Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

The authors have aimed at detecting and tracking players using video cameras in field sports. However, there is a problem that the detection accuracy is lowered at the place where players have an occlusion. Deep learning is a solution to this problem, but it requires the manual creation of large amounts of training data which is costly. In this research, the authors propose a method for automatically generating training data to build a detector that can identify players with high accuracy for field sports, and a method for updating this detector to input it to various videos.

DOI： 10.14923/transinfj.2021skp0029

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

In recent years, effective safety management measures based on the Internet of Things (IoT) have been established to prevent industrial accidents in construction sites. In response to these efforts, technologies that use object detection methods to obtain the location information of workers and construction vehicles can contribute toward safety management. However, it is difficult to detect workers and construction vechiles from video images by object detection methods in construction site where dangerous areas are constantly changing due to their coexistence. Therefore, the application of deep learning can be considered, but in order to detect them accurately, it is necessary to update the detection model specialized for construction sites. However, it takes a lot of cost to manually create a training data for constructing model. Therefore, in this research, we propose an automatic generation method of training data for deep learning to realize high-precision for detecting workers and construction vehicles in construction sites. Experiment was performed with application of the proposed system to the video data at construction site, and its usefulness was confirmed.

DOI： 10.2208/jscejcei.78.2_i_179

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Language：Japanese   Publisher：トレーニング科学研究会  

CiNii Books

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Language：Japanese  

CiNii Books

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Language：English   Publisher：SANKEI DIGITAL Inc.  

Research on tracking and performance analysis of athletes using video images has been actively conducted with the aim of improving athletes' competitive performance. However, when filming plays in field sports, it is difficult to capture the entire field with a single camera without filming from a specific point, such as a spectator's seat on the corner side, because the field is long sideways. Even if the entire field is captured, the players at the back of the field appear small, making analysis difficult. Other issues include the fact that since many coaches and analysts film where the play is progressing, it is hard for them to track the ball seamlessly when the position of play changes significantly depending on the position of ball. To solve this problem, we develop in this study a technology to automatically generate panoramic video images that cover the entire field by using two video cameras. Using this technology, we aim to generate panoramic images of the entire field that makes it possible to surely measure and analyze all players and the ball.

DOI： 10.51015/jdl.2022.2.12

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Language：Japanese   Publisher：Japan Society of Civil Engineers  

In Japan, owing to the steadily declining working population, innovative technologies that improve productivity in construction sites using i-Construction are urgently required. This necessitates the tracking of not only construction vehicles but also workers using technologies such as AI and IoT. Against this background, many technologies that were able to track both workers and construction equipment on construction sites had been developed. However, challenging subjects for automating tracking tasks remained as those technologies were applied in sections where extended and heavy occlusion occurs frequently. Therefore, an identification method that matches appearance features of workers and construction vehicles before and after occlusion is proposed in this research, thereby contributing to the development of tracking technologies that enable successive tracking through occlusion sections. Experiments conducted using videos from actual construction sites showed that the method was capable of restoring tracking progress in occlusion sections by identifying each worker and construction vehicles individually before and after each section.

DOI： 10.2208/jscejcei.78.2_i_189

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：[出版社不明]  

近年では，センサ技術やIT技術の発展により計測装置の小型化が進んだため，バッティング直後に，スイングの特徴を把握できるようになった．しかし，アマチュア野球選手の指導現場では，いまだに，科学的なデータに基づいた指導方法は確立されていない．その原因として，これまで我が国の野球において，合理的な指導と非合理的な指導が混在していることに加えて，スイングの計測装置によって算出された数値に対する解釈が現場では難しいことが考えられる．そこで，本研究では，経験豊富な指導者の主観的評価によって分類された打者の打撃タイプ別あるいは競技レベル別におけるスイング特性を明らかにし，測定値によって打者の打撃タイプの判別方法について提案する．
In recent years, we became able to measurement data of the bat swing just after baseball batting, because measurement devices have been downsized by the development of a sensor technology and the IT technology. However, a coaching method based on such scientific data has not yet been established in amateur baseball clubs because of the mixture of rational and practical instruction and the difficulty of the interpretation from calculated numerical values. Therefore, the purpose of this study is to examine the characteristics of a batter's swing using an evaluation from baseball coach with a lot of experience when assessing batting skills. Finally, its practically and effectively is verified through this present finding.

DOI： 10.20729/00209346

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In recent years, as measurement devices have advanced due to sensor and information technology, we have been able to measure bat swing data just after baseball impact. Therefore, the purpose of this study was to examine the characteristics of a batter’s swing using batting skill assessments from baseball coaches with significant experience. Finally, the practicality and effectiveness of baseball coaching methods, particularly for batting, were verified through this study. The subjects were 25 male university baseball players (age: 19.8 ± 1.0 yrs, body height: 174.5 ± 5.4 cm; body weight: 72.8 ± 5.1 kg). The participants were instructed to hit the ball placed on a tee stand. Nine types of tee-batting positions (course / height) were set for each participant depending on the upper and lower limits of the strike zone according to the baseball rules. Our main findings were as follows: 1) The swing characteristics (Depth: swing time and vertical bat angle, Height: head speed, rolling angular velocity, bat radius of rotation, horizontal bat angle, and vertical bat angle, Course: rolling angular velocity) varied with respect to ball positions, 2) Through batting skill assessment by two baseball coaches with significant experience, a good batter’s swing can be characterized as high bat speed, short swing time, and high efficiency of rotational movement around the vertical axis. Additionally, the coaches suggested that for a good batter’s swing, the vertical bat angle should be stable and smaller than 9°. These results provide useful information on assessment of bat swing training methods and exercises to hit the ball to different positions. Furthermore, this study can aid baseball coaches and/or players to objectively analyze a bat swing of a player.

DOI： 10.1299/transjsme.21-00158

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In the field of sports engineering, though policies for developing human resources in sports are promoted nationally, lack of managers and coaches who can give highly-qualified instruction to an individual player is an urgent problem. Therefore, a swing measurement unit is developed for quantitatively analyzing a batter’s swing form in baseball. However, it is difficult for managers and coaches to utilize the sensor data and give players an instruction based on the data. The purpose of the study is to find out new knowledge for giving appropriate advice to individual players by analyzing the swing characteristics with the swing measurement unit. In order to verify whether the swing characteristics of university baseball players can be properly classified, the swing data and batting performance data were classified individually using the k-means method. As a result, when the swing characteristics and batting performance were classified into two cluster by the k-means method, the players could be classified with high accuracy. Furthermore, the principal component analysis was performed to examine the relationship between the measurement results obtained from the swing measurement device and the swing characteristics in conjunction with this classification result. The results of principal component analysis also showed that it was possible to classify high-ranked players and low-ranked players. From these results, it showed elements of the measurement items related to classification. It was found that players with long swing rotational radius, short swing time and high head speed were classified as high-ranked players.

DOI： 10.1299/transjsme.20-00240

DOI： 10.1299/transjsme.21-00158_references_DOI_PcxXFemWVvSjaGQoRCdNEeT0y6

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Language：Japanese   Publisher：[出版社不明]  

スポーツ工学分野では，スポーツ人材の育成のための政策が国家的に推進されているが，各選手に質の高い指導を実施できる監督・コーチなどの指導者の不足が喫緊の課題となっている．一方，MEMS（Micro Electro Mechanical Systems）技術の発展により，慣性計測装置の小型化が進んでいる．そのため，その慣性センサを用いた科学的な分析結果に基づくコーチング方法を確立する必要性が高まっている．特に，日本の代表的なスポーツである野球を対象に，打者のスイングフォームを定量的に分析することを目的とした慣性センサの開発が進められている．このセンサより取得された計測データから打者の特性を分析することで，各選手の能力向上につながるスイングフォームの改善点を提示することが可能となる．しかし，大学などの高等教育機関だけでなく，小中高の教育現場において，その分析方法は確立されていない．具体的には，監督・コーチなどの指導者が，そのセンサデータをどのように利活用すればよいか，いい換えると，それを基にどのような指導を実施すべきかを判断することは難しい．そこで，本研究では，スイング計測装置から得られる1スイングだけの情報を基に，スイングフォームを多角的に分析することで，各選手に的確なアドバイスをするための新たな知見が得られるかを検証する．実験は，各個人のティーバッティングと試合でのスイングの計測値に乖離が少なく再現性が高いと考えられるプロ野球選手のスイングを対象とした．
In the field of sports engineering, though policies for developing human resources in sports are promoted nationally, lack of leaders including managers and coaches who can give highly qualified instruction to individual player is an urgent problem. On the other hand, inertial measurement units are getting miniaturized, due to technological development of MEMS (Micro Electro Mechanical Systems). Accordingly, there is an increase in need for establishing a coaching method based on scientific analysis using the inertial sensor. In particular, a specific type of inertial sensor is being developed, which is aimed for quantitatively analyzing a batter's swing form in baseball, a representative kind of sport in Japan. Analysis of characteristics of the batter based on the measurement data obtained from this sensor will make it possible to indicate points for improvement in the swing form that lead to capacity building of each player. However, no method of such analysis has been established in educational sites of not only higher education systems such as universities but also primary, junior high, and senior high schools. Specifically, it is difficult for the leaders such as managers and coaches to judge how to utilize the sensor data, or in other words, what kind of instruction to give based on the data. The purpose of this study is to find out new knowledge for giving appropriate advice to individual player by analyzing the swing forms from various aspects based on the information of only one swing data obtained from the swing measurement unit. We made the experiments with the swings of professional baseball players are assumed that was reproducible and there are few difference between sensor value in tee batting and in the game.

