Thermally driven 3D seamless textile actuators for soft robotic applications

Abstract

Soft wearable robotic devices have emerged as a promising solution for human mobility assistance and rehabilitation, yet current solutions suffer from issues such as bulkiness, high cost, nonscalability, noise, and limited portability. This study introduces a novel approach to soft robotic assistive devices using untethered, soft actuators with seamlessly integrated sensing, heating, and actuation properties through digital machine knitting and low-boiling liquid. The proposed soft actuator operates under a voltage of less than 12.5 V, generating a tip force of up to 50 mN. This actuator achieves a bending motion when filled with 2 mL of low-boiling liquid and supplied with 15 W. The dynamic response of the actuator is examined under consistent parameters, revealing a 60-second inflation time and a subsequent natural cooling period of 30 s at room temperature. Notably, over 12 cycles, the tip force of the actuator exhibits minimal variation, highlighting its durability for prolonged usage. The proposed approach paves the way for overcoming the limitations of existing technologies, particularly in terms of motion assistance and rehabilitation applications, with an emphasis on at-home usage during daily activities.