Aerodynamic Study of Ski Jumping Flight Based on Inertia Sensors (171)

Abstract

Aerodynamic forces, drag and lift were estimated by the body attached inertia sensors and high speed videography in ski jumping. Last ISEA conference, the authors presented our new method for the aerodynamic study on ski jumping. In this paper, we propose more robust and reliable measurement system by using wireless technology. Wireless 6DOF inertia sensor platform, which has a built-in tri-axial accelerometer and three single axial gyroscopes, was attached on the jumper’s low back. The authors adopted IEEE802.15.4 for the start trigger and real time monitoring during long training session. Sensor also has a flush memory inside for one hour data storage at 250Hz. The primary target of the present study is to extract the aerodynamic force data during real jumping flight. Angular velocity on the sagittal plane was directly measured from the gyroscope. Then we could obtain the jumper’s body pitch angle by its time integration. The accelerations with respect to the body local coordinate system which was determined by the body pitch angle, indicated the drag and lift forces. The assessment of the aerodynamic forces of ski jumping was examined by both of the sensor data and the kinematical data in this study.