Development of new methods to calibrate centre of pressure obtained from force platform

Kinetics and kinematics data are measured using force platforms and three-dimensional cameras in the gait analysis laboratory. Reducing errors related to the force platform when collecting data was necessary. This study describes a new calibration method for centre of pressure of laboratory force platforms using a sandal with extended bar. Firstly, a subject was asked to put his weight vertically on various places of the force platforms using the sandal to create a correction table. Secondly, nine validation trials were conducted to examine the accuracy of the force platforms after correction. The data taken from the centre of pressure and the motion capture were analyzed. Then the erroneous position of the centre of pressure data was translated to the correct position by using weighted average of the vector mostly close to the validation point. The method used in this study allowed to reduce the maximum error from 24.6 mm to 2.7 mm