Single-Actuator-Based Lower-Limb Soft Exoskeleton for Preswing Gait Assistance.

Area of Science:

• Biomedical Engineering
• Rehabilitation Robotics
• Biomechanics

Background:

• Muscle weakness impacts gait, necessitating assistive devices.
• Conventional exoskeletons often use multiple motors, increasing weight and complexity.
• Existing designs may face challenges like rotary motor slip during actuation.

Purpose of the Study:

• To propose a novel lower-limb soft exoskeleton with a single motor for assistive forces.
• To assist hip flexion during the preswing phase of the gait cycle.
• To reduce metabolic cost and gait deviation in users with muscle weakness.

Main Methods:

• A single-motor actuation system using a pulley and slider mechanism was designed.
• The system converted rotational motion to linear motion for pulling knee braces via cables.
• Actuation was triggered by detecting the end of thigh backward swing.
• A prototype was fabricated and tested on 7 healthy subjects.

Main Results:

• The soft exoskeleton provided an assistive force of 100 N.
• Testing showed negligible gait deviation when wearing the exoskeleton.
• A significant reduction in metabolic cost during walking was observed.
• The single-motor design prevented slip issues associated with rotary motors.

Conclusions:

• The developed single-motor soft exoskeleton is effective in providing assistive forces.
• The lightweight design offers a promising solution for reducing metabolic cost in walking.
• This technology has potential for integration into advanced exosuits for comprehensive gait assistance.