A Clip-on Shoe-Mounted Wearable System for Gait Analysis

In this work, we present a low-cost miniature foot-mounted positioning system and its potential for gait analysis. The system includes an inertial measurement unit and three time-of-flight proximity sensors. The addition of proximity sensors can provide an absolute measure for real-time vertical reference for the inertial sensor fusion. An extended Kalman filter is used for sensor fusion which uses the proximity sensor measurements and zero velocity updates to correct for the inertial integration drift. Monitoring of orientation of foot and vertical distance is used to enhance detection of zero velocity periods. The steps are segmented based on the zero velocity periods, and different measures such as foot hight, vertical and horizontal speeds are depicted in graphs.