JP4350918B2 - Golf swing simulation method and golf club design system using the simulation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a golf swing simulation method and a golf club design system using the simulation method. More specifically, the behavior of a golf club during a swing is analyzed by a simulation that takes into account the torsion of the golf club, and the time for trial production and trial hitting is reduced. A golf club that is reduced and suitable for each golfer is designed.
[0002]
[Prior art]
For golfers, the type of golf club to be used influences the content of play, and it is necessary to select an appropriate golf club according to the individual's swing, physical strength, and the like. However, it is difficult for golfers to clearly grasp the characteristics of their own golf clubs when swinging, and it is suitable for themselves among the ready-made golf clubs by referring to advice such as sales points. The golf club that seems to be selected.
[0003]
Since golfers have different swing patterns depending on individuals, various proposals have been made to obtain golf clubs corresponding to the swing patterns of all golfers. For example, an anisotropic shaft, which is a shaft having an elastic main axis different from a geometric main axis, has been proposed. The anisotropic shaft is configured as described above, so that the shaft is twisted due to the distortion of the shaft during the swing (bending + twisting), and the direction of the face (the direction of the normal of the face surface) is the target direction at the time of impact. It can be modified and adjusted to suit.
[0004]
[Problems to be solved by the invention]
However, the anisotropic shaft as described above is constructed by laminating fiber reinforced resin layers, and in order to obtain a golf club that fits each golfer's individual swing, the anisotropic shaft is actually composed of various laminated patterns. It is necessary to produce a flexible shaft. For this reason, although a golf club suitable for a golfer can be obtained, there is a problem that much time and cost are required for trial production and trial hitting of a golf club.
[0005]
In addition to anisotropic shafts, the current selection of golf clubs is whether the golfer actually swings and makes a test shot with several prototype golf clubs. Have confirmed. Therefore, when any of the golf clubs is inappropriate, there is a problem that a complicated repeated operation is required in which a shaft having a different configuration (such as a laminated configuration of fiber reinforced resin layers) is made as a trial and similarly subjected to trial hitting.
[0006]
In particular, anisotropic shafts twist the shaft due to the bending of the shaft during the swing, so the behavior of the golf club during the swing is more complex than the normal shaft, and the face orientation suitable for you is In order to select a golf club to be obtained, there is a problem that it takes a lot of time to repeat trial hits.
[0007]
In order to reduce the number of trials and trial hits of the golf club as described above, there has also been proposed to select a golf club suitable for each golfer by simulating the golf swing of each golfer. However, a simulation method that takes into account the bending and twisting of a golf club has not been established, and accurate analysis results regarding the direction of the face surface of the head at the time of impact cannot be obtained. Golf club design is difficult.
[0008]
The present invention has been made in view of the above-described problems, and does not repeat the trial production and trial hitting of a golf club, and considers the influence of bending and twisting of the golf club, and the like such as the face surface of the head at the time of impact. It is an object of the present invention to provide a golf swing simulation method and a golf club design system that enable analysis and obtain an analysis result of a golf club corresponding to each golfer with high accuracy.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a golf club grip measurement point, calculates a three-dimensional coordinate based on an image of a golfer's swing behavior using the golf club, ,
Time history data on the coordinates of the grip of the golf club, time history data on the tilt angle of the grip, and time history data on the rotation angle of the grip around the shaft axis, which is the geometric center axis of the shaft, when the golfer swings. And
The golf club model is given x, y, z translational acceleration of the center of gravity of the grip from the time history of the three-dimensional coordinates of the grip, and x, y of the center of gravity of the grip from the time history data of the tilt angle of the grip. , Rotational angular acceleration (rad / sec) about the z axis, and rotational angular acceleration (rad / sec) about the local coordinate axis from the time history data of the rotational angle of the grip about the shaft axis which is the geometric central axis of the shaft. ) And give a forced angular acceleration in the time history to rotate around the axis,
Analyzing the behavior of the golf club model by simulating by giving three motions: translation of the grip relative to the global coordinates, rotational motion relative to the global coordinates, and rotational motion (torsion) around the geometric center axis of the grip. A golf swing simulation method is provided.
[0010]
Thus, by performing simulation based on the above-mentioned three types of data near the grip during actual swing measured in advance, the golf club torsion (twist), the angle of the wrist gripping the grip, and the overall coordinates of the golf club Thus, it is possible to know the behavior of the golf club model, such as the deflection and twist of the shaft and the orientation of the face surface of the head of the golf club model at the time of impact. Therefore, once the swing data of each golfer is obtained, each golfer can select a golf club corresponding to each swing by using the simulation result without swinging the actual object. Therefore, the number of trial productions, the number of trial hits, and the time required for matching with a golfer can be reduced.
