101 A study on the motion measurement method in sports using inertial and magnetic field sensors

Abstract

This paper proposes the method to estimate the 3D posture of body segment using inertial and magnetic field sensors. The measurement system in this study that consists of 3-axis gyro sensor, 3-axis accelerometer, and 3-axis magnetic field sensor measures 3-axis angular velocity and 3-axis acceleration and 3-axis magnetic field. The sensor fusion compensates drift error of gyro sensor output and the error of rotational components of acceleration (centrifugal and tangential accelerations) of accelerometer output, and it estimates the 3D posture (Roll-Pitch-Yaw angle) of multiple link in global coordinate by applying to Extended Kalman filter. The measurement experiment was conducted to indicate the accuracy of the proposed method using experimental setup installing rotary encoders. The 3D posture estimated by the proposed method corresponded with the 3D posture obtained by rotary encoders. This result indicates that drift error of gyro sensor and the error of rotational components of acceleration are compensated. Therefore, the effectiveness of the proposed method was indicated and the proposed method can be used to the measurement of motion generating rotational components of acceleration of multiple link .