Patent Application
20160236061
1. Technical Field
The present invention relates to a motion analysis method, a motion analysis apparatus, and a storage device.
2. Related Art
JP-A-2008-73210 has proposed an apparatus in which a three-axis acceleration sensor and a three-axis gyro sensor are attached to a golf club, and a swing is analyzed by using output from the sensors. If the apparatus is used, convenience is improved since a camera is not necessary.
Meanwhile, especially, when a golf putter is used among golf clubs, both directionality and the perception of distance are most important in order to put a ball into a cup.
On the other hand, even if both of the directionality and the perception of distance are accurate, it is common that a ball is not dropped in a cup due to rotation of the hit ball, or for other reasons such as duffing caused by a down-blow swing or topping caused by an upper-blow swing.
In cases of golf clubs other than the putter, duffing or topping causes a ball not to be shot as intended, but, while using an iron, appropriate down blow is recommended, and, while using a wood, appropriate upper blow is recommended.
There are cases where a ball is intentionally hit low or high.
However, in a motion analysis apparatus employing an inertial sensor, there is a problem in that an inclined angle of a hitting surface of an exercise appliance cannot be estimated during impact.
An advantage of some aspects of the invention is to provide a motion analysis method and a motion analysis apparatus capable of estimating an angle at which a hitting surface of an exercise appliance comes into contact with a ball during impact, and a storage device.
(1) An aspect of the invention relates to a motion analysis method including specifying a difference between an inclined angle of a hitting surface of an exercise appliance during impact and a reference inclined angle which is acquired in advance by using an output signal from an inertial sensor.
According to the aspect of the invention, the difference between the inclined angle relative to a vertical plane of the hitting surface of the exercise appliance during impact and the reference inclined angle is specified. Consequently, it is possible to learn an angle at which the hitting surface of the exercise appliance comes into contact with a hit ball during impact, with high reproducibility, and thus to intentionally control the angle so as to control the hit ball or to reduce shot errors.
(2) In the aspect of the invention, the exercise appliance may be a golf club, and the reference inclined angle may be a standard value of a loft angle of a club head. The loft angle is an angle formed between the hitting surface (face surface) and a surface which is perpendicular to the ground surface when a sole (bottom surface) of the club head is brought into contact with the flat ground surface. If the above-described difference is small, an impact is applied in a state in which the loft angle is close to the standard value, and if the difference is large, an impact is applied in a state in which the loft angle is greatly deviated relative to the standard value. In a case of using a putter, if a swing is performed in a state in which the loft angle is the standard value, rotation of a hit ball becomes better, and thus it is possible to achieve the perception of distance as intended. On the other hand, for example, in a case where a ball is hit low with an iron, the face surface may be covered so that the loft angle is reduced, or when a ball is hit in a bunker with a sand wedge, the face surface may be intentionally opened so that the loft angle is increased. As mentioned above, the method of the invention may be used in a case of changing a loft angle as intended.
(3) In the aspect of the invention, the reference inclined angle may be specified by using an output signal from the inertial sensor when the exercise appliance is stopped. With this configuration, for example, in a case of a golf club, it is possible to verify whether or not a loft angle which is set during address (during stoppage) can be reproduced during impact by evaluating the difference.
(4) In the aspect of the invention, the inclined angle of the hitting surface and the reference inclined angle may be displayed in a coordinate system. With this configuration, it is possible to visually recognize the difference between the reference inclined angle and the inclined angle displayed in the coordinate system.
(5) In the aspect of the invention, an image of the exercise appliance may be displayed in the coordinate system in a superimposed manner in a front view of viewing a user handling the exercise appliance from the front side. With this configuration, it is possible to visually recognize an angle of the hitting surface from the image displayed in the coordinate system in a superimposed manner.
(6) In the aspect of the invention, the image of the exercise appliance may be displayed at a predetermined position on a display screen, and a display position of the reference inclined angle may be rotated by an angle which is the same as the difference so as to be displayed. With this configuration, an image of a relatively complex shape may be fixed on the screen, and then the coordinate system fixed as a background may be rotated by an angle which is the same as the difference so as to be displayed. Therefore, there is an advantage in that display image control is not complicated.
(7) In the aspect of the invention, an inclined angle of the hitting surface specified in the past may be displayed in the coordinate system so as to be differentiated from an inclined angle of the hitting surface specified this time. With this configuration, it is possible to visually recognize achievement of a practice effect when exercises are repeatedly performed.
(8) In the aspect of the invention, a target region including the reference inclined angle may be displayed so as to be differentiated from other regions. With this configuration, in a case where achieving the reference inclined angle during impact is a goal, since a target is a zone rather than a line, a target achievement ratio is increased, the user feels comfortable, and thus an exercise practice effect can be improved.
