US20160175681A1

US20160175681A1 - Exercise analysis device, exercise analysis method, program, recording medium, and exercise analysis system

Info

Publication number: US20160175681A1
Application number: US14/965,394
Authority: US
Inventors: Akira Inagaki; Masaki UKAWA
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2014-12-18
Filing date: 2015-12-10
Publication date: 2016-06-23
Also published as: JP2016116566A

Abstract

A first imaginary plane specifying unit specifies a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of an inertial sensor. A second imaginary plane specifying unit specifies a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis. An exercise analysis unit calculates a trajectory of a swing of the user based on an output of the inertial sensor. A trajectory determination unit determines whether the trajectory of the swing passes through a predetermined region specified based on the first and second axes.

Description

BACKGROUND

1. Technical Field
The present invention relates to an exercise analysis device, an exercise analysis method, a program, a recording medium, and an exercise analysis system.
2. Related Art
JP-A-2010-82430 discloses that an image is acquired by performing photographing from the rear side in a hitting direction between an address state to the end of a swing and the image is split into at least three regions by a first straight line passing through a shaft axis of a golf club in the address state and a second straight line intersecting the first straight line and passing through the root of an installed tee and the base of the neck of a golfer.
However, a V zone is known as an index for indicating goodness and badness of a swing. In general, when a trajectory of a swing is included in a V zone, the swing is estimated to be a good swing.
In JP-A-2010-82430, a golfer at the time of address is photographed from the rear side of the hitting direction using a camera and, for example, a user draws a line in the photographed image to specify a V zone. In JP-A-2010-82430, the golfer performing a swing is photographed using a camera and it is visually confirmed whether a trajectory of the swing of the golfer is contained in the V zone drawn by the user. Therefore, in JP-A-2010-82430, there is a problem that it is difficult to estimate a swing.

SUMMARY

An advantage of some aspects of the invention is that it provides a technology for simply estimating a swing.
A first aspect of the invention is directed to an exercise analysis device including: a first specifying unit that specifies a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of an inertial sensor; a second specifying unit that specifies a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis; an analysis unit that calculates a trajectory of a swing of the user based on an output of the inertial sensor; and a determination unit that determines whether the trajectory passes through a predetermined region specified based on the first and second axes.
According to the first aspect of the invention, the exercise analysis device can change the display form of the trajectory of the swing according to the passage state of the trajectory of the swing through the predetermined region specified based on the first and second axes. Thus, the user can easily see whether the trajectory of a swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform a swing estimation.
The determination unit may determine a portion of the trajectory which passes through the predetermined region and a portion of the trajectory which does not pass through the predetermined region.
With this configuration, the exercise analysis device can change the display form of the trajectory of the swing in the portion of the trajectory of the swing which passes through the predetermined region and the portion of the trajectory of the swing which does not pass through the predetermined region. The user can easily see whether the trajectory of a swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
The exercise analysis device may further include an image generation unit that generates image data in which a display form of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.
With this configuration, in accordance with the difference in the display from of the trajectory of the swing, the user can easily see whether the trajectory of the swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
The image generation unit may generate the image data in which a color of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.
With this configuration, in accordance with the difference in the color of the trajectory of the swing, the user can easily see whether the trajectory of the swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
The image generation unit may generate the image data in which the trajectory continuously lights and blinks to distinguish the portion which passes through the predetermined region from the portion which does not pass through the predetermined region.
With this configuration, in accordance with the continuous lighting or blinking of the trajectory of the swing, the user can easily see whether the trajectory of the swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
The image generation unit may generate the image data in which a kind of line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.
With this configuration, in accordance with the difference in the kind of the trajectory of the swing, the user can easily see whether the trajectory of the swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
The image generation unit may generate the image data in which a thickness of a line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.
With this configuration, in accordance with the difference in the thickness of the line of the trajectory of the swing, the user can easily see whether the trajectory of the swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
The first specifying unit may specify a first imaginary plane including the first axis and the hitting direction. The second specifying unit may specify a second imaginary plane including the second axis and the hitting direction. The predetermined region may be a region interposed between the first and second imaginary planes.
With this configuration, the user can easily see whether the trajectory of the swing passes through the predetermined region interposed between the first and second imaginary planes, and thus can simply perform the swing estimation.
The image generation unit may define first and second regions interposing the predetermined region outside the predetermined region, and generate image data in which the predetermined region, the first region, and the second region are distinguished and displayed.
With this configuration, the user can easily see how the trajectory of the swing passes through the first and second regions, and thus can simply perform the swing estimation.
A second aspect of the invention is directed to an exercise analysis method including: specifying a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of an inertial sensor; specifying a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis; calculating a trajectory of a swing of the user based on an output of the inertial sensor; and determining whether the trajectory passes through a predetermined region specified based on the first and second axes.
According to the second aspect of the invention, the exercise analysis device can change the display form of the trajectory of the swing according to the passage state of the trajectory of the swing through the predetermined region specified based on the first and second axes. Thus, the user can easily see whether the trajectory of a swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
In the determining of the trajectory, a portion of the trajectory which passes through the predetermined region and a portion of the trajectory which does not pass through the predetermined region may be determined.
Thus, in the exercise analysis method, the display form of the trajectory of the swing can be changed in the portion of the trajectory of the swing which passes through the predetermined region and the portion of the trajectory of the swing which does not pass through the predetermined region. The user can easily see whether the trajectory of a swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
A third aspect of the invention is directed to a program causing a computer to perform: specifying a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of an inertial sensor; specifying a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis; calculating a trajectory of a swing of the user based on an output of the inertial sensor; and determining whether the trajectory passes through a predetermined region specified based on the first and second axes.
According to the third aspect of the invention, the computer can change the display form of the trajectory of the swing according to the passage state of the trajectory of the swing through the predetermined region specified based on the first and second axes. Thus, the user can easily see whether the trajectory of a swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
Another aspect of the invention is directed to a recording medium that records a program causing a computer to perform: specifying a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of an inertial sensor; specifying a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis; calculating a trajectory of a swing of the user based on an output of the inertial sensor; and determining whether the trajectory passes through a predetermined region specified based on the first and second axes.
According to the another aspect of the invention, the computer can change the display form of the trajectory of the swing according to the passage state of the trajectory of the swing through the predetermined region specified based on the first and second axes. Thus, the user can easily see whether the trajectory of a swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
A fourth aspect of the invention is directed to an exercise analysis system including: an inertial sensor; a first specifying unit that specifies a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of the inertial sensor; a second specifying unit that specifies a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis; an analysis unit that calculates a trajectory of a swing of the user based on an output of the inertial sensor; and a determination unit that determines whether the trajectory passes through a predetermined region specified based on the first and second axes.
According to the fourth aspect of the invention, the exercise analysis system can change the display form of the trajectory of the swing according to the passage state of the trajectory of the swing through the predetermined region specified based on the first and second axes. Thus, the user can easily see whether the trajectory of a swing passes through the predetermined region specified based on the first and second axes, and thus can simply perform the swing estimation.
Still another aspect of the invention is directed to an exercise analysis device that determines whether a trajectory of a swing of a user passes through a V zone.
A display form of the trajectory may differ between a portion of the trajectory which passes through the V zone and a portion of the trajectory which does not pass through the V zone.
The exercise analysis device may further include an image generation unit that generates image data in which the display form of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.
The image generation unit may generate image data in which a color of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.
The image generation unit may generate image data in which the trajectory continuously lights and blinks to distinguish the portion which passes through the predetermined region from the portion which does not pass through the predetermined region.
The image generation unit may generate image data in which a kind of line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.
The image generation unit may generate image data in which a thickness of line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIG. 1 is a diagram illustrating an overview of an exercise analysis system according to an embodiment of the invention.