[0011]
In particular, by using the time history data of the rotation angle of the grip around the shaft axis, which is the geometric central axis of the shaft, as the input data for the simulation, it is difficult to torsion of the golf club model (around the shaft axis) Swing simulation in consideration of the rotation). As a result, the orientation of the face surface of the torsional golf club model head at the time of impact between the head and the ball can be accurately predicted. Accordingly, it is possible to make it difficult to close the open face surface, and it is possible to select a golf club corresponding to each golfer.
[0012]
In addition, by using the time history data of the coordinates of the grip and the time history data of the tilt angle of the grip as input data, the position of the wrist at the time of swing, the swing speed, the angle between the wrist and the golf club, etc. The swing behavior can be accurately reproduced by simulation. From the above, it is possible to evaluate shaft deflection and twist.
[0013]
The data obtained by the three-dimensional coordinates, is it line simulation. Acquiring the above data with three-dimensional coordinates improves the accuracy of the three time history data, so that the golf club model twists during swing, the angle of the wrist gripping the grip, the overall coordinates of the golf club model, etc. The behavior can be grasped more accurately. Therefore, it is possible to improve the analysis accuracy of the behavior of the golf club model such as shaft deflection and twist.
[0014]
Specifically , as described above, in performing the swing simulation by obtaining the above time history data with the three-dimensional coordinates, the x, y, z translation of the center of gravity position of the grip is obtained from the time history of the grip three- dimensional coordinates. Acceleration is given, and rotational angle acceleration (rad / sec) around the x, y, and z axes of the center of gravity of the grip is given from the time history data of the tilt angle of the grip, and the shaft axis that is the geometrical central axis of the shaft Rotation angle acceleration (rad / sec) around the local coordinate axis (geometric center axis of cylindrical rigid body that models the grip) is given from the time history data of the rotation angle of the grip at, and forced to rotate around the axis Give a typical angular acceleration with time history. That is, the grip is a rigid element, the coordinate data of the grip is given to the grip composed of the rigid element, a forced acceleration and a rotational acceleration about the shaft axis are given, and the speed and acceleration are input every moment, and the golf club model To realize the simulation.
[0015]
As described above, the above three time history data are given to the grip, and the three motions of the translational motion with respect to the overall coordinates of the grip, the rotational motion with respect to the overall coordinates, and the rotational motion (torsion) around the geometric center axis of the grip. Can be realized and a swing simulation can be performed. That is, the control necessary for expressing the swing by simulation is a translational motion with respect to the global coordinates, a rotational motion with respect to the global coordinates (wrist movement), and a rotational motion (twisting) around the geometric center axis of the grip.
[0016]
The above data can also be obtained by two-dimensional coordinates. In the case of two-dimensional coordinates, it is preferable to take coordinate data on the swing plane. Since the swing trajectory is almost on the same plane, the plane that is almost the same as the swing trajectory is used as a swing plane, and the two-dimensional coordinate data is taken on that plane (swing plane) to improve the accuracy of the analysis results. Can be improved.
[0017]
The shaft of the golf club or / and the golf club model can be an anisotropic shaft. Since an anisotropic shaft twists the shaft due to the bending of the shaft that occurs during the swing, the behavior of the golf club during the swing is particularly complicated. However, since the simulation method takes into account the twisting and bending of the shaft, the behavior of such an anisotropic shaft can be accurately grasped. Therefore, according to this simulation, since the effect of adjusting the orientation of the face surface at the time of impact peculiar to the anisotropic shaft can be further extracted and the direction of the hitting ball can be easily adjusted, the golfer can adjust the golf club suitable for his swing. Can be easily selected.
[0018]
In order to obtain the time history data of the coordinates of the grip of the golf club at the time of swing and the time history data of the tilt angle of the grip, it is preferable to measure the coordinates of two points of the grip at the time of swing. The time history data of the tilt angle of the grip can be obtained from the coordinates of the two points of the grip. Note that the two points on the grip can be any two points, but one point is preferably closer to the grip end, and the distance between the two points is more accurate.
