KnitSkin

We present KnitSkin, a bio-inspired sleeve that can traverse diverse cylindrical terrains, ranging from a user’s forearm at a wearable scale, to pipes and tree branches at an environmental scale. Fabricated with a machine knitted substrate, the sleeve configures a stepped array of knitted scales that exhibit anisotropic friction. Coupled with the extension of actuators enclosed in the sleeve, the scales enable effective directional locomotion on cylindrical surfaces with varying slopes, textures, and curvatures. KnitSkin’s substrates are characterized by scales whose geometries and materials can be fine-tuned and channels that can accommodate diverse actuators. We introduce the design elements of KnitSkin in which we characterize a series of substrate parameters and their resulting anisotropic behaviors. In evaluating the locomotion, we examine the variables associated with the surface and actuator characteristics. KnitSkin obtains diverse applications across different scales, including wearable interfaces, industrial pipe-monitoring, to agricultural robots.

This project was supported by a generous grant from Accenture Labs & in part by NSF under grant IIS#2047249

Publication:
KnitSkin: Machine Knitted Scaled Skin for Locomotion

Jin-Hee (Heather) Kim, Shreyas Patil, Sarina Matson, Melissa Conroy, Cindy Hsin-Liu Kao✉

ACM Human Factors in Computing Systems (CHI) 2022 PDF I DOI

Project Credits: Hybrid Body Lab at Cornell University, directed by Cindy Hsin-Liu Kao
Research Team: Jin Hee (Heather) Kim (Lead Researcher), Shreyas Patil, Sarina Matson, Melissa Conroy, Prof. Cindy Hsin-Liu Kao

Press Inquiries: Press Image Kit: Available Upon Request (License: CC by-NC-SA 4.0) Press Contact: Prof. Dr. Cindy Hsin-Liu Kao, cindykao@cornell.edu

By modifying channels into pockets for a portable pesticide dispenser KnitSkin can further work as an agricultural robot. (Photo: Hybrid Body Lab)

KnitSkin’s ground layer can be knit with a wide range of materials, including water-soluble PVA yarn. When the interface travels along a leaking pipe, the PVA yarn dissolves and stiffens as the yarn dehydrates. The hardened surface of KnitSkin could serve as a temporary protective layer on the point of leakage. (Photo: Hybrid Body Lab)

KnitSkin demonstrates potential as a wearable interface carrying a microphone. The interface locomotes down the arm to help a user pick up calls or send voice messages. (Photo: Hybrid Body Lab)

Pictured is a close-up of KnitSkin’s knitted scales, which is bio-inspired from the scales of snakeskin (top right is a closeup of rattlesnake skin). In the knit substrate when monofilament is drawn laterally it forms a downward arch. The collection of arches is configured on an elastic knit substrate to mimic the mechanical property of snake scales

The sleeve configures three channels with pleated actuators enclosed. The scales are knitted on the inside to make contact with the surface. (Photo: Hybrid Body Lab)

During contraction of the interface, the sliding end now sticks to the surface and lets the other end retract. This movement alternates as the interface repeats extension and contraction, giving directionality to the motion. (Photo: Hybrid Body Lab)

KnitSkin ACM CHI 2022 Conference Presentation by Ph.D. researcher Heather Kim