FIG. 2 is a diagram illustrating examples of a shaft plane and a Hogan's plane.

FIG. 3 is a block diagram illustrating an example of the configuration of an exercise analysis system.

FIG. 4 is a flowchart illustrating an example of an exercise analysis process.

FIG. 5 is a plan view illustrating a golf club and a sensor unit at the time of stopping of a user when viewed from the negative side of the X axis.

FIG. 6 is a diagram illustrating a cross section obtained by cutting the shaft plane along the YZ plane when viewed from the negative side of the X axis.

FIG. 7 is a diagram illustrating a cross section obtained by cutting the Hogan's plane along the YZ plane when viewed from the negative side of the X axis.

FIG. 8 is a diagram illustrating examples of angular velocities output from the sensor unit.

FIG. 9 is a diagram illustrating an example of a norm of an angular velocity.

FIG. 10 is a diagram illustrating an example of a differential value of the norm of an angular velocity.

FIG. 11 is a diagram (a diagram projected to the YZ plane) illustrating the shaft plane and the Hogan's plane when viewed from the negative side of the X axis.

FIG. 12 is a diagram illustrating an example of a screen displayed on a display unit.

FIG. 13 is a flowchart illustrating an example of operations of a trajectory determination unit and an image generation unit.

FIG. 14 is a diagram illustrating an example of a screen in which a region outside a V zone including a line segment and a Hogan's plane is displayed.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the invention will be described with reference to the drawings. Hereinafter, an exercise analysis system performing analysis of a golf swing will be described as an example.
FIG. 1 is a diagram illustrating an overview of an exercise analysis system according to an embodiment of the invention.
An exercise analysis system 1 includes a sensor unit 10 and an exercise analysis device 20.
The sensor unit 10 can measure acceleration generated in each axis direction of three axes and an angular velocity generated in each rotation of the three axes as an inertial sensor and is mounted on a golf club 3. For example, the sensor unit 10 is fitted on a part of the shaft of the golf club 3 when one axis among three detection axes (the x axis, the y axis, and the z axis), for example, the y axis, conforms to the major axis direction of the shaft. Preferably, the sensor unit 10 is fitted at a position close to a grip in which a shock at the time of a shot is rarely delivered and a centrifugal force is not applied at the time of a swing. The shaft is a portion of the handle excluding the head of the golf club 3 and also includes the grip.
A user 2 performs a swing motion of hitting a golf ball (not illustrated) in a pre-decided procedure. For example, the user 2 first holds the golf club 3, takes a posture of address so that the major axis (longitudinal direction) of the shaft of the golf club 3 is vertical to a target line (a hitting target direction), and stops for a predetermined time or more (for example, 1 second or more). Next, the user 2 performs a swing motion to hit the golf ball. The posture of address in the present specification includes a posture in a stop state of the user before start of a swing or a posture in a state in which the user shakes an exercise tool (waggling) before start of a swing. The target line refers to any hitting direction and is decided as, for example, a hitting target direction in the embodiment.
While the user 2 performs the motion to hit the golf ball in the above-described procedure, the sensor unit 10 measures triaxial acceleration and triaxial angular velocities at a predetermined period (for example, 1 ms) and sequentially transmits the measurement data to the exercise analysis device 20. The sensor unit 10 may immediately transmit the measurement data, or may store the measurement data in an internal memory and transmit the measurement data at a desired timing such as the end of a swing motion of the user 2. Communication between the sensor unit 10 and the exercise analysis device 20 may be wireless communication or wired communication. Alternatively, the sensor unit 10 may store the measurement data in a recording medium such as a memory card which can be detachably mounted and the exercise analysis device 20 may read the measurement data from the recording medium.
The exercise analysis device 20 analyzes a swing exercise performed with the golf club 3 by the user 2 using the data measured by the sensor unit 10. In particular, in the embodiment, the exercise analysis device 20 specifies a shaft plane (which corresponds to a first imaginary plane or a first axis according to the invention) and a Hogan's plane (which corresponds to a second imaginary plane or a second axis according to the invention) at the time of stopping of the user 2 (the time of address) using the data measured by the sensor unit 10.
The exercise analysis device 20 calculates a trajectory of the golf club 3 (for example, a trajectory of the head) at a swing after the user 2 starts the swing motion. The exercise analysis device 20 changes a display form of the trajectory according to a passage state of the trajectory of the golf club 3 through a region referred to as a V zone between the shaft plane and the Hogan's plane and displays the display form of the trajectory on a display device. At this time, the exercise analysis device 20 does not display the shaft plane and the Hogan's plane indicating the V zone in the display device. That is, when the exercise analysis device 20 changes the display form of the trajectory of the golf club 3 by displaying the display form in the display device, the user 2 sees how the trajectory of the golf club 3 passes through the V zone.
For example, the exercise analysis device 20 displays a trajectory outside the V zone with a first color such as red in the display device and displays a trajectory inside the V zone with a second color, such as blue, different from the first color in the display device. Thus, the user 2 can see how the trajectory of his or her swing passes through the V zone even when the shaft plane and the Hogan's plane indicating the V zone is not displayed in the display device.
The exercise analysis device 20 may be, for example, a portable device such as a smartphone or a personal computer (PC). In FIG. 1, the exercise analysis device 20 is mounted on the waist of the user 2, but the mounted position is not particularly limited. Further, the exercise analysis device 20 may not be mounted on the user 2.
FIG. 2 is a diagram illustrating examples of the shaft plane and the Hogan's plane. In the embodiment, an XYZ coordinate system (global coordinate system) in which a target line indicating a hitting target direction is an X axis, an axis on a horizontal plane vertical to the X axis is a Y axis, and an upward vertical direction (which is an opposite direction to the direction of the gravity acceleration) is a Z axis is defined. In FIG. 2, the X, Y, and Z axes are shown.
A shaft plane 30 at the time of address of the user 2 is an imaginary plane which includes a first line segment 51 serving as a first axis which lies in the major axis direction of the shaft of the golf club 3 and a third line segment 52 serving as a third axis indicating a hitting target direction and has four vertexes T1, T2, S1, and S2. In the embodiment, a position 61 of the head (blow portion) of the golf club 3 is set as the origin O (0, 0, 0) of the XYZ coordinate system. The first line segment 51 is a line segment which connects the position 61 (the origin O) of the head of the golf club 3 to a position 62 of a grip end. The third line segment 52 is a line segment which has T1 and T2 on the X axis as both ends, has a length TL, and centers on the origin O. When the user 2 takes the above-described address posture at the time of the address, the shaft of the golf club 3 is vertical to the target line (the X axis). Therefore, the third line segment 52 is a line segment which is perpendicular to the major axis direction of the shaft of the golf club 3, that is, a line segment perpendicular to the first line segment 51. The shaft plane 30 is specified by calculating the coordinates of the four vertexes T1, T2, S1, and S2 in the XYZ coordinate system. A method of calculating the coordinates of the four vertexes T1, T2, S1, and S2 will be described in detail below.
