Rigid, Soft, Passive, and Active: A Hybrid Occupational Exoskeleton for Bimanual Multijoint Assistance

Physically demanding work is still common in western countries, with large proportions of the workforce that are exposed for more than a quarter of their working time to tiring postures or repetitive tasks: the shoulder is one of the main body areas susceptible to work-related musculo-skeletal disorders. Recent advancements in assistive technology have provided new instruments to promote safety and reduce workload. Colloquially referred to as occupational exoskeletons (OEs), these wearable devices are usually spring-loaded, and provide gravity support for overhead tasks. OEs for upper limbs are usually single joint exoskeletons and assist shoulder flexion/extension; they do not provide support to distal joints such as the elbow. In the present work, starting from a commercially available exoskeleton, we propose an innovative concept of hybrid upper-limb OEs. We combined a spring-loaded shoulder exoskeleton with an active elbow exosuit to extend the capability of the OEs to provide gravitational support to both shoulder and elbow flexion-extension in strenuous manual tasks. The proposed device can reduce up to 32% of the biceps activity during the elbow flexion and up to 31% of the deltoids actiNit:k . during the shoulder abduction. In-lab experimentation showed the potentials of such a hybrid approach in reducing the strain of the upper-limb muscles.

Automated summary

Physically demanding work is still common in western countries, with a large proportion of workers exposed to tiring postures or repetitive tasks. Recent advancements in assistive technology, such as occupational exoskeletons (OEs), have provided new tools to promote safety and reduce workload. This study proposes a hybrid upper-limb OE concept that combines a spring-loaded shoulder exoskeleton with an active elbow exosuit, providing gravitational support for both shoulder and elbow flexion-extension in strenuous manual tasks.