关键词: 运动监测, 柔性传感纱, 纺织基摩擦发电机, 智能可穿戴

Abstract: "In recent years, with the development of smart wearables, flexible sensors for human movement monitoring have gained increasing popularity. These flexible sensors are highly functional and safe. Among them, textile-based triboelectric sensors have lower cost, higher stability, stronger integration, and greater advantages in human motion monitoring. To explore the feasibility of applying intelligent textiles for human motion monitoring, a flexible triboelectric sensing yarn with a core-shell structure featuring a double-helix electrode was fabricated using weaving technology. The core yarn (electrode yarn) consists of silver-plated nylon double-helix wrapped around spandex yarn, while the shell yarn is made of PP yarn. The electrical performance, durability and stability of the sensing yarn were tested using a custom-built electrical output test platform. The sensor yarn is integrated with the human body and connected to the test system to monitor the movement status of the human body. The double-helix electrode structure divides the electrode into multiple small regions, and this fragmented structure enhances the triboelectric charge density and improves friction efficiency, thereby boosting the sensor's output efficiency. The results show that the output voltage of the sensing yarn with a double-helix core yarn is significantly higher than that of traditional sensing yarns. The sensing yarn can withstand various mechanical deformations such as bending, twisting, wrapping, and knotting, making it well-suited for integration with the human body; when the PP yarn is woven with 6 strands, the resulting sensing yarn exhibits the most uniform and tight coverage. Additionally, when the conductive yarn has a fineness of 15 tex, the sensing yarn's voltage reaches its peak at 8.84 V. The output current of the sensing yarn in the frequency range of 1–2.5 Hz increases with the acceleration of the frequency, and the output voltage does not change significantly. In the pressure range of 5 N–65 N, both the output voltage and current increase with increasing  pressure. After 500 cycles of movement, bending, and twisting, as well as 20 washes, the sensing yarn maintains stable output, demonstrating good durability, stability, and washability. When encapsulated and integrated into the sole of a shoe, the sensing yarn responds to different motion states such as walking, running, and jumping. The core-shell triboelectric sensing yarn demonstrates the feasibility of applying smart textiles to human motion monitoring and motion state recognition, lays the foundation for research on triboelectric motion monitoring sensors, and also provides inspiration for broadening the application scenarios of textile-based TENG. Smart textiles can also be utilized for optimizing athletic performance, monitoring environmental conditions, and various military applications, among others. The research results can provide reference for the design and development of textile-based sensors."

Key words: motion monitoring, flexible sensing yarn, textile-based friction generators, smart wearables