The Hogan's plane 40 is an imaginary plane which includes the third line segment 52 and a second line segment 53 serving as a second axis and has four vertexes T1, T2, H1, and H2. In the embodiment, the second line segment 53 is a line segment which connects the position 62 (which is an example of a blow position) of the head (which is a blow portion) of the golf club 3 to a predetermined position 63 (which is, for example, the position of the base of the neck or the position of one of the right and left shoulders) on a line segment connecting both shoulders of the user 2 to one another. Here the second line segment 53 may be a line segment which connects the predetermined position 63 to the position (which is an example of the blow position) of a ball at the time of address. A Hogan's plane 40 is specified by calculating the coordinates of the four vertexes T1, T2, H1, and H2 in the XYZ coordinate system. A method of calculating the coordinates of the four vertexes T1, T2, H1, and H2 will be described in detail below.
FIG. 3 is a block diagram illustrating an example of the configuration of an exercise analysis system.
The sensor unit 10 includes a control unit 11, a communication unit 12, an acceleration sensor 13, and an angular velocity sensor 14.
The acceleration sensor 13 measures acceleration generated in each of mutually intersecting (ideally, orthogonal) triaxial directions and outputs digital signals (acceleration data) according to the sizes and directions of the measured triaxial accelerations.
The angular velocity sensor 14 measures an angular velocity generated at axis rotation of mutually intersecting (ideally, orthogonal) three axes and outputs digital signals (angular velocity data) according to the sizes and directions of the measured triaxial angular velocities.
The control unit 11 controls the sensor unit in an integrated manner. The control unit 11 receives the acceleration data and the angular velocity data from the acceleration sensor 13 and the angular velocity sensor 14, appends time information, and stores the acceleration data and the angular velocity data in a storage unit (not illustrated). The control unit 11 generates packet data in conformity to a communication format by appending time information to the stored measurement data (the acceleration data and the angular velocity data) and outputs the packet data to the communication unit 12.
The acceleration sensor 13 and the angular velocity sensor 14 are ideally fitted in the sensor unit 10 so that the three axes of each sensor match the three axes (the x axis, the y axis, and the z axis) of the rectangular coordinate system (sensor coordinate system) defined for the sensor unit 10, but errors of the fitting angles actually occur. Accordingly, the control unit 11 performs a process of converting the acceleration data and the angular velocity data into data of the xyz coordinate system, using correction parameters calculated in advance according to the errors of the fitting angles.
The control unit 11 may perform a temperature correction process of the acceleration sensor 13 and the angular velocity sensor 14. Alternatively, a temperature correction function may be embedded in the acceleration sensor 13 and the angular velocity sensor 14.
The acceleration sensor 13 and the angular velocity sensor 14 may output analog signals. In this case, the control unit 11 may perform A/D (analog/digital) conversion on each of an output signal of the acceleration sensor 13 and an output signal of the angular velocity sensor 14, generate measurement data (acceleration data and angular velocity data), and generate packet data for communication using the measurement data.
The communication unit 12 performs, for example, a process of transmitting the packet data received from the control unit 11 to the exercise analysis device 20 or a process of receiving control commands from the exercise analysis device 20 and transmitting the control commands to the control unit 11. The control unit 11 performs various processes according to the control commands.
The exercise analysis device 20 includes a control unit 21, a communication unit 22, an operation unit 23, a storage unit 24, a display unit 25, and a sound output unit 26.
The communication unit 22 performs, for example, a process of receiving the packet data transmitted from the sensor unit 10 and transmitting the packet data to the control unit 21 or a process of transmitting a control command from the control unit 21 to the sensor unit 10.
The operation unit 23 performs a process of acquiring operation data from the user and transmitting the operation data to the control unit 21. The operation unit 23 may be, for example, a touch panel type display, a button, a key, or a microphone.
The storage unit 24 is configured by, for example, any of various IC memories such as a read-only memory (ROM), a flash ROM, and a random access memory (RAM) or a recording medium such as a hard disk or a memory card.
The storage unit 24 stores, for example, programs used for the control unit 21 to perform various calculation processes or control processes, or various programs or data used for the control unit 21 to realize application functions. In particular, in the embodiment, the storage unit 24 stores an exercise analysis program which is read by the control unit 21 to perform an analysis process. The exercise analysis program may be stored in advance in a nonvolatile recording medium. Alternatively, the exercise analysis program may be received from a server via a network by the control unit 21 and may be stored in the storage unit 24.
In the embodiment, the storage unit 24 stores body information of the user 2, club specification information indicating the specification of the golf club 3, and sensor-mounted position information. For example, when the user 2 operates the operation unit 23 to input the body information such as a height, a weight, and a sex, the input body information is stored as body information in the storage unit 24. For example, the user 2 operates the operation unit 23 to input a model number of the golf club 3 (or selects the model number from a model number list) to be used and sets specification information regarding the input model number as the club specification information among pieces of specification information for each model number (for example, information regarding the length of the shaft, the position of the center of gravity, a lie angle, a face angle, a loft angle, and the like) stored in advance in the storage unit 24. For example, when the user 2 operates the operation unit 23 to input a distance between the position at which the sensor unit 10 is mounted and the grip end of the golf club 3, information regarding the input distance is stored as the sensor-mounted position information in the storage unit 24. Alternatively, by mounting the sensor unit 10 at a decided predetermined position (for example, a distance of 20 cm from the grip end), information regarding the predetermined position may be stored in advance as the sensor-mounted position information.
The storage unit 24 is used as a work area of the control unit 21 and temporarily stores, for example, data input from the operation unit 23 and calculation results performed according to various programs by the control unit 21. The storage unit 24 may store data necessarily stored for a long time among the data generated through the processes of the control unit 21.
The display unit 25 displays a processing result of the control unit 21 as text, a graph, a table, animations, or another image. The display unit 25 may be, for example, a cathode ray tube (CRT) display, a liquid crystal display (LCD), an electrophoretic display (EPD), a display using an organic light-emitting diode (OLED), a touch panel type display, or a head-mounted display (HMD). The functions of the operation unit 23 and the display unit 25 may be realized by one touch panel type display.
The sound output unit 26 outputs a processing result of the control unit 21 as audio such as a sound or a buzzer tone. The sound output unit 26 may be, for example, a speaker or a buzzer.
The control unit 21 performs a process of transmitting a control command to the sensor unit 10, various calculation processes on data received from the sensor unit 10 via the communication unit 22, and other various control processes according to various programs. In particular, in the embodiment, the control unit 21 executes an exercise analysis program to function as a sensor information acquisition unit 210, a first imaginary plane specifying unit 211 (which corresponds to a first specifying unit according to the invention), a second imaginary plane specifying unit 212 (which corresponds to a second specifying unit according to the invention), an exercise analysis unit 213 (which correspond to an analysis unit according to the invention), a trajectory determination unit 214 (which corresponds to a determination unit according to the invention), an image generation unit 215, and an output processing unit 216. The sensor information acquisition unit 210, the first imaginary plane specifying unit 211, the second imaginary plane specifying unit 212, the exercise analysis unit 213, the trajectory determination unit 214, the image generation unit 215, and the output processing unit 216 may be realized by separate calculation units or some or all thereof may be realized by the same calculation unit.