(9) In the aspect of the invention, a ratio of the number of times in which an inclined angle of the hitting surface enters the target region to the number of exercises in which the inclined angle of the hitting surface is specified may be displayed. With this configuration, a target achievement ratio can be recognized as a numerical value, and thus a notification of an exercise practice effect can be performed in a quantitative manner.
(10) Another aspect of the invention relates to a motion analysis method including specifying a tangential direction during impact with respect to a movement trajectory of an exercise appliance projected onto a vertical plane by using an output signal from an inertial sensor; and specifying an intersection angle between a target direction projected onto the vertical plane and the tangential direction.
According to the aspect of the invention, the intersection angle between the tangential direction during impact with respect to the movement trajectory of the exercise appliance projected onto the vertical plane and the target direction projected onto the vertical plane is specified. Consequently, it is possible to learn an angle (an incidence angle or the like of an upper blow or a down blow) at which the hitting surface of the exercise appliance is incident to a hit ball during impact, with high reproducibility, and thus to intentionally control the angle so as to control the hit ball or to reduce shot errors. The same aspects as in the above (3) to (9) are applicable to other aspects of the invention. Particularly, when the aspect of (5) is applied, images of the exercise appliance may be displayed at a plurality of positions along a movement trajectory prior to impact. In the above-described way, it becomes easier to visually recognize the trajectory of an upper blow or a down blow.
(11) Still another aspect of the invention relates to a motion analysis apparatus including an impact analysis unit that specifies an inclined angle of a hitting surface of an exercise appliance during impact by using an output signal from an inertial sensor; and a difference analysis unit that specifies a difference between the inclined angle of the hitting surface and a reference inclined angle which is acquired in advance. According to the aspect of the invention, it is possible to appropriately perform the motion analysis method of (1) according to the aspect of the invention.
(12) Yet another aspect of the invention relates to a motion analysis apparatus including an impact analysis unit that specifies a tangential direction during impact with respect to a movement trajectory of an exercise appliance projected onto a vertical plane by using an output signal from an inertial sensor; and an intersection angle analysis unit that specifies an intersection angle between a target direction projected onto the vertical plane and the tangential direction. According to the aspect of the invention, it is possible to appropriately perform the motion analysis method of (10) according to the aspect of the invention.
(13) Still yet another aspect of the invention relates to a storage device storing a motion analysis program causing a computer to execute specifying an inclined angle of a hitting surface of an exercise appliance during impact by using an output signal from an inertial sensor; and specifying a difference between the inclined angle of the hitting surface and a reference inclined angle which is acquired in advance.
(14) Further another aspect of the invention relates to a storage device storing a motion analysis program causing a computer to execute specifying a tangential direction during impact with respect to a movement trajectory of an exercise appliance projected onto a vertical plane by using an output signal from an inertial sensor; and specifying an intersection angle between a target direction projected onto the vertical plane and the tangential direction.
The program may be built into the storage device of the motion analysis apparatus performing the method of the invention, or may be installed to the storage device of the motion analysis apparatus from a server or a storage medium.
The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. The embodiment described below is not intended to improperly limit the content of the invention, and all constituent elements described in the present embodiment are not essential as solving means of the invention.
Here, when the inertial sensor 12 is attached, one (z axis) of detection axes of the inertial sensor 12 matches the axis of the shaft 13a. Another detection axis (x axis) of the inertial sensor 12 matches a direction in which a direction (face normal direction) perpendicular to a face surface (hitting surface) 13c1 is projected on a horizontal plane in a state in which a sole (grounding surface) of the club head 13c is made horizontal. The face surface is not limited to a vertical surface, and is inclined with respect to the vertical surface, and thus the x axis is set in the direction in which the face normal direction is projected onto a horizontal surface. The y axis is perpendicular to the x axis and the z axis. A sensor coordinate system Σxyz is defined by the x axis, the y axis, and the z axis.
The golf swing analysis apparatus 11 includes a calculation processing circuit 14. The calculation processing circuit 14 is connected to the inertial sensor 12. A predetermined interface circuit 15 is connected to the calculation processing circuit 14. In connection, the interface circuit 15 may be connected to the inertial sensor 12 in a wired manner, and may be connected to the inertial sensor 12 in a wireless manner. A detection signal is supplied to the calculation processing circuit 14 from the inertial sensor 12.
The calculation processing circuit 14 is connected to a storage device 16. The storage device 16 can store, for example, a golf swing analysis software program (motion analysis program) 17 and related data. The calculation processing circuit 14 realizes a golf swing analysis method by executing the golf swing analysis software program 17. The storage device 16 may include a dynamic RAM (DRAM), a large capacity storage device unit, a nonvolatile memory, and the like. For example, when a golf swing analysis method is performed, the golf swing analysis software program 17 is downloaded from, for example, a server and is temporarily held in the DRAM. Alternatively, the golf swing analysis software program 17 may be preserved in the large capacity storage device unit such as a hard disk drive (HDD) along with data. The nonvolatile memory stores a program or data with a relatively small capacity, such as a basic input/output system (BIOS).
