Supervised by Prof. Tung-Wu Lu, Dept. of BioMedical Engineering, NTU

MATLAB programs, which use the data derived from a motion capture system and force plates, for human motion analysis, including motion tracking, evaluation of body balance, and derivation of joint forces and torques of the lower body, etc.

1. MATLAB 2015 (or newer versions)
2. MTIMESX function(Fast Matrix Multiply with Multi-Dimensional)

The transformation between global & local coordinates of marker position on lower body segments.

Derive the COP from data of two force plates and display the positions relative to the force plates.

1. Represent the rotations of body segemnts with Euler angle and fixed angle.
2. Display the difference of Euler angle before and after static calibration of the individual.
   

1. Smoothen the data curve and display the angular velocity of the lower body.
2. Consider the right foot only, compare the results of analytic solution of angular acceleration & 1st derivation of angular velocity.
3. Consider the right thigh only, compare the angular velocity derive from 12 sequences of Euler angle.
   The one with Gimbal lock during motion can be easily observed and avoided.    

1. Write the function "unwrapEP.m" to eliminate the discontinuity of Quaternions data.  
2. Compare angular velocity & angular acceleration derived from Euler angle and Quaternions(EP).
    

1. Compare the rotation axis and angle derived from the Screw axis and Quaternoins.
2. Determine the joint center & rotation axis with least-square error from several rotation axes derived during the motion.
    

1. Derive & compare the COM position of the whole body using Dempster's anthropometrical data with simplifying the body model as 7, 11, 12, & 13 segments.
2. Display the COM positions. (Yellow: markers' position, green: COM of body segments, purple: COM of the whole body).
   

Derive the COP data while the recipient is standing still. It determined the eclipse covering 95% of these COPs with Principal Component Analysis (PCA). The area of the eclipse and the length of its axes can be an indicator for evaluating one's body balancing ability.  

Derive the angular momentum and 1st derivation of angular momentum during the motion.

Derive the joint moment & joint force of angular momentum during the motion. The results are normalized by being divided by the weight of recipient.