Towards an Untethered Knit Fabric Soft Continuum Robotic Module with Embedded Fabric Sensing

Design and Characterization of Soft Fabric Omnidirectional Bending Actuators

“…We also characterized and demonstrated the OBA's capabilities for stiffness modulation and deformation compensation, which make OBA potential for practical applications under various payloads. Table 2 provides a comparative analysis of the OBA relative to two other omnidirectional fabric actuators that can be found in the literature: an omnidirectional knit fabric actuator in [34] and a woven fabric-based actuator from [33]. A notable feature of the OBA is its streamlined fabrication process, which employs a minimal set of fabrication tools to achieve efficient construction (see Video S1).…”

“…Regarding physical attributes, the OBA demonstrates a reduced mass and volume, yet provides a range of motion (RoM) and payload capacity comparable to those of its counterparts, with the reduced mass contributing to a superior force-to-weight ratio. However, it is essential to acknowledge the unique twisting and extending capabilities of the actuator documented in [34]. While [33] shows an actuator with a higher bending payload, it has longer actuator length.…”

“…The design philosophy of the OBA is rooted in the anisotropy of knit fabrics [21,22,25,27,34]. The OBA consists of three actuation chambers that parallel along the length and 120 • apart in the cross section.…”

“…They generally comprise a single chamber made of two distinct fabric layers, with the layers' geometry dictating the type of motion. For both woven and knit actuators, multiple actuator modules can be combined to achieve complex, multi-degree-of-freedom (multi-DoF) motions [33][34][35][36]. While woven fabric actuators have been extensively researched and thoroughly characterized in terms of motion/force capabilities for various designs [1,2,10,23,28,33,[35][36][37][38][39][40][41][42][43][44][45], research on knit fabric actuators is less developed [21,22,25,27,34].…”

“…For both woven and knit actuators, multiple actuator modules can be combined to achieve complex, multi-degree-of-freedom (multi-DoF) motions [33][34][35][36]. While woven fabric actuators have been extensively researched and thoroughly characterized in terms of motion/force capabilities for various designs [1,2,10,23,28,33,[35][36][37][38][39][40][41][42][43][44][45], research on knit fabric actuators is less developed [21,22,25,27,34]. Despite their simpler fabrication methods and potential for enhanced performance, studies on knit fabric actuators, especially those offering omnidirectional capabilities, remain limited [34].…”