The storage device 16 stores club specification information indicating a specification of the golf club 13, sensor attachment position information, and the like. For example, a user operates an input device 21 and sequentially inputs type numbers of the golf club 13 to be used (alternatively, selects a type number from a type number list) so that specification information (for example, information regarding the length of the shaft, a central position, a face angle, and a loft angle) for each type number is stored in the storage device 16 in advance. In this case, specification information of an input type number is used as the club specification information. Alternatively, the sensor unit 12 may be attached at a predetermined position (for example, a distance of 20 cm from the grip) which is set so that information regarding the predetermined position is stored as the sensor attachment position information in advance. As exercise conditions, for example, in a case of a golf putter, a distance from an address position to a cup, a size of the cup, and speed on the turf are stored in the storage device 16 via the input device 21.
The calculation processing circuit 14 is connected to an image processing circuit 18. The calculation processing circuit 14 sends predetermined image data to the image processing circuit 18. The image processing circuit 18 is connected to a display device 19. In connection, the image processing circuit 18 is connected to a predetermined interface circuit (not illustrated). The image processing circuit 18 sends an image signal to the display device 19 on the basis of input image data. An image specified by the image signal is displayed on a screen of the display device 19. The calculation processing circuit 14 or the image processing circuit 18 can convert a coordinate space of the sensor coordinate system Σxyz into an absolute reference coordinate system ΣXYZ (for example, an X-Z plane is a horizontal plane, and an X-Y plane is a vertical plane) which is a real space (three-dimensional space). The display device 19 employs a liquid crystal display or other flat panel displays, and displays a three-dimensional image or a two-dimensional image in the absolute reference coordinate system ΣXYZ. Here, the calculation processing circuit 14, the storage device 16, and the image processing circuit 18 are provided as, for example, a computer device.
The calculation processing circuit 14 is connected to the input device 21. The input device 21 includes at least alphabet keys and numerical keys. Text information or numerical value information is input to the calculation processing circuit 14 from the input device 21. The input device 21 may be constituted of, for example, a keyboard. The combination of the display device, the computer device, and the keyboard may be replaced with a portable terminal such as a smart phone or a tablet PC.
The swing position coordinate detection unit 50 detects coordinates of the club head 13c during a swing from a swing start position (address position) to a swing end position (finish position) through a swing turning position (top position) and a hitting position (impact virtual vertical plane position).
The speed detection unit 60 detects a speed V of the club head 13c, for example, during impact by using an output signal from the inertial sensor 12 (refer to
The plan-view direction analysis unit 90 analyzes the direction of the club head 13c in a plan view. The plan-view direction analysis unit 90 analyzes at least one of a first deviation angle θ1 (absolute face angle) between the face surface 13c1 during impact and a virtual vertical plane 13c2 with respect to a hitting target direction (a target line direction which is, for example, a direction in which the normal direction of the face surface 13c1 during address is projected onto the X-Z plane) as illustrated in
The hit point analysis unit 100 analyzes a deviation amount δ of a hit point (hitting position) of a ball 22 during impact relative to a virtual reference position P0 set on the face surface 13c1, on the basis of angular velocity around the shaft 13a, as illustrated in
The front-view direction analysis unit 110 analyzes the direction of the club head 13c in a front view of viewing a golfer (a user handling an exercise appliance) from the front side. The front-view direction analysis unit 110 analyzes at least one of a third deviation angle θ3 (delta-loft angle) between an inclined angle (actual loft angle) with respect to the vertical surface of the face surface 13c1 during impact and a reference inclined angle (which is, for example, a loft angle as a standard value of the putter 13 and is illustrated as a substantially vertical surface in
The stroke analysis unit (swing width analysis unit) 120 specifies a swing width from a first position to a second position on a swing trajectory on the basis of coordinates of the two positions (the first position and the second position) from the swing position coordinate detection unit 50. For example, as illustrated in
As illustrated in
In the screen center of
An angle in the angle axis of the polar coordinate system is exaggerated to be larger than an actual angle, and, for example, an angle range of ±5 degrees is illustrated to be exaggerated to an angle range of 90 degrees or more. This is so that deviation of a hitting direction relative to a hitting target direction can be easily viewed. Another axis of the polar coordinate system is a speed axis. An end position of the line segment indicating the hitting direction extending from the face surface of the image indicating the club head 13c of the putter 13 indicates a speed of the club head 13c (the face surface 13c1) during impact.
