311 Impact Force Measurement using the Inertial Sensor for Contact Play in Rugby Football

Abstract

Micro sensors have begun to be used in the scientific research of safe improvement and technical analysis of rugby. This paper aims to develop a system to measure the impact forces of contact plays using an acceleration and gyro sensor. The acceleration vector provided from a sensor uses a peculiar local coordinate system. Therefore, the acceleration vector of the local coordinate system is converted to the acceleration vector of the absolute coordinate system by Rotation matrix. The displacement and the velocity are calculated by integrating accelerations of the absolute coordinate system. The impact force is calculated from the relationship between the momentum increment and the impulse. This article reports the practical skill experiment that measured the impact forces of the contact plays. The experimental results clarified the quantitative error and problems in the measurement using the inertial sensors. The measurement success rate was 50% with velocity, 40% with impact force and 20% with the coefficient of restitution, respectively.