A Gait Deviation Correction Method for Stable Walking With a Wearable Self-Balancing Exoskeleton Robot: A Technical...

Area of Science:

• Robotics
• Biomechanics
• Control Systems

Background:

• Self-balancing lower-limb exoskeletons (SBLLER) can improve mobility for individuals with motor dysfunction.
• Yaw-direction rotational friction in the support foot is a critical factor affecting gait stability.
• Conventional momentum compensation strategies are not suitable for waist-less SBLLER designs.

Purpose of the Study:

• To propose and evaluate a multi-level stable walking control method for waist-less SBLLERs.
• To address yaw axis deviation caused by neglecting support foot friction.
• To enhance the stability of the human-exoskeleton system during locomotion.

Main Methods:

• A car-table based model predictive control (MPC) was used for initial gait trajectory generation.
• Angular momentum controllers were implemented to supplement MPC for pitch and yaw stability.
• Comparative experiments were conducted on flat ground with varying user parameters.

Main Results:

• The proposed multi-level control method effectively reduced yaw axis deviations.
• The method improved the overall stability of the human-exoskeleton system.
• Robust stable walking was achieved under specific dynamic load conditions in tests with healthy subjects and a stroke patient.

Conclusions:

• The developed multi-level stable walking control method is feasible and effective for SBLLERs.
• The approach successfully mitigates gait trajectory deviations and enhances system stability.
• This control strategy offers a promising solution for stable locomotion in waist-less lower-limb exoskeletons.