JP2013215349A - Swing simulation system, simulation apparatus, and simulation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swing simulation system capable of simulating a swing without amplifying errors contained in measured values on three-dimensional coordinates of a grip during the swing.SOLUTION: A simulation system includes at least two imaging devices for imaging identification features capable of identifying a closed virtual plane that follows a grip of a golf club during a swing; and a simulation apparatus for simulating the swing, based on position information on the virtual plane.

Description

  The present invention relates to a swing simulation system, a simulation apparatus, and a simulation method.

  During the swing by the golfer, the golf club shaft is deformed such as bending or twisting, and the head rotates. The head speed also changes. The behavior of the golf club including the deformation of the shaft, the rotation of the head, the change of the head speed, and the like is mainly caused by an input from an object that is a swing operation subject such as a golfer. It is considered very important for golfers to select a golf club that can achieve ideal golf club behavior.

  Therefore, it is very useful for the golfer to analyze the behavior of the golf club during the swing in order to select the optimum golf club from the existing golf clubs. The information obtained by such analysis is also very effective in developing a new golf club.

  As a method of analyzing the behavior of a golf club during a swing by a golfer, conventionally, there is a method of simulating a swing by calculating input parameter information for simulation from a change over time of the three-dimensional coordinates of the golf club grip during the swing. It has been proposed (see, for example, Patent Document 1). In such a method, in the simulation, from the time-dependent change of the grip coordinates measured three-dimensionally, 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 (twisting) around the geometric center axis of the grip. It is possible to simulate a swing with two movements.

JP 2002-331060 A

However, in the simulation method described in Patent Document 1, the three-dimensional coordinates of the grip at the time of swing are image-measured, and the time history data of the coordinates of the grip and the time history of the tilt angle of the grip are based on the measured three-dimensional coordinates. Data and time history data of the rotation angle of the grip around the shaft axis were calculated, and these were input as parameters. Based on these parameters, the x, y, z translational acceleration of the center of gravity of the grip, the rotational acceleration (rad / sec ² ) around the x, y, z axis of the center of gravity of the grip, and the local coordinate axis The rotation angular acceleration (rad / sec ² ) was calculated to simulate the swing.

  In such a method, it is necessary to perform a two-stage calculation on the measured value of the measured three-dimensional coordinates of the grip at the time of the swing, and the calculation is complicated. The error included in the measurement value of the grip's three-dimensional coordinates is amplified, which may adversely affect the accuracy of the simulation result. Here, the two-stage calculation means performing the calculation for the simulation based on the input parameter in addition to the calculation for calculating the input parameter of the simulation such as the translational acceleration and the rotational angular acceleration described above. Say.

  Therefore, an object of the present invention made in view of such circumstances is that the swing can be simulated while avoiding the amplification of the error included in the measurement value of the three-dimensional coordinates of the grip at the time of swing. A simulation system, a simulation apparatus, and a simulation method are provided.

A swing simulation system according to the present invention that achieves the above object is a swing simulation system using a golf club by a golfer,
At least two imaging devices that image identification features that can identify a closed virtual plane that follows the grip of the golf club during the swing;
A simulation device for simulating the swing based on the position information of the virtual plane;
It is characterized by providing.

  According to the swing simulation system of the present invention, the swing can be simulated without amplifying the error included in the measured value of the three-dimensional coordinates of the grip during the swing.

Further, in the swing simulation system according to the present invention, the simulation apparatus comprises:
An image acquisition unit for acquiring an image of the identification feature during the swing from the imaging device;
A position information acquisition unit that recognizes the identification feature from the acquired image, and acquires position information of the virtual plane from position information of the recognized identification feature;
It is preferable to include a simulation unit that simulates the swing using the position information of the virtual plane as a model of a golf club.

  According to this configuration, the swing can be easily simulated without amplifying the error included in the measurement value of the three-dimensional coordinates of the grip at the time of swing by each functional unit included in the simulation apparatus.

  Further, in the swing simulation system according to the present invention, the simulation unit sets the grip portion as a rigid body and the shaft portion as an elastic body on a golf club model having a grip portion and a shaft portion, and the virtual plane Preferably, the swing is simulated by associating the position information with the model.

