Should Ankle Exoskeletons Also Provide Assistance During Swing Phase?

Area of Science:

• Biomechanics
• Robotics
• Human-Computer Interaction

Background:

• Ankle exoskeletons can aid walking by providing powered assistance.
• Current research explores optimizing assistance timing and direction for improved user performance.

Purpose of the Study:

• To evaluate novice exoskeleton user responses to combined stance and swing phase assistance.
• To determine if adding swing phase dorsiflexion assistance enhances performance beyond stance phase plantar flexion assistance.

Main Methods:

• Participants walked with an untethered ankle exoskeleton under two conditions: plantar flexion assistance only, and combined plantar/dorsiflexion assistance.
• A baseline condition with the exoskeleton mechanically disconnected but with added mass was included.
• Metabolic power, muscle activity, and gait mechanics were measured.

Main Results:

• No significant differences were found in steady-state metabolic power, muscle activity, or toe clearance between assistance conditions.
• A strong positive correlation (0.913) was observed between improvements in metabolic power across different assistance conditions.
• Individual responses to assistance varied, but those benefiting from one type also benefited from the other.

Conclusions:

• Combined stance and swing phase assistance did not yield statistically significant improvements for novice users in this study.
• The strong correlation in metabolic power improvements suggests potential for personalized exoskeleton control strategies.
• Future research should focus on tailoring assistance to individual user needs and biomechanics for optimal exoskeleton performance.