FURI | Spring 2025

Design and Characterization of a 3D Printed, Highly Back-Drivable Cable-Driven Actuator for Gait Rehabilitation

Powered exoskeletons are widely used for gait rehabilitation but face a tradeoff between torque density and back-drivability. This study details the design and control of a quasi-direct drive actuator that allows lower extremity joint control using bilaterally opposing cables, primarily supporting ankle lateral movement leading to sprain. The actuator utilizes a brushless DC motor-driven QDD paired with a belt drive and planetary gear system to simulate a 9:1 reduction ratio. The actuator’s torque capability and bandwidth are tested using a bench setup. The study aims to validate if the device can effectively prevent ankle sprain during standing and walking tasks.