Pitching Machine Research Articles

The effect of spin on the flight of a baseball

Measurements are presented of the Magnus force on a spinning baseball. The experiment utilizes a pitching machine to project the baseball horizontally, a high-speed motion analysis system to determine the initial velocity and angular velocity and to track the trajectory over 5m of flight, and a ruler to measure the total distance traversed. Speeds in the range v=50–110mph and spin rates ω (topspin or backspin) in the range 1500–4500rpm were utilized, corresponding to Reynolds numbers of Re=(1.1–2.4)×105 and spin factors S≡Rω∕v in the range 0.090–0.595. Least-squares fits were used to extract the initial parameters of the trajectory and to determine the lift coefficients. Comparison is made with previous measurements and parametrizations, and implications for the effect of spin on the flight of a baseball are discussed. The lift coefficient CL is found not to depend strongly on v at fixed values of S.

A Study on Throw Simulation for Baseball Pitching Machine with Rollers and Its Optimization

Pitching machine is widely used in venues ranging from professional baseball stadiums to batting centers. However, the throw performance of the pitching machines that have been developed so far for use during batting practice is not very high. Pitches such as the fastball, curveball and screwball are easily achieved by the pitching machine with three rollers which were developed by the authors. In this study, the moving behavior and contact stress state of the ball pitched with the three rollers type pitching machine is analyzed using dynamic finite element analysis software (ANSYS/LS-DYNA). The effect of the seam of a baseball to the throw accuracy is analyzed numerically. In the analysis, the finite element models of a detailed baseball with a seam and a pitching machine with three rollers are used. Additionally, convex and concave rollers are made and those are analyzed. From the analytical results, it is understood that the convex roller is higher than other rollers in throw accuracy. The convex roller geometry is optimized, and the optimum conditions (shapes and material properties) of the convex roller are decided. Moreover, the validity of the condition is confirmed by the throw experiment.

Study on Throw Accuracy for Baseball Pitching Machine with Roller (Study of Seam of Ball and Roller)

The most common commercial pitching machines for baseball are the “roller” type and the “arm” type. Pitches such as the fastball, curveball and screwball are easily achieved by the pitching machine with three rollers which were developed by the authors. In this study, the moving behavior and contact stress state of the ball pitched with the three rollers type pitching machine is analyzed using dynamic finite element analysis software (ANSYS/LS-DYNA). The effect of a seam of a baseball to the throw accuracy is analyzed numerically. In the analysis, the finite element models of a detailed baseball with a seam and a pitching machine with three rollers are used. Additionally, the initial velocity and the spin rate of the pitched ball are filmed using a high-speed videograph, and those pictures are compared with the finite element analysis. From the analytical results, it is understood that the coefficient of friction between the baseball and the rollers is not affected. Additionally, it is obvious that the ball's velocity and spin rate are relatively unaffected by the seam orientation, while the throw's horizontal and vertical angles are notably affected by the relative angular velocity of the rollers and the orientation of the seam.

Research on the Development of Baseball Pitching Machine Controlling Pitch Type using Neural Network

The most common commercial pitching machines for baseball are the arm type and the two type. These machines tend to have certain limitations. In particular, it is very difficult to simultaneously change both ball speed and direction. In addition, some types of pitches, such as the curveball or screwball, are not easily achieved. In this study, we will explain the hardware and software design of a new intelligent pitching machine which can pitch repeatedly with selectable speed, direction and ball rotation. The machine has three rollers and the motion of each is independently controlled by a hierarchical neural network. If the ball speed, direction and rotation are given as input data to this network, signals for controlling the three rollers are produced as output data. The results of a throw experiment with the machine that we developed are shown, which has the ability to pitch assorted breaking balls with a wide range of speeds, from 19.4 to 44.4 m/s. The machine has a speed error of less than about 3%, and a distance error of about 0.15m (twice the length of a ball's diameter).