[0019]
In order to obtain the time history data of the rotation angle of the grip around the shaft axis, which is the geometric central axis of the shaft, in order to consider the torsion of the golf club, a plurality of measurement points with a very light weight with respect to the golf club It is preferable to provide the ball so as to follow the movement of the golf club in the vicinity of the grip (near the boundary between the grip and the shaft) without being parallel to the grip. Specifically, two measurement points such as styrene foam spheres are fixed to a golf club (shaft or grip) via a wire or the like so as not to hinder the swing, and the two measurement points are used to move the golf club. Set to follow. Since the distance between the two measurement points is constant, when the shaft twists and the positional relationship between the two changes according to the movement, the twist angle can be obtained from the coordinates of the two. That is, by measuring the time history coordinates of two measurement points and tracking the positional relationship of the measurement points in the space from time to time, the rotation angle of the grip around the shaft axis, which is the geometric center axis of the shaft, is determined. Time history data can be obtained. In order to obtain the rotation angle of the grip around the shaft axis, it is preferable to install two measurement points on a straight line orthogonal to the grip. In order to obtain accurate coordinates by image processing or the like, it is preferable to set the color of the measurement point to a color that can be easily distinguished from the surroundings.
[0020]
In order to obtain grip coordinate data, it is preferable to perform coordinate measurement using an image. It is preferable to calculate the coordinates by calculation based on a plurality of images taken every moment by a plurality of cameras from different directions. It is also possible to measure two-dimensional coordinates by installing one camera in a direction perpendicular to the swing plane.
[0021]
For example, there is a DLT method for measuring three-dimensional coordinates using an image. Thereby, the measurement accuracy of the coordinate position can be improved.
[0022]
Even if the weight or length of the golf club changes, it is assumed that the swing behavior of the individual golf clubs is substantially the same, and swing simulations of various golf clubs can be performed based on the actually measured swing data.
[0023]
In addition, by using the finite element method, it is possible to perform simulation easily and accurately. When analyzing the shaft of the golf club model by the finite element method, since the shaft is hollow, the pipe-shaped surface is made thick. At the time of analysis, it seems that there is no element volume. However, since the thickness is input as described above, the volume of the shaft is taken into consideration in the calculation, and it is necessary to input a value of the material density.
[0024]
In the anisotropic shaft, the laminated structure of the fiber reinforced resin layer is modeled. Specifically, the physical properties (fiber direction) of each layer are input to each element of the shell constituting the shaft model for the laminated portion of the fiber reinforced resin (fiber reinforced prepreg) constituting the golf club model. Thus, since the laminated structure is modeled, the anisotropy of the shaft can be easily adjusted during simulation, and the simulation accuracy of bending and twisting can be improved. Depending on the type of anisotropic shaft, even with the same swing, the shaft bends and twists differently, and the face orientation at the time of impact changes. It becomes easier to select. Note that not only the shaft but also the head can be modeled and simulated, and adjustment can be made by the rigidity of the head, the orientation of the face surface, the loft angle, and the like.
[0025]
In the simulation method of the present invention, swing simulation using all types of golf clubs such as drivers, irons, and putters can be performed. Further, the present invention is not limited to a golf club material such as a fiber reinforced resin or metal shaft material, and can be applied to any golf club.
[0026]
A golf club design system using the golf swing simulation method of the present invention is also provided. According to the golf swing simulation method of the present invention, a golf club suitable for each golfer can be designed in a virtual space by a computer without making a prototype or trial hit. Therefore, it becomes easy to design a golf club such as changing shaft anisotropy using swing data of individual golfers, and it is possible to design and manufacture a golf club optimum for each golfer.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a golf swing simulation method of the present invention will be described with reference to the drawings.
In the simulation method of the present invention, the golf club swing behavior is measured using the actual golf club,
Time history data on the coordinates of the grip of the golf club, time history data on the tilt angle of the grip, and time history data on the rotation angle of the grip around the shaft axis, which is the geometric center axis of the shaft, when the golfer swings. And
Based on the three time history data, a swing motion is given to the golf club model, and the behavior of the golf club model is analyzed by simulation in consideration of the torsion of the golf club model.
[0028]
First, the golfer's swing behavior is measured using the actual golf club. Specifically, as shown in FIG. 1, a golf club 10 that actually performs a swing is made of a fiber reinforced resin having carbon fibers as reinforcing fibers, and includes a normal shaft 11 that is not anisotropic, A driver head 12 and a grip 13 are attached.
[0029]
In the golf club 10, two measurement points S1 and S2 are set on the grip 13 in order to measure the swing behavior. Further, in order to consider the torsion of the golf club 10, two measurement points T <b> 1 and T <b> 2 made of a foamed polystyrene sphere are fixed to the shaft 11 via the wire 15 from the boundary line between the shaft 11 and the grip 13. The measurement points T1 and T2 are red so that they can be easily distinguished from the surroundings, and are very light with respect to the golf club 10. The wire 15 and the shaft 11 are orthogonal to each other, and the measurement points T1 and T2 are set so as not to hinder the swing and follow the movement of the golf club 10.
