From Knitting Technology to Robotics: Untethered Thermally Actuated Textile Exoskeleton for Dexterity Applications

Abstract

Soft wearable robotic devices offer significant potential for human mobility assistance and rehabilitation; however, existing solutions are often hindered by bulkiness, limited scalability, and restricted portability. This study introduces a textile-based exoskeleton glove equipped with thermally driven actuators, achieving dexterous motion in under 12 s using only 10.8 W of power while maintaining a low operating temperature of 48 °C. This performance surpasses the fastest previously reported system in terms of power input and operating temperature, which achieved actuation in 10 s but required 15 W and operated at 100 °C. In comparison, recent studies report response times of 120 s, with 14 W consumption and temperatures near 95 °C. The actuators utilize low-boiling-point liquids that undergo phase transitions upon heating, enabling fast, untethered actuation without external systems. The seamless knitted structure integrates sensing and actuation functionalities, including self-return to initial position capability. This is achieved through digital machine knitting of specific patterns using functional yarns. The actuators demonstrate 270° bending, generating 2 N gripping force while maintaining energy consumption efficiency. The glove is mountable on an industrial robotic arm, demonstrating its ability to grasp and relocate objects. This study presents a quick-response, scalable, energy-efficient solution for wearable robotics.