Development and Evaluation of Wearable Posture Tracker

Abstract

Wearable sensor systems have recently been used to track human movement in and outside the office. In this thesis, we present a wearable posture tracker for monitoring poor sitting postures in daily life. The wearable posture tracker could be used to correct, measure poor postures. This device contains a posture correction band, which attached an accelerometer and a stretch sensor. The accelerometer was placed at the xiphoid process position to measure poor sitting postures, namely: hunched, leaning back, left, and right unbalanced postures based on the sensor’s tilting angle. Besides, a stretch sensor, which was attached to the subject’s upper back, was used to measure rounded shoulder posture. The capacitance of the stretch sensor changes linearly according to changes in the shoulder movement. The major contribution of this thesis is the development of the wearable posture tracker with two kinds of sensors and the quantitative verification of each sensor to monitor five poor sitting postures. To verify measurement of this device, a motion analysis system was used as the reference to compare the tilted angles which were obtained by the accelerometer with the tilted angles acquired from the camera system, the change in the rounded angles of the shoulders with the change in the stretch sensor’s capacitance. The results showed that there is high correlation between the changes, of which the correlation coefficients are larger than 0.9. Based on the positive correlation between data from sensors and the camera system, the system could be used as a wearable posture tracker for monitoring five kinds of poor sitting postures, specifically: rounded shoulder, hunched, leaning back, left and right unbalanced postures.