# Simulation Presentation

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Simulation Presentation
Digitalized Data
 Angular  displacement
of the hip, knee and                            θthigh
ankle vs. time was
digitalized, and the
angle of the foot
θknee
above the ground
during any period of θ = Resulting Angle of
F

time was calculated    Foot Above Ground
Ground
from this data.                        θankle
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…..
     The graph shows the angular displacement and velocity versus
time.
DIGITALIZED DATA - Angular Displacement and Angular Velocity vs.
Time
1

0.5

0
0     0.1           0.2              0.3                 0.4                 0.5                0.6               0.7   0.8

-0.5

-1

-1.5

-2

Time (s)
Angular Displacement   Angular Velocity     Poly. (Angular Displacement)   Poly. (Angular Velocity)
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.           Weight
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.

   θF = angle of the foot measured         LT    Ka,Ca
from the ground to the bottom of the
shoe
θF       LH
   LH = length of foot from heel to
ankle pivot

   Ka and Ca = spring stiffness and
damping
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 (k=0) = -25.3 [rad/s]
 This is significantly more then the footslap
velocity calculated from the digital data (V =-
 The correct stiffness value was determined by
varying the value of stiffness until the simulation
results matched the digital data results.
Simulation to Find Stiffness
 Itwas found that will a spring stiffness of
k=117 [Nm/rad] the footslap velocity of the
simulation would be equal to that of the

 The  following graph illustrates the
Displacement and Velocity of the foot for
the digital data and the footslap.
Dgital vs. Simulation Data for Displacement and Velocity

0.6

0.5

0.4

0.3

0.2

0.1

0
0   0.05                       0.1                          0.15                      0.2      0.25
-0.1

-0.2

-0.3

-0.4

-0.5
Time (s)
Digital Displacement          Digital Velocity               Simulation Displacement
Simulation Velocity           Poly. (Digital Displacement)   Poly. (Digital Velocity)

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 views: 13 posted: 6/12/2012 language: English pages: 7