JP2011050674A - Method of measuring excitation force - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of measuring exciting force capable of highly accurately finding the excitation force generated in a golf club head. <P>SOLUTION: The method of measuring excitation force includes: a step of applying known first excitation force to a prescribed position on the face surface of the golf club head, measuring a first response signal in a prescribed place of the golf club head at the time, finding a response function from the known first excitation force and the first response signal, and storing the response signal; a step of making a golf ball collide at the prescribed position of the face surface of the same golf club head whose response function is found, and measuring a second response signal in the prescribed place at the time; and a step of measuring second excitation force generated in the golf club head when the golf ball collides by using the second response signal and the response function. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for measuring an excitation force generated on a golf club head when the golf ball is hit by an impact force applied to the golf club head or a golf swing by a golfer or the like, and particularly, the excitation force generated on the golf club head is high. The present invention relates to a method for measuring an excitation force that can be obtained with accuracy.

Currently, a golf club head is modeled as a finite element, and for example, when a golf ball collides with a face, that is, an analysis of the behavior of the golf club head at the time of impact is performed using FEM.
In the analysis of the golf club head, the analysis is performed using the thickness, shape, material, and the like of the face as design parameters. Thereby, for example, the face is optimized for each swing speed.

The golf ball is also modeled by a finite element model and analyzed by FEM when it collides with the face of the golf club head, that is, the deformation of the golf ball at impact, the rebound angle of the golf ball after impact, the rebound speed, etc. .
Golf balls are analyzed using, for example, structures such as a two-layer structure and a three-layer structure, the thickness of each layer, and the material of the golf ball as design parameters. Thereby, for example, the thickness of each layer of the golf ball, the material of the golf ball, and the like are optimized for each swing speed.

As described above, when FEM analysis is performed on a golf club head, for example, it is preferable that an impact force (excitation force) by a golf ball colliding with a face is accurate. For this reason, when FEM analysis is performed, it is necessary to accurately determine the excitation force applied to the golf club head.
Further, even when FEM analysis is performed on a golf ball, the excitation force is not always constant depending on the structure, material, and the like. For this reason, when accurately analyzing the characteristics of a golf ball such as the rebound of the golf ball after the collision of the face, depending on the structure and material of the designed golf ball, the collision with the face surface for each golf ball. It is necessary to accurately determine the impact force (vibration force) generated by.

  As a method of measuring the impact force of the ball against the golf club head, a method of measuring by impacting the load cell at a predetermined ball speed can be considered. However, it is presumed that the golf club head has a lower rigidity than the load cell, and the impact force of the golf club is lower at the same ball speed than the load cell. Thus, the present condition is not established about the method of calculating | requiring correctly the exciting force added to a golf club head. Therefore, it is currently desired to develop a method for accurately obtaining the excitation force applied to the golf club head and the excitation force according to the structure and material of the golf ball.

  An object of the present invention is to provide a method for measuring an excitation force that can solve the problems based on the prior art and obtain an excitation force generated in a golf club head with high accuracy.

  In order to achieve the above object, according to the present invention, a known first excitation force is applied to a predetermined position of a face surface of a golf club head, and a first position at a predetermined position of the golf club head at this time is applied. Measuring the response signal, obtaining a response function from the known first excitation force and the first response signal, storing the response function, and the same golf club head as obtaining the response function Using the step of causing the golf ball to collide with the predetermined position of the face surface and measuring the second response signal at the predetermined location, and using the second response signal and the response function, And a step of measuring a second excitation force generated in the golf club head when the golf ball collides with the golf ball.

  In the present invention, it is preferable that the first response signal and the second response signal are acceleration signals measured using an acceleration sensor.

  In the present invention, for example, when the first response signal is acceleration, the acceleration is A, the response function is H, and the first excitation force is F, the response function H is , H = A / F, the second response signal is acceleration, and when the acceleration is A1, and the second excitation force by the golf ball is F1, the golf ball The second excitation force F1 is obtained by F1 = A1 / H.

  In the present invention, for example, when the first response signal is acceleration, the acceleration is A, the response function is H1, and the first excitation force is F, the response function H1 is , H1 = F / A, the second response signal is acceleration, and when the acceleration is A1, and the second excitation force by the golf ball is F1, the golf ball The second excitation force F1 is obtained by F1 = A1 · H1.

