How adaptation, training, and customization contribute to benefits from exoskeleton assistance

Area of Science:

• Biomechanics and Human Augmentation
• Robotics and Human-Machine Interaction

Background:

• Exoskeletons offer potential for enhanced human mobility, yet the underlying mechanisms of their effectiveness remain poorly understood.
• Key unknowns include the optimal training strategies, user adaptation processes, and the benefits of customized assistance for exoskeleton use.

Purpose of the Study:

• To investigate the relative importance and optimal types of training for enhancing exoskeleton effectiveness.
• To determine the impact of customized assistance on user performance and adaptation.
• To quantify the contributions of training and customization to metabolic cost reduction during exoskeleton-assisted walking.

Main Methods:

• Experiments were conducted with naive users learning to walk using ankle exoskeletons under three distinct training regimens with varying device behavior.
• Assistance was customized for a subset of participants.
• Metabolic rate, user adaptation, and exoskeleton power output were measured to assess effectiveness and learning.

Main Results:

• Moderate-variation training combined with customized assistance significantly reduced metabolic rate by 39%.
• Training accounted for approximately half of the observed benefit, while customization contributed about one-quarter.
• Expertise acquisition varied significantly by training type; moderate-variation training was most effective, while high-variation training hindered learning.

Conclusions:

• Effective exoskeleton use relies heavily on appropriate training and customization, demanding more research attention.
• User adaptation involves a reduction in exoskeleton power output over time, suggesting complex neuromuscular integration.
• The findings underscore the need for tailored training protocols and adaptive assistance strategies to maximize exoskeleton benefits for mobility enhancement.