Energy-Efficient Hybrid Shoulder Exoskeleton With Magnetic Spring Joints

Shoulder disorders, a significant subset of work-related musculoskeletal disorders, are a major cause of disability among industrial workers, driving the development of preventive shoulder exoskeletons. Passive exoskeletons are lightweight and portable but provide a fixed torque profile based on shoulder angle, which limits adaptability to diverse work tasks. In contrast, active exoskeletons offer task-specific assistive torque, but are heavier and less energy-efficient, reducing their practicality in industrial settings. Hybrid exoskeletons present a promising solution by addressing the adaptability limitations of passive exoskeletons and the energy inefficiency of active exoskeletons. This article introduces a hybrid shoulder exoskeleton that integrates a magnetic spring-based counterweight mechanism with a quasi-direct-drive motor, achieving an 86.4% reduction in power consumption during arm elevation compared to a single actuator. The exoskeleton covers 90.3% of the shoulder’s natural range of motion and, in human performance tests, reduces anterior deltoid muscle activation by an average of 40% during overhead and waist-level tasks.