This paper presents the design, implementation, and experimental validation of a 3-degree-of-freedom (3-DOF) parallel robotic ankle based on a 2SPU-1RU (two Spherical-Prismatic-Universal kinematic chains and one Revolute-Universal kinematic chain) architecture for transtibial prosthesis applications. The proposed design aims to replicate the complex kinematics of the human ankle across the sagittal, frontal, and transverse planes, addressing the limitations of conventional prosthetic ankles, which typically offer reduced mobility. The system was developed in accordance with ISO 10328:2016 load requirements (P4 level) and incorporates a parallel mechanism that enhances structural rigidity. A comprehensive methodology, including CAD modeling, kinematic simulation, finite element analysis (FEA), and electronic system integration, was implemented. Structural analysis results showed a maximum Von Mises stress of 193.2 MPa and a safety factor of 2.17, ensuring operation within elastic limits. The prototype, fabricated using 3D printing (PLA), integrates linear actuators, a servomotor, and a sensing system with closed-loop PID control. Experimental validation under noload conditions demonstrated that the system achieved clinically relevant ranges of motion, including 41.0° of plantarflexion, 16.5° of dorsiflexion, 26.1° of inversion, and 12.4° of eversion. The maximum angular deviation with respect to target values was 3.5°, confirming high kinematic fidelity. These results show the feasibility of the 2SPU-1RU configuration as a compact, efficient solution for advanced ankle prostheses, with potential for future integration into functional assistive devices.
Autor(es):Oshiro, Gonzalo
Lazares, Brayam J.
Casanova, Claudia
Abarca, Victoria E.
Elias, Dantes A.
Año: 2026
Título de la revista: IEEE Xplore
Ciudad: Lima, Perú
Url: https://doi.org/10.1109/CoDIT70676.2026.11631200