Spider Legs Inspired Soft Robotic Extensor for Hand Rehabilitation

Soft robotics, which could be operated with higher degrees of freedom than their rigid counterparts, have a wide range of applications. Although 3D printing technologies have significantly advanced the development of soft robotics with fast iterations of designs and direct construction of complex structures, most 3D-printed soft robots to date are designed to rest in a straight line and bend when actuated. Inspired by the joints of a spider leg, this paper presents a novel soft robot design that curves in its resting position and extends when pneumatically actuated with the intent to form an easy-to-use hand rehabilitation device for stroke survivors with curled fingers and hands. Two prototypes were fabricated using Fused Deposition Modeling (FDM) 3D printing technology with thermoplastic polyurethane (TPU) filament. A testing apparatus was designed and built to investigate the relationship between the forces created by the soft robotic extensor and the air pressures supplied for actuation. Comparing our extensor prototypes' preliminary force testing results to available literature focusing on hand rehabilitation demonstrates the likelihood of using our spider legs-inspired, 3D-printed soft robotic extensor for at-home hand rehabilitation.