In the present invention, for example, the first response signal and the second response signal are signals (strain signals) representing a strain amount measured using a strain gauge.
In the present invention, for example, the first response signal and the second response signal are signals (sound pressure signals) representing sound pressure levels measured using a sound pressure meter.
In the present invention, it is preferable that the first excitation force is provided by an impulse hammer.

  According to the present invention, in the golf club head, the excitation force generated when the golf ball collides with the face surface can be measured with high accuracy.

It is a schematic diagram which shows the measuring apparatus used for the measuring method of the exciting force of embodiment of this invention. It is a graph which shows the time waveform of the applied excitation force, and the time waveform of the excitation force calculated | required by calculating backward, taking an output value on a vertical axis | shaft and taking time on a horizontal axis. It is a schematic diagram which shows the drop test apparatus used for the measurement of an exciting force. (A) is a typical perspective view which shows the modeled golf club head, (b) is typical sectional drawing of Fig.4 (a).

Hereinafter, a method for measuring an excitation force of the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a schematic diagram showing a measuring device used in the method for measuring the excitation force of the embodiment of the present invention.

A measuring apparatus 10 shown in FIG. 1 measures, for example, an excitation force applied to a golf club head 20 by a golf ball or the like.
A measuring apparatus 10 shown in FIG. 1 includes an impulse hammer 12, an FFT analyzer 14, an acceleration sensor 16, an amplifier 18, and a computer (hereinafter referred to as a PC) 19 that apply a predetermined excitation force to the golf club head 20. Have.
The acceleration sensor 16 is connected to the FFT analyzer 14 via the amplifier 18, and the impulse hammer 12 is connected to the FFT analyzer 14.

  The impulse hammer 12 is a vibration hammer having a built-in force sensor for measuring the natural frequency of the structure and performing modal analysis. When the impulse hammer 12 strikes the face surface 22 of the golf club head 20, for example, an excitation force signal is output from the built-in force sensor to the FFT analyzer 14. By using the impulse hammer 12, a known excitation force (first excitation force) can be applied to the golf club head 20.

The acceleration sensor 16 measures acceleration generated in the golf club head 20 when an excitation force is applied to the face surface 22 of the golf club head 20.
The acceleration sensor 16 is attached below the hosel portion 24 of the golf club head 20, for example. The position where the acceleration sensor 16 is attached is referred to as an attachment position D.
For the acceleration sensor 16, for example, a lightweight acceleration pickup is used. This lightweight acceleration pickup outputs an acceleration signal in the form of electric charges. The acceleration pickup is preferably an ultralight one. For example, a material having a mass of 0.6 g may be used. This is because a large mass increases the influence on the vibration of the face surface 22.

  The amplifier 18 is connected to the acceleration sensor 16. The amplifier 18 receives the acceleration signal obtained by the acceleration sensor 16 in the form of electric charges, for example. The amplifier 18 converts the acceleration signal input in the form of the electric charge into a voltage, amplifies it, and outputs it to the FFT analyzer 14 as an acceleration signal.

  The FFT analyzer 14 takes the acceleration signal from the acceleration sensor 16 output in the form of voltage from the amplifier 18 and the excitation force signal output from the impact hammer 12 in time series, and further obtains a frequency response function as described later. Is.

  In the FFT analyzer 14, for example, the acceleration signal from the acceleration sensor 16 and the excitation force signal from the impact hammer 12 are struck, and then, for example, 4 at a sampling period of about 1 millisecond (4 seconds / 4096 intervals). Capture seconds (sampling time). The FFT analyzer 14 acquires time series data (time waveform) of acceleration by the acceleration sensor 16 and time series data (time waveform) of excitation force by the impact hammer 12.

The FFT analyzer 14 performs fast Fourier transform (hereinafter referred to as FFT) on time series data (time waveform) of acceleration by the acceleration sensor 16 and time series data (time waveform) of excitation force by the impact hammer 12. And a function of performing inverse fast Fourier transform (hereinafter referred to as inverse FFT).
Further, the FFT analyzer 14 has a function of obtaining a frequency response function based on time series data (time waveform) of acceleration by the acceleration sensor 16 and time series data (time waveform) of excitation force by the impact hammer 12. In addition, the FFT analyzer 14 has a function included in a general FFT analyzer.

The time series data (time waveform) of the acceleration by the acceleration sensor 16 and the time series data (time waveform) of the excitation force by the impact hammer 12 acquired by the FFT analyzer 14 are output to the PC 19.
Further, the result of FFT performed by the FFT analyzer 14, the result of inverse FFT, and the obtained frequency response function are also output to the PC 19.