  According to this configuration, it is possible to reduce the influence of the error included in the measurement value of the three-dimensional coordinates of the grip during the swing on the simulation accuracy.

In order to achieve the above object, a swing simulation apparatus according to the present invention comprises:
A swing simulation device using a golf club by a golfer,
The swing is simulated based on position information of the virtual plane from an image obtained by capturing an identification feature that can identify a closed virtual plane that follows the grip of the golf club during the swing. .

  According to the swing simulation apparatus of the present invention, it is possible to simulate a swing without amplifying an error included in the measured value of the grip three-dimensional coordinates during the swing.

In order to achieve the above object, a swing simulation method according to the present invention includes:
Imaging an identification feature capable of specifying a closed virtual plane that follows the grip of the golf club during the swing by at least two imaging devices;
Simulating the swing based on the position information of the virtual plane;
It is characterized by including.

  According to the swing simulation method of the present invention, a swing can be simulated without amplifying an error included in the measured value of the three-dimensional coordinates of the grip during the swing.

  According to the present invention, it is possible to simulate a swing without amplifying an error included in the measured value of the three-dimensional coordinates of the grip at the time of swing.

1 is a schematic diagram of a swing simulation system according to an embodiment of the present invention. It is a functional block diagram which shows schematic structure of the simulation apparatus of the swing which concerns on one Embodiment of this invention. 5 is a flowchart for explaining a swing simulation method according to an embodiment of the present invention. It is a figure which shows an example of the golf club used with the simulation system which concerns on one Embodiment of this invention. It is a figure which shows an example of the golf club model used with the simulation system which concerns on one Embodiment of this invention. It is a figure which shows an example of the simulation result by the simulation system which concerns on one Embodiment of this invention. It is a figure which shows the other example of the simulation result by the simulation system which concerns on one Embodiment of this invention.

  Hereinafter, a swing simulation system, a simulation apparatus, and a simulation method according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a swing simulation system according to an embodiment of the present invention. A swing simulation system 1 shown in FIG. 1 is a simulation system for simulating a swing using a golf club 5 by a golfer 4. The simulation system 1 includes a first camera 2A and a second camera 2B, which are at least two imaging devices, and a simulation device 3 that simulates a swing based on the captured image of the golf club 5.

  The first camera 2 </ b> A and the second camera 2 </ b> B capture an image of a marker (not shown) that is an identification feature that can identify a closed virtual plane that follows the grip of the golf club 5 during a swing. Here, “following” the grip means that the grip moves as the grip moves. That is, the behavior of a plurality of markers that can identify a closed virtual plane following the grip reflects the movement of the grip. The marker will be described later with reference to FIG. 4. For example, the marker has a spherical shape and is configured with a color and a material that can be distinguished from the surroundings on the captured golf club image. The first camera 2A and the second camera 2B are, for example, high-speed video cameras that construct a motion capture system, and can capture an object with much motion with high sensitivity. The frame rate at the time of swing imaging of the first camera 2A and the second camera 2B is, for example, 160 Hz.

  The simulation device 3 acquires position information of the virtual plane from the image of the marker at the time of swing by the golfer 4 captured by the first camera 2A and the second camera 2B, and simulates the swing. The simulation apparatus 3 is configured by a computer including, for example, a CPU (Central Processing Unit) and a DSP (Digital Signal Processor).

  FIG. 2 is a functional block diagram illustrating a schematic configuration of the simulation apparatus 3. The simulation apparatus 3 recognizes the markers from the acquired images and the interfaces (I / F) 6A and 6B constituting the image acquisition unit that acquires the image of the marker at the time of swing from the first camera 2A and the second camera 2B. A position information acquisition unit 11 that acquires the position information of the virtual plane described above from the position information of the recognized marker, and a simulation unit 12 that simulates a swing by associating the position information of the virtual plane with the golf club model; Have. The position information acquisition unit 11 and the simulation unit 12 are provided in the calculation unit 7 constituted by a CPU and a DSP. Furthermore, the simulation apparatus 3 stores the control unit 8 that controls the overall operation of the simulation apparatus 3, the display unit 9 that displays the simulation result, the measurement result by the position information acquisition unit 11, and the simulation result by the simulation unit 12. A database 10 can be provided.