DOI： 10.20729/00204508

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS LTD  

This study aimed to (a) develop an algorithm that could estimate a baseball bat trajectory from the beginning of the swing to the follow-through phase during a practice swing without a ball and (b) evaluate the accuracy of the proposed method using a three-dimensional motion capture system. The sensor fusion using the adaptive Kalman filter for compensating velocity decreased the error of acceleration integration during the follow-through phase. Further, the three-dimensional bat trajectory in a global coordinate was estimated by combining the sensor fusion and compensation by motion characteristics. The three-dimensional bat trajectory from the swing beginning to the follow-through phase estimated by the proposed method was compared with the three-dimensional bat trajectory obtained by the three-dimensional motion capture system. The proposed method achieved a root mean square of the error of 7.72 km/h for velocity, which was less than the root mean square of the error (8.91 km/h) obtained by simple time integration of forward direction. These results indicate that the error by acceleration integration during the follow-through phase is compensated. The proposed method is, thus, deemed effective and can be used to evaluate baseball swing, including the follow-through phase, with high accuracy.

DOI： 10.1177/1754337119871436

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmemag.119.1172_414

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Language：Japanese   Publisher：Japan Association for Wind Engineering  

Aerostatic bearing load cell which is available to measure 3-components aerodynamic forces and torque is developed. Each table to detect the forces is floating by air pressure and balanced by a pair of coil springs. The model in the wind tunnel is connected with fine piano wires to a light frame on the unit. The wind loads acting on the model shift the each table within short distances. These shift magnitudes are measured with laser displacement devices. Aerodynamic torque is counted by spinning decay ratios of the model. As a result, this load cell has some specific characteristics to measure the forces, such as good linearity, high resolution, less interference and less temperature drift. The validity of this new apparatus is shown by the aerodynamic forces and torque measurements on highly spinning golf ball.

DOI： 10.5359/jwe.41.48

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Other Link： http://id.ndl.go.jp/bib/027332456

Publisher：IEEE  

DOI： 10.1109/bigdata.2015.7364049

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Other Link： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15K12639/

Language：Japanese   Publisher：The Japan Research Association for Textile End-Uses  

DOI： 10.11419/senshoshi.56.9_713

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Publisher：Elsevier BV  

DOI： 10.1016/j.proeng.2014.06.132

DOI： 10.3390/app10175877_references_DOI_PLxD7p5ktZjUKjqJMyfaBUUZzrn

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Publisher：Springer Science and Business Media LLC  

DOI： 10.1038/srep01871

DOI： 10.1038/srep15108_references_DOI_Ms9ykxrPBnAioQqlUxp4diQbALV

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Other Link： http://www.nature.com/articles/srep01871.pdf

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmemag.116.1138_632

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Publishing type：Part of collection (book)  

The relation between the golf club head and golf ball coefficient of restitution (COR), with the frequency as well as face thickness of golf club heads were investigated. Also a sensitivity analysis was conducted to investigate the ratio of effect by the wall thickness of each part of the face, namely the rigidity on head frequency. By this, it was found that the sensitivity of the wall thickness on the heal side was greater than the sensitivity of the wall thickness on the toe side and had a greater effect on frequency of the head. It was found that the reason for this was because with heads having constant thickness, the strain occurring at the heal part is smaller than the strain occurring at the toe part when impact is made at the center of the face. Also, when COR distribution was measured, golf club heads with variable thickness design with the heel part made thinner had a wider range of high COR compared with golf club heads with constant thickness, having the same maximum COR.

Scopus

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Publishing type：Part of collection (book)  

To conduct a 3-dimensional trajectory analysis of a golf ball, a 3-dimension equation of motion of a ball in flight was formulated. The trajectory equation of a ball in flight was obtained under two assumptions of (1) the mechanism of slices or hooks of a ball is caused by an inclining of the ball rotating axis and (2) the direction given to the rotating axis of the ball is constant. On the other hand, a device to rotate an actual golf ball stably at a maximum of 10,000 rev/min was developed. By this, drag, dynamic lift, aerodynamic momentum (aerodynamic forces) applied on the ball under various flight conditions were measured in a wind tunnel air current. Using these aerodynamic force coefficients, mathematical calculation of flight trajectory equation was made by time integral calculus, and 3-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Ejection experiments were made using a robot and flight distance and side deviation distance were obtained. The validity of the theory was verified by comparing the calculation results with the experiment results.

Scopus

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Language：Japanese   Publisher：一般社団法人 日本機械学会  

DOI： 10.1299/jsmemag.115.1128_773

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Language：Japanese   Publisher：日本フットボール学会  

CiNii Books

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：TAYLOR & FRANCIS LTD  

Aerodynamic forces and torque acting on the ball were measured under various flight conditions in a wind tunnel flow. Using the aerodynamic force coefficients, mathematical calculation of flight trajectory equation was made by time integral calculus, and 3-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Furthermore the logarithmic law was applied to trajectory formation of a golf ball in order to include influence of atmospheric boundary layer. The trajectory formation considering atmospheric boundary layer was verified by two experiments. One of the experiments was conducted to measure wind velocity distribution. By this experiment, logarithmic law could be verified. Other experiment was conducted in order to verify 3-dimensional flight trajectory applied logarithmic law. Many golf balls were hit under various initial conditions of golf ball (initial velocity, launch angle, spin rate) by a professional golfer using various golf clubs. Initial conditions just after golf balls launched were measured by launch monitor and wind velocity distribution in the direction that golf ball flied was measured. In addition, golf ball trajectory under atmospheric boundary layer was calculated by using measured initial launch conditions and wind velocity distribution. As a result, the calculated result of drop positions by trajectory analysis agreed with the actual measured data. So far, we know the influence of wind upon trajectory only qualitatively. Flight trajectory considering natural wind was calculated by using 3-dimensional flight trajectory formation applied logarithmic law under various initial conditions in detail. As a result, we could get knowledge about 3-dimensional flight trajectory influenced by natural wind. Such as we found out that there are conditions that distance reduces by tailwind and showed the conditions. In addition, we could get quantitative data: the influence of spin rate and launch angle including wind upon distance. Moreover we analyzed the quantitative influence of spin rate and launch angle including wind upon curving e.g. hooks and slices.

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In sports that are one of the life science fields, the performance of tools such as wear, shoes, clubs and so on advances remarkably, and the record has improved spectacularly. However, it tends to the restriction of “tools that expand distance of a jump” in golf that is one of ball sports toward the target in the distance. The improvement of the sports skill will need not only improvement of tools performance but also improvement of human's sports skill in the future. In the previous paper, we related the golfer's cock-roll motions in the golf driver swing and eight club head and/or ball motions (head velocity, ball velocity, upper angle, side angle, back spin, side spin, carry and traverse) by experiment and multiple regression analysis method. In this paper, the club performance is newly added to the explaining variable. Moreover, by using measured variables and/or factors, the estimated system at head and ball velocity based on the neural network is proposed. When the estimated value by the suggesting method is compared with the measurement value, the maximum error margin and the average error margin are smaller. When the presumption value is compared with the measurement value, the maximum and the average error of the suggesting method are smaller than that of the previous method. Using the sensitivity analysis, we found that the most important factors in improving the head velocity and ball velocity

DOI： 10.1299/kikaic.73.3265

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

For a rubber baseball, which is a baseball made entirely of rubber, the softness of the ball makes it very difficult to increase the coefficient of restitution (COR) of the ball-bat impact by modifying the stiffness of the bat. In order to direct modification of the baseball bat, precise analysis of the impact phenomenon is required. In order to establish a powerfull tool for analyzing the baseball-bat impact, numerical analysis programs based on the three-dimensional finite element method have been developed. After verifying the developed programs by comparing calculated and experimental results, the impact characteristics of an aluminum bat in collision with a rubber baseball were investigated precisely. The results show that the COR decreases with increasing impact velocity, and that the COR is greatly affected by the hoop rigidity of the barrel of the bat, which has a hollow shell structure. Moreover, at high impact velocities, the COR is maximized at an impact location about 600 mm from the end of the bat handle.

DOI： 10.1299/kikaic.73.1307

DOI： 10.1299/transjsme.19-00169_references_DOI_EpsTK1Om52j0hLcFWIz22n7n2eN

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Language：Japanese   Publisher：Japan Ergonomics Society  

In this paper, we investigate the relation between the variables of golfer's cock-roll motion and golf club performance and variables of club head velocity by the experiment and the statistical method. First, to measure cock-roll motion, we used the three dimensional gyro sensor that we developed. To measure head velocity, we used the ball analytical system of Mizuno Ltd.. Next, variables of the cock-roll motion and the club performance related to the head velocity were selected by the stepwize method. By the multiple regression analysis method, the relation between selected variables and head velocity was estimated. As result of test on accuracy of regression equation which is estimated by Adjusted R-square and analysis of variance, the equation of the head velocity showed significance. Finally, we extracted variables affecting the head velocity. This paper related that the improvement of not only the performance of club but also the technique of golfer who is actually using club was an element necessary for improving the head velocity.

DOI： 10.5100/jje.43.19

DOI： 10.5100/jje.51.14_references_DOI_ZGxsZA54uLRDicaeLCTgPAcfMYP

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In this paper, we relate the golfer's cock and roll motions in the golf driver swing and eight club head and/or ball motions (head velocity, ball velocity, upper angle, side angle, back spin, side spin, carry and traverse) by experiment and statistical method. First, to be measured cock and roll motion variables, we used the three dimensional gyro sensor that we developed. Second, by using measured cock and roll motion variables, we classified with three groups by cluster analysis. By the multiple regression analysis method, the relation between selected 3 variables and eight club head and/or ball motions was estimated. As result of giving official approval accuracy of estimated regression equation with Adjusted R-square and analysis of variance, the equation of head velocity, ball velocity and carry had the significance. Finally, we extracted the cock and roll motions that affected head velocity, ball velocity and carry. From the sensitivity analysis, we found that the most important factors in improving the three motions are (1) angular velocity of roll is slower, (2) angle of cock is smaller, (3) when cock angle arised in driver swing, angular velocity of cock is faster.