P-24 Study of humerus injury under impact loading for baseball

In the United States and Japan, baseball is a very popular sport played by a great many people. However the ball used is hard and moves fast. A professional baseball pitcher in good form can throw a ball at up to 41.7m/s (150km/hr). If a ball at this speed hits the batter, serious injury is quite likely. In this paper we will describe our investigations of the impact of a baseball with living tissues by numerical methods and experiments. The experiments were done to characterize the material and structure of the baseball. Baseballs were fired at a load cell plate using a specialized pitching machine previously described in publications. The pitching machine had three rollers which were controlled by a neural network to produce a desired combination of linear and angular ball velocity vectors. The dynamic properties of the ball were determined by comparing the experimentally measured force history to a FE model. A different FE model representing a human humerus and surrounding tissue was then used in simulated impact experiments. The properties of the human tissues were not measured here were taken from published results. The dynamic finite element analysis was done by ANSYS/LS-DYNA. The results include an estimate of the peak stress in the bone and confirm what we know from experience - that a fast ball can cause a bone to break. Some methods to practicably reduce the severity of injuries in the game of baseball are also discussed.

On Study of Impact Force and Humerus Injury for a Baseball

In the United States and Japan, baseball is a very popular sport played by many people. However, the ball used is hard and moves fast. A professional baseball pitcher in good form can throw a ball at up to 41.7 m/s (150km/hr). If a ball at this speed hits the batter, serious injury is quite likely. In this paper we will describe our investigations on the impact of a baseball with living tissues by finite element analysis. Baseballs were projected at a load cell plate using a specialized pitching machine. The dynamic properties of the baseball were determined by comparing the wall-ball collision experimentally measuring the time history of the force and the displacement using dynamic finite element analysis software (ANSYS/LS-DYNA). The finite element model representing a human humerus and its surrounding tissue was simulated for balls pitched at variable speeds and pitch types (knuckle and fast ball). In so doing, the stress distribution and stress wave in the bone and soft tissue were obtained. From the results, the peak stress of the bone nearly yielded to the stress caused by a high fast ball. If the collision position or direction is moved from the center of the upper arm, it is assumed that the stress exuded on the humerus will be reduced. Some methods to reduce the severity of injury which can be applied in actual baseball games are also discussed.

Baseball

In this study, we aimed to determine the direction of the spin axis and the spin rate of pitched baseballs and to estimate the associated aerodynamic forces. In addition, the effects of the spin axis direction and spin rate on the trajectory of a pitched baseball were evaluated. The trajectories of baseballs pitched by both a pitcher and a pitching machine were recorded using four synchronized video cameras (60 Hz) and were analyzed using direct linear transform (DLT) procedures. A polynomial function using the least squares method was used to derive the time‐displacement relationship of the ball coordinates during flight for each pitch. The baseball was filmed immediately after ball release using a high‐speed video camera (250 Hz), and the direction of the spin axis and the spin rate (ω) were calculated based on the positional changes of the marks on the ball. The lift coefficient was correlated closely with ωsina (r = 0.860), where a is the angle between the spin axis and the pitching direction. The term ωsinα represents the vertical component of the velocity vector. The lift force, which is a result of the Magnus effect occurring because of the rotation of the ball, acts perpendicularly to the axis of rotation. The Magnus effect was found to be greatest when the angular and translational velocity vectors were perpendicular to each other, and the break of the pitched baseball became smaller as the angle between these vectors approached 0°. Balls delivered from a pitching machine broke more than actual pitcher's balls. It is necessary to consider the differences when we use pitching machines in batting practice.

