A Unified Knee and Ankle Design for Robotic Lower-Limb Prostheses

The recent development in robotic lower-limb prostheses have helped amputees restore their joint functions and enabled them to perform diverse and energetically challenging daily locomotive activities, which are usually beyond the functionality of the passive prostheses. Although robotic knee prosthesis and ankle prosthesis have their common purpose of restoring joint functions for lower-limb amputees, they have generally been treated as distinct, standalone devices. Realizing such common objective and leveraging the similarities between the knee and ankle design, in this paper, a new unified design approach is proposed, which adopts a Common Core Components Knee-Ankle Prosthesis design. This research specifically targets the robotic knee/ankle joint design unification as a major goal, while fulfilling their biomechanical requirements, especially the torque, speed, and range of motion and form factor requirements associated with the knee/ankle joints. Based on such requirements, a unified knee/ankle joint design was developed, which features an identical transmission mechanism and system layout while still providing the desired level of flexibility (joint-specific customization) through swappable timing-belt pulleys.