In the present embodiment, in light of a hitting direction and a speed of the face surface 13c1 during impact being associated with the directionality and the perception of distance of a hit ball, the hitting direction and the speed of the face surface 13c1 during impact are displayed in the same coordinate system. The user checks deviation of a hitting direction relative to the hitting target direction and a speed during impact for each swing motion of the putter 13, and can thus gain accuracy of reproducing the directionality and the perception of distance of a hit ball. Here, the hitting direction during impact may be set to a direction in which the normal direction to the face surface 13c1 during impact is projected onto the projection plane. Since the face surface 13c1 is not limited to a plane which is parallel to the vertical surface and may be inclined with respect to the vertical surface, the direction in which the normal direction of the face surface 13c1 is projected onto the projection plane (horizontal plane) may be assumed to be a hitting direction. Specifying a hitting direction will be described later, and a hitting direction (a tangential direction during impact with respect to a movement trajectory of the face surface) during impact may be specified on the basis of a movement vector of the face surface 13c1.
The hitting target direction may be specified as a direction in which a normal direction to the face surface 13c1 during address (during stoppage) before starting a swing motion is projected onto the projection plane. The hitting target direction may be a preset known fixed direction, but may be specified on the basis of the direction of the face surface 13c1 during stoppage for each swing motion before starting the swing motion so as to easily recognize deviation between intended swing and actual swing.
In the image indicating the putter 13 in a plan view, the face surface 13c1 is set to be directed in a hitting direction and is displayed in the polar coordinate system illustrated in
In the polar coordinate system illustrated in
In the polar coordinate system illustrated in
If “Histogram” on the lower left in
In
If “Histogram” on the screen lower left of
Circular marks illustrated in
A circular mark indicated by diagonal lines indicates the most recent hitting position of a ball. In the example illustrated in
In
At the screen center of
An angle in the angle coordinate system is exaggerated larger than an actual angle, and an angle range of 1 degree is illustrated to be exaggerated several times to several tens of times. This is so that a deviation of the inclined angle relative to the reference inclined angle can be easily visually recognized.
In the angle coordinate system illustrated in
In the angle coordinate system illustrated in
If “Histogram” on the screen lower left in
In
If “Histogram” on the screen lower left of
A description will be made of calculation performed by the swing position coordinate detection unit 50 illustrated in
As illustrated in
A three-dimensional coordinate position is represented by the following Equation (1) as a quaternion q indicating rotation of a position vector.
q=(w,x,y,z) (1)
In Equation (1), if a rotation angle of target rotation is θ, and unit vectors of a rotation axis are (rx, ry, rz) w, x, y, and z are represented by the following Equation (2).
Since the sensor unit 12 is stopped at the time point t=0 at the time of starting a swing (address), a quaternion q(0) indicating rotation at θ=0 and the time point t=0 is as in the following Equation (3) on the basis of Equation (1) obtained by assigning θ=0 to Equation (2).
q(0)=(1,0,0,0) (3)
Next, the swing position coordinate detection unit 50 updates the time point t to t+1 (step S3). Here, the time point t=0 is updated to a time point t=1.
Next, the swing position coordinate detection unit 50 computes a quaternion Δq(t) indicating rotation per unit time at the time point t on the basis of three-axis angular velocity data at the time point t (step S4).
For example, if the three-axis angular velocity data at the time point t is ω(t)=[ωx(t), ωy(t), ωz(t)], the magnitude |ω(t)| of angular velocity per sample measured at the time point t is computed by using the following Equation (4).
|w(t)|=√{square root over (ωx(t)2+ωy(t)2+ωz(t)2)} (4)
The magnitude |ω(t)| of angular velocity corresponds to a rotation angle per unit time, and thus quaternion Δq(t+1) indicating rotation per unit time at the time point t is computed by using the following Equation (5).
Here, since t is 1, the swing position coordinate detection unit 50 computes Δq(1) by using Equation (5) on the basis of three-axis angular velocity data ω(1)=[ωx(1), ωy(1), ωz(1)] at the time point t=1.
Next, the swing position coordinate detection unit 50 computes a quaternion q(t) indicating rotation from the time point 0 to the time point t (step S4). The quaternion q(t) is computed by using the following Equation (6).
q(t)=q(t−1)·Δq(t) (6)
Here, since t is 1, the swing position coordinate detection unit 50 computes q(1) by using Equation (6) on the basis of q(0) in Equation (3) and Δq(1) computed in step S4.
Next, the swing position coordinate detection unit 50 repeatedly performs the processes in steps S3 to S5 until t becomes N. If t becomes N (YES in step S6), the swing position coordinate detection unit 50 computes a quaternion p(N) indicating an attitude at the time point N on the basis of the quaternion p(0) indicating the initial attitude computed in step S2 and the quaternion q(N) indicating rotation from time points t=0 to N computed in the previous step S5 (step S7), and finishes the process.