The control unit 21 may be realized by a computer that includes a central processing unit (CPU) which is a calculation device, a random access memory (RAM) which is a volatile storage device, a ROM which is a non-volatile storage device, an interface (I/F) circuit connecting the control unit 21 to the other units, and a bus mutually connecting these units. The computer may include various dedicated processing circuits such as image processing circuits. The control unit 21 may also be realized by an application specific integrated circuit (ASIC) or the like.
The sensor information acquisition unit 210 receives the packet data received from the sensor unit 10 by the communication unit 22 and acquires the time information and the measurement data from the received packet data. The sensor information acquisition unit 210 stores the acquired time information and measurement data in the storage unit 24 in association therewith.
The first imaginary plane specifying unit 211 performs a process of specifying the first line segment 51 in the major axis direction (longitudinal direction) of the shaft of the golf club 3 at the time of stopping of the user 2, using the measurement data output by the sensor unit 10. Further, the first imaginary plane specifying unit 211 performs a process of specifying the shaft plane (first imaginary plane) 30 (see FIG. 2) including the first line segment 51 and the third line segment 52 indicating the hitting target direction.
The first imaginary plane specifying unit 211 may calculate the coordinates of the position 62 of the grip end of the golf club 3 using the measurement data output by the sensor unit 10 and specify the first line segment 51 based on the coordinates of the position 62 of the grip end. For example, the first imaginary plane specifying unit 211 may calculate an inclination angle (an inclination relative to the horizontal plane (the XY plane) or the vertical plane (the XZ plane)) of the shaft of the golf club 3, using the acceleration data measured by the acceleration sensor 13 at the time of stopping of the user 2 (the time of the address) and specify the first line segment 51 using the calculated inclination angle and information regarding the length of the shaft included in the club specification information.
The first imaginary plane specifying unit 211 may calculate the width of the shaft plane 30 using the length of an arm of the user 2 based on the body information and the length of the first line segment 51.
The second imaginary plane specifying unit 212 performs a process of specifying the second line segment 53 forming a predetermined angle relative to the first line segment 51 specified by the first imaginary plane specifying unit 211, using the hitting target direction (the third line segment 52) as the rotation axis. Further, the second imaginary plane specifying unit 212 performs a process of specifying the Hogan's plane (second imaginary plane) 40 (see FIG. 2) including the second line segment 53 and the third line segment 52.
For example, the second imaginary plane specifying unit 212 performs a process of estimating the predetermined position 63 between the head and the chest of the user 2 at the time of stopping of the user 2 (for example, on a line segment connecting both shoulders to one another) using the body information and the measurement data output by the sensor unit 10 and specifying the second line segment 53 connecting the estimated predetermined position 63 to the position 62 of the head (blow portion) of the golf club 3. The second imaginary plane specifying unit 212 performs a process of specifying the Hogan's plane 40 including the second line segment 53 and the third line segment 52.
The second imaginary plane specifying unit 212 may estimate the predetermined position 63 using the coordinates of the position 62 of the grip end calculated by the first imaginary plane specifying unit 211 and the length of the arm of the user 2 based on the body information. Alternatively, the second imaginary plane specifying unit 212 may calculate the coordinates of the position 62 of the grip end of the golf club 3 using the measurement data output by the sensor unit 10. In this case, the first imaginary plane specifying unit 211 may specify the shaft plane 30 using the coordinates of the position 62 of the grip end calculated by the second imaginary plane specifying unit 212.
The second imaginary plane specifying unit 212 may calculate the width of the Hogan's plane 40 using the length of the arm of the user 2 based on the body information and the length of the first line segment 51.
The exercise analysis unit 213 performs a process of analyzing a swing exercise of the user 2 using the measurement data output by the sensor unit 10. Specifically, the exercise analysis unit 213 first calculates an offset amount included in the measurement data using the measurement data (the acceleration data and the angular velocity data) at the time of stopping of the user 2 (the time of the address), which is stored in the storage unit 24. Next, the exercise analysis unit 213 subtracts the offset amount from the measurement data after start of a swing, which is stored in the storage unit 24 to correct a bias and calculates the position and posture of the sensor unit 10 during a swing motion of the user 2 using the measurement data in which the bias is corrected.
For example, the exercise analysis unit 213 calculates the position (initial position) of the sensor unit 10 at the time of stopping of the user 2 (the time of the address) in the XYZ coordinate system (global coordinate system), using the acceleration data measured by the acceleration sensor 13, the club specification information, and the sensor-mounted position information, integrates the subsequent acceleration data, and chronologically calculates a change in the position of the sensor unit 10 from the initial position. Since the user 2 stops at a predetermined address posture, the X coordinate of the initial position of the sensor unit 10 is 0. Further, the y axis of the sensor unit 10 is identical to the major axis direction of the shaft of the golf club 3, and the acceleration sensor 13 measures only the gravity acceleration at the time of stopping of the user 2. Therefore, the exercise analysis unit 213 can calculate an inclination angle of the shaft (an inclination relative to the horizontal plane (the XY plane) or the vertical plane (the XZ plane)), using y-axis acceleration data. Then, the exercise analysis unit 213 can calculate the Y and Z coordinates of the initial position of the sensor unit 10 using the inclination angle of the shaft, the club specification information (the length of the shaft), and the sensor-mounted position information (the distance from the grip end) and specify the initial position of the sensor unit 10. Alternatively, the exercise analysis unit 213 may calculate the coordinates of the initial position of the sensor unit 10 using the coordinates of the position 62 of the grip end of the golf club 3 calculated by the first imaginary plane specifying unit 211 or the second imaginary plane specifying unit 212 and the sensor-mounted position information (the distance from the grip end).
The exercise analysis unit 213 calculates the posture (initial posture) of the sensor unit 10 at the time of stopping of the user 2 (the time of the address) in the XYZ coordinate system (global coordinate system), using the acceleration data measured by the acceleration sensor 13, performs rotation calculation using the angular velocity data measured subsequently by the angular velocity sensor 14, and chronologically calculates a change in the posture from the initial posture of the sensor unit 10. The posture of the sensor unit 10 can be expressed by, for example, rotation angles (a roll angle, a pitch angle, and a yaw angle) around the X axis, the Y axis, and the Z axis, Eulerian angles, quaternions, or the like. At the time of stopping of the user 2, the acceleration sensor 13 measures only the gravity acceleration. Therefore, the exercise analysis unit 213 can specify an angle formed between of each of the x, y, and z axes of the sensor unit 10 and a gravity direction using triaxial acceleration data. Since the user 2 stops at the predetermined address posture, the y axis of the sensor unit 10 is present on the YZ plane at the time of stopping of the user 2. The exercise analysis unit 213 can specify the initial posture of the sensor unit 10.
The control unit 11 of the sensor unit 10 may calculate the offset amount of the measurement data and correct the bias of the measurement data or a bias correction function may be embedded in the acceleration sensor 13 and the angular velocity sensor 14. In this case, it is not necessary to correct the bias of the measurement data by the exercise analysis unit 213.
