An elbow passive exoskeleton with controllable assistance: Design and experimental

Area of Science:

• Robotics
• Biomechanics
• Wearable Technology

Background:

• Existing passive elbow exoskeletons have limited assistance capabilities and applications.
• Wearable robotic devices offer physical support and facilitate movement.

Purpose of the Study:

• To propose and validate a controllable elbow passive exoskeleton (CEPE) addressing limitations of current devices.
• To introduce a novel design incorporating a ratchet-based self-energy storage mechanism (RSSM) and Candan gravity compensation mechanism (CGCM).

Main Methods:

• Mathematical modeling of the RSSM and design specification for CEPE and RSSM.
• Analysis of design parameters' influence on power assistance performance.
• Experimental validation including static strength, no-load, and loaded power assistance tests.

Main Results:

• CEPE demonstrated significant elbow joint torque compensation: 68.8% (0°), 93.8% (30°), and 70.7% (60°) shoulder angles without load.
• With a 5kg load, torque reduction on the elbow joint increased from 86% to 91.2% as shoulder angle shifted from 30° to 60°.
• The adjustable RSSM allows CEPE to operate in four distinct modes, broadening its application scope.

Conclusions:

• The developed CEPE effectively compensates for elbow joint torque, validating its feasibility through experimental testing.
• The integration of RSSM and CGCM enhances assistance capabilities and expands the range of applications for passive elbow exoskeletons.
• The CEPE represents a significant advancement in wearable robotic assistance for movement facilitation.