Feed-forward torque control for plantar flexion support

Recent studies suggest that a reduction of the plantar-flexion muscle EMG can improve the efficiency of human locomotion. In this study, an attempt is made to reduce the maximal EMG of the gastrocnemius medialis and soleus by providing a feed-forward torque support around the ankle. The strategy only requires the ankle kinematics to define the appropriate support torque. The maximal amount of support applied was equal to 30% of the total ankle torque of a human during steady state walking. Five untrained subjects walked on a treadmill at 4km/h and completed 3 test sessions of about 45 minutes each. The final EMG measurements showed a maximal reduction of 30% for the soleus and a slight increase of the gastrocnemius medialis EMG pattern for the case where 50% of the maximal support was applied. The tests showed a significant change in the ankle angle patterns when walking with maximal support. The findings suggest that the human prioritizes invariant ankle torque pattern over an invariant kinematic pattern. The results suggest that feed-forward torque control is capable to reduce the soleus muscle EMG and could possibly increase the walking efficiency of human locomotion.

Subject

Exoskeleton
EMG

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http://resolver.tudelft.nl/uuid:39c08d45-71cc-44fb-881d-7a8fa0fdf807

Embargo date

2014-08-23

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Student theses

Document type

master thesis

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Thesis_Laurent_Huberty.pdf

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