  FIG. 3 is a flowchart for explaining a swing simulation method according to an embodiment of the present invention. Here, the golfer 4 swings using the golf club 5. First, a marker that can identify a closed virtual plane that follows the grip of the golf club 5 during a swing is imaged by the first cameras 2A and 2B, which are at least two imaging devices (step S01). Thereafter, the simulation apparatus 3 acquires the image data of the marker at the time of swing from the first cameras 2A and 2B by using the I / Fs 6A and 6B constituting the image acquisition unit (step S02). The image data of this marker may be moving image data of any format captured by the first cameras 2A and 2B.

  The simulation apparatus 3 extracts arbitrary image data from the image data captured by the first cameras 2A and 2B and acquired in step S02 by the position information acquisition unit 11, recognizes a marker for the extracted image data, and recognizes the marker. The position information of the virtual plane is acquired from the position information of the marker (step S03).

  The position information acquisition unit 11 recognizes, for example, a marker attached to the golf club 5 by, for example, a circle fitting method for an arbitrary number of frames extracted from the moving image data acquired from the first camera 2A and the second camera 2B. To do. The circle fitting method is a method of calculating the virtual center point of a marker by extracting the contour of a circular (spherical in a three-dimensional space) marker, setting a circle that approximates the extracted contour. Further, the position information acquisition unit 11 performs three-dimensional image measurement as a marker position information by a general method such as triangulation, and acquires the three-dimensional coordinates of the marker. Further, the position information acquisition unit 11 can store the acquired three-dimensional coordinate information and the golfer who performed the swing in the database 10 in association with each other.

  And the simulation apparatus 3 simulates a swing using the simulation part 12 based on the positional information on the virtual plane acquired in step S03 (step S04). The simulation apparatus 3 can display an image of the simulation result on the display unit 9. The display of the simulation result on the display unit 9 is, for example, the deformation of the golf club during the swing or the time-series change of the head speed. Based on the time-series change of the position information of the virtual plane measured using the golf club 5, the swing of the golfer 4 when another golf club having a different specification from the golf club 5 is used is simulated, and the display unit 9 Can be displayed.

  The simulation unit 12 associates the position information of the virtual plane acquired by the position information acquisition unit 11 with the golf club model. The position information of the virtual plane corresponds to the time-series data of the three-dimensional coordinates of the marker at a predetermined time interval set by the position information acquisition unit 11. The simulation method follows, for example, the multibody dynamics theory. The simulation unit 12 associates the three-dimensional coordinate information of the marker acquired by the position information unit 11 by the three-dimensional image measurement with the golf club model as an input parameter for the simulation without performing further calculation processing.

  Here, multi-body dynamics is a theory for deriving what kind of motion a system composed of a plurality of interacting rigid bodies and elastic bodies as a whole, and further generating the force in the process. As input parameters when carrying out simulation according to the multibody dynamics theory, for example, the mass, center of gravity position, inertia tensor, constraint condition (joint, forced displacement) for each of the rigid and elastic bodies that are components of the system, Force conditions (spring, damping force, friction force, contact force, gravity, external force), initial conditions (initial position, initial speed, initial posture, initial angular velocity), numerical analysis conditions (solver selection, step size, tolerance, Analysis time). From these various parameters, it is general to perform simulation by giving the minimum necessary parameters for defining the motion of the system. Prior to the simulation, the simulation unit 12 holds input parameters for executing the simulation from the specifications of the target golf club and data acquired by prior measurement by a predetermined measuring device. The essential input parameters are, for example, information on the center of gravity, position of center of gravity, and moment of inertia for the head, and information on the length, density, cross-sectional shape, bending rigidity, torsional rigidity, vibration characteristics, and damping characteristics for the shaft. For the grip, information on the weight, the position of the center of gravity, and the moment of inertia is retained. The moment of inertia can be measured by a dedicated measuring device such as a moment of inertia measuring device. Then, in addition to these, the simulation unit 12 performs a simulation using the position information acquired by the position information unit 11. As an analysis software using such multi-body dynamics theory, for example, MADYMO (registered trademark) can be used.