The swing position coordinate detection unit 50 can obtain coordinates (X, Y, Z) in the absolute reference coordinate system of the club head 13c of the putter 13 at the time points t=0 to N on the basis of the attitude information acquired in the above-described way, and distance information from the sensor unit 12 to the club head 13c (first and second measurement points 13d and 13e which will be described later). The speed detection unit 60 illustrated in
Next, with reference to
As illustrated in
The position specifying portion 72 specifies a second line segment L2 which is perpendicular to the face surface 13c1 in the absolute reference coordinate system ΣXYZ during stoppage. The second line segment L2 vertically intersects the face surface 13c1 at the first measurement point 13d=rh(0). The position specifying portion 72 specifies the first line segment L1 when specifying the second line segment L2. The position specifying portion 72 sets the second line segment L2 in a vertical direction to the first line segment L1 at the first measurement point 13d. The second line segment L2 indicates a so-called target line which is a hitting target direction. In this case, the second line segment L2 is projected onto the horizontal plane which is perpendicular to the Y axis in the absolute reference coordinate system ΣXYZ in the same manner as the first line segment L1.
The impact analysis unit 80 includes, as illustrated in
The trajectory specifying portion 82 specifies a movement trajectory of the first measurement point 13d in the absolute reference coordinate system ΣXYZ during impact. When the movement trajectory is specified, as illustrated in
The speed specifying portion 63 specifies a speed of the face surface 13c1 during impact, displayed along with the absolute face angle θ1 or the square degree θ2 in the polar coordinate system. The speed of the face surface 13c1 during impact may be obtained on the basis of information regarding acceleration or the like at an impact position.
The plan-view direction analysis unit 90 includes, as illustrated in
The second deviation angle analysis portion 92 is connected to the attitude specifying portion 81 and the trajectory specifying portion 82 of the impact analysis unit 80. The second deviation angle analysis portion 92 temporarily specifies the hitting direction L5 to a vertical direction to the third line segment L3 specified by the attitude specifying portion 81. In other words, as described above, the accurate hitting direction L4′ is set on the extension line (a tangential direction during impact with respect to a movement trajectory) of a movement vector (the fourth line segment L4), but the face surface 13c1 in an actual attitude may not necessarily be perpendicular to the accurate hitting direction L4′. This is because the face surface 13c1 is closed or opened during impact and thus is not perpendicular to the accurate hitting direction L4′. The second deviation angle analysis portion 92 specifies the intersection angle θ2 between the accurate hitting direction L4′ and the virtual hitting direction L5 as a square degree. The square degree θ2 indicates a deviation angle between a virtual vertical plane with respect to the accurate hitting direction L4′ and the face surface 13c1 measured during impact.
The statistical analysis unit 140 calculates a statistical value indicating variation in the absolute face angle θ1, the square degree θ2, or the speed V during impact. The statistical analysis unit 140 includes a histogram generation portion 141. The histogram generation portion 141 sorts the absolute face angle θ1, the square degree θ2, or the speed V measured as data for the histogram illustrated in
The image processing circuit 18 may generate display information illustrated in
The image processing circuit 18 may display a ratio (for example, 46%) of the number of times in which a hitting direction enters a target region to the number of exercises in which the hitting direction is specified on the basis of information from the statistical analysis unit 140. In the above-described manner, a target achievement ratio can be recognized as a numerical value, and thus notification of an exercise practice effect can be performed in a quantitative manner.
The hit point analysis unit 100 illustrated in
Here,
y=−0.0604x+2.4944 (7)
A contribution ratio is “R2=0.8954”.
The above Equation (7) is calculated in advance and is stored in the storage device 16. Consequently, the deviation amount analysis portion 102 can calculate the deviation amount δ of a hitting position relative to the sweet spot on the basis of information from the inertial sensor 12 and the storage device 16.
The statistical analysis unit 140 may calculate a statistical value indicating variation in the deviation amount δ. The histogram generation portion 141 sorts the measured deviation amount δ into a plurality of zones, and counts the number of samples of the deviation amount δ included in each zone in the same manner as in
The image processing circuit 18 may generate the display information illustrated in
The image processing circuit 18 may display a ratio (for example, ±5 mm from the sweet spot) of the number of times in which the deviation amount δ enters a target region to the number of exercises in which the deviation amount δ is specified on the basis of information from the statistical analysis unit 140. In the above-described manner, a target achievement ratio can be recognized as a numerical value, and thus notification of an exercise practice effect can be performed in a quantitative manner.
Next, a description will be made of analysis and display of the stroke (swing width) L illustrated in
The stroke (swing width) determination portion 122 may calculate the length of a route following a swing trajectory from the first position (address position) to the second position (swing turning position) as the swing width L. Since a plurality of sampled coordinate positions from the first position to the second position are acquired, it is possible to substantially accurately calculate the length of the route by integrating a distance in a three-dimensional space between coordinate positions adjacent to each other, sampled with a fine pitch.
