Pre-programmable pneumatic actuator: leveraging mechanical anisotropy of nonwoven fabrics with an integrated tensile sensor

Abstract

The emergence of flexible fabric-based pneumatic actuators (FPAs) with pre-programmable motion capabilities, enhanced security and versatile interaction features significantly advances the construction of sophisticated soft robotic systems, owing to their enhanced security and versatile interaction features. Despite these promising attributes, the commercial viability of FPA products faces a considerable amount of challenges, primarily stemming from the scarcity of highly deformable fabric structures and the availability of industrial fabrication approaches. Taking inspiration from the anisotropic nature of lobster antennae, we propose a scalable and economical strategy to fabricate functional FPAs using nonwoven fabric material with superior mechanical anisotropy. This innovative method involves the adoption of tunable inelastic constrained wires sewn onto extensible nonwoven fabrics with regular wrinkles. This nonwoven fabric-based pneumatic actuator (NFPA) demonstrates specific motion profiles with curvature of over 0.6 cm⁻¹ and output forces of over 140 cN under adjustable pressure conditions. Guided by the constrained wire combinations, NFPA enables diverse programmable motions like spiraling, assistance, and grasping. Furthermore, NFPA incorporated with specific sensors exhibits significant potential in wearable devices with real-time environmental detection for rehabilitation applications. Our work contributes a distinctive insight into the design of programmable NFPAs and enlightens an arena toward versatile soft robotic applications.