The exercise analysis unit 213 defines an exercise analysis model (a double pendulum model or the like) in consideration of the body information (the height (length of the arm) of the user 2), the club specification information (the length or the position of the center of the shaft), the senor-mounted position information (the distance from the grip end), features (rigid body and the like) of the golf club 3, and features of a human body (for example, a joint bending direction is decided), and then calculate a trajectory of the golf club 3 at a swing of the user 2 using the exercise analysis model and the information regarding the position and posture of the sensor unit 10.
The exercise analysis unit 213 detects a timing (a timing of impact) at which a ball is hit during a period of a swing motion of the user 2, using time information and the measurement data stored in the storage unit 24. For example, the exercise analysis unit 213 calculates a composite value of the measurement data (the acceleration data or the angular velocity data) output by the sensor unit 10 and specifies a timing (time) at which the user 2 hits the ball based on the composite value.
Using the exercise analysis model and information regarding the position and posture of the sensor unit 10, the exercise analysis unit 213 may generate a rhythm of a swing from a backswing to follow-through, a head speed, an incident angle (club pass) or a face angle at the time of hitting, shaft rotation (a change amount of face angle during a swing), information regarding a deceleration rate or the like of the golf club 3, or information regarding a variation in each piece of information when the user 2 performs the swing a plurality of times.
The trajectory determination unit 214 determines whether the trajectory of the golf club 3 calculated by the exercise analysis unit 213 passes through a V zone (a region between the shaft plane 30 specified by the first imaginary plane specifying unit 211 and the Hogan's plane 40 specified by the second imaginary plane specifying unit 212). Specifically, the trajectory determination unit 214 determines a portion of the trajectory of the golf club 3 which is calculated by the exercise analysis unit 213 and passes through the V zone and a portion of the trajectory which does not pass the V zone.
The image generation unit 215 performs a process of generating image data corresponding to an image of an exercise analysis result displayed on the display unit 25. In particular, in the embodiment, the image generation unit 215 generates image data in which a display form of the trajectory of the golf club 3 is changed in the portion of the trajectory of the golf club 3 which is determined by the trajectory determination unit 214 and passes through the V zone and the portion of the trajectory of the golf club 3 which does not pass the V zone. For example, the image generation unit 215 generates the image data in which the color of the trajectory is changed in the portion of the trajectory of the golf club 3 which passes through the V zone and in the portion of the trajectory of the golf club 3 which does not pass through the V zone. Specifically, the image generation unit 215 generates the image data in which a first color is set to the trajectory of the golf club 3 in the portion of the trajectory of the golf club 3 which passes outside the V zone and a second color different from the first color is set to the trajectory in the portion of the trajectory of the golf club 3 which passes through the V zone.
The first imaginary plane specifying unit 211, the second imaginary plane specifying unit 212, the exercise analysis unit 213, the trajectory determination unit 214, and the image generation unit 215 also perform a process of storing various kinds of calculated information in the storage unit 24.
The output processing unit 216 performs a process of causing the display unit 25 to display various images (including not only an image corresponding to the image data generated by the image generation unit 215 but also text, signs or the like). For example, the output processing unit 216 causes the display unit 25 to display the image corresponding to the image data generated by the image generation unit 215 automatically or according to an input operation of the user 2 after a swing motion of the user 2 ends. Alternatively, the sensor unit 10 may include a display unit, the output processing unit 216 may transmit the image data to the sensor unit 10 via the communication unit 22, and various images may be displayed on the display unit of the sensor unit 10.
The output processing unit 216 performs a process of causing the sound output unit 26 to output various kinds of audio (also including sound, buzzer tone or the like). For example, the output processing unit 216 reads various kinds of information stored in the storage unit 24 and causes the sound output unit 26 to output audio or sound for exercise analysis automatically or at the time of performing a predetermined input operation after a swing motion of the user 2 ends. Alternatively, the sensor unit 10 may include a sound output unit, the output processing unit 216 may transmit various kinds of audio data or sound data to the sensor unit 10 via the communication unit 22, and the sound output unit of the sensor unit 10 may be caused to output the various kinds of audio or sound.
The exercise analysis device 20 or the sensor unit 10 may include a vibration mechanism and various kinds of information may be converted into vibration information by the vibration mechanism to be presented to the user 2.
FIG. 4 is a flowchart illustrating an example of an exercise analysis process. The control unit 21 executes an exercise analysis program stored in the storage unit 24 to perform the exercise analysis process in the procedure of the flowchart illustrated in FIG. 4.
First, the sensor information acquisition unit 210 acquires the measurement data of the sensor unit 10 (step S10). When the control unit 21 acquires the first measurement data in a swing motion (also including a stopping motion) of the user 2, the control unit 21 may perform processes subsequent to step S20 in real time. Alternatively, after the control unit 21 acquires some or all of the series of measurement data in the swing motion of the user 2 from the sensor unit 10, the control unit 21 may perform the processes subsequent to step S20.
Next, the exercise analysis unit 213 detects a stopping motion (address motion) of the user 2 using the measurement data acquired from the sensor unit 10 (step S20). When the control unit 21 performs the process in real time and detects the stopping motion (address motion), for example, the control unit 21 outputs a predetermined image or audio. Alternatively, the sensor unit 10 may include a light-emitting diode (LED) and blinks the LED to notify the user 2 that the stopped state is detected so that the user 2 confirms the notification and subsequently starts a swing.
Next, the first imaginary plane specifying unit 211 specifies the shaft plane 30 (the first imaginary plane) using the measurement data (the measurement data in the stopping motion (address motion) of the user 2) acquired from the sensor unit 10 and the club specification information (step S30).
Next, the second imaginary plane specifying unit 212 specifies the Hogan's plane 40 (the second imaginary plane) using the measurement data (the measurement data in the stopping motion (address motion) of the user 2) acquired from the sensor unit 10 and the body information (step S40).
Next, the exercise analysis unit 213 calculates the initial position and the initial posture of the sensor unit 10 using the measurement data (the measurement data in the stopping motion (address motion) of the user 2) acquired from the sensor unit 10 (step S50).
Next, the exercise analysis unit 213 detects a series of motions (rhythm) from the start of the swing to the end of the swing using the measurement data acquired from the sensor unit 10 (step S60).
The exercise analysis unit 213 calculates the position and posture of the sensor unit 10 during the swing motion of the user 2 concurrently with the process of step S60 (step S70).
Next, the exercise analysis unit 213 calculates the trajectory of the golf club 3 during the swing motion of the user 2 using the rhythm detected in step S60 and the position and posture of the sensor unit 10 calculated in step S70 (step S80).
Next, the trajectory determination unit 214 determines whether the trajectory of the golf club 3 calculated in step S80 passes through the V zone (the region between the shaft plane 30 specified in step S30 and the Hogan's plane 40 specified in step S40) (step S90). Specifically, the trajectory determination unit 214 determines the portion of the trajectory of the golf club 3 which is calculated by the exercise analysis unit 213 and passes through the V zone and the portion of the trajectory which does not pass through the V zone.