Alternatively, the stroke (swing width) determination portion 122 may obtain the swing width L from the first position to the second position by obtaining a distance between coordinates on a horizontal axis X of the first position and the second position projected onto a projection plane (for example, the vertical X-Y plane in the absolute reference coordinate system). This is because, for a golfer, as the swing width L during a backswing, it is sufficient to acquire a pulled length (that is, a distance between projected coordinates) in a backswing direction rather than a swing width of a more accurate route. In
The statistical analysis unit 140 may calculate a statistical value indicating variation in the swing width L. The histogram generation portion 141 sorts a swing width or a speed measured as data for the histogram illustrated in FIG. 14 or 16 into a plurality of zones, and counts the number of samples included in each zone. The variation analysis portion 142 of the statistical analysis unit 140 calculates an average value, a standard deviation, and the like of the whole number of samples of the swing width L or the speed V. In the above-described way, a statistical value indicating the swing width L or the speed V is displayed, and thus it is possible to estimate reproducibility of the swing width L or the speed V of an exercise appliance according to a traveled distance of a hit ball.
The image processing circuit 18 may generate the display information illustrated from
The image processing circuit 18 may generate the display information illustrated from
The image processing circuit 18 may sequentially display the images indicating the putter 13 displayed at a plurality of positions in
The first position which is a start point of the swing width L and the second position are not limited to setting to the above-described address position and swing turning position. As a combination of the first position and the second position, a combination of a swing turning position and an impact position for defining a swing width L of a downswing, a combination of an impact position and a swing end position for defining a swing width of follow-through, or a combination of a swing start position and a swing end position for defining a swing width L of the entire swing may be employed. Such a swing width L has a relation to a swing width of a backswing, and can contribute to gaining good reproducibility of the perception of distance, for example, in a half swing of a golf putter or iron.
Next, with reference to
As illustrated in
The position specifying portion 72 specifies a second line segment L2 which is perpendicular to the face surface 13c1 in the absolute reference coordinate system ΣXYZ during stoppage. The second line segment L2 vertically intersects the face surface 13c1 at the first measurement point 13d=rh(0). The position specifying portion 72 specifies the first line segment L1 when specifying the second line segment L2. The position specifying portion 72 sets the second line segment L2 in a vertical direction to the first line segment L1 at the first measurement point 13d. The second line segment L2 indicates a so-called target line which is a hitting target direction. In this case, the second line segment L2 is projected onto the horizontal plane which is perpendicular to the Z axis in the absolute reference coordinate system ΣXYZ in the same manner as the first line segment L1.
The attitude specifying portion 81 of the impact analysis unit 80 specifies an attitude of the face surface 13c1 in the absolute reference coordinate system ΣXYZ during impact. When the attitude is specified, for example, as illustrated in
The trajectory specifying portion 82 specifies a movement trajectory of the first measurement point 13d in the absolute reference coordinate system ΣXYZ during impact. When the movement trajectory is specified, as illustrated in FIG. 30, the trajectory specifying portion 82 specifies a first coordinate point P1 on the absolute reference coordinate system ΣXYZ indicating a position rh(imp) of the first measurement point 13d during impact, and a second coordinate point P2 on the absolute reference coordinate system ΣXYZ indicating a position rh(imp−1) of the first measurement point 13d as a sampling point preceding the impact. Here, a sampling point right before the impact time may be allocated to the second coordinate point P2. The first coordinate point P1 and the second coordinate point P2 are connected to each other via a fourth line segment L4. The direction and the length of the fourth line segment L4 respectively indicate a direction and the magnitude of a movement vector. In this case, in the same manner as described above, the fourth line segment L4 is projected onto the vertical plane which is perpendicular to the Z axis in the absolute reference coordinate system ΣXYZ. A direction L4′ (a tangential direction during impact with respect to a movement trajectory projected onto the vertical plane) in which the fourth line segment L4 projected onto the vertical plane is defined as a hitting direction during impact.
The front-view direction analysis unit 110 includes, as illustrated in
The fourth deviation angle analysis portion 112 is connected to the attitude specifying portion 71 of the address analysis unit 70 and the trajectory specifying portion 82 of the impact analysis unit 80. The fourth deviation angle analysis portion 112 specifies, for example, the extension line L4′ of the fourth line segment L4 specified by the trajectory specifying portion 82 as a hitting direction. The fourth deviation angle analysis portion 112 calculates an intersection angle between the second line segment L2 (which is parallel to a hitting target direction or a target line) which is perpendicular to the face surface 13c1 at the first measurement point 13d on the face surface 13c1 during address, and the extension line L4′ (accurate hitting direction) of the fourth line segment L4 which is perpendicular to the face surface 13c1 at the first measurement point 13d on the face surface 13c1 during impact, as the fourth deviation angle θ4 (attack angle).
