3D knitted structure design for wearable pressure sensors

Abstract

The rise of the Internet of Things (IoT) and wearable electronics has driven a growing demand for soft, flexible textile sensors. In particular, a fabric-based pressure sensor that can be integrated into garments, such as compression wear, intimate apparel, and tight-fit medical devices, is highly desirable, as it provides insights into treatment effectiveness and wearer comfort. Various approaches exist for fabricating pressure sensors using textiles or soft materials. However, many of these methods face limitations: the fabrication process can be too complex for practical application, or the resulting sensors may lack stability and accuracy. This highlights a significant opportunity to improve textile pressure sensors for everyday use. This study aims to design a novel knitted spacer fabric sensor for body pressure measurement. Conducted as a non-funded study from April 2020 to March 2023 in collaboration with Prof. Ishii Yuya from Kyoto Institute of Technology, the research introduces an innovative five-layer weft-knit fabric with a spacer structure that functions as a capacitive sensor and can be knitted in a single process. This design leverages the inherent flexibility and compressibility of knitted fabrics, representing a breakthrough in textile sensor technology. The outer layers, made from insulated yarn, ensure the sensor is safe and comfortable for skin contact. Notably, this fabric sensor can be produced on a standard double-bed weft-knitting machine in one seamless process, eliminating the need for additional coating, lamination, or assembly. This greatly simplifies both production and practical application. The outcomes of this research open new avenues for the development of textile pressure sensors and wearable electronics. The flexible and breathable nature of the knitted sensor makes it suitable for applications in health monitoring, sports, and interactive textiles. The research findings have been disseminated through academic papers, patents, newspaper reports, and conferences.