Next, the image generation unit 215 generates the image data including the trajectory of the golf club 3 based on the determination result of step S90 (step S100). At this time, the image generation unit 215 does not include images of the shaft plane 30 and the Hogan's plane 40 in the image data and generates the image data in which the display form of the trajectory of the golf club 3 is changed according to a passage state of the trajectory of the golf club 3 through the V zone. For example, the image generation unit 215 generates the image data in which the color of the trajectory is changed in the portion of the trajectory of the golf club 3 which passes through the V zone and the portion of the trajectory which does not pass through the V zone.
The image data generated by the image generation unit 215 is output to the display unit 25 by the output processing unit 216. Then, the control unit 21 ends the process of the flowchart illustrated in FIG. 4.
In the flowchart of FIG. 4, the sequence of the processes may be appropriately changed within a possible range.
Next, an example of the process (the process of step S30 in FIG. 4) of specifying the shaft plane (the first imaginary plane) will be described in detail.
As illustrated in FIG. 2, the first imaginary plane specifying unit 211 first calculates the coordinates (0, G_Y, G_Z) of the position 62 of the grip end based on the acceleration data at the time of the stopping measured by the sensor unit 10 and the club specification information by using the position 61 of the head of the golf club 3 as the origin O (0, 0, 0) of the XYZ coordinate system (global coordinate system). FIG. 5 is a plan view illustrating the golf club 3 and the sensor unit 10 at the time of stopping of the user 2 (the time of the address) when viewed from the negative side of the X axis. In FIG. 5, the position 61 of the head of the golf club 3 is the origin O (0, 0, 0) and the coordinates of the position 62 of the grip end are (0, G_Y, G_Z). Since the gravity acceleration G is applied to the sensor unit 10 at the time of stopping of the user 2, a relation between the y axis acceleration y(0) and an inclination angle (an angle formed by the major axis of the shaft and the horizontal plane (XY plane)) a of the shaft of the golf club 3 is expressed in equation (1).
y(0)=G·sin α (1)
Accordingly, when L₁is the length of the shaft of the golf club 3 included in the club specification information, G_Yand G_Zare calculated using the length L₁and the inclination angle α of the shaft in equations (2) and (3), respectively.
G _Y =L ₁·cos α (2)
G _Z =L ₁·sin α (3)
Next, the first imaginary plane specifying unit 211 multiplies the coordinates (0, G_Y, G_Z) of the position 62 of the grip end of the golf club 3 by a scale factor S to calculate the coordinates (0, S_Y, S_Z) of a midpoint S3 of the vertexes S1 and S2 of the shaft plane 30. That is, S_Yand S_Zare calculated using equations (4) and (5).
S _Y =G _Y ·S (4)
S _Z =G _Z ·S (5)
FIG. 6 is a diagram illustrating a cross section obtained by cutting the shaft plane 30 in FIG. 2 along the YZ plane when viewed from the negative side of the X axis. The length (the width of the shaft plane 30 in a direction perpendicular to the X axis) of a line segment connecting the origin O to the midpoint S3 of the vertexes S1 and S2 is S times the length L₁of the first line segment 51. The scale factor S is set to a value so that the trajectory of the golf club 3 during the swing motion of the user 2 falls within the shaft plane 30. For example, when L₂is the length of an arm of the user 2, the scale factor S may be set as in equation (6) so that a width S×L₁in the direction perpendicular to the X axis of the shaft plane 30 is twice a sum of the length L₁of the shaft and the length L₂of the arm.
$\begin{matrix} S = \frac{2 \cdot (L_{1} + L_{2})}{L_{1}} & (6) \end{matrix}$
The length L₂of the arm of the user 2 has correlation with a height L₀of the user 2. For example, based on statistical information, a correlation equation as in equation (7) is expressed when the user 2 is male, and a correlation equation as in equation (8) is expressed when the user 2 is female.
L ₂=0.41×L ₀−45.5 [mm] (7)
L ₂=0.46×L ₀−126.9 [mm] (8)
Accordingly, the length L₂of the arm of the user is calculated by equation (7) or (8) using the height L₀and sex of the user 2 included in the body information.
Next, the first imaginary plane specifying unit 211 calculates the coordinates (−TL/2, 0, 0) of the vertex T1, the coordinates (TL/2, 0, 0) of the vertex T2, the coordinates (−TL/2, S_Y, S_Z) of the vertex S1, and the coordinates (TL/2, S_Y, S_Z) of the S2 of the shaft plane 30 using the coordinates (0, S_Y, S_Z) of the midpoint S3 calculated as described above and the width (the length of the third line segment 52) TL of the shaft plane 30 in the X axis direction. The width TL in the X axis direction is set to a value so that the trajectory of the golf club 3 during the swing motion of the user 2 falls within the shaft plane 30. For example, the width TL in the X axis direction may be set to be the same as the width S×L₁in the direction perpendicular to the X axis, that is, twice the sum of the length L₁of the shaft and the length L₂of the arm.
The shaft plane 30 is specified based on the coordinates of the four vertexes T1, T2, S1, and S2 calculated in this way.
Next, an example of the process (the process of step S40 in FIG. 4) of specifying the Hogan's plane (the second imaginary plane) will be described in detail.
First, the second imaginary plane specifying unit 212 estimates the predetermined position 63 on the line segment connecting both shoulders of the user 2 to one another to calculate the coordinates (A_X, A_Y, A_Z), using the coordinates (0, G_Y, G_Z) of the position 62 of the grip end of the golf club 3 calculated as described above and the body information of the user 2.
FIG. 7 is a diagram illustrating a cross section obtained by cutting the Hogan's plane 40 in FIG. 2 along the YZ plane when viewed from the negative side of the X axis. In FIG. 7, the midpoint of the line segment connecting both shoulders of the user 2 to one another is set as the predetermined position 63, and the predetermined position 63 is present on the YZ plane. Accordingly, the X coordinate A_Xof the predetermined position 63 is 0. Then, the second imaginary plane specifying unit 212 estimates that a position obtained by moving the position 62 of the grip end of the golf club 3 by the length L₂of the arm of the user 2 in the positive direction of the Z axis is the predetermined position 63. Accordingly, the Y coordinate A_Yof the predetermined position 63 is the same as the Y coordinate G_Yof the position 62 of the grip end, and the Z coordinate A_Zof the predetermined position 63 is calculated as a sum of the Z coordinate G_Zof the position 62 of the grip end and the length L₂of the arm of the user 2, as in equation (9).
A _Z =G _Z +L ₂ (9)
The length L₂of the arm of the user is calculated in equation (7) or (8) using the height L₀and sex of the user 2 included in the body information.
Next, the second imaginary plane specifying unit 212 multiples the Y coordinate A_Yand the Z coordinate A_Zof the predetermined position 63 by a scale factor H to calculate the coordinates (0, H_Y, H_Z) of a midpoint H3 of the vertexes H1 and H2 of the Hogan's plane 40. That is, H_Yand H_Zare calculated using equations (10) and (11).
H _Y =A _Y ·H (10)
H _Z =A _Z ·H (11)
As illustrated in FIG. 7, a length (a width of the Hogan's plane 40 in a direction perpendicular to the X axis) of a line segment connecting the origin O to the midpoint H3 of the vertexes H1 and H2 is H times the length L₃of the second line segment 53. The scale factor H is set to a value so that the trajectory of the golf club 3 during the swing motion of the user 2 falls within the Hogan's plane 40. For example, the Hogan's plane 40 may have the same shape and size as the shaft plane 30. In this case, since a width H×L₃of the Hogan's plane 40 in the direction perpendicular to the X axis is identical to the width S×L₁of the shaft plane 30 in the direction perpendicular to the X axis and is twice the sum of the length L₁of the shaft of the golf club 3 and the length L₂of the arm of the user 2, the scale factor H may be set as in equation (12).
$\begin{matrix} H = \frac{2 \cdot (L_{1} + L_{2})}{L_{3}} & (12) \end{matrix}$
The length L₃of the second line segment 53 is calculated from equation (13) using the Y coordinate A_Yand the Z coordinate A_Zof the predetermined position 63.
L ₃=√{square root over (A _Y ² A _Z ²)} (13)
