3.4 Prosthetic Foot & harvesting equipments
Propulsion is generated from
the reaction between the foot and
the ground in
the standing phase. To improve the propulsion function of the foot prosthesis and
stump system, it must shorten the first period of the standing phase
when the ankle power is
negative and
more quickly release energy in
the second period. Decreasing the elastic modulus of
the material of
the energy storing element could greatly increase the energy stored and
energy released. The elastic modulus of the material has
only a small effect on
the propulsion index, but the stored and released energy
changes significantly with it. [17]
Considering the motion and
power variation in
the ankle joint in
the standing phase, during the muscles contract and
the direction of
reaction force exerted by the ground coincides with the direction of the relative motion. The muscular power during that period is defined to be negative. During the standing phase, the muscles
extend, the reaction force is in the opposite direction to the relative motion, and the power is defined as positive. [49-51]
The test stand can adjust the angle of
the prosthetic foot position. To test the suitable positions to
harvest energy from
foot while walking, standing and swing position.
The film piezoelectric were
placed in the sole position, in the bottom of the foot. Sole is the first position to touch the ground when
walking forward.
Many positions in this foot can be used to harvest electricity.
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