A study on gait analysis by measuring axis rotation based on 3D magnetic and acceleration sensors

Human gait analysis has been an active research topic for many years. Most gait studies are classified into two groups. One is the vision-based approach that generally uses a video camera. The other is the wearable-sensor approach that typically uses acceleration and/or gyro sensors. The vision-based approach is mainly used for post analysis enabling accurate evaluation of 3D gait behavior; however, a fixed viewing angle involving a calibration process may be required. In contrast, the wearable-sensor approach can be used for real-time analysis without limits to the viewing angle. In this paper, we introduce a new wearable-sensor-based gait analysis method using a combination of 3D acceleration and magnetic sensors that make it possible to measure 3D arbitrary-axis rotation. To confirm the accuracy of measurement, we measured the behavior of the thigh angle while applying various forms of walking. The validity of the proposed approach was confirmed by applying a newly built sensor system.