Next, the second imaginary plane specifying unit 212 calculates the coordinates (−TL/2, 0, 0) of the vertex T1, the coordinates (TL/2, 0, 0) of the vertex T2, the coordinates (−TL/2, H_Y, H_Z) of the vertex H1, and the coordinates (TL/2, H_Y, H_Z) of the H2 of the Hogan's plane 40 using the coordinates (0, H_Y, H_Z) of the midpoint H3 calculated as described above and the width (the length of the third line segment 52) TL of the Hogan's plane 40 in the X axis direction. The width TL in the X axis direction is set to a value so that the trajectory of the golf club 3 during the swing motion of the user 2 falls within the Hogan's plane 40. In the embodiment, the width TL of the Hogan's plane 40 in the X axis direction may be set to be the same as the width of the shaft plane 30 in the X axis direction, and thus may be set to be twice the sum of the length L₁of the shaft and the length L₂of the arm, as described above.
The Hogan's plane 40 is specified based on the coordinates of the four vertexes T1, T2, H1, and H2 calculated in this way.
Next, an example of the process (the process of step S60 in FIG. 4) of detecting a timing at which the user 2 hits a ball will be described in detail.
The exercise analysis unit 213 detects a series of motions (also referred to as a rhythm) from the start of the swing to the end of the swing, for example, the start of the swing, a backswing, a top, a downswing, an impact, follow-through, and the end of the swing, using the measurement data acquired from the sensor unit 10. A specific rhythm detection procedure is not particularly limited. For example, the following procedure can be adopted.
First, the exercise analysis unit 213 calculates a sum (referred to as a norm) of the magnitudes of the angular velocities around the axes at each time t using the acquired angular velocity data of each time t. The exercise analysis unit 213 may integrate the norm of the angular velocities at each time t by time.
Here, a case of a graph in which angular velocities around three axes (x, y, and z axes) are shown, for example, in FIG. 8 (which is a diagram illustrating examples of angular velocities output from the sensor unit) will be considered. In FIG. 8, the horizontal axis represents a time (msec) and the vertical axis represents an angular velocity (dps). The norm of the angular velocities is shown in the graph illustrated in, for example, FIG. 9 (which is a diagram illustrating an example of the norm of the angular velocities). In FIG. 9, the horizontal axis represents a time (msec) and the vertical axis represents the norm of the angular velocities. A differential value of the norm of the angular velocity is shown in a graph illustrated in, for example, FIG. 10 (which is a diagram illustrating an example of the differential value of the norm of the angular velocity). In FIG. 10, the horizontal axis represents a time (msec) and the vertical axis represents the differential value of the norm of the angular velocity. FIGS. 8 to 10 are exemplified to facilitate understanding of the embodiment and do not show accurate values.
The exercise analysis unit 213 detects a timing of an impact in the swing using the calculated norm of the angular velocities. For example, the exercise analysis unit 213 detects a timing at which the norm of the angular velocities is the maximum as the timing of the impact (T5 in FIG. 9). For example, the exercise analysis unit 213 may detect a former timing between timings at which the value of the differential of the calculated norm of the angular velocities is the maximum and the minimum as the timing of the impact (T5 in FIG. 10).
For example, the exercise analysis unit 213 detects a timing at which the calculated norm of the angular velocities is the minimum before the impact as a timing of a top of the swing (T3 in FIG. 9). For example, the exercise analysis unit 213 specifies a period in which the norm of the angular velocities is continuously equal to or less than a first threshold value before the impact, as a top period (which is an accumulation period at the top) (T2 to T4 in FIG. 9).
For example, the exercise analysis unit 213 detects a timing at which the norm of the angular velocities is equal to or less than a second threshold value before the top, as a timing of the start of the swing (T1 in FIG. 9).
For example, the exercise analysis unit 213 detects a timing at which the norm of the angular velocities is the minimum after the impact, as a timing of the end (finish) of the swing (T7 in FIG. 9). For example, the exercise analysis unit 213 may detect a first timing at which the norm of the angular velocities is equal to or less than the third threshold value after the impact, as the timing of the end (finish) of the swing. For example, the exercise analysis unit 213 specifies a period in which the norm of the angular velocities is continuously equal to or less than a fourth threshold value after the timing of the impact and close to the timing of the impact, as a finish period (T6 to T8 in FIG. 9).
In this way, the exercise analysis unit 213 can detect the rhythm of the swing. The exercise analysis unit 213 can specify each period (for example, a backswing period from the start of the swing to the start of the top, a downswing period from the end of the top to the impact, and a follow-through period from the impact to the end of the swing) during the swing by detecting the rhythm.
Hereinafter, the trajectory determination unit 214 and the image generation unit 215 will be described in detail.
FIG. 11 is a diagram (a diagram projected to the YZ plane) illustrating the shaft plane and the Hogan's plane when viewed from the negative side of the X axis. In FIG. 11, the shaft plane 30, the Hogan's plane 40, and a trajectory 3 a of the golf club 3 are illustrated. The trajectory 3 a indicated by a dotted line of FIG. 11 is a trajectory of the golf club 3 in a backswing and the trajectory 3 a indicated by a one-dot chain line is a trajectory of the golf club 3 in a downswing.
The trajectory determination unit 214 divides a space defined with the XYZ coordinate system (global coordinate system) into predetermined regions. For example, the trajectory determination unit 214 divides the space into a region (a V zone 71 indicated by diagonal lines in FIG. 11) interposed between the shaft plane 30 specified by the first imaginary plane specifying unit 211 and the Hogan's plane 40 specified by the second imaginary plane specifying unit 212 and the other region. The trajectory determination unit 214 determines whether the trajectory 3 a of the golf club 3 calculated by the exercise analysis unit 213 passes through the V zone 71. Specifically, the trajectory determination unit 214 determines a portion in which the trajectory 3 a of the golf club 3 passes through the V zone 71 and a portion in which the trajectory 3 a of the golf club 3 does not pass through the V zone 71.
For example, in the case of FIG. 11, the trajectory 3 a of a portion indicated by ranges A1 and A2 does not pass through the V zone 71 and the trajectory 3 a of a portion out of the ranges A1 and A2 passes through the V zone 71. Accordingly, in the case of FIG. 11, the trajectory determination unit 214 determines that the trajectory 3 a of the portion indicated by the ranges A1 and A2 does not pass through the V zone 71 and determines that the trajectory 3 a of the portion out of the ranges A1 and A2 passes through the V zone 71.
When the image generation unit 215 generates the image data of the trajectory 3 a of the golf club 3, the image generation unit 215 changes a display form of the trajectory 3 a of the golf club 3 based on the determination result of the trajectory determination unit 214. For example, the image generation unit 215 generates image data in which the trajectory 3 a inside the V zone 71 (the trajectory 3 a indicated by a dotted line and the trajectory 3 a indicated by a one-dot chain line inside the V zone 71) is set with blue. For example, the image generation unit 215 generates image data in which the trajectory 3 a indicated by the ranges A1 and A2 outside the V zone 71 is set with red.
FIG. 12 is a diagram illustrating an example of a screen displayed on a display unit. The image data generated by the image generation unit 215 is output to the display unit 25 by the output processing unit 216. A screen 80 illustrated in FIG. 12 is a screen example displayed on the display unit 25. The screen 80 is a screen example viewed from the rear side in the hitting direction.
In the screen 80, the trajectory 3 a of the golf club 3 is displayed without displaying the V zone. Whether the trajectory 3 a of the golf club 3 enters the V zone is indicated by the color of the trajectory 3 a.
For example, trajectories 3 aa and 3 ac indicated by thick lines represent trajectories outside the V zone in a backswing (for example, see the ranges A1 and A2 in FIG. 11) and are indicated with red. Trajectories 3 ab and 3 ad indicated by thin lines represent trajectories inside the V zone in the backswing and are indicated with, for example, blue.