  The sampling period for the acceleration signal and the excitation force signal by the FFT analyzer 14 is not limited to about 1 millisecond, and can be changed as appropriate according to the required vibration measurement accuracy. Furthermore, the acquisition time (sampling time) for the acceleration signal and the excitation force signal by the FFT analyzer 14 is not limited to 4 seconds, but depends on the characteristics of the golf club head 20 and the required measurement accuracy. It can be changed as appropriate.

  The PC 19 is a processing device and has a configuration similar to that of a general personal computer, and includes a CPU (not shown) and a memory (not shown), and is used for input of a computer such as a keyboard and a mouse. An input unit (not shown), and a monitor 19a such as an LCD for displaying input information from the input unit and information processed by the CPU.

  The PC 19 receives time series data (time waveform) of the acceleration signal from the acceleration sensor 16 from the FFT analyzer 14 and time series data (time waveform) of the excitation force signal of the impulse hammer 12, for example, a memory, a hard disk ( (Not shown) and the like, and has a function of displaying on the monitor 19a in the form of graphs, numerical values, and the like.

  The PC 19 can directly capture the acceleration signal from the acceleration sensor 16 from the amplifier 18 without using the FFT analyzer 14, and can directly capture the excitation force signal of the impact hammer 12. In this case, an AD conversion board that AD converts the acceleration signal from the acceleration sensor 16 and the excitation force signal of the impact hammer 12 is incorporated in the PC 19 and connected to the amplifier 18 so that the acceleration signal and the excitation force signal are directly taken into the PC 19. It is good.

Next, a method for measuring the excitation force of the golf club head 20 of the present embodiment will be described.
The acceleration sensor 16 is attached to the attachment position D of the golf club head 20.
First, the impact hammer 12 strikes the center point P of the face surface 22 of the golf club head 20. At the time of this impact, an excitation force signal is output from the impact hammer 12 to the FFT analyzer 14. The acceleration (first response signal) generated in the golf club head 20 by the hit is measured by the acceleration sensor 16, and the acceleration signal of the acceleration is output to the FFT analyzer 14 via the amplifier 18.

  In the FFT analyzer 14, for example, the acceleration signal from the acceleration sensor 16 and the excitation force signal from the impact hammer 12 are captured for 4 seconds (sampling time) at a sampling period (4 seconds / 4096 intervals) of about 1 millisecond, and golf club The time series data of the acceleration of the head and the time series data of the excitation force by the impact hammer 12 are acquired.

Next, a frequency response function at the center point P is calculated by the FFT analyzer 14 based on the time series data of acceleration and the time series data of the excitation force by the impact hammer 12.
The time series data of the acceleration of these golf club heads, the time series data of the excitation force by the impact hammer 12 and the frequency response function are output to the PC 19 and stored in the memory, hard disk, etc. of the PC 19.

The frequency response function is represented by a ratio of an input Fourier spectrum and an output Fourier spectrum. The input Fourier spectrum is the Fourier spectrum of the excitation force signal of the impact hammer. The output Fourier spectrum is the Fourier spectrum of the acceleration signal of the golf club head.
In the present embodiment, when the frequency response function is H, the frequency response function H is expressed by the following formula 1.

  H = A (f) / F (f) (1)

In Equation 1, F (f) is the complex Fourier spectrum of the excitation force signal of the impact hammer, and A (f) is the complex Fourier spectrum of the acceleration of the golf club head.
Further, for example, the complex Fourier spectrum of the excitation force signal of the excitation force (second excitation force) generated when the golf ball 26 collides with the center point P of the face surface 22 is F1 (f). For example, the complex Fourier spectrum of the acceleration signal of the acceleration (second response signal) generated in the golf club head 20 when the golf ball 26 collides with the center point P of the face surface 22 is A1 (f). At this time, the complex Fourier spectrum F1 (f) of the excitation force signal can be obtained by the following mathematical formula 2.

  F1 (f) = A1 (f) / H (2)

  In the present embodiment, when the frequency response function H is obtained, first, FFT (Fast Fourier Transform) is performed on the time series data of the acceleration of the golf club head and the time series data of the excitation force by the impact hammer 12 by the FFT analyzer 14. Made. Thereby, the complex Fourier spectrum about the acceleration of the golf club head, that is, A (f) is obtained. Furthermore, a complex Fourier spectrum for the excitation force by the impact hammer 12, that is, F (f) is obtained.