3829 ピッチングマシンの投球シミュレーションとその精度評価(J14 ヒューマンダイナミクス,J14 ヒューマンダイナミクス)

A pitching machine of roller type for baseball is easily achieved a variable balls. An official hard-baseball, having a seam, is observed to affect variations in the ball's spin and the projected angle. In this study, a moving behavior and a contact stress state of the pitched ball with the roller type pitching machine is analyzed using a commercial dynamic finite element code (ANSYS/LS-DYNA). The linear velocity and the spin revolution of the pitched ball are monitored using a high-speed video camera, and those pictures compared with the finite element analysis. It is considered that the seam of the ball negatively influences the throw accuracy of the pitching machine.

1164 FEMによる野球ボールの投球シミュレーション解析(S10 インパクトバイオメカニクス)

The most common commercial pitching machines for baseball are the "roller" type and also the "arm" type. The pitching, such as the fast, curve and sinking ball, is easily achieved by the roller type. In this study, a moving behavior and a contact stress state of the pitched ball with the roller type pitching machine is analyzed using the dynamic FEM analysis software (ANSYS/LS-DYNA). In addition, the initial velocity and the spin of the pitched ball are filmed using a high-speed videography, and those pictures compared with the FEM analysis. Furthermore, a model of the ball with a seam is analyzed, and those influence is considered.

野球ボールの衝撃力測定とシミュレーション解析(野球(1))

In the baseball as popular sports, there are many impact damage accidents by the ball. However, until now there are very few examples which the impact loads and its influence at the time of a ball collision are analyzed. This research clarifies the influence of a ball crash against a living body. In order to create the FEM analysis model of a ball, the material testing of a ball is performed and the material constants are presumed. An impact experiment of the ball with target using the pitching machine and the impact simulation using the dynamic FEM are performed. From the results, the impact force, the contact time and the deformation behavior of ball are obtained.

엘리트 야구 선수의 타격 특성 연구

The purpose of this study was to investigate the batting characteristics in elite baseball players. Seven skilled collegiate players hit the ball which was thrown by a pitching machine linearly and strongly to the center of the field. Time, velocity, angle and pound reaction force variables were measured by using high-speed video cameras and pound reaction force analyzer. The results were as follows: 1. The elite players finished their stride performance in a short time and they stayed longer in a swing phase. The increases in the range of trunk rotation were associated with the delay of the swing phase. 2. The 'take-back' phenomenon in the trunk was showed after the stride phase. 3. The down swing demonstrated powerful line drives. 4. Equivalent body weights were placed on both feet during the ready phase. 95% of the body weights were moved to the rear foot during the stride phase, whereas the body weights were driven to the front foot during the swing phase. 95% of the body weights were placed on the front foot at impact.

Development Research of Intelligent Pitching Machine Using Neural Network.

It is very difficult to change simultaneously the pitching speeds and the courses in the usual used pitching machines of the arm type and the two rollers type. In this study, the pitching machine which is able to pitch exactly a base ball into various courses and speeds using the three rollers controlled independently the number of rotations, is developed. In the pitching machine, the layered neural network system in which the learning data use each course and speeds as input data and the number of rotation of each roller as output data is used. This machine is one of the intelligent sport machine. In this paper, the system and its mechanism are described.

1009 ニューラルネットワークを用いた新型知的ピッチングマシンの開発とその性能評価

1009 ニューラルネットワークを用いた新型知的ピッチングマシンの開発とその性能評価

Design of a full degree-of-freedom baseball pitching machine

The design, implementation, and experimental validation of a new kind of baseball pitching machine is discussed. This machine provides accurate and repeatable release conditions with full degree-of-freedom control over the linear and angular velocity vectors, by using separate mechanisms to impart each. It provides a research tool for use in understanding the aerodynamic effects of linear and angular velocity variations on the ball’s trajectory as well as providing a potentially more robust training tool to athletes who play the game. Design of the pneumatic propulsion system is based on a thermodynamic model of the gas flow in the plenum and barrel. Release speeds up to 45 m · s–1 and spin rates up to 40 revolutions per second are achieved. The direction of the angular velocity vector is fully adjustable relative to the translational velocity vector, which itself may be controlled in pitch and yaw. High-speed video experiments used to validate the machine’s performance show that speed and spin rate are controllable to ≈2% and 5%, respectively.

