Seungmoon Song's Research Projects
Foot-ankle biomechanics and locomotion
The foot plays a special role in legged locomotion. It is the segment that interacts with the environment by taking impacts, securing grip, and transmitting power. Along with this special role, the human foot has evolved, as already Leonardo da Vinci observed, into a “masterpiece of engineering” that comprises about 30 segments and joints, 20 muscle-tendon units, and over 100 ligaments. I am interested in relating the functional roles and the biomechanical structures of the human foot.
In the simulation study with our neuromuscular human walking model, we investigated the windlass mechanism's potential of improving the energy efficiency of walking. We showed that walking with feet that incorporate the windlass mechanism could save more than 15% of the energetic cost as compared to walking without the mechanism.
We hypothesized that the potential energy saving of the windlass mechanism comes either from the foot compliance introduced by the windlass mechanism or from its property of reducing the effective foot length in swing.
S. Song and H. Geyer, The energetic cost of adaptive feet in walking, IEEE ROBIO, 2011. [paper] [slides]
The windlass mechanism of human foot (2011 ~ )
– compliance and effective length of the foot
The windlass mechanism of human feet
One of the unique features of human feet is the windlass mechanism. The windlass mechanism engages the longitudinal foot arch and the toe segment by the plantar fascia, a thick ligament that spans from the underside of the heel to the toe.
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| J. H. Hicks, 1954 |
In the simulation study with our neuromuscular human walking model, we investigated the windlass mechanism's potential of improving the energy efficiency of walking. We showed that walking with feet that incorporate the windlass mechanism could save more than 15% of the energetic cost as compared to walking without the mechanism.
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| Song et al., ROBIO, 2011 | a robotic foot design inspired by the windlass mechanism
(CAD drawing by David Matten) |
We hypothesized that the potential energy saving of the windlass mechanism comes either from the foot compliance introduced by the windlass mechanism or from its property of reducing the effective foot length in swing.
The effect of foot compliance on the energetics of human walking
Do compliant feet improve the energy efficiency of walking? The preliminary results of our simulation and experimental study show that the compliant feet actually worsen the energy efficiency of walking. This suggests that the energy saving of the windlass mechanism originates rather from the foot length changing between stance and swing.
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| simulation model and result |
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| experimental setup and result |
Paper
S. Song, C. LaMontagna, S. H. Collins, and H. Geyer, The effect of foot compliance encoded in the windlass mechanism on the energetics of human walking, IEEE EMBC, 2013. [paper]S. Song and H. Geyer, The energetic cost of adaptive feet in walking, IEEE ROBIO, 2011. [paper] [slides]