A Novel Passive Occupational Shoulder Exoskeleton With Adjustable Peak Assistive Torque Angle for Overhead Tasks

Area of Science:

• Biomechanical Engineering
• Occupational Health
• Human-Robot Interaction

Background:

• Overhead tasks frequently cause work-related musculoskeletal disorders.
• Passive shoulder exoskeletons offer a lightweight, affordable solution but often compromise range of motion or compactness.
• Existing designs struggle to balance adaptability for diverse tasks with user mobility.

Purpose of the Study:

• To develop and validate a novel passive occupational shoulder exoskeleton adaptable to various overhead tasks.
• To ensure sufficient range of motion (ROM) and maintain device compactness.
• To reduce shoulder physical loads and enhance user experience during industrial work.

Main Methods:

• Formulation of kinematic models and simulations to design an ergonomic shoulder structure.
• Integration of a torque generator with an adjustable peak assistive torque angle and a passive clutch mechanism.
• Functional validation through a screwing task performed by ten healthy participants.

Main Results:

• The exoskeleton demonstrated sufficient ROM, achieving 164° in sagittal and 158° in horizontal flexion/extension.
• Significant reductions in muscle activation (up to 49.6%), perceived effort, and frustration were observed.
• Participants reported an improved user experience, scoring 79.7 out of 100.

Conclusions:

• The proposed exoskeleton facilitates natural movements and provides effective assistance for overhead work.
• It shows potential in reducing the risk of musculoskeletal disorders in industrial settings.
• The design offers insights into multi-task adaptability and efficient assistance for broader exoskeleton applications.