Development and Experimental Validation of a Passive Exoskeletal Vest

Area of Science:

• Ergonomics
• Biomechanics
• Human-Computer Interaction

Background:

• Manufacturing workers experience muscle fatigue due to repetitive upper limb tasks.
• Existing passive upper limb exoskeletons offer limited assistance, insufficient for dynamic shoulder joint loads.
• The need for exoskeletons that provide adaptive support without restricting arm mobility is critical.

Purpose of the Study:

• To design and evaluate a novel passive exoskeletal vest for reducing shoulder muscle fatigue.
• To assess the exoskeleton's impact on muscle activation, arm stability, accuracy, and user comfort.
• To determine if the exoskeleton impedes or restrains arm movements during various tasks.

Main Methods:

• A passive exoskeletal vest with a unique ratchet bar mechanism for two operating states (engaged/separated) was designed.
• Assistive torque is load-dependent, allowing free arm movement when separated and locking at any vertical position when engaged.
• Seven subjects performed static, precision, and dynamic tasks to evaluate the exoskeleton's performance.

Main Results:

• The exoskeleton significantly reduced muscle activation levels across various tasks.
• Arm accuracy and stability were unaffected during heavy work.
• Subjective measures indicated high comfort and portability (score of 8/10).
• Minimal restriction on the arm's range of motion was observed.

Conclusions:

• The designed exoskeletal vest effectively alleviates shoulder burden for workers.
• The device provides substantial assistive torque without compromising arm mobility or task performance.
• This passive exoskeleton offers a promising solution for reducing occupational musculoskeletal strain in the upper limbs.