硬式野球ボール型センサを用いた投球解析システムの開発

抄録

The purpose of this study is to develop the system analyzing pitching data using baseball-type sensor and to examine the accuracy of the developed system using Doppler radar system (Trackman baseball, Trackman) and high speed camera. The developed baseball-type sensor in this study, which consists of accelerometer, gyroscope, and Magneto-Impedance sensor, measured 6-axis acceleration, 3-axis angular velocity, and 3-axis magnetic field. The weight, moment of inertia, and material in baseball-type sensor was the same as a normal baseball. The spin rate of pitched ball was calculated from data of 3-axis magnetic field using zero crossing method. The spin axis of pitched ball was calculated from data of 12-axis sensor using the sensor fusion by extended Kalman Filter. The measurement experiment was conducted to indicate the accuracy of the developed system. The spin rate calculated by the proposed method was corresponded with the spin rate obtained by the Doppler radar system (r = 0.99, R² = 0.99). Also, it was indicated that the developed system could measure the low spin rate (less than 8.3 rps) which Doppler radar system could not measure. In overthrow data, it was indicated that the spin axis calculated by the proposed method was corresponded with the spin axis obtained by the Doppler radar system. From these result, the developed system can be used to evaluate baseball pitching skill with high accuracy.