A Novel Approach to Mechanized Crochet

Abstract

Textiles are increasingly recognized in architecture and robotics for their adaptability to diverse shapes, low environmental impact, and lightweight character. While automated knitting has enabled the production of three dimensional fabric shapes, the low internal strength and geometric limits of knitted fabrics restrict their structural potential. Crochet, by contrast, offers higher tensile strength, greater three dimensional extensibility, and the ability to generate arbitrary topological surfaces through its flexible stitch geometry. This project introduces a new framework for robotic crochet which translates the handcraft from a hook to a loom. Through a manual study, we established the ability to create fabric that is topologically equivalent to crochet on a pegboard loom. We demonstrated that on a loom it is possible to create any crochet stitch that does not require front or back loop insertion points, and that loom crochet permits the realization of crochet patterns with stitches that cross several rows. To characterize the created fabric relative to crochet, we then performed a tensile test on swatches created on different loom sizes. For looms up to twice the natural gauge of crocheted fabric, tensile strength was equivalent to controls (p = .048, TOST; 90% CI [→0.108, 0.100]; equivalence bounds = ±15%), indicating the utility of loom created crochet pieces for high strength applications. We then created a robotic prototype to automate loom crochet production using a 3D printed end effector for a UR3 robotic arm. The robot was able to successfully create chains, slip stitches, and decreases, with a 74% stitch level success rate for slip stitches. This work establishes the viability of loom crochet for automated production of complex, high strength textiles.