  FIG. 4 is a view showing an example of a golf club used in a simulation system according to an embodiment of the present invention. The golf club 5 has a grip 14, a shaft 15, and a head 16. Furthermore, the golf club 5 includes markers M1 to M3 that are at least three identification features that can specify a virtual plane that follows the grip 14. The markers M1 and M3 are arranged on the shaft axis, that is, on the central axes of the shaft 15 and the grip 14, so that the centers of the markers coincide with each other, and the marker M2 is arranged on a mounting member 17 provided so as to protrude from the shaft 15. Is done.

  The configuration feature of the identification feature is not limited to the markers M1 to M3 as shown in the figure, and may be any feature that can specify a virtual plane that follows the movement of the grip 14 during a swing. For example, in FIGS. 4A and 4B, the markers M1 and M3 are arranged on the shaft axis so that the centers of the markers coincide with each other. However, the marker M3 is also mounted on a mounting member that protrudes from the shaft 15 like the marker M2. It is also possible to arrange them. It is of course possible to arrange the marker M1 at a position other than on the shaft axis. Furthermore, it is of course possible to configure the identification feature with an element other than the marker.

  The surfaces of the markers M1 to M3 are covered with a reflective tape, for example. Even if it is other than the reflective tape, the markers M1 to M3 may be covered with a material whose contrast with surrounding pixels is equal to or higher than a predetermined value on the images taken by the first camera 2A and the second camera 2B. it can.

  The length from the center of the marker M2 attached to the tip of the attachment member 17 to the shaft axis is, for example, less than 50 mm, but is not limited thereto. However, if the length of the attachment member 17 is too long, the attachment member 17 itself is distorted during the swing, which may adversely affect measurement accuracy. For this reason, it is necessary to make the attachment member 17 into a length that does not cause bending. The attachment member 17 is made of a material having a sufficiently high rigidity, such as a steel jig.

  According to the swing simulation system as described above, calculation processing for calculating simulation input parameters (for example, translational acceleration and rotational angular acceleration of the center of gravity of the grip) is performed on the marker position information obtained by the three-dimensional image measurement. A swing simulation can be carried out without applying it. Accordingly, such a simulation system can simulate a swing without amplifying an error included in the measured value of the grip three-dimensional coordinates during the swing. Further, since the simulation of the swing can be performed by the simulation system as described above, the number of golf clubs to be actually prototyped can be drastically reduced when developing the golf club. Furthermore, it is possible to provide useful information when a golfer selects a golf club capable of realizing an ideal swing from existing golf clubs.

  Further, the simulation unit 12 sets a grip unit and a head unit as a rigid body and a shaft unit as an elastic body on a golf club model having a grip unit, a shaft unit, and a head unit, and measures by the position information acquisition unit 11. It is preferable to simulate the swing by associating the position information of the virtual plane thus made with the golf club model. This point will be described in more detail below with reference to FIG.

  FIG. 5 is a diagram illustrating an example of a golf club model used in the simulation system according to the embodiment of the present invention. The golf club model 5S has a grip portion 14S, a shaft portion 15S, and a head portion 16S, similarly to the golf club 5 shown in FIG. Furthermore, the golf club model 5S has marker portions M1S to M3S corresponding to the markers M1 to M3 shown in FIG. A virtual plane 18S is defined by the marker portions M1S to M3S. The virtual plane 18S is a closed plane defined by the marker portions M1S to M3S. Conventionally, the entire golf club has been apt to be set as one elastic body element in the simulation because it is deformed by the influence of the force generated during the swing. However, in the golf club model 5S used in the present embodiment, the grip portion 14S is set as a rigid body.

In FIG. 5, with respect to the position information of the markers M1 to M3 measured by the position information acquisition unit 11, the positions of the marker parts M1S to M3S at time tn are represented by dots M1 _{tn to} M3 _tn , respectively. Now, the positions of the marker portions M1S to M3S at time t1 are dots M1 _{t1 to} M3 _t1 , and the positions of the marker portions M1S to M3S at time t2 are dots M1 _{t2 to} M3 _t2 , respectively. If no error occurs in the three-dimensional image measurement by the position information acquisition unit 11, the relative positional relationship between the dots M1 _{t1 to} M3 _{t1 and} the relative positional relationship between the dots M1 _{t2 to} M3 _t2 are the same. . However, it is very rare that the position information obtained by the three-dimensional image measurement contains no error, and in many cases, some error is included even if it is about several millimeters.