DOI： 10.1299/kikaic.72.3372

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

This paper describes a novel method to measure the rotation of golf swing form. The sensor employed in the measurement method is a gyro sensor with rotation measuring. Because this sensor is small and light, the suggested method enables us to utilize it easily not only in limited places such as university and company research facilities but also out door. The system developed by using the three dimensional gyro sensors set at the left hand, fore arm, shoulder and waist can catch the three dimensional rotations. The method achieves a difficult measurement of cock and roll motion. This measurement system can analyze the major features of golf swing, which makes it an effective method for suggesting more dieal swing form. The method is developed for golf swing form measurement, but it can applied to baseball, tennis and so on.

DOI： 10.1299/kikaic.72.850

DOI： 10.1299/transjsme.2014dr0385_references_DOI_BJAVpblHNUtaRPPyTnfkVxDCK0E

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Publishing type：Part of collection (book)  

Aerodynamic forces and torque acting on the ball were measured under various flight conditions in a wind tunnel. Using the aerodynamic force coefficients, mathematical calculation of flight trajectory was made by time integral calculus. Three-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Furthermore the logarithmic law was applied to trajectory formation of a golf ball in order to include influence of atmospheric boundary layer. Moreover, an experiment was conducted in order to verify the logarithmic law and the trajectory formulation. Wind velocity distribution in the vertical direction was measured. As a result, the measured result almost matched the logarithmic law. Golf balls were hit under various initial launch conditions by a professional golfer using various golf clubs. Initial launch conditions of the golf balls were measured and wind velocity distribution in the golf ball direction was also measured. The golf ball trajectory under atmospheric boundary layer was calculated by using measured initial launch conditions and wind velocity distribution. The calculated drop positions by trajectory analysis agreed with the actual measured results. © 2006 Springer-Verlag New York.

DOI： 10.1007/978-0-387-46050-5_27

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Language：Japanese   Publisher：日本トレーニング科学会  

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

A device to rotate a real golf ball at a maximum of 10 000 rpm in the wind with a maximum speed of 80 m/s was developed. Aerodynamic forces and torque acting on the ball were measured under various flight conditions in a wind tunnel flow. As a result, it was found that drag, lift, and torque coefficients under the real conditions depended on the spin parameter but were independent of the Reynolds number. Using the measured aerodynamic force coefficients and a ball initial condition measured by ejection experiments, mathematical calculation of trajectory equation was made by time integral calculus. Ejection experiments were conducted by a robot. The correctness of the trajectory analysis and measured aerodynamic force was verified by comparing the calculated results with measured results.

DOI： 10.1299/kikaib.70.2371

DOI： 10.1299/transjsme.16-00482_references_DOI_NrPvXKXxlCO6393ytuai7f0okg7

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Language：Japanese   Publisher：The Japan Society of Fluid Mechanics  

A device to rotate an actual golf ball stably at a maximum of 10, 000 rev/min was developed. By this, drag, dynamic lift, and aerodynamic torque applied on the ball under various flight conditions were measured in a wind tunnel air current. Also equations of golf ball flight trajectory had been restricted to 2-dimension so far, but 3-dimensional flight trajectory was formulated in our study. The trajectory equation of a ball in flight was obtained under a concept that the mechanism of slices or hooks of a ball is caused by an inclining of the balls rotating axis, and the direction in relate to the rotating axis of the ball is constant. Using the aerodynamic force coefficients, mathematical calculation of the flight trajectory equation was made by time integral calculus, and 3-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Ejection experiments were made using a robot. Ball initial conditions, flight distance, and side deviation distance were obtained in the experiments. The validity of the formulation was verified by comparing the calculation results with the experiment results.

DOI： 10.11426/nagare1982.23.203

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Publisher：Japan Association for Wind Engineering  

DOI： 10.5359/jawe.2004.100_37

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：TECHNO-PRESS  

The orbit of a golf ball flight has always on 3-dimensional trajectory distorted from initially shot direction. An aerodynamic cause of this phenomenon had been explained by a side spin concept in a vertical axis of the ball, and believed without aerodynamic formulations during long time. Here, 3-D ball equilibrium equations of aerodynamic and gravity forces in flight are newly constructed under two assumptions. One is for existence of slightly inclined or tilted backspin axis of the ball from the horizontal direction. We call this as "Inclined Rolling Angle". The other is for constant rolling angle during all flight time to the standstill coordinate system. The aerodynamic forces and torque in flight were measured by wind tunnel test. As a result, the 3-D all process of the golf ball flight became possible to calculate using initial conditions of ball speed, direction, rotation speed and rolling angle. 3-D trajectory experiments by robot shooting system showed almost correct results of the formulation.

Web of Science

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Publisher：Fuji Technology Press Ltd.  

<jats:p>The development and simulation of robots that have athletic skill close to human beings is very much useful for testing and developing sport goods. This paper discusses the development and simulation of a tennis robot. The developed tennis robot has two joints controlled by a servolike human muscle, and its characteristics are satisfying and similar to a human. The simulation for the whole system including racket, ball and tennis robot is set up. The simulation results agree well with experimental results.</jats:p>

DOI： 10.20965/jrm.2001.p0074

DOI： 10.20965/jrm.2016.p0005_references_DOI_44xpkD5WhZjOJWTiu1XozOc02Fi

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Language：Japanese   Publisher：Japan Society of Sports Industry  

The effects of the inertia property of a club head to the restitution property of golf balls were investigated. The three-dimensional inertia properties of a golf club head were expressed by using the inertia ellipsoid. The inertia ellipsoid was cut in the plane which was parallel to the club face and passed through the center of gravity. The correlation between the cut ellipsoid and the restitution property was shown. It became possible by using the cut ellipsoid to express the restitution property on the golf club face. The restitution property was predicted by using the collision model of the rigid bodies. Furthermore, it became possible to prescribe the area of the high restitution on the golf club face from the inertia property of golf club head, its mass and the mass of the golf ball. With the technique used in this research, it is possible to predict the direction in which a high restitution area spreads out in the restitution property specially at the design. And a high restitution area can be predicted on the basis of three measurements of the inertia moment. Furthermore, rigid body collision simulation Twas examined. The simulation is consistent with the result of the experiment. By using this simulation it is possible to do more suitable design of the golf club head.

DOI： 10.5997/sposun.11.73

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Other Link： https://jlc.jst.go.jp/DN/JALC/00382735637?from=CiNii

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In this paper, dynamic behavior of golf club shafts before impact is analyzed. Firstly, we have established the measuring system of bending stiffness distribution of the shafts. Then we measure bending strain of the shafts on swinging. We model the shaft as a cantilever beam and we calculate deflection of the shaft before impact with data of bending stiffness distribution and data of bending strain. Additionally, we estimate "Kick Point" of golf shafts. We calculate changing curvature of shafts before impact, so that we make clear which part of shafts are bended and changed curvature exceedingly on swinging. We have proposed the share of this changing ratio in cach a third of overall shaft and we call it "Dynamic Flexible Ratio". The resuits are summarized as follows: (1)It is possible to classify the type of golfers by comparing deflections of the shaft before impact, and to calculate velocity of golf club head and angle at the tip of shaft by deflection. (2)"Dynamic Flexible Ratio" is closely related to angle at the tip of shaft by deflection.

DOI： 10.1299/kikaic.65.572

DOI： 10.1299/kikaia.77.201_references_DOI_T9lRdC8pL2MTUdBWhvS79BvjG1v

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Language：Japanese   Publisher：Japan Society of Sports Industry  

Golfers always want to improve their score. Here we investigated what are the most important factors to increase skill in swinging the driver and finally improving average score. Under the assumption that good golfers hit well with a driver, we tried to find the relation between a golfer's average score and the various factors in driver swing by conducting experiments with golfers who earn varying scores. The swing speed, ball speed and club face angle at impact have been considered important factors. In this study, we add body twist factors. The average score of a golfer is accurately estimated by a linear function of the conventional factors and the body twist factors. From the sensitivity analysis of the linear function, we found that the most important factors in improving score are: (1) faster driver head speed, (2) greater driver angle, (3) lower standard deviation of ball speed, (4) faster body twist angular acceleration, (5) later time of maximum body twist acceleration than impact time.

DOI： 10.5997/sposun.8.49

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Language：Japanese   Publisher：Japan Society of Sports Industry  

In this paper, the difference of paralysis on hitting a baseball ball among various bats is examined by Scheffe's paired comparison that is one of sensory evaluation. To find the cause of the difference of paralysis, the grip acceleration of the bat on hitting a baseball ball is measured, the frequence of the acceleration is analysed by MEM and modal analysis is executed. Further by using sensitivity analysis, FRP bat which the paralysis is not low less than metal bat is produced.

