抄録
In order to evaluate ski jumber's performance, many researchers have been examined their flight paths by using the video based analysis. However, since the range of motion of the ski jump is enormously huge, the resolution and the accuracy of video-based analysis have been poor. For that, the authors developed a measurement system for the ski jumber's trajectory using an infrared red 2D laser scanner. This real time monitoring system continuously gives us the information of the flight path of the ski jumber during their training. Laser scanner could obtain the reflection from the target maximally 45 to 50m in our experimental setting. With the RFID tracking system, the automated obtained jumber's trajectories were easy to calculate its velocity and the acceleration. A particle system model was adopted to estimate the flight dynamics of the ski jump. The authors examined the drag and filt force of each ski jump trial from the obtained jumber's trajectory. Instead of the drag and lift force, the drag and lift area show us the change of the jumber's aerodynamics at the early flight phase. Around 1.5 to 1.6 second after the take-off, the lift area decreased steeply. It was assumed that the target location of the reflection might be continuously changed and switched from front to back, or from the body to head, etc., However, the advantage of this lase scanner system must be the instantaneous visual skill feedback to the jumpers and coaches with the flight trajectory right after their trial.