The statistical analysis unit 140 calculates a statistical value indicating variation in the third deviation angle θ3 or the fourth deviation angle θ4. The statistical analysis unit 140 sorts the third deviation angle θ3 or the fourth deviation angle θ4 measured as data for the histogram illustrated in
The image processing circuit 18 may generate the display information illustrated from
Next, a description will be made of the score analysis unit 130 which scores swings on the basis of the above-described plurality of analysis data items. The scoring is roughly classified into scoring of analysis items (the first to fourth deviation angles θ1 to θ4, the swing width L, the deviation amount δ relative to a sweet spot, and the speed V during impact) and scoring of the total point obtained by weighting a plurality of analysis items.
The performance score (PS) is represented by the following equation.
PS=P−(1−Ta)×S (8)
Here, P indicates a perfect score (100 points), and Ta indicates target zone estimation and is represented by the following equation.
Ta=(Tz−(|T−R|))/Tz (9)
Here, Tz indicates a target zone, T indicates a target value, and R indicates analysis data. If (1−Ta) is 0 to 1, this indicates that convergence to the target zone occurs. It is indicated that (1−Ta) coming closer to 0 approaches the target value. If (1−Ta) is equal to or greater than 1, this indicates a deviation relative to the target zone. In addition, S indicates a scale number and is used for scale matching between a point and a data numerical value. S is represented by P/A, and, here, A indicates an analysis possible range.
If a square impact is applied toward a target line, the first deviation angle θ1 is 0, and, in this case, 100 points are given as PsF. A score of the first deviation angle θ1 is computed by assigning, for example, P=100, T=0, Tz=1°, A=30, and R=θ1 to Equations (8) and (9). In this case, the target zone Tz is a variable value which may be set to ±arcsin (R/L) by using the radius R of the cup and a distance L from the address position to the cup center as described above.
If a square impact is applied on a club path, the second deviation angle θ2 is 0, and, in this case, 100 points are given as PsS. A score of the second deviation angle θ2 is computed by assigning, for example, P=100, T=0, Tz=1°, A=30, and R=θ2 to Equations (8) and (9).
If hitting is performed at the sweet spot, the as deviation amount δ is 0, and, in this case, 100 points are given as PsH. A score of the deviation amount δ is computed by assigning, for example, P=100, T=0, Tz=5°, A=100, and R=δ to Equations (8) and (9).
It is targeted that the swing width L is put in a standard deviation of 1σ. A score of the swing width L is computed by assigning, for example, P=100, T=0, Tz=1σ°, A=100, and R=L to Equations (8) and (9).
It is targeted that the impact speed V is also put in a standard deviation of 1τ. A score of the impact speed V is computed by assigning, for example, P-100, T=0, Tz=1τ°, A=10, and R=V to Equations (8) and (9).
If an impact is applied according to a standard loft angle or an actually measured loft angle during address, the third deviation angle θ3 is 0, and, in this case, 100 points are given as PsL. A score of the third deviation angle θ3 is computed by assigning, for example, P=100, T=0, Tz=1°, A=15, and R=θ3 to Equations (8) and (9).
If an impact which is parallel to a target line is applied, the fourth deviation angle θ4 is 0, and, in this case, 100 points are given as PsA. A score of the fourth deviation angle θ4 is computed by assigning, for example, P=100, T=0, Tz=1°, A=15, and R=θ4 to Equations (8) and (9).
The performance score PS of each analysis item is displayed as a numerical value in the PS column of the above-described analysis screen of the analysis item.
The above-described analysis items are roughly classified into the analysis items (the first deviation angle θ1, the second deviation angle θ2, and the deviation amount δ relative to the sweet spot) regarding the directionality and the analysis items (the impact speed V, the swing width L, the third deviation angle θ3, and the fourth deviation angle θ4) regarding the perception of distance. Therefore, as total points obtained by weighting the analysis items, three types of total points are useful, including 1) a total point regarding the directionality, 2) a total point regarding the perception of distance, and 3) a total point regarding the directionality and the perception of distance.
Weighting factors when the three analysis items (the first deviation angle θ1, the second deviation angle θ2, and the deviation amount δ relative to the sweet spot) regarding the directionality are defined as follows. A weighting factor of the performance score PsS regarding the first deviation angle θ1 (absolute face angle) is set to WS, a weighting factor of the performance score PsF regarding the second deviation angle θ2 (square degree) is set to WF, and a weighting factor of the performance score PsH regarding the deviation amount δ relative to the sweet spot is set to WH.
When an extent of an influence on the directionality of a hit ball is taken into consideration, the weighting factor WS for the first deviation angle θ1 is higher than the weighting factor WH for the deviation amount δ (WS>WH). The weighting factor WH for the deviation amount δ is higher than the weighting factor WF for the second deviation angle θ2 (WH>WF). Therefore, the three weighting factors have the following relationship.
