Wireless MEMS Sensors System Applied in Baseball Pitcher''s Pitching Movement Analysis

• Main Authors: Ming-Yang Ching, 金明央
• Other Authors: Hung-Chih Wu
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/65852769637264851225

碩士 === 樹德科技大學 === 資訊工程系碩士班 === 99 === This study applies wireless MEMS sensors system developed by using wireless sensor components such as tri-axis accelerometer and tri-axis gyroscope to analyze the pitching movement of baseball pitchers. The purposes are first to analyze how the velocity of ball correlates the acceleration of gravity (g, with 1g=9.81m/s2), angular velocity, and movement stability of pitcher’s limbs. Second, it aims to explore the difference in time series between two groups (fast and slow) of pitchers when kinetic chain of pitching occurs. Finally, it analyzes the difference between two groups of pitchers in terms of the acceleration of gravity (g) against the angular velocity of pitcher’s limbs. Ten pitchers from the adult division A baseball team of Kao Yuan University participate this experiment as subjects; they are categorized into fast and slow groups based on their pitching velocity. The velocity of ball is measured by wireless MEMS sensors system; MS Excel and SPSS are used to conduct statistical analysis of gathered data through Pearson product-moment correlation coefficient and independent-sample t-test. The results are as follows: 1. In right waist, right shoulder and right wrist of the upper body, and both left and right ankles of the lower body, the correlation between g value of pitcher’s limbs and the velocity of ball is found significant. 2. In right waist of the upper body and both left and right ankles and knees of the lower body, the correlation between the velocity of ball and the angular velocity of pitcher’s limbs is found significant. 3. Only left knee shows a significant correlation between the pitcher’s movement stability of limbs and the velocity of ball. 4. This study has found that on certain limbs, there is a difference in time series between two groups of pitchers when kinetic chain of pitching occurs. In addition, the time series of the maximum g value during the kinetic chain of pitching starts from the lead leg and ends at the pivot leg. As for joints in the waist, shoulder, elbow and wrist of the upper body, the pitching movement is finished during the shift of center of gravity between two legs. 5. In right waist, right wrist of the upper body and in both left and right ankles and knees of the lower body, difference in g value of pitchers’ limbs between two groups is found significant. 6. In both left and right ankles and knees of the lower body, the difference in angular velocity of pitcher’s limbs between two groups is found significant.