DOI： 10.5997/sposun.3.27

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Language：Japanese  

フィールドスポーツでは，移動軌跡を可視化し，戦術分析のための研究が行われている．その多くの研究では，画像処理ライブラリのOpenCVを用いて選手の位置や移動軌跡を取得する技術が実装されている．しかし，選手同士がオクルージョンする場合，選手の特徴の一部が消失するため，追跡対象を見失う課題がある．そこで，本研究では，サッカーを対象とし，オクルージョンによる選手IDの入れ替わりに対して，各選手ごとの特徴を学習した深層学習モデルにより，識別によるフレーム間での対応付けを行うことで解決する．これにより，オクルージョンに頑強な選手追跡手法を提案し，フィールドスポーツの実現場に適応可能な手法を目指す．

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Language：Japanese  

我が国では，街頭や商業施設に定点カメラが設置されており，それらの動画像から人流を把握する技術の開発が盛んに取り組まれている．特に，人物を同定，追跡する技術は，防犯や迷子，徘徊人の探索の他マーケティング分析にも活用できる．既存研究では，人物の外見的特徴により人物を同定する手法が提案されているが，人物が走行など素早く動作した際に不明瞭な人物画像が抽出されるため，精度が低下する課題がある．そこで，本研究では，動画像から検出した人物画像を深層学習により鮮明化することで，人物が走行している場合でも適用できる人物同定手法を提案する．そして，実証実験を通して，提案手法の有用性を確認した．

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Language：Japanese  

フィールドスポーツでは，選手の競技力向上やチームの戦術分析のために，撮影した試合映像から取得した選手の位置情報や移動軌跡を可視化する研究が行われている．これらの研究では，一般的に背景差分法や深層学習による物体検出手法が用いられるが，前述の手法では日照環境の変動や背景に含まれる物体の影響を受け，正確な選手領域の検出ができない課題がある．そこで，本研究では，GANを利用した画像生成モデルの一種であるpix2pixを用いて，選手と審判以外の背景を除去するシステムを提案する．そして，実証実験では，サッカーの試合映像を対象とし，選手領域の検出精度を評価することで，提案手法の有用性を検証する．

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Language：Japanese   Publisher：土木学会  

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Language：Japanese   Publisher：土木学会  

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Language：Japanese   Publisher：関西大学先端科学技術推進機構  

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Language：Japanese   Publisher：Japan Society for Fuzzy Theory and Intelligent Informatics  

According to the guidelines on instruction by athletic clubs that the Ministry of Education, Culture, Sports, Science, and Technology established in 2013, it is important that coaches not only depend on their own experiences, but also learn from scientific studies by sports specialists. In recent years, measurement devices have been developed that can immediately give feedback on a batter’s swing; the measurement devices were further refined and were reduced in size by the development of sensor technology. The device then became able to assess the characteristics of the batter’s swing from the measurement data. However, a coaching method based on such scientific data has not yet been established in amateur baseball clubs because of the mixture of rational and practical instruction and the difficulty of the interpretation from calculated numerical values. Therefore, the purpose of this study is to examine the characteristics of a batter’s swing using an evaluation from a baseball coach with a great deal of experience when assessing batting skills.

DOI： 10.14864/fss.35.0_41

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The purpose of this study was to test the validity of using a one- and a two-segment models for determining elbow joint valgus stress during baseball pitching. The one-segment model consisted of a single segment representing the ball, hand and forearm together as a rigid segment. The two-segment model consisted of a distal segment representing the ball, hand and forearm together as a rigid segment and a proximal segment representing the upper arm. In addition, a three-segment model, which is the most widely and frequently used model for determining the valgus stress of baseball pitching, was defined to provide a reference value for testing the validity of the fewer segment models. The three-segment model was comprised of a distal segment representing the ball and hand together as a rigid segment, a mid-segment representing the forearm and the proximal segment representing the upper arm. Fourteen university students with the baseball experience were asked to throw a baseball with their maximum effort and a motion capture analysis system (VICON, Oxford Metrics) was used to measure the motions of the segments. The result showed that the maximum values of the valgus stress determined with one- and two-segment models (approx. 64 Nm for fast balls) were significantly greater than the corresponding value determined with three-segment model (47 Nm), but the correlations among the three models were found to be significantly high (r > 0.83, p < 0.01). These findings suggest that the fewer segment models can be used to compare the magnitude of valgus stress among subjects and among pitches for evaluation of risk of elbow injuries.

DOI： 10.1299/jsmeshd.2018.a-33

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Language：Japanese   Publisher：Japan Society for Fuzzy Theory and Intelligent Informatics  

According to the Ministry of Education, Culture, Sports, Science and Technology guidelines in 2013 on instruction in athletic club activities, it is important that coaches use not only their own experience, but also understand and use the results of studies by sports science specialists. In recent years, a device that provides measured results immediately after the batting swing has been developed by downsizing of the device following advances in sensor technology and IT techniques. This device measures the bat swing characteristics from the measurement data. However, coaching methodology based on scientific data is not yet established in amateur baseball clubs, possibly because of a mixture of rational and irrational instruction and difficulty in interpretation of the calculated numerical values. Therefore, the purpose of this study was to investigate the effect of using a data-based evaluation sheet on the understanding and motivation for batting practice in high school baseball players, and to examine the coaching method for baseball hitting using a swing measurement device.

DOI： 10.14864/fss.34.0_49

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The purpose of this study is to examine the accuracy of the system analyzing pitching data using baseball-type sensor (MAQ) and to measure kinematic parameter (ball velocity, spin rate, and spin axis) of baseball pitches by various pitchers. The accuracy of the developed system using a 3D motion analysis system and the high-speed cameras were examined. The spin axis of pitched ball was calculated from data of 12-axis sensor using the sensor fusion by extended Kalman Filter. The ball velocity and spin rate calculated by MAQ and the 3D motion analysis system showed similar values (ball velocity: <i>r</i> = 0.95 spin rate: <i>r</i> = 0.90). In several data, it was indicated that the spin axis calculated by MAQ, the 3D motion analysis system, and the high-speed camera showed similar values. In addition, there was a correlation between ball velocity and spin rate over the velocity range from 6.7 m/s to 41.0 m/s (n=188). From these results, the developed system can be used to evaluate baseball pitching skill with high accuracy.

DOI： 10.1299/jsmeshd.2018.a-18

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Language：Japanese   Publisher：電子情報通信学会  

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

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 (<i>r</i> = 0.99, <i>R</i>² = 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.

DOI： 10.1299/jsmeshd.2017.b-3

DOI： 10.1299/transjsme.18-00440_references_DOI_AUiUl6LeNFNwTRaMlVaHsb7lrfA

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Aerodynamics of spinning golf balls were investigated by Wind Tunnel Test and Computational Fluid Dynamics at the wind speed of 25 and 40 m/s. For CFD analysis, turbulence model (<i>k-ω</i> SST) with transition <i>γ</i>-model was applied. As for both methods, a golf ball with shallower dimples has higher <i>C_L</i> at U=40m/s while drastic reduction in <i>C_L</i> was confirmed at U=25 m/s and <i>Sp</i> =0.1. The increase in <i>C_D</i> as with the decrease in <i>Sp</i> was also confirmed at this <i>C_L</i> reduction phase. It seems that the flow around golf ball changes from turbulent to laminar as with the decrease in <i>Sp</i>. Visualization of CFD results indicates that the separation point of the shallower ball upper side shifts forward for the condition of U=25m/s and <i>Sp</i> =0.1 compared with the other conditions.

DOI： 10.1299/jsmeshd.2017.b-31

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Language：Japanese   Publisher：一般社団法人 日本体育学会  

野球の打者は投手が投じたボールを守備者に阻まれないようにどの方向にも打ち返すことが求められる。そこで本研究では、野球選手を対象に、引っ張り、センター、流しの３方向へ打ち分けた場合のバットの動きの特徴を明らかにすることとした。被検者は、野球選手39名とした。実験は、最大努力によるティー打撃を各方向７回実施した。その際、バットスイング解析システム（MIZUNO Swing Tracer）を用い、８つのパラメータ（スイング時間、スイング速度（最大時、ボールインパクト時）、インパクト加速度、ローリング、スイング回転半径、ヘッド角度、スイング軌道）を計測した。その結果、引っ張り方向はその他の方向と比較して、ローリングが大きく、スイング時間が長く、スイング回転半径が小さかった。流し方向は、その他の方向と比較して、スイング時間が短いものの、スイング速度、ローリング、スイング軌道が小さかった。したがって、野球打者は打撃方向によって、バットの動きを制御し打ち分けていることが示唆された。今回の測定方法は、打ち分けた場合のバットの動きを評価することができ、トレーニングや練習の方法を検討する上での重要な資料になることが示された。

DOI： 10.20693/jspehss.68.221_3

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The purpose of this study was to develop the analysis algorithm that is able to estimate the baseball bat trajectory from swing beginning to follow-through phase in the practice swing motion and to examine the accuracy of the proposed method using the 3D motion capture system. The measurement system in this study, which consists of inertial sensor system, measured 3-axis angular velocity and 3-axis acceleration. To compensate the error of velocity during follow-through phase, the backward direction integration from the instance of swing stop was performed. The sensor fusion using the Adaptive Kalman filter by compensating velocity compensated the error of acceleration integration during follow-through phase, and it estimated the 3D bat trajectory in a global coordinate by combining the sensor fusion and the compensation using motion characteristics. The measurement experiment was conducted to indicate the accuracy of the proposed method using 3D motion capture system. The 3D bat trajectory from swing beginning to follow-through phase estimated by the proposed method corresponded with the 3D bat trajectory obtained by the 3D motion capture system. This result indicates that the error by acceleration integration during follow-through phase is compensated. Therefore, the effectiveness of the proposed method was indicated and the proposed method can be used to evaluate baseball swing include follow-through phase with high accuracy.