WS>WH>WF (10)
A total point of the analysis items regarding the directionality of a hit ball is as follows in a case of using the three data items θ1, θ2, and δ.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsF×WF+PsS×WS+PsH×WH)/(WF+WS+WH) (11)
A total point of the analysis items regarding the directionality of a hit ball is as follows in a case of using the two data items θ1 and δ.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsF×WF+PsH×WH)/(WF+WH) (12)
A total point of the analysis items regarding the directionality of a hit ball is as follows in a case of using the two data items θ2 and δ.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsS×WS+PsH×WH)/(WS+WH) (13)
A total point of the analysis items regarding the directionality of a hit ball is as follows in a case of using the two data items θ1 and θ2.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsF×WF+PsS×WS)/(WF+WS) (14)
Weighting factors when the four analysis items (the impact speed V, the swing width L, the third deviation angle θ3, and the fourth deviation angle θ4) regarding the perception of distance are defined as follows. A weighting factor of the performance score PsI regarding the impact speed V is set to WI, a weighting factor of the performance score PsB regarding the swing width L is set to WB, a weighting factor of the performance score PsL regarding the third deviation angle θ3 (delta-loft angle) is set to WL, and a weighting factor of the performance score PsA regarding the fourth deviation angle θ4 (attack angle) is set to WA.
When the extent of the influence on the perception of distance of a hit ball is taken into consideration, the weighting factor WI for the impact speed V is higher than the weighting factor WB for the swing width L (WI>WB). The weighting factor WB for the swing width L is higher than the weighting factor WL for the third deviation angle θ3 and the weighting factor WA for the fourth deviation angle θ4 (WI>WB>WL, and WI>WB>WA). The weighting factor WL for the third deviation angle θ3 and the weighting factor WA for the fourth deviation angle θ4 may set to be equal to each other since the weighting factor WL for the third deviation angle θ3 and the weighting factor WA for the fourth deviation angle θ4 have a correlation to each other (WL=WA). Therefore, the four weighting factors have the following relationship.
WI>WB>WL=WA (15)
A total point of the analysis items regarding the perception of distance of a hit ball is as follows in a case of using the four data items V, L, θ3, and θ4.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsI×WI+PsB×WB+PsL×WL+PsA×WA)/(WI+WB+WL+WA) (16)
A total point of the analysis items regarding the perception of distance of a hit ball is as follows in a case of using the three data items V, L, and θ3.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsI×WI+PsB×WB+PsL×WL)/(WI+WB+WL) (17)
A total point of the analysis items regarding the perception of distance of a hit ball is as follows in a case of using the three data items V, L, and θ4.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsI×WI+PsB×WB+PsA×WA)/(WI+WB+WA) (18)
A total point of the analysis items regarding the perception of distance of a hit ball is as follows in a case of using the two data items V and L.
SUM(respective PSs×weighting factors)/SUM(respective weighting factors)=(PsI×WI+PsB×WB)/(WI+WB) (19)
Of the directionality and the perception of distance of a hit ball, the directionality of a hit ball is emphasized when taking into consideration the extent of the influence on swing improvement or sports. An analysis item (for example, V or L) which has a great influence among the analysis items regarding the perception of distance of a hit ball may be emphasized more than an analysis item (for example, θ2) which has a small influence among the analysis items regarding the directionality of a hit ball. Therefore, the weighting factors for the seven analysis items (θ1, θ2, δ, V, L, θ3, and θ4) regarding the directionality and the perception of distance of a hit ball have the following relationship on the basis of Equations (10) and (15).
WS>WH>WI>WB>WF>WL=WB (20)
A comprehensive performance score Ps (directionality+perception of distance) of the performance score Ps (directionality) regarding the directionality represented by any one of Equations (11) to (14) and the performance score Ps (perception of distance) regarding the perception of distance represented by any one of Equations (16) to (18) is as follows.
Performance score Ps(directionality+perception of distance)=a×performance score Ps(directionality)+b×performance score Ps(perception of distance) (21)
Here, the weighting factors a and b may be a=b=1, and, in other cases, may be a>b so that the directionality is emphasized.
The performance score Ps (directionality+perception of distance) and a×performance score Ps (directionality) or b×performance score Ps (perception of distance) may be displayed as scores, and analysis data of the plurality of analysis items used for the displayed performance scores may also be displayed with, for example, a radar chart.
Although the present embodiment has been described in detail, it is easily understood by a person skilled in the art that various modifications may occur without substantially departing from the novel matters and effects of the invention. Therefore, such modification examples are all intended to be included in the scope of the invention. For example, in the specification or the drawings, a terminology which is described at least once along with another terminology which has a broader meaning or the same meaning may be replaced with another terminology in any location of the specification or the drawings. In addition, configurations and operations of the inertial sensor 12, the golf club 13, the calculation processing circuit 14, and the like are not limited to those described in the present embodiment and may be variously modified. For example, the invention is not limited to golf, and is applicable to exercise appliances of baseball or tennis.
The entire disclosure of Japanese Patent Application No. 2015-025694, filed Feb. 12, 2015 is expressly incorporated by reference herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-025694 | Feb 2015 | JP | national |
