Stimuli-responsive fiber/fabric actuators for intelligent soft robots: From current progress to future opportunities

Bioinspired soft actuators with adaptive, reconfigurable, and multifunctional features have gained increasing attention in soft-robotic applications of intelligent responsive devices. Fueled by the development of wearable electronics, fiber/fabric actuators are of particular interest owing to their unique characteristics of mechanical flexibility/stretchability, high degree-of-freedom morphing, body-compatible shape factor, and mature industrial producing. In this review, the state-of-arts of fiber/fabric-based actuators and soft-robotic systems including preparations, structures, stimulating mechanisms, and functional applications are comprehensively investigated. The analysis of advantages and disadvantages in practical actuation scenarios is highlighted, starting from the introduction of the fabrication routes and typical structural designs. Furthermore, the actuating mechanisms of fiber/fabric-based robots are examined in terms of the key stimulus types (single/multiple stimulating schemes), and the wide spectrum of application fields are illustrated: namely, smart clothing, artificial muscles, intelligent devices, and flexible electronics. Finally, the challenges and opportunities for next-generation fiber/fabric-based actuators/robots are discussed in terms of manufacturing scalability for pervasive use, multifunctionality for enhanced adaptability, and self-healability/degradability for recyclable design.