DOI： 10.1299/jsmeshd.2016.a-29

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Language：Japanese   Publisher：Japan Ergonomics Society  

DOI： 10.5100/jje.51.s218

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The purpose of this study was to develop the analysis algorithm that is able to estimate the baseball bat trajectory in the practice swing motion and to examine the accuracy of the proposed method using 3D motion capture system. The measurement system in this study, which consists of inertial sensor system, measured 3-axis angular velocity and 3-axis acceleration. The sensor fusion using the extended Kalman filter compensated the drift error of the gyro sensor output and the error of dynamic acceleration of the accelerometer, and it estimated the 3D bat trajectory in a global coordinate by combining the sensor fusion and the compensation using motion characteristics. The measurement experiment was conducted to indicate the accuracy of the proposed method using 3D motion capture system. The 3D bat trajectory estimated by the proposed method corresponded with the 3D bat trajectory obtained by the 3D motion capture system. This result indicates that the drift error of gyro sensor and the error by dynamic acceleration are compensated. Therefore, the effectiveness of the proposed method was indicated and the proposed method can be used to evaluate baseball swing skill with high accuracy.

DOI： 10.1299/jsmeshd.2015._a-22-1_

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Language：Japanese   Publisher：一般社団法人 日本機械学会  

DOI： 10.1299/jsmeshd.2015._-2-1_

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In this study, we developed a system measuring bat behavior during a baseball swing by mounting an inertial sensor unit which incorporated the acceleration sensor and the gyro sensor to bat grip end. We compared the bat behavior that measured by between developed system and three-demensional motion capture system (MAC3D system; Motion Analysis). As a result, accuracy of the bat behavior calculated by developed system was varified. Furthremore, we defined eight parameters to express a characteristic of the bat behavior. In this way, players and coachers can evaluate baseball swing quantitatively. Eight parameters are "swing time", "swing speed (impact)", "swing speed (max)", "impact acceleration", "rolling", "bat radius of rotation", "bat angle" and "swing orbit".

DOI： 10.1299/jsmeshd.2015._a-21-1_

DOI： 10.1299/transjsme.20-00240_references_DOI_L4InxMLMOtP4jcZeQM8eVSgMxSE

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Language：Japanese   Publisher：福岡工業大学総合研究機構エレクトロニクス研究所  

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Aerodynamic characteristics of some golf balls whose dimples have different depths were measured. As a result, it was found that the shallower the dimple was, the larger the lift coefficient was. However, when the depth of the dimples was much shallower, the lift coefficient was extremely-little on the slow velocity, i.e. under 28m/s. We searched for a golf ball with dimple patterns that had a high lift coefficient at all velocities. As a result, it was found that a golf ball with a dimple pattern that has extremely small dimples between large shallow dimples has a high lift coefficient at all velocities, including under 28m/s. In order to investigate the cause of the results, a flow visualization experiment was conducted. Visualization of flow around a golf ball was conducted by smoke wire method. Moreover pictures of flow were taken by high-speed video and we analyzed them by PIV (Particle Image Velocimetry). As a result, there was the difference in the streamline distribution between golf balls.

DOI： 10.1299/jsmeshd.2014._b-29-1_

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

PIV methods coupled with smoke wire techniques have been studied. The wire arrangements of these methods were perpendicular to the wind tunnel flow until now, however in our new proposal, the arrangements are parallel to the main flow direction of wind tunnel. The former wind speed, which was available to the flow observation, had been restricted only 0〜4.0 m/s. But, according to our new method, the maximum wind speed was ranging 40 m/s with 1 second duration time of smoke, which is available to the image captures by high speed camera of 20000 fps. The increase of wake turbulence behind these wires were measured by PIV method itself. We showed some examples of stream line measurements behind spinning golf balls and baseball balls under 40 m/s wind speed.

DOI： 10.1299/jsmeshd.2014._b-26-1_

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The purpose of this study was to investigate how the surface conditions (wet or dry, smooth or rough surface) of the metal baseball bat affect the batted ball characteristics of rubber-ball baseball. A bat swing robot was used for generating bat-ball impact. The experimental results showed that the wet surface of the normal metal baseball bat makes the ball slippery and it would cause worse batting performance. To prevent the slipping phenomenon, an additional bat was also tested. By knurling the surface of the additional bat, it inhibited the larger slip of the ball even under the wet surface condition. Furthermore, a questionnaire revealed that most rubber-ball baseball players wipe up water drops from the bat surface, which corresponded to the experimental results.

DOI： 10.1299/jsmeshd.2014._b-2-1_

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

An air suspended load cell, which is available to measure steady aerodynamic forces on the spinning golf ball in the wind tunnel flow, has been developing during these five years. The characteristic to measure two components of forces as drag and side ones had already been accomplished with sufficient accuracy. However, the performances of the lift force direction had not been achieved by the influences of atmospheric pressure changes. The sufficient accuracy has accomplished, in this study, mainly by two improvements of the light-weight of ball supporting unit and the cancellation mechanism of atmospheric pressure variations. The lift force on highly spinning golf ball in the wind tunnel flow are measured and compared with the results of gauge type load cell.

DOI： 10.1299/jsmefed.2013._g1101-01_

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In Japan, there are two major baseball competitions, which are baseball and rubber-ball baseball. Players are often confused by the difference because many baseball players go through the transition between those competitions. Purposes of this study were to reveal the difference of the characteristics of the balls for baseball and rubber-ball baseball when those balls are hit by a metal baseball bat and to research experienced perception of the baseball players toward the difference. A bat swing robot was used for researching physical characteristics of those batted balls under stable condition with changing the vertical offset between the center of a bat and that of a ball. As a result, a rubber-ball recorded maximum range by smaller offset than a baseball and it also tended to generate larger vertical angle and smaller speed of the batted ball. Furthermore, the result of the robot test corresponded to the experienced perception of baseball players, which was revealed by a questionnaire.

DOI： 10.1299/jsmeshd.2013._230-1_

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmekyushu.2012.85

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

It is said that rubber-ball baseball is lower score game than baseball. The reason is that coefficient restitution of rubber-ball is smaller than that of baseball ball. One more factor is aerodynamic characteristics. Therefore, in this study rubber-ball and baseball ball was rotated highly and measured aerodynamic forces in the similar real flight situation. We analyzed flight trajectory of rubber-ball and baseball ball in cases of pitching and batting by using measured aerodynamic forces. It is found that coefficient of lift and coefficient of drag of rubber-ball are smaller than those of baseball ball. Therefore trajectory of rubber-ball is lower than that of baseball ball. Moreover batting distance in one case that gets home-run distance of rubber-ball is smaller than baseball ball. It is caused by lower coefficient of lift of rubber-ball.

DOI： 10.1299/jsmeshd.2012.79

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The new NPB Ball was adapted to the Japanese NPB from this year. Compared with the old NPB ball and new one, seem height and width became 0.2[mm] lower and 1.0[mm] wider respectively. In this report, aerodynamics characteristics are measured by using wind tunnel tests. Some calculations of flight trajectory for pitcher's throwing ball and batter's hitting one are conducted.

DOI： 10.1299/jsmeshd.2011.532

DOI： 10.1299/transjsme.18-00440_references_DOI_7VbEq1qO1ZI6uJqTtXYAwThA0y

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In this paper, we constructed a motion measurement system using the triaxial gyro and acceleration sensor as a means of measuring the motion. The pitching form and the ball initial rate at the baseball were measured by using this system.Next,the relation between measured motion parameters and ball initial rate was examined. As a result, we found that there are significant differences in the movement of the upper limb between experienced and inexperienced person. The parameters that affect improvement of the ball initial rate were extracted !) in the experienced group and 4 in the inexperienced group.

DOI： 10.1299/jsmeshd.2011.41

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Language：Japanese   Publisher：一般社団法人 日本機械学会  

DOI： 10.1299/jsmeshd.2011.31

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Four components load cell by air suspension method is developed. 20 time's sensitive sensor and mirror for reflection of sensor infrared rays made good improvements for linearity and resolution. Calibration result with this interference toward another direction was obtained. Performance check of this load cell was conducted for aerodynamic characteristics of high speed spinning golf ball in the wind tunnel flow.

DOI： 10.1299/jsmeshd.2011.66

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Japanese and U.S. baseball ball shape and seam height are measured by circularity measurement equipment. It was measured on the circumference side of the ball. Geometrical tolerance of the ball was measured with 4 seam and 2 seam side. U.S. seam height average lower than the Japanese ball about 0.23mm around 2-seam circumference. The distortion of the surface of the ball was calculated as standard deviation. Japanese ball are five balls though U.S. ball is two balls in the case height of 0.15mm or less distortion. In conclusion, the ball of Japanese can be said that 2-seams are higher than Rawlings's balls. The distortion of Japanese ball is less than that of U.S. ball.

DOI： 10.1299/jsmeshd.2010.32

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Language：Japanese   Publisher：Japan Association for Wind Engineering  

The influence of golf head surface on aerodynamic force was studied. Aerodynamic forces of golf heads that had various surface were measured in a wind tunnel flow. As a result, it was found that drag is greatly different when the surface changes. However the effect to increase the velocity of golf head up to impact was not confirmed when the surface changed. Therefore the golf head that have streamline shape was made and it was confirmed whether the drag decrease improved the head speed. The results showed that the effect to increase the head speed by drag decrease was not confirmed. It is concluded that steady experimental results of wind tunnel are not applied to golf swing which is unsteady phenomenon.

DOI： 10.14887/jaweam.2009.0.74.0

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Aerodynamic forces and torque acting on the ball were measured under various flight conditions in a wind tunnel flow. Using the aerodynamic force coefficients, mathematical calculation of flight trajectory equation was made by time integral calculus, and 3-dimensional flight trajectory, changes in velocity as well as rotation velocity were obtained. Furthermore the logarithmic law was applied to trajectory formation of a golf ball in order to include influence of atmospheric boundary layer. The trajectory formation considering atmospheric boundary layer was verified by two experiments. One of the experiments was conducted to measure wind velocity distribution. The other was to compare the actual measured drop position with calculated data. Wind direction and velocity and initial condition of golf ball flight just after impact were measured to calculate. Flight trajectory considering natural wind was calculated by using 3-dimensional flight trajectory formation applied logarithmic law under various initial conditions in detail. As a result, we found out that there are conditions that distance reduces by tailwind and showed the conditions. In addition, we could get quantitative data: the influence of spin rate and launch angle including wind upon distance. Moreover we analyzed the quantitative influence of spin rate and launch angle including wind upon curving e.g. hooks and slices.

