Motivation: Fibers are important for robotic articulation, actuation and sensing, but adding fibers is a bottleneck. When small numbers of robots are produced for research or by experimenters, the job is usually done by hand.
(examples of running fibers in robotics by hand bottleneck)
(a) Fold-flat bike helmet assembly
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(b) eNable prosthetic hand assembly
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(c) Articulated dragon model assembly
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In soft robotics, fibers control the direction a soft actuator can bend. When a non-stretchable fiber is embedded in one side of a soft inflatable actuator, the actuator curls toward the fiber side. When a fiber is used as a “tendon” to pull on a soft structure, lifelike organic motions can result -- as in this simple example of a soft silicone tube with a thread inside:
Automating the fiber installation task will not only save time and increase uniformity, but will expand the materials available for robotics because of the huge variety of available fibers. Manufacturing techniques like laser cutting and 3D printing set strict tolerances for the types of materials they can process; few labs have lasers that can cut metal. Many materials either don’t melt in a filament-based 3D printer nozzle, or get damaged and lose functionality. Sewing and embroidery do require a thin, strong and flexible thread, but don’t take it far from room temperature. All the materials designated “thread” in this image can be sewn directly, and we have developed sewing-based methods to handle the thicker and softer fibers. Because the water-soluble polyvinyl alcohol sew-able stabilizers and soluble threads used for embroidery don’t interfere with silicone curing, the patterned fiber arrays are easy to transfer to materials used in soft robotics.
(Fibers that can be used for soft robotics projects)