When the simulation unit 12 associates the position information of the virtual plane 18S with the golf club model 5S, the position information of the dots M1 _{tn to} M3 _tn , which is the position information of the marker units M1S to M3S, is given. And the position of the marker parts M1S-M3S attached so that the virtual plane which follows the grip part 14S set as a rigid body on the golf club model 5S can be identified follows the position information acquired by the position information acquisition part 11. To simulate a swing. Here, “follow the position information” means that in the simulation, the dots M1 _{tn to} M3 _tn and the marker part M1S of the golf club model 5S based on the position information acquired by the position information acquisition unit 11 are used. It corresponds to restraining with M3S. Such a calculation can be realized by commercially available software for analysis using multibody dynamics theory, such as MADYMO (registered trademark) described above. Specifically, the positions of the marker portions M1S to M3S of the golf club model 5S are restricted with respect to the dots M1 _{t1 to} M3 _t1 at the time t1, and are restricted with respect to the dots M1 _{t2 to} M3 _t2 at the time t2. .

  In this way, by giving the golf club model 5S position information with time during the swing, a total of six degrees of freedom is given to the three marker portions M1S to M3S constituting the virtual plane 18S. Thereby, the motion of the grip part 14S which is a rigid body can be defined. By giving the movement of the grip part 14S which is a rigid body in this way, the swing is simulated without performing the step of calculating the input parameters for simulation again from the position information of the marker parts M1S to M3S. Is possible. As a result, the accuracy of the measurement value of the three-dimensional coordinates of the grip at the time of swing can be avoided, and the influence of the three-dimensional measurement error by the position information acquisition unit 11 can be prevented from being amplified in the simulation result.

On the other hand, when the entire golf club model is an elastic body, if the relative positional relationship of the dots M1 _{tn to} M3 _tn varies due to measurement errors, the simulation results are greatly affected by the measurement errors. End up. At this time, an unreasonable force is generated in the simulation between M1S to M2S to M3S arranged on the elastic body, and the calculation may diverge. As a result, when there is even one piece of measurement data having a large error, the entire golf club model composed of the elastic body is distorted due to the value, and the entire simulation result is greatly affected.

  Therefore, the golf club model 5S used in the simulation system according to the present embodiment avoids the above-described problems by configuring the grip portion 14S as a rigid body and the shaft portion 15S as an elastic body. Furthermore, by setting the grip portion 14S as a rigid body on the golf club model 5S, it is possible to realize a simulation that is robust against variations in measurement data. Furthermore, after setting the grip portion 14S as a rigid body and giving input parameters as time-dependent position information of the virtual plane 18S as described above, the error included in the position information is a simulation result as a deformation of the golf club model 5S. The information on the swing included in the position information can be reflected 100% as it is in the simulation result.

  Hereinafter, an example of a simulation result by the simulation system according to the present embodiment will be described with reference to FIGS. 6A and 6B.

  6A and 6B are diagrams each illustrating an example of a simulation result by the simulation system according to the embodiment of the present invention. In the figure, the measured value is a head calculated by a golfer using a motion capture system to capture a swing using a golf club having a marker on the head (hereinafter referred to as golf club A) and based on time-series position information of the marker. Is speed. On the other hand, the simulation value is the head speed obtained by the simulation system 1 described above. The position information of the marker (the position of the virtual plane) acquired in advance by the simulation unit 12 of the simulation device 3 and stored in the database 10 for a swing by a golfer using a measurement golf club such as the golf club 5 described above. Information) and parameters necessary for simulation of the golf club A (for example, information on the center of gravity, center of gravity, and moment of inertia for the head, length, density, cross-sectional shape, bending rigidity, torsion for the shaft) Simulations were performed using information on stiffness, vibration characteristics, and damping characteristics, and also the grip (weight, center of gravity, moment of inertia). The golf club 5 is different from the golf club A. Moreover, the simulation apparatus 3 holds the parameters of the golf club A in advance by receiving an input based on the specifications of the golf club A.

