Frontiers in Rehabilitation Sciences · Published 2026-07-03 · DOI 10.3389/fresc.2026.1859475
Andres Garcia, Kevin Fernández, Andres Nenger, Redhwan Algabri, Carlos Salazar, Jonathan Leon, Francisco Yumbla
More than 85% of stroke survivors present motor impairment in the upper limb, yet access to rehabilitation robotics remains concentrated in high-income countries due to costs exceeding 10,000 USD and architectures dependent on external computers. This economic barrier limits the ability of researchers in low- and middle-income countries (LMICs) to develop and validate new therapeutic strategies. This article presents PETRA (Pedestal Exoskeletal Testbed with Real-time Architecture), an open-source, 3-degree-of-freedom kinematic validation testbed manufactured in PETG for upper limb rehabilitation research at a cost under 25 USD per joint. PETRA adopts a fixed pedestal configuration that decouples the robot’s dynamics from the user’s biomechanical disturbances, providing a controlled environment for characterizing parametric cycloidal transmissions and deterministic dual-core firmware without PC/ROS dependency. Experimental validation with over 300 trials confirms positioning accuracies within clinical requirements while identifying polymer friction as the primary technical constraint. By providing a low-cost, replicable methodological standard, PETRA facilitates the transition from conceptual design to robust assistive technology in institutions with limited resources.
Abstract from DOAJ. Public domain (CC0 1.0).
Read the article at the publisher →
Garcia, A., Fernández, K., Nenger, A., et al. (2026). PETRA: a pedestal exoskeletal testbed with real-time architecture for upper limb rehabilitation robotics. Frontiers in Rehabilitation Sciences. https://doi.org/10.3389/fresc.2026.1859475