[0030]
As shown in FIG. 2, the two high-speed cameras 20 (20-1 and 20-2) are photographed from different directions so that the movement of the swing hitting the golfer G and the ball B sufficiently enters the field of view of the camera. It is installed so that it can. The high-speed camera 20 is provided with two units, a first high-speed camera 20-1 at the rear of the bat and a second high-speed camera 20-2 arranged at a position where the batting form can be photographed from the front side in front of the bat. Note that the data obtained by the two high-speed cameras 20 are the same time.
[0031]
When the golfer G swings the golf club 10, the high-speed camera 20 shoots the golf swing from moment to moment until the end of the swing from the address state to the finish as shown in FIG. A swing image is obtained. Based on these images, the three-dimensional coordinates of the measurement points S1 and S2 on the grip 13 of the golf club 10 and the measurement points T1 and T2 are calculated by using the DLT method.
[0032]
As described above, by measuring the swing behavior of the golfer G and obtaining the three-dimensional coordinates, the coordinates of the grip 13 of the golf club 10 when the golfer G swings from the measurement points S1 and S2, as shown in FIG. Time history data and grip inclination angle θ time history data are obtained, and the rotational angle time history data of the grip 13 around the shaft axis which is the geometrical central axis of the shaft 11 is obtained from the measurement points T1 and T2. Yes.
[0033]
That is, time history data of the rotation angle of the grip 13 around the shaft axis i, which is the geometrical central axis of the shaft 11, is obtained from the measurement points T1 and T2 by the method shown in FIGS. Since the two measurement points T1 and T2 are fixed with respect to the golf club 10, the distance between the measurement points T1 and T2 is constant. When the golf club 10 rotates around the shaft axis i during a swing, when the golf club 10 is photographed with a fixed high-speed camera, the distance between the measurement points T1 and T2 is apparent due to the rotation around the shaft axis i. Looks like it has changed. The rotation angle of the grip 13 around the shaft axis i is calculated from the actual distance _R0 between the measurement points T1 and T2 and the apparent distance R between the measurement points T1 and T2. Time history data of the rotation angle of the grip 13 around the shaft axis i is obtained from the change with time of the distance between the apparent measurement points T1 and T2.
[0034]
Next, a golf club model 30 that performs simulation by the finite element method is shown. As shown in FIG. 6, the golf club model 30 has the same shape as the golf club 10, no measurement points are attached, and only the laminated structure of the shaft is changed. Initial conditions are set in the golf club model 30. In the present embodiment, the shaft 31 is divided into 22 sections, 53 sections in the axial direction, and 1166 elements 31a, and the element 31a is a quadrangular shell. Similarly, the head 32 is also divided into elements 32a in a mesh shape. The grip 33 is divided into mesh elements 33a as rigid elements. In addition, the grid | lattice-like line in FIG. 6 is the schematic which shows a mesh.
[0035]
Further, as shown in FIG. 7, the fiber reinforced prepreg 31b is laminated so that the direction of the reinforcing fiber F is unified when the fiber reinforced prepreg is wound, and the shaft 31 of the golf club model 30 is a golf club. 10 is an anisotropic shaft that corrects the swing at the time of actual measurement. The physical property (fiber direction) of each fiber reinforced prepreg layer constituting the shaft is input to each element constituting the shaft 31.
[0036]
As shown in FIG. 8, the grip 33 of the golf club model 30 is a rigid element, and the forced acceleration and the shaft axis are applied to the grip 33 constituted by the rigid element from the coordinate data of the grip 33 calculated by the image measurement of the swing. A rotational acceleration centered on the center is given, and the golf club model 30 is moved by inputting the speed and acceleration every moment to realize the simulation.
[0037]
As described above, the above-mentioned three time history data are given to the grip 33 of the golf club model 30, and the translational motion with respect to the overall coordinates of the grip 33, the rotational motion with respect to the overall coordinates (rotation angle θ), and the geometrical shape of the grip 33. Three motions of rotational movement (twisting) around the central axis are realized, and swing simulation is performed.
[0038]
That is, the swing behavior is simulated every moment when it is assumed that the golfer swings the golf club model 30 formed of an anisotropic shaft. In particular, as shown in FIG. 9, the orientation of the face surface 32a of the head 32 of the golf club model 30 at the time of impact with the ball is analyzed with high accuracy.
