Initialize outer-level
 parallel particle
 swarm optimization

 f
 Minimize outer-level
objective function (i.e.,
3D marker coordinate
 errors for all time
 frames of inner-level
 optimization)


 Adjust outer-level
design variables (i.e.,
model parameters)


False


Initialize inner-level
 non-linear least
squares optimization


 False

 Minimize inner-level
objective function (i.e.,
3D marker coordinate
errors for current time
 frame i)


Terminate inner-level
 non-linear least
squares optimization


 True

Terminate outer-level
 parallel particle
 swarm optimization


Figure 3-10. Two-level optimization approach minimizing the 3D marker coordinate
 errors between the kinematic model markers and experimental marker data
 to determine functional joint axes.