An exoskeleton using controlled energy storage and release to aid ankle propulsion

Area of Science:

• Biomechanics
• Assistive Device Technology
• Human Locomotion

Background:

• Ankle plantarflexion is crucial for efficient walking, providing propulsion and support.
• The triceps surae-Achilles' tendon complex utilizes elastic recoil for energy efficiency.
• Few assistive devices target ankle plantarflexion support, despite its importance.

Purpose of the Study:

• To develop a portable, passive ankle exoskeleton for assisting plantarflexion during walking.
• To replicate the elastic assistance of the human triceps surae-Achilles' tendon complex.
• To create a device that aids propulsion and reduces metabolic cost.

Main Methods:

• Designed a novel ankle exoskeleton inspired by biological elastic mechanisms.
• Integrated a 'smart-clutch' mechanism to engage/disengage parallel springs based on ankle kinematics.
• Ensured the system is purely passive, requiring no external power, motors, or electronics.

Main Results:

• The developed exoskeleton successfully provides mechanical assistance during the stance phase of walking.
• The 'smart-clutch' effectively engages springs for assistance and disengages them for free swing phase motion.
• The purely passive design achieves energy neutrality.

Conclusions:

• A novel passive ankle exoskeleton was created, utilizing a smart-clutch for targeted assistance.
• This energy-neutral device has the potential to restore walking symmetry and reduce metabolic expenditure.
• It offers a promising solution for individuals with impaired ankle plantarflexion, such as those with stroke or spinal cord injury.