The “holey” ball launcher

A homemade pitching machine that launches plastic holey balls can be constructed from drill motors and sanding disks. This could possibly find uses in the physics classroom.

Saving Young Arms and Batters' Heads

To the Editor.— The local baseball commission of the boys' 8- to 10-year-old league recently implemented several changes in an attempt to increase safety and improve instruction. One of these was the use of a pitching machine for the first three innings of every six-inning game. A neutral adult served as a "pitching coach" for both teams and adjusted the height of the pitched ball to correspond to the strike zone of the batter. Pitch speed was regulated to approximate the speed of a ball thrown by an average to good pitcher in that age group.

Sex, Eye Preference and Speed of Stimulus Effect on Anticipation of Coincidence

The intent of this study was examination of effects of sex of subject, eye preference, and speed of stimulus on anticipation of coincidence. 15 men and 15 women made estimates of a baseball's arrival at the front edge of a home plate. Subjects had blocks of trials while standing with either the preferred or nonpreferred eye closest to the oncoming ball, followed by trials of the other eye closest. Balls were projected 45 ft. by a pitching machine at speeds of 35, 40, 45, and 50 mph. Analysis indicated no significant difference for sex or eye preference but a significant speed effect, with the slowest speed being less accurate.

Coincidence-Anticipation Performance of Adolescent Baseball Players and Nonplayers

10 adolescent baseball players and 10 nonplayers made estimates of baseballs' arrival at the front edge of a home plate. Balls were projected 45 ft. by a pitching machine at speeds of 35, 40, 45, and 50 mph. Subjects made estimates with the dominant and nondominant eye closest to the oncoming ball. Analysis indicated that players were no more accurate than nonplayers but did respond significantly earlier and with consistency. Eye dominance had no effect on performance.

Effects of bat composition, grip firmness, and impact location on postimpact ball velocity

The purpose of this investigation was to examine the effects of bat composition (aluminum and wooden), impact location [center of percussion (COP), center of gravity (COG), and end of the bat (E)], and grip firmness [tight (T) and no tension (NT)] on postimpact ball velocity. With the bats placed alternately in NT and T conditions, baseballs were delivered at a speed of 27.1 m.s-1 from a pitching machine positioned 1.5 m from the bat. High-speed photography (400 fps) was performed using a Locam camera positioned 7.54 m from and perpendicular to the principal plane of ball movement. A three-way ANCOVA revealed significant (P less than 0.01) differences in postimpact ball velocity between the three impact locations, with the COP yielding the greatest values, followed by the COG and E. Moreover, there was a significant (P less than 0.01) grip vs bat interaction. A simple-effects procedure revealed the following results: 1) the T grip produced greater (P less than 0.01) velocities than the NT grip across the aluminum (Al) bat; 2) there was no difference (P greater than 0.01) between the T and NT grips across the wooden (W) bat; 3) the W bat produced greater (P less than 0.01) velocities than the Al bat across the NT grip; and 4) there was no difference (P greater than 0.01) between the Al and W bats across the T grip.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental determination of the coefficient of drag of a tennis ball

The standard projectile motion experiment in the general physics laboratory using a spring gun and metal projectile is not sufficiently sensitive to detect air resistance effects of the ball’s motion. These effects may be successfully studied by using a commercial tennis ball pitching machine which is capable of launching balls with speeds up to about 27 m/ s with negligible spin. Assuming an air resistance force of the form f=−bv2, the coefficient b may be shown by direct solution of the equations of motion to be dependent on the muzzle velocity, the horizontal speed of the ball as it strikes the ground, and its landing angle. By measuring these quantities, b may be obtained and its value then used to compute the drag coefficient CD for the ball. Experimental values of CD compare well with similar values obtained for smooth spheres by other methods.