  FIG. 6A and FIG. 6B are comparison results of measured values and simulation values for swings by different subjects, respectively. As is clear from these results, the simulation values and the measured values are in good agreement. Thus, according to the simulation system according to the present embodiment, the swing can be simulated with high accuracy. Therefore, it is possible to provide information effective for designing and developing a golf club. Furthermore, the development period can be greatly shortened by reducing the number of prototypes in the design and development of golf clubs.

  In addition, when it is used for golf club selection by a golfer, if the swing data by one golfer is measured even once, a swing using another golf club of the golfer will be performed based on the data from the next time. Since the simulation can be performed, it is not necessary for the golfer to go to the storefront and repeat the trial run of the golf club. In this way, the time and effort required for the golfer to select an optimal golf club can be reduced.

  It will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention as described above. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims.

  For example, instead of setting a grip as a rigid body and other parts as an elastic body in a golf club model, the entire body is set as an elastic body, and the identification feature (marker) and the position information of the marker obtained by 3D image measurement are set. As a matter of course, it is possible to configure a simulation system so as to absorb the measurement error of the marker position information, assuming that the two are connected by a spring and a damper. According to such a configuration, it is possible to reduce the deformation of the golf club model due to a measurement error caused by image measurement.

Further, for example, in a golf club model made entirely of an elastic body, a virtual plane defined by dots M1 _{tn to} M3 _tn which are time series data of the marker portions M1S to M3S is defined by the marker portions M1S to M3S in a stationary state. Of course, it is possible to configure the simulation system so as to smooth the time-series position information of the marker so that it is always uniform with the virtual plane. In the smoothing, the simulation system performs smoothing so that the characteristics of the swing are not lost. Also with such a configuration, it is possible to reduce the deformation of the golf club model due to a measurement error caused by image measurement.

  Also, for example, in a golf club model made entirely of an elastic body, a virtual plane defined by at least three markers is represented by PID (proportional-integral-derivative) with respect to time-series position information of the at least three markers. Of course, it is also possible to configure the simulation system so as to follow the control. Also with such a configuration, it is possible to reduce the deformation of the golf club model due to a measurement error caused by image measurement.

DESCRIPTION OF SYMBOLS 1 Simulation system 2A, 2B Imaging apparatus 3 Simulation apparatus 5 Golf club 5S Golf club model 6A, 6B Image acquisition part 11 Position information acquisition part 12 Simulation part 14 Grip 14S Grip part 15 Shaft 15S Shaft part 16 Head 16S Head part 18S Virtual plane M1, M2, M3 Marker M1S, M2S, M3S Marker

Claims (5)

A swing simulation system using a golf club by a golfer,
At least two imaging devices that image identification features that can identify a closed virtual plane that follows the grip of the golf club during the swing;
A simulation device for simulating the swing based on the position information of the virtual plane;
A swing simulation system comprising: The simulation apparatus includes:
An image acquisition unit for acquiring an image of the identification feature during the swing from the imaging device;
A position information acquisition unit that recognizes the identification feature from the acquired image, and acquires position information of the virtual plane from position information of the recognized identification feature;
The swing simulation system according to claim 1, further comprising: a simulation unit that simulates the swing by associating position information of the virtual plane with a golf club model. On the golf club model having a grip part and a shaft part, the simulation part sets the grip part as a rigid body, the shaft part as an elastic body, associates the position information of the virtual plane with the model, Simulate a swing,
The swing simulation system according to claim 1, wherein the system is a swing simulation system according to claim 1. A swing simulation device using a golf club by a golfer,
The swing is simulated based on position information of the virtual plane from an image obtained by capturing an identification feature that can identify a closed virtual plane that follows the grip of the golf club during the swing. Simulation device. A swing simulation method using a golf club by a golfer,
Imaging an identification feature capable of specifying a closed virtual plane that follows the grip of the golf club during the swing by at least two imaging devices;
Simulating the swing based on the position information of the virtual plane;
A method of simulating a swing, comprising:

Images