DOI： 10.1299/jsmesports.2009.0_152

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Other Link： http://id.ndl.go.jp/bib/10768630

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Precise evaluations of aerodynamic forces on highly spinning golf ball are very difficult because of less method and technique to measure these basic characteristics. We are challenging this problems using newly introducing air suspension balance method. Atmospheric and supplying air pressure change on air force of Z-direction measurement are studied by introducing cancelling technique by using a dummy balance. In this stage, cancelling result of atmospheric and supplying air pressure change is shown. Drag forces on ψ0.3mm piano wire is measured and is well agreement with well known data. The drag force measurement on spinning golf ball is reported as a result of trial experiments.

DOI： 10.1299/jsmesports.2009.0_157

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Other Link： http://id.ndl.go.jp/bib/10768645

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

New wind tunnel balance for steady aerodynamic force measurement of three orthogonal components and one moment around perpendicular axes, which suspended by air bearing has been developed to measure weak air force on highly spinning golf ball. The each table oriented to each direction is balanced with small values of spring constant one. On the top table, one flame is mounted. In the center of this flame, one golf ball is suspended by fine piano wires. As a result, aerodynamic forces acting on the spinning golf ball are well detected on each table's small displacement. These table shifts are well measured using photonic displacement sensor. In this paper, each displacement is under well calibration stage.

DOI： 10.1299/jsmemecjo.2008.2.0_197

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

High quality measurements of aerodynamic forces acting on golf ball under high speed rotation are very important for correct evaluations of golf ball aerodynamics. More than 3% longer distance of 300 yards ball flight may be achieved by improvements of aerodynamic performance of ball dimple patterns. But in this stage, these precise evaluations to measure aerodynamic forces are impossible because of racks of methods and techniques. We are trying this problem by air suspension balance method. Some valuations of atmospheric and supplying air pressure change effects on air force of Z-direction measurement of wind tunnel experiments are studied by introducing cancelling technique by using a dummy balance.

DOI： 10.1299/jsmesports.2008.0_65

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

By past researches in this laboratory, simultaneous measurements of drag, lift, side force and aerodynamic torque on highly spinning golf ball in wind tunnel flow became possible. In this reports, more accurate measurements of these aerodynamic forces are pursued to make well balanced and stable rotation golf ball, on which were set 3-barance weights on the equator line in every 120° of the ball. As a result, stable spinning of the ball and less scattered aerodynamic data are easily obtained, which compared with formerly carefully selected ball and conducted wind tunnel experiments in this laboratory. These results implied that even if delicate difference of the aerodynamic forces by the ones of dimple patterns on the golf balls enables to detect by wind tunnel tests.

DOI： 10.1299/jsmefed.2007._1201-1_

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

It is known that the presence of a soft stiffness between a baseball and a bat such as the radial compliance of the barrel region of the hollow bat increases the COR. In order to make use of this effect in the case of a rubber-ball baseball, it is obliged to attach a soft material over the barrel actively. Using 3-dimensional finite element analysis system for the impact between the rubber ball and the bat developed by authors, for the bat whose barrel is covered with a sheet of the soft material the effects of Young's modulus, thickness, Poisson's ratio and etc. on the COR are investigated. It is found that a thick material which has the low values of Young's modulus and Poisson's ratio is effective to increase the COR.

DOI： 10.1299/jsmesports.2006.0_94

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Other Link： http://id.ndl.go.jp/bib/9597490

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Highly spinning golf ball aerodynamics is studied by wind tunnel experiments. To estimate a precise trajectory of golf ball 3-D flight, in this stage, more accurate and simultaneous measurement to confirm 4-components of aerodynamic forces on spinning golf ball is needed. We had challenged this problem with freely rotation and it's naturally decaying golf ball experiment system in wind tunnel flow.

DOI： 10.1299/jsmefed.2006._409-a_

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Language：Japanese   Publisher：Japan Society of Kansei Engineering  

Recent years, developer of products emphasizes personal sensitivity, because a consumer come to selecthe product which is fit for oneself. In this paper, we studied ease-of-hitting and preference of a golf club by group method of date handling and neural network. At first, we selected a lot of adjectives which are well used in the case that golf players evaluate a golf club from the viewpoint of how easily he is able to hit a golf ball with it. Next we investigated values of many golf clubs from the viewpoint of the adjectives by questionnaire and analyzed the correlation between the ease-of-hitting and the adjectives. As a result, we got some rules to judge the ease-of-hitting and preference with golf clubs.

DOI： 10.5057/jjske2001.5.3_111

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmefed.2005.239

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Language：Japanese   Publisher：Japan Association for Wind Engineering  

A research was conducted to measure the 3-D golf ball flight trajectory under atmospheric
boundary layer. 3-D flight equations were already confirmed by still air flight experiments
in our research. In this time, we performed offshore experiments of golf ball shot and
measured flight distance. Wind velocity profile distributions were measured up to 5.5m high.
To estimate wind velocity at higher position of golf ball flight, a logarithmic low was
applied. As a result, 3-D flight distance became possible to be calculated under atmospheric
boundary layer.

DOI： 10.14887/kazekosymp.18.0.000040.0

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The golf ball in flies is greatly influenced of the natural style.In this research, three kinds of golf balls marketed are used, the aerodynamics characteristic by each dimple form is searched for by wind tunnel experiment.The aerodynamics characteristic of joining the golf ball which carries out high-speed rotation in an air current is measured.And when a wind blows, in order to be able to perform the exact simulation of distance which flew,The influence of a 3-dimensional air boundary layer is put into a 3-dimensional flies orbital equation, and flies orbital analysis is performed.And an actual hit ball experiment is conducted on the seashore, and it verifies by comparing a calculation value with measured value.

DOI： 10.1299/jsmefed.2004.219

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

It is desirable for the design of a baseball bat to analyze exactly the phenomena of the impact between baseball and bat. In order to establish powerful analytical tool for the baseball-bat impact, the numerical analysis programs based on 3-dimensional finite element method are developed. After the calibration of developed programs due to the comparison between calculated and experimental results, the impact characteristics of an aluminum bat for rubber-ball baseball are investigated precisely. It is found that the COR value decreases as the impact velocity increase and it is deeply affected by the hoop rigidity of the cylindrical shell structure in bat.

DOI： 10.1299/jsmesports.2004.0_95

DOI： 10.1299/transjsme.16-00097_references_DOI_RqYrdJpntL8TvUmQx6ookDTPPiZ

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Other Link： http://id.ndl.go.jp/bib/9595709

Language：Japanese  

The research was conducted to measure the aerodynamic characteristics of highly spinning golf ball immersed in uniform flow of a wind tunnel. The balls, which were used in this study, are two kinds of balls, Skyway and Callaway. We compared the data of Skyway ball with the aerodynamic characteristics of Callaway ball. We added the wind velocity profile of atmospheric boundary layer in the equation of 3-D ball trajectory to cosider the influence of the wind that is probable in practical golf course. We used logarithmic law in that case. As a result, 3-D flight distance became possible to calculate from multiple initial conditions.

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

In this paper, we propose the Kansei information processing using GMDH method and neural network. At first, we selected many sensitivity attribute words about golf, and we picked up 4 factors form them using SD method. From these factors we made a new questionnaire obtain them. And we picked up some high correlation attribute words about easy hitting using GMDH. We were learned NN about the relation of these attribute words as input and easy hitting as output. Finally, we analyzed sensitivity analysis and as result we took some high correlation attribute words about easy hitting.

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Language：Japanese   Publisher：一般社団法人電子情報通信学会  

CiNii Books

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Language：Japanese   Publisher：Japan Society of Kansei Engineering  

It is difficult for developer of products to investigate which part and element of a product is closely related to its attraction and ease-of-use. So we propose a method which investigates what has an influence on facility and preference with a product by adopting C4.5, which is a useful algorithm for building decision tree. In this paper, we investigate what viewpoint a golf player values ease-ofhitting with golf clubs from. At first, we selected a lot of adjectives which are well used in the case that golf players evaluate a golf club from the viewpoint of how easily he is able to hit a golf ball with it. Next we investigated values of many golf clubs from the viewpoint of the adjectives by questionnaire and analyzed the correlation between the ease-of-hitting and the adjectives. As a result, we got some rules to judge the ease-of-hitting and preference with golf club.

DOI： 10.5057/jjske2001.2.2_65

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

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Publisher：The Society of Instrument and Control Engineers  

This paper is aimed at describing how to measure the sports form. The measurements can be used for the quantitative sports skill evaluation for example. Here we focus our discussion on the golf driver swing form which is most difficult to measure and is one of the difficult sport forms to skill up.<br>The presented measurement derived by the kinematic human body model analysis and the system developed by using the three dimensional rate gyro sensors set at the several body positins can catch the three dimensional rotation motions and the three dimensional translational motions of various parts of body. The system can measure the golf driver swing forms by various golfers correctly. Form the data caught by the measurement system, some skill criteria linguistically written in the internationally famous golf lesson text books are quantitatively expressed. The quantitative data for the criteria by a novice golf player and a middle class player show the reasonable and appropriate results.

