Design of a Novel 3D-Printed Soft Actuator for Clenched Fist Rehabilitation

This paper presents a novel 3D-printed, fold-based, soft pneumatic actuator for hand rehabilitation of patients with clenched fist deformity. Actuator design is specially focused on following the orientation of a clenched fist. The proposed actuator provides active extension for hand rehabilitative training. Actuator design considerations, fabrication method and the appropriate 3D printing parameters are specified in the paper. Experiments were conducted to characterize the performance of the actuator in terms of range of motion (ROM) and tip force. The bending trajectories, ROM of proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints were analyzed under different pressure levels. Tip force capabilities of the actuator is quantified using a blocked force test. The actuator shows maximum DIP and PIP angles (ROM) of 176° and 163° respectively at 300 kPa (Gauge). Also, at the same pressure, it has shown a maximum tip force of 1.8 N. The actuator shows minimal hysteresis and the potential for use in a future glove development for clenched fist rehabilitation.