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…..
    V = -14.15 [rad/s].
     The graph shows the angular displacement and velocity versus
    time.
                                                   DIGITALIZED DATA - Angular Displacement and Angular Velocity vs.
                                                                                Time
                                          1
    Displacement [rad] and Velocity/wn




                                         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 =-
  14.15 [rad/]).
 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
  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.
                                                               Dgital vs. Simulation Data for Displacement and Velocity

                                          0.6

                                          0.5

                                          0.4
Displacement (rad) and Velocity (rad/s)




                                          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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posted:6/12/2012
language:English
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