DOI： 10.9746/sicetr1965.38.922

DOI： 10.1299/jamdsm.3.299_references_DOI_QKYSXmbg1wqW8fN0hHHtX3288Kz

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Language：Japanese  

We developed a device that could rotate a real golf ball up to 10000rpm in a wind tunnel. By using this device, we can measure aerodynamics forces with highly rotating golf ball under various spin parameters. Golf ball trajectory could be calculated by using this aerodynamics force. However, some undesirable circulated oscillations to measure the aerodynamic forces had occurred with the condition of highly rotating golf ball. Then some improvements had made to restrain these oscillations. As a result, less oscillation device had achieved in this study. The influence of the ball oscillation against aerodynamics force and trajectory calculation of golf ball was discussed.

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

It was examined about Kansei information processing by using the result of SD method and the design value of the golf club are examined about the system using the neural network by this research. Because it changes by the various factors such as a human taste and habit, physical condition, it isn't easy to search for direct relations with the amount of physics as for the sensitivity evaluation. And, when designer make a new product at present, he decides some design values and make prototype based on this. This research enforced the process easily and efficiently.

DOI： 10.1299/jsmesports.2001.0_89

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Other Link： http://id.ndl.go.jp/bib/9595048

Language：Japanese   Publisher：Japan Society of Sports Industry  

The effects of the inertia property of a club head to the restitution property of golf balls were investigated. The three-dimensional inertia properties of a golf club head were expressed by using the inertia ellipsoid. The inertia ellipsoid was cut in the plane which was parallel to the club face and passed through the center of gravity. The correlation between the cut ellipsoid and the restitution property was shown. It became possible by using the cut ellipsoid to express the restitution property on the golf club face. The restitution property was predicted by using the collision model of the rigid bodies. Furthermore, it became possible to prescribe the area of the high restitution on the golf club face from the inertia property of golf club head, its mass and the mass of the golf ball. With the technique used in this research, it is possible to predict the direction in which a high restitution area spreads out in the restitution property specially at the design. And a high restitution area can be predicted on the basis of three measurements of the inertia moment. Furthermore, rigid body collision simulation Twas examined. The simulation is consistent with the result of the experiment. By using this simulation it is possible to do more suitable design of the golf club head.

DOI： 10.5997/sposun.11.73

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

For the impact of a tennis ball with a tennis racket, the strings have a very important role. Since the restitution of the string depends on its tension, many reserchers are interested in the actual tension of the strings and their effect on the impact. We investigated the mechanism to loosen the strings, the values of the reduced tensions and the effects of string tension on a ball rebound. It is found that the strings are unfastened to minimize the frame displacements after the stringing and the coefficient of restitution increases with the reduction of the string tensions.

DOI： 10.1299/jsmesports.2001.0_64

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Other Link： http://id.ndl.go.jp/bib/9594986

Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

The purpose of this study was to investigate the hand movement during the baseball catching motion. Finger and palm pressure distributions in the baseball gloves were measured during the catching motion by using Glove Scan system. Results showed that grasp motion was initiated with high pressure on the fingertip, then it was completed by the pinching motion with high pressure on the thumb and little and/or ring fingers. Player do not initiate grasp motion when feedback the force on the band, but initiate it with prediction of ball motion into the baseball glove.

DOI： 10.1299/jsmesports.2000.0_17

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Other Link： http://id.ndl.go.jp/bib/9593551

Language：Japanese   Publisher：日本機械学会  

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：日本機械学会  

CiNii Books

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Language：Japanese   Publisher：日本機械学会  

CiNii Books

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Language：Japanese   Publisher：日本機械学会  

CiNii Books

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Language：Japanese  

CiNii Books

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Language：Japanese   Publisher：日本機械学会  

CiNii Books

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Language：Japanese   Publisher：日本機械学会  

CiNii Books

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Language：Japanese   Publisher：日本機械学会  

CiNii Books

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Language：Japanese   Publisher：日本機械学会  

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Event date： 2021

Language：Japanese  

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Event date： 2021

Language：Japanese  

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Event date： 2019.1

Language：Japanese  

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Event date： 2019

Language：Japanese  

According to the guidelines on instruction by athletic clubs that the Ministry of Education, Culture, Sports, Science, and Technology established in 2013, it is important that coaches not only depend on their own experiences, but also learn from scientific studies by sports specialists. In recent years, measurement devices have been developed that can immediately give feedback on a batter’s swing; the measurement devices were further refined and were reduced in size by the development of sensor technology. The device then became able to assess the characteristics of the batter’s swing from the measurement data. However, a coaching method based on such scientific data has not yet been established in amateur baseball clubs because of the mixture of rational and practical instruction and the difficulty of the interpretation from calculated numerical values. Therefore, the purpose of this study is to examine the characteristics of a batter’s swing using an evaluation from a baseball coach with a great deal of experience when assessing batting skills.

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Event date： 2018

Language：Japanese  

The purpose of this study is to examine the accuracy of the system analyzing pitching data using baseball-type sensor (MAQ) and to measure kinematic parameter (ball velocity, spin rate, and spin axis) of baseball pitches by various pitchers. The accuracy of the developed system using a 3D motion analysis system and the high-speed cameras were examined. The spin axis of pitched ball was calculated from data of 12-axis sensor using the sensor fusion by extended Kalman Filter. The ball velocity and spin rate calculated by MAQ and the 3D motion analysis system showed similar values (ball velocity: <i>r</i> = 0.95 spin rate: <i>r</i> = 0.90). In several data, it was indicated that the spin axis calculated by MAQ, the 3D motion analysis system, and the high-speed camera showed similar values. In addition, there was a correlation between ball velocity and spin rate over the velocity range from 6.7 m/s to 41.0 m/s (n=188). From these results, the developed system can be used to evaluate baseball pitching skill with high accuracy.

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Event date： 2018

Language：Japanese  

The purpose of this study was to test the validity of using a one- and a two-segment models for determining elbow joint valgus stress during baseball pitching. The one-segment model consisted of a single segment representing the ball, hand and forearm together as a rigid segment. The two-segment model consisted of a distal segment representing the ball, hand and forearm together as a rigid segment and a proximal segment representing the upper arm. In addition, a three-segment model, which is the most widely and frequently used model for determining the valgus stress of baseball pitching, was defined to provide a reference value for testing the validity of the fewer segment models. The three-segment model was comprised of a distal segment representing the ball and hand together as a rigid segment, a mid-segment representing the forearm and the proximal segment representing the upper arm. Fourteen university students with the baseball experience were asked to throw a baseball with their maximum effort and a motion capture analysis system (VICON, Oxford Metrics) was used to measure the motions of the segments. The result showed that the maximum values of the valgus stress determined with one- and two-segment models (approx. 64 Nm for fast balls) were significantly greater than the corresponding value determined with three-segment model (47 Nm), but the correlations among the three models were found to be significantly high (r > 0.83, p < 0.01). These findings suggest that the fewer segment models can be used to compare the magnitude of valgus stress among subjects and among pitches for evaluation of risk of elbow injuries.

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Event date： 2018

Language：Japanese  

According to the Ministry of Education, Culture, Sports, Science and Technology guidelines in 2013 on instruction in athletic club activities, it is important that coaches use not only their own experience, but also understand and use the results of studies by sports science specialists. In recent years, a device that provides measured results immediately after the batting swing has been developed by downsizing of the device following advances in sensor technology and IT techniques. This device measures the bat swing characteristics from the measurement data. However, coaching methodology based on scientific data is not yet established in amateur baseball clubs, possibly because of a mixture of rational and irrational instruction and difficulty in interpretation of the calculated numerical values. Therefore, the purpose of this study was to investigate the effect of using a data-based evaluation sheet on the understanding and motivation for batting practice in high school baseball players, and to examine the coaching method for baseball hitting using a swing measurement device.

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Event date： 2017.10

Language：Japanese  

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Event date： 2017

Language：Japanese  

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 (<i>r</i> = 0.99, <i>R</i>² = 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.

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Event date： 2017

Language：Japanese  

Aerodynamics of spinning golf balls were investigated by Wind Tunnel Test and Computational Fluid Dynamics at the wind speed of 25 and 40 m/s. For CFD analysis, turbulence model (<i>k-ω</i> SST) with transition <i>γ</i>-model was applied. As for both methods, a golf ball with shallower dimples has higher <i>C_L</i> at U=40m/s while drastic reduction in <i>C_L</i> was confirmed at U=25 m/s and <i>Sp</i> =0.1. The increase in <i>C_D</i> as with the decrease in <i>Sp</i> was also confirmed at this <i>C_L</i> reduction phase. It seems that the flow around golf ball changes from turbulent to laminar as with the decrease in <i>Sp</i>. Visualization of CFD results indicates that the separation point of the shallower ball upper side shifts forward for the condition of U=25m/s and <i>Sp</i> =0.1 compared with the other conditions.

