Studies on the motion analysis of skiing turn using the measurement systems of orientation and gliding trajectory

Abstract

This paper proposes the analysis method for skiing turn using the systems which measure the orientation and gliding trajectory of a skier on an outside actual snowfield. The orientation measurement system that consists of 3D gyro sensor, 3-axis acceleration sensor and 3-axis magnetic field sensor provides orientation relative to the global frame and 3-axis acceleration. The trajectory measurement system that consists of GPS receiver provides gliding trajectory of skiing turn. The gliding velocity is estimated using the information from these measurement systems and Kalman filter in this analysis method. The measurement experiment has been performed to confirm the performance of proposed measurement systems. In this experiment, the orientation and trajectory measurement systems have been installed on the right foot boot and head of skier, respectively. The proposed systems have provided the rotation matrix that transforms the global frame, acceleration relative to the global frame and gliding trajectory. The analysis method has provided the gliding velocity relative to the global and local frame using information from the proposed systems. The gliding trajectory has indicated significantly different moving distance between skidding turn and carving turn. The gliding velocity relative to the local frame has indicated the different period and the effect of strike slip between skidding turn and carving turn. The results which are obtained from the proposed systems and analysis method indicated the effectiveness and the validity. The proposed method that can analyze the major features of skiing turn is able to quantitatively evaluate the skill.