A data processing algorithm for digital 3D motion analysis

Motion analysis system has been widely used in tracking and analyzing human body motion for visualizing a new engineering design and ergonomic analysis of an existing design. In this paper, a data processing algorithm was proposed to enhance noise immunity of the motion analysis system so that a smooth trajectory of a captured object could be generated. The algorithm has taken the proportional-integral-derivative (PID) approach. The integral process dealed with removal of unwanted vibration of raw data and determination of the displacement curve of the captured object by using the quadratic spline interpolation method, while the derivative process was used to obtain other motion output such as the velocity of the object. In order to illustrate the applicability of the proposed algorithm, a simple pendulum experiment has been carried out to serve as an illustrative example. After implementing the PID data processing algorithm, the estimated velocity curve of the simple pendulum was found to have high noise immunity as compared with the raw data.