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Event date： 2017

Language：Japanese  

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Event date： 2017

Language：Japanese  

野球の打者は投手が投じたボールを守備者に阻まれないようにどの方向にも打ち返すことが求められる。そこで本研究では、野球選手を対象に、引っ張り、センター、流しの３方向へ打ち分けた場合のバットの動きの特徴を明らかにすることとした。被検者は、野球選手39名とした。実験は、最大努力によるティー打撃を各方向７回実施した。その際、バットスイング解析システム（MIZUNO Swing Tracer）を用い、８つのパラメータ（スイング時間、スイング速度（最大時、ボールインパクト時）、インパクト加速度、ローリング、スイング回転半径、ヘッド角度、スイング軌道）を計測した。その結果、引っ張り方向はその他の方向と比較して、ローリングが大きく、スイング時間が長く、スイング回転半径が小さかった。流し方向は、その他の方向と比較して、スイング時間が短いものの、スイング速度、ローリング、スイング軌道が小さかった。したがって、野球打者は打撃方向によって、バットの動きを制御し打ち分けていることが示唆された。今回の測定方法は、打ち分けた場合のバットの動きを評価することができ、トレーニングや練習の方法を検討する上での重要な資料になることが示された。

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Event date： 2016

Language：Japanese  

The purpose of this study was to develop the analysis algorithm that is able to estimate the baseball bat trajectory from swing beginning to follow-through phase in the practice swing motion and to examine the accuracy of the proposed method using the 3D motion capture system. The measurement system in this study, which consists of inertial sensor system, measured 3-axis angular velocity and 3-axis acceleration. To compensate the error of velocity during follow-through phase, the backward direction integration from the instance of swing stop was performed. The sensor fusion using the Adaptive Kalman filter by compensating velocity compensated the error of acceleration integration during follow-through phase, and it estimated the 3D bat trajectory in a global coordinate by combining the sensor fusion and the compensation using motion characteristics. The measurement experiment was conducted to indicate the accuracy of the proposed method using 3D motion capture system. The 3D bat trajectory from swing beginning to follow-through phase estimated by the proposed method corresponded with the 3D bat trajectory obtained by the 3D motion capture system. This result indicates that the error by acceleration integration during follow-through phase is compensated. Therefore, the effectiveness of the proposed method was indicated and the proposed method can be used to evaluate baseball swing include follow-through phase with high accuracy.

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Event date： 2015

Language：Japanese  

In this study, we developed a system measuring bat behavior during a baseball swing by mounting an inertial sensor unit which incorporated the acceleration sensor and the gyro sensor to bat grip end. We compared the bat behavior that measured by between developed system and three-demensional motion capture system (MAC3D system; Motion Analysis). As a result, accuracy of the bat behavior calculated by developed system was varified. Furthremore, we defined eight parameters to express a characteristic of the bat behavior. In this way, players and coachers can evaluate baseball swing quantitatively. Eight parameters are "swing time", "swing speed (impact)", "swing speed (max)", "impact acceleration", "rolling", "bat radius of rotation", "bat angle" and "swing orbit".

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Event date： 2015

Language：Japanese  

The purpose of this study was to develop the analysis algorithm that is able to estimate the baseball bat trajectory in the practice swing motion and to examine the accuracy of the proposed method using 3D motion capture system. The measurement system in this study, which consists of inertial sensor system, measured 3-axis angular velocity and 3-axis acceleration. The sensor fusion using the extended Kalman filter compensated the drift error of the gyro sensor output and the error of dynamic acceleration of the accelerometer, and it estimated the 3D bat trajectory in a global coordinate by combining the sensor fusion and the compensation using motion characteristics. The measurement experiment was conducted to indicate the accuracy of the proposed method using 3D motion capture system. The 3D bat trajectory estimated by the proposed method corresponded with the 3D bat trajectory obtained by the 3D motion capture system. This result indicates that the drift error of gyro sensor and the error by dynamic acceleration are compensated. Therefore, the effectiveness of the proposed method was indicated and the proposed method can be used to evaluate baseball swing skill with high accuracy.

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Event date： 2001

Language：Japanese  

For the impact of a tennis ball with a tennis racket, the strings have a very important role. Since the restitution of the string depends on its tension, many reserchers are interested in the actual tension of the strings and their effect on the impact. We investigated the mechanism to loosen the strings, the values of the reduced tensions and the effects of string tension on a ball rebound. It is found that the strings are unfastened to minimize the frame displacements after the stringing and the coefficient of restitution increases with the reduction of the string tensions.

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Other Link： http://id.ndl.go.jp/bib/9594986

Event date： 2000.9

Language：Japanese  

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Event date： 2000

Language：Japanese  

The purpose of this study was to investigate the hand movement during the baseball catching motion. Finger and palm pressure distributions in the baseball gloves were measured during the catching motion by using Glove Scan system. Results showed that grasp motion was initiated with high pressure on the fingertip, then it was completed by the pinching motion with high pressure on the thumb and little and/or ring fingers. Player do not initiate grasp motion when feedback the force on the band, but initiate it with prediction of ball motion into the baseball glove.

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Other Link： http://id.ndl.go.jp/bib/9593551

Event date： 1999.10

Language：Japanese  

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Event date： 1999.4

Language：Japanese  

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Event date： 1998.10

Language：Japanese  

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Event date： 1997.7

Language：Japanese  

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Event date： 1997.7

Language：Japanese  

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Event date： 1997.3

Language：Japanese  

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Event date： 1996.10

Language：Japanese  

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Event date： 1996.10

Language：Japanese  

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Event date： 1995.10

Language：Japanese  

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Event date： 1995.10

Language：Japanese  

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Applicant：美津濃株式会社

Application no：特願2017-562378  Date applied：2017.8

Patent/Registration no：特許第6283776号  Date registered：2018.2 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：JP2017028813  Date applied：2017.8

Publication no：WO2018-030424  Date published：2018.2

J-GLOBAL

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Applicant：美津濃株式会社, 国立大学法人秋田大学

Application no：特願2016-217234  Date applied：2016.11

Announcement no：特開2018-075071  Date announced：2018.5

Patent/Registration no：特許第6806327号  Date registered：2020.12 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2016-215483  Date applied：2016.11

Announcement no：特開2018-068899  Date announced：2018.5

Patent/Registration no：特許第6935999号  Date registered：2021.8 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2016-044229  Date applied：2016.3

Announcement no：特開2016-128032  Date announced：2016.7

Patent/Registration no：特許第6017719号  Date registered：2016.10 

J-GLOBAL

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Applicant：国立大学法人 筑波大学, 国立大学法人大阪大学, 美津濃株式会社

Application no：特願2015-207449  Date applied：2015.10

Announcement no：特開2017-077403  Date announced：2017.4

Patent/Registration no：特許第6163635号  Date registered：2017.6 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2015-195815  Date applied：2015.10

Announcement no：特開2017-064246  Date announced：2017.4

Patent/Registration no：特許第6480846号  Date registered：2019.2 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2015-123613  Date applied：2015.6

Announcement no：特開2017-006293  Date announced：2017.1

J-GLOBAL

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Applicant：公立大学法人首都大学東京, 美津濃株式会社

Application no：特願2015-119483  Date applied：2015.6

Announcement no：特開2017-000546  Date announced：2017.1

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2014-240018  Date applied：2014.11

Announcement no：特開2016-102678  Date announced：2016.6

Patent/Registration no：特許第5945314号  Date registered：2016.6 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2014-073452  Date applied：2014.3

Announcement no：特開2015-197293  Date announced：2015.11

Patent/Registration no：特許第5841631号  Date registered：2015.11 

J-GLOBAL

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Applicant：美津濃株式会社, 富士通株式会社

Application no：特願2014-025389  Date applied：2014.2

Announcement no：特開2015-150130  Date announced：2015.8

Patent/Registration no：特許第6027038号  Date registered：2016.10 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2013-229431  Date applied：2013.11

Announcement no：特開2014-204950  Date announced：2014.10

Patent/Registration no：特許第5902140号  Date registered：2016.3 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2012-030386  Date applied：2012.2

Announcement no：特開2013-165808  Date announced：2013.8

Patent/Registration no：特許第5331908号  Date registered：2013.8 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2011-255095  Date applied：2011.11

Announcement no：特開2013-106839  Date announced：2013.6

Patent/Registration no：特許第5420626号  Date registered：2013.11 

J-GLOBAL

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Applicant：美津濃株式会社

Application no：特願2010-190518  Date applied：2010.8

Announcement no：特開2011-087916  Date announced：2011.5

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Publication no：WO2001-083049  Date published：2001.11

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Applicant：美津濃株式会社, 学校法人福岡工業大学

Application no：特願2006-287545  Date applied：2006.10

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Patent/Registration no：特許第4982148号  Date registered：2012.4 

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Applicant：美津濃株式会社, 伊藤忠テクノソリューションズ株式会社

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Applicant：美津濃株式会社

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Applicant：株式会社フォトロン, 美津濃株式会社

Application no：特願2001-340625  Date applied：2001.11

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Patent/Registration no：特許第3778427号  Date registered：2006.3 

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Applicant：美津濃株式会社, 渡邊 嘉二郎

Application no：特願2001-165294  Date applied：2001.5

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Patent/Registration no：特許第3986736号  Date registered：2007.7 

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Application no：特願平11-246452  Date applied：1999.8

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Applicant：美津濃株式会社

Application no：特願平9-364116  Date applied：1997.12

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Patent/Registration no：特許第3280299号  Date registered：2002.2 

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Applicant：美津濃株式会社

Application no：特願平9-227332  Date applied：1997.8

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Application no：特願平9-081845  Date applied：1997.3

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Announcement no：特開平10-248978  Date announced：1998.9

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Applicant：美津濃株式会社

Application no：特願平9-081846  Date applied：1997.3

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Applicant：美津濃株式会社

Application no：特願平7-347424  Date applied：1995.12

Announcement no：特開平9-164225  Date announced：1997.6

Patent/Registration no：特許第2992470号  Date registered：1999.10 

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Applicant：美津濃株式会社

Application no：特願平8-513093  Date applied：1995.10

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Patent/Registration no：特許第3061640号  Date registered：2000.4 

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Applicant：美津濃株式会社

Application no：特願平7-149565  Date applied：1995.5

Announcement no：特開平8-308969  Date announced：1996.11

Patent/Registration no：特許第2909002号  Date registered：1999.4 

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Applicant：美津濃株式会社

Application no：特願平6-186343  Date applied：1994.7

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Patent/Registration no：特許第2822151号  Date registered：1998.9 

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Applicant：美津濃株式会社

Application no：特願平4-186322  Date applied：1992.6

Announcement no：特開平6-182010  Date announced：1994.7

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