Textile fabrics are compliant, lightweight, and inherently anisotropic, making them promising for the design of soft pneumatic actuators. In this article, we present the design, modeling, and evaluation of a class of soft fabric-based pneumatic actuators (SFPAs) for soft wearable assistive gloves that can simultaneously assist the thumb abduction and finger flexion and extension motions for brachial plexus injury patients. We investigate the mechanical behaviors of various woven fabrics and rib weft-knitted fabric structures, guiding us to design a thumb-abduction SFPA, a finger-flexion SFPA, and a finger-extension SFPA. We further develop a mathematical model to evaluate the influence of the geometric parameters on the blocked tip forces of the finger-flexion SFPAs and extension torques of the finger-extension SFPAs, which are also verified by the experimental results. We then integrate our SFPAs into a soft wearable assistive glove with a portable control system. The glove is finally tested on a healthy volunteer and a brachial plexus injury patient. The clinical evaluation results demonstrate the effectiveness of our designed glove in assisting hand motions and grasping tasks.
Keywords: finger flexion and extension; soft fabric-based pneumatic actuators; soft wearable assistive glove; thumb abduction; woven and knitted fabrics.