Next, the FFT analyzer 14 calculates a frequency response function H using the complex Fourier spectrum A (f) of acceleration and the complex Fourier spectrum F (f) of the excitation force. Thereby, the frequency response function H is obtained, and the frequency response function H is output to the PC 19 and stored.
Next, the golf ball 26 is caused to collide at a predetermined speed against the center point P hit with the impact hammer 12 with respect to the same golf club head 20 whose frequency response function H has been measured. At this time, the acceleration (second response signal) generated in the golf club head 20 by the acceleration sensor 16 is measured and output to the FFT analyzer 14 via the amplifier 18. In the FFT analyzer 14, time series data of the acceleration of the golf club head 20 is acquired.

Next, the time series data of the acceleration of the golf club head 20 is fast Fourier transformed by the FFT analyzer 14 to obtain the Fourier transform data of the acceleration of the golf club head 20. Thereby, the complex Fourier spectrum A1 (f) of the acceleration generated in the golf club head 20 when the golf ball 26 is caused to collide is obtained.
Next, the frequency response function H stored in the PC 19 and the complex Fourier spectrum A1 (f) of acceleration are output to the FFT analyzer 14, and the FFT analyzer 14 collides with the golf ball 26 using Equation 2 above. Then, a complex Fourier spectrum F1 (f) of the excitation force generated in the golf club head 20 is obtained.

Next, the FFT analyzer 14 performs inverse FFT (Inverse Fast Fourier Transform) on the complex Fourier spectrum F1 (f) of the obtained excitation force to obtain inverse Fourier transform data. Thereby, time series data of the exciting force at the time of collision of the golf ball 26 is obtained.
The FFT analyzer 14 extracts the maximum value of the excitation force in the time series data of the excitation force obtained by the inverse Fourier transform. The maximum value of the excitation force is output from the FFT analyzer 14 to the PC 19 as the excitation force F1 when the golf ball 26 collides with the face surface, and stored in the PC 19. In this manner, the excitation force generated in the golf club head 20 when the golf ball 26 collides can be obtained.

  Note that the processing itself of the fast Fourier transform and the inverse fast Fourier transform is a known method, and a function built in a commercially available FFT analyzer can be used. For this reason, the detailed description is abbreviate | omitted.

In this embodiment, the complex Fourier spectrum F (f) of the excitation force is obtained from the excitation force by the impact hammer 12 based on the obtained acceleration signal and the frequency response function using Equation 1. . The complex Fourier spectrum F (f) was subjected to inverse FFT transform to obtain time series data of the excitation force signal.
As a result, as shown in the graph 30 of FIG. 2, a curve 32 indicating time series data of the excitation signal of the impact hammer 12 obtained by calculation, and a curve 34 indicating time series data of the excitation signal of the impact hammer 12 are obtained. Then, the peak values almost coincided. As described above, when the impulse response is obtained by using the impulse hammer 12 so that the excitation force can be known, the acceleration at the time of applying the excitation force such as when the golf ball 26 is collided is obtained. The excitation force can be obtained from the series data.

Next, the excitation force obtained by the excitation force measuring method of the present invention will be verified.
FIG. 3 is a schematic diagram showing a drop test apparatus used for measuring the excitation force.
A drop test apparatus (hereinafter simply referred to as a test apparatus) 40 shown in FIG. 3 includes a load cell 42, a cylinder 44, an amplifier 18a, an FFT analyzer 14, a PC 19, and a monitor 19a.
The load cell 42 measures the excitation force by the golf ball 26 and is placed on the horizontal plane B. The load cell 42 is connected to the amplifier 18a. The amplifier 18a amplifies the output signal generated in the load cell 42 by a predetermined factor according to the excitation force. This amplified output signal is output to the FFT analyzer 14.

  The FFT analyzer 14, the PC 19 and the monitor 19a have the same configuration as the FFT analyzer 14, the PC 19 and the monitor 19a of the measuring apparatus 10 shown in FIG.

The cylinder 44 has an inner diameter through which the golf ball 26 can pass. The cylinder 44 is provided with its opening 44 a facing the load cell 42, and the axis of the cylinder 44 is provided perpendicular to the horizontal plane B.
The golf ball 26 is dropped from the opening 44 b above the cylinder 44, passes through the inside of the cylinder 44, and collides with the load cell 42. The excitation force generated in the load cell 42 by the fall of the golf ball 26 is measured.

