Upper Limb Model (Python and MATLAB)

Script Name: upperLimbModel_Static
Language: Matlab, Python (2.7)

Summary – upperLimb_Static code:

This file is supplied to illustrate the normal operation of the Nexus to Matlab or Python interface. Oxford Metrics and Vicon Motion Systems accept no responsibility for its correct operation. This script is to be run on the static trial where the MEP markers are present on the subject. The companion VST is “Upper_Limb.VST” which is also provided. The full list of required markers are in the VST. To get the best results, there should be no gaps in the trial. Multiple VST’s can be attached to the trial if the subject wants to analyze another object. This script will import the trajectory data into Matlab or Python, create upper arm coordinate systems, perform a global to local transformation placing the MEP markers in the upper arm coordinate systems, and will be written to the VSK as subject parameters. The glenohumeral joint is also created and placed in the upper arm coordinate system and written to the VSK as a subject parameter. These subject parameters will be used in the companion upperLimbModel_Dynamic script to recreate the MEP and GH markers.

Summary – upperLimb_Dynamic code:

This script is to be run on the dynamic trials. Prior to running this script on the dynamic trials, the upperLimbModel_Static file should have been run on the static trial. The VSK must have the following subject parameters which are generated by running the upperLimbModel_Static file on the static trial:

• LGHRelLUPTechX
• LGHRelLUPTechY
• LGHRelLUPTechZ
• RGHRelRUPTechX
• RGHRelRUPTechY
• RGHRelRUPTechZ
• LMEPRelLUPTechX
• LMEPRelLUPTechY
• LMEPRelLUPTechZ
• RMEPRelRUPTechX
• RMEPRelRUPTechY
• RMEPRelRUPTechZ

Multiple VST’s can be attached to the trial if the subject wants to analyze another object.

There should be no unlabelled markers, and the trial must contain no gaps. Desired trajectory filtration should be performed before running this script. Alternatively, the model outputs can be modelled after the script has been run depending on the users filtering preference.

This script will import the trajectory data into Matlab or Python, create upper arm coordinate systems, perform a local to global transformation recreating the MEP and GH markers. Coordinate systems will be made for the thorax, upper arm, forearm and wrist segments. There are two angle outputs for the shoulder (YZY and XZY) and one for the elbow and wrist (XZY):

• Euler angles sequence: YZ’Y”. Plane of elevation, elevation, internal-external rotation
• Euler angles sequence: XZ’Y”. Flexion-extension, ab-adduction, internal-external rotation

The following Python modules must be installed:

• numpy
• tkinter
• tkSimpleDialog

Transcribed to Matlab and Python from BodyBuilder by Nev Pires