Simulation Presentation

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Simulation Presentation
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Digitalized Data

• Angular displacement of the hip, knee and ankle
  vs. time was digitalized, and the angle of the
  foot above the ground during any period of time
  was calculated from this data.

?F Resulting Angle of Foot Above Ground
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Digital Data Results

• It was determined from the digital data that
  during footslap the angular velocity of the foot
  of a healthy male runner was..
• V -14.15 rad/s.
• The graph shows the angular displacement and
  velocity versus time.

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Model Setup

• The purpose of the model was to simulate the
  position and velocity of the foot from the
  heelstrike to footslap period of the Gait cycle.
  The simulation results would then be compared to
  the results of the digital data to obtain an
  accurate magnitude of ankle stiffness in a
  healthy male runner.
• ?F angle of the foot measured from the ground
  to the bottom of the shoe
• LH length of foot from heel to ankle pivot
• Ka and Ca spring stiffness and damping

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Simulation Findings

• The simulation was run with a zero stiffness in
  order to find the angular velocity of footslap
  that Jason would experience without the brace.
• Angular Velocity (k0) -25.3 rad/s
• This is significantly more then the footslap
  velocity calculated from the digital data (V
  -14.15 rad/).
• The correct stiffness value was determined by
  varying the value of stiffness until the
  simulation results matched the digital data
  results.

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Simulation to Find Stiffness

• It was found that will a spring stiffness of
  k117 Nm/rad the footslap velocity of the
  simulation would be equal to that of the
  digitalized data (V-14.15 rad/s).
• The following graph illustrates the Displacement
  and Velocity of the foot for the digital data and
  the footslap.

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