Moisture-Sensitive Response and High-Reliable Cycle Recovery Effectiveness of Yarn-Based Actuators with Tether-Free, Multi-Hierarchical Hybrid Construction

Abstract

Yarn-based muscle actuators are highly desired for applications in soft robotics, flexible sensors, and other related applications due to their actuation properties. Although the tethering avoiding release of inserted twist, the complex preparation process and harsh experimental conditions make tether-free structures yarn actuator with reliable cycle recovery effectiveness is needed. Herein, a tether-free, multi-hierarchical hybrid construction of a moisture-sensitive responsive yarn-based actuator with the viscose/PET ratio (VPR) = 0.9 exhibited a contraction stroke of 83.15%, a work capacity of 52.98 J·kg–1, and an exerting force of 0.15 MPa. Additionally, the maximum cycle recovery rate of 99% is comparable to that of human skeletal muscles, confirming the advantages of a two-component hybrid structure. The underlying mechanism is discussed based on geometric characterization and energy conversion analysis between the actuation source and the spring frame. The mechanical manufacturing process makes it simple to expand the structurally stable yarn muscles into fabric muscles, opening up new opportunities to advance the usage of yarn-based actuators in smart textiles, medical materials, intelligent plants, and other versatile fields.

Advanced Design of Fibrous Flexible Actuators for Smart Wearable Applications

“…Uncommonly, a humidity textile actuator is woven into a smart emergency tourniquet (Fig. 12d) [108]. When a wound bleeds, the tourniquet can be curled to stop bleeding and recover to its normal shape after the wound stops bleeding.…”

Flexible Actuators with Hygroscopic Adaptability for Smart Wearables and Soft Grippers

“…To critically address the limitations of humidity-sensitive actuators that are difficult for large-scale production, which are hindered by the mismatch between mechanical and actuation performance, the TbHs-FAs have been designed. Figure 2a displays the humidity-sensitive yarn (viscose/PET = 9:1, with a twist rate of 450 turn/m) 47 that is created using a straightforward pretreatment process (Figure S1a, Supporting Information). This yarn is then woven (Figure 2b) to produce laboratory-produced TbHs-FAs (Figure 2c, size: 35 × 35 cm).…”

Soft Robot Design, Manufacturing, and Operation Challenges: A Review

“…Unlike conventional rigid robots that utilize electric motor actuators, soft robots employ soft actuators that can be activated through various means, such as pressure [28][29][30], magnetic fields [31,32], electric stimulation [33][34][35][36], light or photonic stimuli [37][38][39], moisture-responsive mechanisms [40][41][42], and explosive triggers [43][44][45]. Furthermore, Son et al [46] have conducted an extensive review on the four-dimensional (4D) shape changes that can provide versatile functional advantages to soft robots in response to external environmental stimuli including heat, acidity (pH), light, electricity, or pneumatic triggers.…”