[0039]
In this way, the swing of each golfer is measured in a three-dimensional manner taking into account the torsion, so that the golf club is not repeatedly prototyped or trial hitted, and the influence of the deflection or twist of the golf club is taken into consideration. The movement of the wrist at the time and the face direction of the head before impact can be analyzed, and the analysis result of the golf club corresponding to each golfer can be obtained with high accuracy. In particular, since the simulation considering the torsion of the golf club can be performed, it is possible to accurately analyze even a golf club made of an anisotropic shaft that exhibits a complicated behavior of shaft deflection and torsion during a swing.
[0040]
In this embodiment, the golf club shaft to be simulated is an anisotropic shaft made of fiber reinforced resin, but it may be a normal shaft made of fiber reinforced resin instead of anisotropy, or a metal shaft. Good. Further, the head attached to the shaft is not limited to the driver, but may be an iron, a putter or the like. The golf club that initially measures the swing data may also be anisotropic, and various golf clubs can be used as described above.
[0041]
By applying such a golf swing simulation method to the design of a golf club, from the measurement of swing data to the selection of the optimal golf club can be realized in a short time, and the user's request can be met. A golf club design system can be provided.
[0042]
【The invention's effect】
As is clear from the above description, according to the present invention, simulation can be performed in consideration of the influence of the deflection and twist of the shaft of the golf club, in particular, the torsion around the shaft axis. The direction of the surface can be analyzed with high accuracy.
[0043]
Accordingly, it is possible to select a golf club corresponding to each golfer based on the analysis result of the simulation without repeatedly performing trial manufacture and trial hitting of the golf club. Therefore, the golf club can be easily designed without requiring complicated work and time.
[0044]
Furthermore, since it is possible to analyze golf clubs with a complicated swing behavior such as an anisotropic shaft, it is possible to study the adaptability of golf clubs with various patterns to each golfer. A golf club suitable for a golfer can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view of a golf club for measuring swing behavior.
FIG. 2 is a diagram showing a shooting situation of a golf swing.
FIG. 3 is a diagram showing a series of swing behaviors of a golfer.
FIG. 4 is a diagram illustrating a measurement point and a movement of the measurement point when the golf club swings.
FIGS. 5A and 5B are diagrams showing a calculation method of a rotation angle of a grip around a shaft axis in consideration of twisting of a golf club.
FIG. 6 is a schematic view of a golf club model.
FIG. 7 is a view showing a laminated structure of fiber reinforced prepregs of a golf club model.
FIG. 8 is a diagram showing a result of behavior analysis by simulation of a golf club model.
FIG. 9 is a diagram showing a state of a face surface of a head at the time of impact of a golf club model.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Golf club 11 Shaft 12 Head 13 Grip 20 High-speed camera 30 Golf club model S1, S2 Measurement point T1, T2 Measurement point

Claims (4)

A golf club grip measurement point is provided, and a three-dimensional coordinate is calculated based on an image of a golfer's swing behavior using the golf club. From the three-dimensional coordinate ,
Time history data on the coordinates of the grip of the golf club, time history data on the tilt angle of the grip, and time history data on the rotation angle of the grip around the shaft axis, which is the geometric center axis of the shaft, when the golfer swings. And
The golf club model is given x, y, z translational acceleration of the center of gravity of the grip from the time history of the three-dimensional coordinates of the grip, and x, y of the center of gravity of the grip from the time history data of the tilt angle of the grip. , Rotational angular acceleration (rad / sec) about the z axis, and rotational angular acceleration (rad / sec) about the local coordinate axis from the time history data of the rotational angle of the grip about the shaft axis which is the geometric central axis of the shaft. ) And give a forced angular acceleration in the time history to rotate around the axis,
Analyzing the behavior of the golf club model by simulating by giving three motions: translation of the grip relative to the global coordinates, rotational motion relative to the global coordinates, and rotational motion (torsion) around the geometric center axis of the grip. A golf swing simulation method. 2. The golf swing simulation method according to claim 1, wherein the golf club or / and the golf club model shaft is an anisotropic shaft, and the golf club model inputs a laminated portion of fiber reinforced prepreg . Golf swing simulation method according to any one of claims 1 or claim 2 predicts the direction of the face surface of the head at the time of impact between the head and the ball of the upper Kigo Ruff club model. Golf Club Design System Using a golf swing simulation method according to any one of 請 Motomeko 1 to claim 3.

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