Enhancing Patient Safety in Upper Limb Rehabilitation: A 2-DOF Parallel Robot with Integrated Safety Systems

This study presents the design and development of a 2-degree-of-freedom (DOF) parallel robot system specifically tailored for upper limb rehabilitation. The primary focus is on integrating comprehensive safety measures to ensure secure operation within a clinical environment. The robot system incorporates a parallel safety control system featuring multiple redundant safety mechanisms, including biosignal sensors, force sensors, and an emergency "Enable" switch. These features are designed to monitor and respond to potential hazards such as excessive force, abnormal patient biosignals, and deviations from the prescribed motion range. Additionally, electrical safety is reinforced through the use of an isolation transformer, grounding, and circuit protection to prevent electrical hazards, maintain low leakage currents, and ensure proper insulation. Experimental validation demonstrated that the developed robot system achieves high repeatability, operates quietly within noise targets, and effectively responds to safety-critical conditions, thereby meeting existing safety standards for rehabilitation robots. This research underscores the critical importance of safety in the design and application of rehabilitation robotics, providing a robust solution that prioritizes patient safety during therapeutic processes.