pyCGM_Single.pycgmCalc.getKinetics

pyCGM_Single.pycgmCalc.getKinetics(data, Bodymass)

Estimate center of mass values in the global coordinate system.

Estimates whole body CoM in global coordinate system using PiG scaling factors for determining individual segment CoM.

Parameters

dataarray

Array of joint centres in the global coordinate system. List indices correspond to each frame of trial. Dict keys correspond to name of each joint center, dict values are arrays of (x, y, z) coordinates for each joint centre.

Bodymassfloat

Total bodymass (kg) of subject

Returns

CoM_coords3D numpy array

CoM trajectory in the global coordinate system.

Notes

The PiG scaling factors are taken from Dempster – they are available at: http://www.c-motion.com/download/IORGaitFiles/pigmanualver1.pdf

Examples

>>> from .pyCGM_Helpers import getfilenames
>>> from .pycgmIO import loadData, loadVSK
>>> from .pycgmStatic import getStatic
>>> from .pycgmCalc import calcAngles
>>> from numpy import around
>>> dynamic_trial,static_trial,vsk_file,_,_ = getfilenames(x=3)
>>> motionData  = loadData(dynamic_trial)
SampleData/Sample_2/RoboWalk.c3d
>>> staticData = loadData(static_trial)
SampleData/Sample_2/RoboStatic.c3d
>>> vsk = loadVSK(vsk_file,dict=False)
>>> calSM = getStatic(staticData,vsk,flat_foot=False)
>>> _,joint_centers=calcAngles(motionData,start=None,end=None,vsk=calSM,
...                            splitAnglesAxis=False,formatData=False,returnjoints=True)
>>> CoM_coords = getKinetics(joint_centers, calSM['Bodymass'])
>>> around(CoM_coords[0], 2) 
array([-942.76, -3.58, 865.33])