A method to calibrate installation orientation errors of inertial sensors for gait analysis

Gait analysis by using wearable inertial sensors has gained tremendous achievements in recent years. A limitation of using inertial measurement unit (IMU) is that inertial signals heavily rely on the correctness of sensor installation. A slight installation orientation error could lead to inaccurate results for quantitative estimation of gait parameters. In this paper, a calibration method was proposed to deal with installation orientation errors of IMU, where the errors were considered as an IMU frame rotating around the standard coordinate system. The proposed method could generate a three-dimensional rotation matrix to calibrate gait signals. By using the calibrated signals, estimation of gait parameters such as calculation of stride length and detection of gait phase can be more accurate. An experiment was performed on our gait monitoring platform based on IMU, and the experimental results demonstrate the effectiveness of the proposed method.