Further, in this test apparatus 40, a modeled golf club head 46 shown in FIGS. 4A and 4B was used in place of the load cell. The excitation force applied to the modeled golf club head 46 is measured.
The modeled golf club head 46 shown in FIGS. 4A and 4B has a portion 50 corresponding to the face and a portion 52 corresponding to the sole. In the portion 52 corresponding to the sole, a thick portion 52a is formed on the opposite side of the portion 50 corresponding to the face.
Further, the modeled golf club head 46 is provided with substantially triangular ribs 54 that reach the thick portion 52a of the portion 52 corresponding to the sole from the back surface 50b on both sides of the portion 50 corresponding to the face.

By using the modeled golf club head 46, the acceleration sensor 16a can be attached to the back surface 50b of the portion 50 corresponding to the face. Therefore, when the golf ball 26 collides with the center point P on the surface 50a of the portion 50 corresponding to the face, the excitation force at the center point P can be measured. Accordingly, it is possible to apply an excitation force to the modeled golf club head 46 and measure the excitation force under the same conditions as when the golf ball 26 collided with the load cell 42.
The surface 50a of the portion 50 corresponding to the face corresponds to the face surface.

  The acceleration sensor 16a is the same as the acceleration sensor 16 used in the measurement apparatus 10 shown in FIG. For this reason, the detailed description is abbreviate | omitted. The acceleration sensor 16a is connected to the amplifier 18a, and an acceleration signal is input to the FFT analyzer 14.

In the test apparatus 40 shown in FIG. 3, a drop test was performed on the load cell 42 using three types of golf balls 1 to 3. The excitation force at this time was measured.
Further, in the test apparatus 40 shown in FIG. 3, a modeled golf club head 46 is arranged instead of the load cell 42. At this time, the height of the surface 50a of the portion corresponding to the face of the modeled golf club head 46 is set to the same height as the portion of the load cell 42 where the golf ball collides. Similar to the load cell 42, a drop test was performed using three types of golf balls 1 to 3. The excitation force at this time was measured.
The test conditions in the drop test are the same for the load cell and the modeled golf club head, and the contact time between the golf ball and the vibrating portion at the time of the collision of the golf ball is similar.

  In addition, since the measuring method of an exciting force is a well-known measuring method using a load cell, an acceleration sensor, and an FFT analyzer, the detailed description is abbreviate | omitted. The measurement results of the measured excitation force are shown in Table 1 below.

  In Table 1 below, normalization is based on the excitation force of the modeled golf club head 46 obtained with the ball 1. In the load cell column, the numerical values shown in parentheses are normalized based on the excitation force of the load cell obtained with the ball 1 in the drop test using the load cell.

  As shown in Table 1 above, the difference in excitation force depending on the type of ball is the same between the load cell and the modeled golf club head. Also, the load cell and the modeled golf club head have different excitation forces even when the same golf ball is used. This is affected by the difference in the rigidity of the colliding portion between the thin hollow structure such as a golf club head and the load cell placed directly on the horizontal plane B. As described above, the test conditions are the same for both the load cell and the modeled golf club head. From these, it can be said that the value of the excitation force obtained for the modeled golf club head is a value with high accuracy.

As described above, according to the measurement method of the present embodiment, if the frequency response function is obtained in advance for the golf club head 20, the excitation force when the golf ball collides can be obtained with high accuracy. . Thereby, for example, when FEM analysis is performed on a golf club head, the excitation force that actually acts can be used, so that the analysis accuracy can be increased.
In addition, since the excitation force can be accurately determined, it is possible to measure the difference in the excitation force depending on the speed of the golf ball serving as the excitation source for applying the excitation force or the type of the golf ball. Can be evaluated.

Further, in the present embodiment, the frequency response function H is defined as Equation 1 above, but is not limited to this. For example, a frequency response function H1 represented by the following formula 3 may be used. This frequency response function H1 is the reciprocal of the frequency response function H.
In this case, the complex Fourier spectrum F1 (f) of the excitation force signal generated in the golf club head 20 when the golf ball 26 is collided can be obtained by the following mathematical formula 4. Even when this frequency response function H1 is used, if the frequency response function H1 is obtained in advance for the golf club head 20, the excitation force when the golf ball 26 is caused to collide can be obtained accurately as described above. it can.
For example, when FEM analysis is performed on a golf club head, since the excitation force that actually acts can be used, the analysis accuracy can be increased. In addition, since the excitation force can be obtained accurately, the difference in the excitation force due to the difference in the excitation force depending on the speed of the golf ball that gives the excitation force, the type of golf ball, etc. is also measured. Furthermore, it can be evaluated.

