Comparison of Carving and Skidding Turns by Joint Torque of Skier and Gliding Velocities in Ski Running on Alpine Ski Slope

Abstract

This paper deals with the motion analysis of ski turns using the joint torque of skier and the gliding velocity. In this study, we used the inertial and magnetic field sensors, 6-axis force sensors and the GPS receiver for the motion measurement of skier. The joint angles and torque of skier and the gliding velocity are estimated from the measurement information by using the Kalman filter, the Extended Kalman filter and the Newton-Euler method. We conducted the measurement experiment of carving and skidding turns by skier gliding on an alpine ski slope, and we estimated the joint torque of skier and the gliding velocity. The analytical results by the joint torque of skier showed the force information about the usage of side curve in carving turns and the usage of side skidding in skidding turns. The analytical results by the gliding velocity showed the smoothness of turns and the effect by side skidding of skis. The analytical results by combining the joint torque and the gliding velocity indicated the relationship between the control force of skier and the change of gliding velocity. We could indicate the factors of mechanism of ski turns and the major features of ski turns. These results can be used to clarify the mechanism of ski turns.