Diseño e implementación de un prototipo de exoesqueleto manual de bajo coste para la rehabilitación funcional de pacientes con discapacidades en las extremidades superiores: Design and implementation of a low-cost hand exoskeleton prototype for functional rehabilitation in patients with upper limb disabilities

Abstract

Introduction: Hand motor impairment is one of the most common functional limitations following neurological injuries, particularly stroke, highlighting the need for rehabilitation technologies that are accessible, safe, and easy to use. However, many existing hand exoskeleton systems rely on complex sensing architectures and expensive components, limiting their applicability in resource-constrained environments.

Objective: To design, implement, and experimentally validate a low-cost, modular dorsal hand exoskeleton capable of providing controlled flexion–extension assistance with software-defined safety thresholds.

Method: A prototype was developed based on biomechanical alignment criteria, incorporating five independent linear actuators, strain gauge-based force sensors with analog amplification, and an open-source microcontroller platform. Validation was conducted using a staged experimental protocol to evaluate threshold behavior, force measurements across repeated trials, residual error, and dynamic actuation during 30-second rehabilitation sessions (600 samples per trial).

Results: The system demonstrated stable force within defined rehabilitation intervals, with RMSE values of approximately 2 kg and no activation beyond the upper safety threshold. Dynamic analysis showed consistent rise times, controlled transient slopes, minimal threshold-crossing delay, and reliable multi-actuator synchronization.

Conclusions: The proposed low-cost modular architecture provides stable, repeatable, and safe force-assisted motion. These results support the feasibility of modular exoskeleton designs as scalable solutions for hand rehabilitation technologies.