  H1 = F (f) / A (f) (3)

  F1 (f) = H1 × A (f) (4)

  Further, in the method for measuring the excitation force of the present embodiment, when evaluating the difference in excitation force due to the golf ball, the golf club head is not used, but it is made to collide with a simple plate material, and the frequency response function at that time is It can also be used. Further, the golf club head is not limited to an actual golf club head, and may be modeled.

  In the modeled golf club head 46, the material, width W, height H, and thickness t of the portion 50 corresponding to the face, for example, the face of the golf club head to be designed or the golf club head to be analyzed are analyzed. Same as face. Thereby, the exciting force generated by the collision of the golf ball can be accurately measured. As a result, the accuracy of FEM analysis can be improved.

  In the measuring apparatus 10 shown in FIG. 1, the acceleration sensor 16a is attached to the back surface 50b of the portion 50 corresponding to the face using the modeled golf club head 46, and the excitation force at the center point P is measured. Can do.

In the measurement method of the present embodiment, the impact position of the impulse hammer 12 for which the frequency response function is determined, the collision position of the golf ball 26, and the mounting position D of the acceleration sensor 16 for which the frequency response function is determined are the same even when the golf ball 26 collides. Must be in the same position.
This is because the golf club head 20 may have different vibration characteristics depending on the location of the face surface 22, and furthermore, the acceleration caused by hitting may vary depending on the position at which the acceleration is measured.

  In the present embodiment, the acceleration is measured when hit, but the acceleration is not limited as long as it can be detected as a response signal. For example, instead of acceleration, a signal (strain signal) representing a strain amount measured using a strain gauge is a signal (sound pressure signal) representing a sound pressure level measured using a sound pressure gauge. May be. In addition, when using a strain gauge, it is set as the attachment position where the force by impact does not act directly on the strain gauge.

  Furthermore, in the present embodiment, the object to be measured is not limited to the golf club head, and if it is a hollow structure, for example, the exciting force is applied to a metal bat, table tennis racket, tennis racket, etc. Can be requested. Further, the golf club head is not limited to a hollow golf club head.

  The present invention is basically as described above. As mentioned above, although the measuring method of the exciting force of this invention was demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, you may make a various improvement or change. Of course.

DESCRIPTION OF SYMBOLS 10 Measuring apparatus 12 Impulse hammer 14 FFT analyzer 16, 16a Acceleration sensor 18, 18a Amplifier 19 Computer (PC)
DESCRIPTION OF SYMBOLS 20 Golf club head 22 Face surface 24 Hosel part 26 Golf ball 40 Drop test apparatus (test apparatus)
42 Load cell 44 Tube 46 Modeled golf club head

Claims (7)

A known first excitation force is applied to a predetermined position of the face surface of the golf club head, and a first response signal at a predetermined position of the golf club head at this time is measured, and the known first Obtaining a response function from the excitation force and the first response signal, and storing the response function;
A step of causing a golf ball to collide with the predetermined position of the face surface of the same golf club head from which the response function is obtained, and measuring a second response signal at the predetermined position at this time;
Using the second response signal and the response function to measure a second excitation force generated in the golf club head when the golf ball collides. Force measurement method.   The method according to claim 1, wherein the first response signal and the second response signal are acceleration signals measured using an acceleration sensor. The first response signal is acceleration. When the acceleration is A, the response function is H, and the first excitation force is F, the response function H is expressed by H = A / F. Is,
The second response signal is acceleration, and when the acceleration is A1, and the second excitation force by the golf ball is F1, the second excitation force F1 by the golf ball is F1 = A1. The method of measuring an excitation force according to claim 2, which is obtained by / H. The first response signal is acceleration, and when the acceleration is A, the response function is H1, and the first excitation force is F, the response function H1 is expressed by H1 = F / A. Is,
The second response signal is acceleration, and when the acceleration is A1, and the second excitation force by the golf ball is F1, the second excitation force F1 by the golf ball is F1 = A1. The method for measuring an excitation force according to claim 2 obtained by H1.   The method according to claim 1, wherein the first response signal and the second response signal are signals representing a strain amount measured using a strain gauge.   The method according to claim 1, wherein the first response signal and the second response signal are signals representing sound pressure levels measured using a sound pressure gauge.   The method of measuring an excitation force according to any one of claims 1 to 6, wherein the first excitation force is given by an impulse hammer.

Images