation upon heating. Rapid cooling stiffens the fabric into a load-bearing structure.
The last component of the fabric is electrically-conductive ink, which acts as a sensor when painted onto the fabric to detect curvature and stretch by a change in electrical resistance. The lab demonstrated this by developing a“smart” fabric tourniquet that compresses when damaged is sensed, thus providing immediate medical assistance.
The challenge with working with fabric, Buckner argues, is the two-dimensional nature of the material. Not only does the minimal material thickness restrict the types of components that can be used, but the thin structure also limits its lifting power and load capacity. As the component technologies improve and their interactions are optimized, however, its structural and assistive applications in robotics could drastically expand. The lab’s next project is to create a robotic fabric that can walk and carry its own battery!
Buckner, T. L., Bilodeau, R. A., Kim, S. Y., & Kramer-Bottiglio, R. (2020). Roboticizing fabric by integrating functional fibers. Proceedings of the National Academy of Sciences, 117(41), 25360–25369. https://doi.org/10.1073/pnas.2006211117