Knit architectures for sensing and actuation

The field of robotics has begun to adopt textiles as materials of choice for wearable robots and smart garments due to their light weight, high flexibility, and breathability. To realize an entire wearable robot, many subsystems must be considered including sensors, actuators, and integration components, all requiring specialized mechanical properties. Current cut-and-sew manufacturing strategies pair these discrete textile components together; however, they are effort-intensive and can lead to failure at connection points. Weft knitting represents an especially promising alternative for creating fully integrated wearable robots because it uses only a single additive manufacturing process, and because of the mechanical diversity achievable through varying the topology via stitch design. Surprisingly, knit actuators and sensors have predominantly utilized jersey and garter structures to date. Here we explore a candidate structure to program fluidic actuation and a candidate structure to improve resistive strain sensing sensitivity, both using alternative knit stitches. We evaluate how features of the textile structure, including yarn linearity, intersections, and yarn stiffness, program the fabric mechanics necessary for these applications.