Biological-Fidelity, Knitted Computational Skin for Physical AI
Vision
We are looking to achieve biological-fidelity tactile and pressure sensing that mimics the complex mechanoreceptors in human skin while remaining computationally scalable and highly manufacturable. As AI expands to computational ‘brain’ power, there is a critical lack of physical sensing and perception capabilities that prevents robots from achieving a full loop of sense-compute-actuate and thus fully taking advantage of rich environmental data to learn and interact.
Human skin ranges from 50-200 mechanoreceptors per cm2, a density of tactile and pressure sensors that would be astounding for physical AI systems to interact with and learn from their environment. Using knitting as an additive manufacturing technique that enables stitch-level tuning of fabric mechanical properties, we envision creating flexible, application-specific, and highly dense tactile sensors from our custom-made functional yarns composed of a conductive yarn core dip-coated with an insulation layer. Our dip-coating fabrication of insulated layers allows for highly dense looping of yarns and enables pressure-based capacitive sensing and Triboelectric Nanogenerator (TENG) sensing while preventing electrical shorts.
Leveraging our lab’s strength in computational engineering, our long-term vision is to build unique sensing architectures that facilitate simultaneous TENG and capacitive sensing in the same fabric layers and mimic both the fast-adapting (TENG) and slow-adapting (capacitive) mechanoreceptors in our skin. Unique architectures also deliver scalability in sensor computation and energy efficiency via hierarchical sensing. TENG layers act as wake-up signals that indicate a touch and relative location, prompting the capacitive layer to do a deeper scan of the touched area for precise force mapping and subtle tactile changes.
We aim to create manufacturable and scalable knitted sensing grids for human health applications such as prosthetic fit and force monitoring, biometric sensing, and athletic recovery/performance. We also see applications in robotic tactile skins for hands and body-scale sensing in manufacturing, caregiving, and dexterous manipulation applications.
Progress
We have created a custom dip-coating fabrication setup that allows us to coat yarns in Thermoplastic Polyurethane (TPU) insulation. We dissolve TPU in dimethylformamide (DMF) and draw silver-plated nylon yarns through the different TPU percentage solutions at varying speeds to create yarns of varying thicknesses. The customizability of our yarns allows us to achieve very low bending stiffness allowing the yarns to be highly compatible with machine knitting techniques while maintaining good insulation properties.
We will be presenting a poster of our work at the 2026 UIST conference in Detroit, MI this coming November. We outline the mechanical characterizations of our custom yarns, draw lessons from our current dip-coating setup, and create basic capacitive pressure sensors with our knit structures.
Ongoing Research Questions
Yarn Fabrication
- Understanding how material choice and dip-coating parameters (solution viscosity and withdrawal speed) affect coating thickness.
Yarn-Level and Fabric-Level Properties
- Understanding how yarn coating thickness affects both yarn-level and fabric-level mechanical stiffness and electrical insulation.
Sensing Application
- How does knit stitch pattern impact capacitive change when pressure is applied to 2-layer sensing architectures?
- How does yarn coating thickness affect capacitive sensitivity along intersecting functional yarns?
- To what extent does changing coating thickness in full knit sensing garments affect capacitive response to known forces or fabric deformations?
- How do fabric deformations impact sensing capability?
- How do we calibrate for these changes while also sensing their presence?
- How can material choice for yarn coating support different sensing modalities (TENG, capacitive, resistive, etc…)
Publications
Towards Knitted Textile Electromechanical Systems
Machine Knittable Yarns for Interactive Pressure Sensing Textiles
Team
Ph.D and Postdoctoral
John Martins
Undergraduate
Abigail Hou
Rishi Garg
Wenchi Liu
Ben Kim
Alejandro Goldstein
Andres Turollols
Collaborator
Prof. Jian Cao
Alumni
Noah Tannas
Brandon Tendilla
Michael Miller
