Development and Validation of a Self-Aligning Knee Exoskeleton With Hip Rotation Capability

Area of Science:

• Robotics
• Biomechanics
• Rehabilitation Engineering

Background:

• Exoskeleton self-alignment is crucial for user comfort and effective motion assistance.
• Designing exoskeletons that simultaneously assist knee and hip movements while accommodating joint misalignment is challenging.

Purpose of the Study:

• To propose a novel spatial self-aligning mechanism for a knee exoskeleton.
• To enable simultaneous assistance in knee flexion/extension (FE) and hip internal/external rotation (IER).
• To analyze kinematic compatibility and optimize the exoskeleton design for improved performance.

Main Methods:

• Development of a spatial self-aligning mechanism for a knee exoskeleton.
• Establishment and analysis of a kinematic model to ensure kinematic compatibility.
• Proposal and application of a global torque manipulability (GTM) index for design optimization.
• Experimental validation of the exoskeleton's performance.

Main Results:

• The proposed exoskeleton enables simultaneous assistance in knee FE and hip IER.
• Kinematic analysis confirmed the exoskeleton's compatibility with human joint axes misalignment.
• Optimization using the GTM index improved exoskeleton performance.
• Experimental results demonstrated lower interaction forces and torques compared to existing exoskeletons.

Conclusions:

• The novel spatial self-aligning mechanism significantly improves knee exoskeleton comfort and motion assistance.
• The developed exoskeleton effectively reduces interaction forces and torques during combined knee and hip movements.
• This design offers a promising advancement for wearable robotic systems in rehabilitation and assistive applications.