For example, a trajectory 3 ae indicated by a thin line represents a trajectory inside the V zone in a downswing and is indicated with blue. A trajectory 3 af indicated by a thick line represents a trajectory outside the V zone in the downswing (for example, see the range A2 in FIG. 11) and is indicated with, for example, red.
Thus, the user 2 can know which portion of his or her swing is deviated or not deviated from the V zone. For example, when the trajectory 3 a is displayed with the colors of the foregoing example, the user 2 can recognize his or her swing is deviated from the V zone in the red trajectories 3 aa, 3 ac, and 3 af.
In order to clarify a difference between the trajectories 3 ab, 3 ad, and 3 ae inside the V zone and the trajectories 3 aa, 3 ac, and 3 af outside the V zone in FIG. 12, the trajectories 3 aa, 3 ac, and 3 af outside the V zone are indicated by the thick lines, but may be displayed with solid lines with the same thickness as the trajectories 3 ab, 3 ad, and 3 ae inside the V zone.
The screen 80 illustrated in FIG. 12 may be a 3-dimensional image of which a display angle (viewpoint at which an image is viewed) can be changed according to an operation of the user 2.
FIG. 13 is a flowchart illustrating an example of operations of the trajectory determination unit and the image generation unit. The flowchart of FIG. 13 is a flowchart illustrating the detailed processes of steps S90 and S100 of FIG. 4.
First, the trajectory determination unit 214 specifies the V zone based on the shaft plane 30 specified in step S30 of FIG. 4 and the Hogan's plane 40 specified in step S40 of FIG. 4 (step S901).
Next, the trajectory determination unit 214 determines whether the trajectory of the golf club 3 calculated in step S80 of FIG. 4 is inside the V zone specified in step S901 (step S902). For example, the trajectory determination unit 214 determines whether the trajectory of the golf club 3 is inside the V zone specified in step S901, for example, in order from an address position to impact.
When the trajectory determination unit 214 determines in step S902 that the trajectory of the golf club 3 is inside the V zone (“Yes” in S902), the image generation unit 215 generates image data in which a first color is set to the trajectory of the golf club 3 (step S903). That is, the image generation unit 215 generates the image data in which the first color is set to the trajectory of the golf club 3 inside the V zone. When the image generation unit 215 generates the image data in which the first color is set to the trajectory, the process proceeds to step S905.
When the trajectory determination unit 214 determines in step S902 that the trajectory of the golf club 3 is not inside the V zone (“No” in S902), the image generation unit 215 generates image data in which a second color is set to the trajectory of the golf club 3 (step S904). That is, the image generation unit 215 generates the image data in which the second color is set to the trajectory of the golf club 3 outside the V zone. When the image generation unit 215 generates the image data in which the second color is set to the trajectory, the process proceeds to step S905.
The image generation unit 215 determines whether the processes from step S902 to step S904 are performed from the address of the trajectory of the golf club 3 to the impact (step S905). That is, the image generation unit 215 determines whether to generate the image data in which the trajectory from the address to the impact is subjected to a coloring process. When the image generation unit 215 determines that the trajectory from the address to the impact is not subjected to the coloring process (“No” in S905), the process proceeds to step S902. When the image generation unit 215 determines that the trajectory from the address to the impact is subjected to the coloring process (“Yes” in S905), the process proceeds to step S906.
When the image generation unit 215 determines in step S905 that the trajectory from the address to the impact is subjected to the coloring process (“Yes” in S905), the generated image data is output to the output processing unit 216 (step S906).
Thus, for example, the screen 80 described in FIG. 12 is displayed on the display unit 25. For example, the first color is set to the trajectories 3 aa, 3 ac, and 3 af indicated by the thick lines in FIG. 12 and the second color is set to the trajectories 3 ab, 3 ad, and 3 ae indicated by the thin lines. Accordingly, the user 2 can confirm whether the trajectory 3 a of the golf club 3 enters the V zone in the screen 80, and thus can simply performs swing estimation of the golf club 3.
As described above, when the trajectory of the golf club 3 is inside the V zone, the first color (for example, red) is set to the trajectory of the golf club 3. When the trajectory of the golf club 3 is outside the V zone, the second color (for example, blue) is set to the trajectory of the golf club 3. However, the color of the trajectory of the golf club 3 may be changed according to whether a swing is a backswing or a downswing.
For example, the image generation unit 215 generates image data in which a first color (for example, red) is set to a trajectory outside a V zone in a backswing and a second color (for example, purple) is set to a trajectory outside a V zone in a downswing. Further, the image generation unit 215 generates image data in which a third color (for example, blue) is set to the trajectory inside the V zone in the backswing and a fourth color (for example, black) is set to the trajectory inside the V zone in the downswing.
In this case, for example, the first color (for example, red) is set to the trajectories 3 aa and 3 ac (trajectories outside the V zone in the backswing) in FIG. 12 and the second color (for example, purple) is set to the trajectory 3 af (a trajectory outside the V zone in the downswing). Further, the third color (for example, blue) is set to the trajectories 3 ab and 3 ad (trajectories inside the V zone in the backswing) in FIG. 12 and the fourth color (for example, black) is set to the trajectory 3 ae (a trajectory inside the V zone in the downswing).
Thus, the user 2 can recognize whether the trajectory 3 a of the golf club 3 is deviated from the V zone in the backswing and is deviated from the V zone in the downswing, and thus can simply perform a swing estimation of the golf club 3.
As described above, the exercise analysis device 20 determines that the trajectory of the golf club 3 passes through the V zone. Thus, the exercise analysis device 20 can change a display form of the trajectory according to a passage state of the trajectory of the golf club 3. Thus, the user 2 can easily see which portion of the trajectory of the golf club 3 passes through the V zone and can simply perform the swing estimation of the golf club 3.
Since the exercise analysis device 20 specifies the shaft plane 30 and the Hogan's plane 40 using the sensor unit 10, it is not necessary to use a large-scale device such as a camera and restriction on a place where the type of swing is estimated is small.
As described above, the image generation unit 215 generates the image data in which the color of the trajectory is changed between the portion of the trajectory of the golf club 3 which passes through the V zone and the portion of the trajectory of the golf club 3 which does not pass through the V zone, but may generate the image data so that the trajectory continuously lights and the trajectory blinks. For example, the image generation unit 215 may generate the image data so that the trajectory inside the V zone continuously lights and the trajectory outside the V zone blinks.
The image generation unit 215 may generate the image data in which kinds of lines of the trajectories of the golf club 3 are changed. For example, the image generation unit 215 may generate the image data in which the trajectory inside the V zone is displayed with a solid line and the trajectory outside the V zone is displayed with a dotted line or a broken line.
The image generation unit 215 may generate the image data in which the thicknesses of the lines of the trajectories of the golf club 3 are changed. For example, the image generation unit 215 may generate the image data so that the trajectory inside the V zone is displayed with a thin line and the trajectory outside the V zone is displayed with a thick line.
The image generation unit 215 may generate the image data so that the trajectory inside the V zone is not displayed and only the trajectory outside the V zone is displayed.
The image generation unit 215 may generate the image data in which first and second regions interposing a V zone are defined outside the V zone, and the V zone and the first and second regions are distinguished and displayed.
The image generation unit 215 may generate the image data in which predetermined colors are set to a region opposite to the V zone including the shaft plane 30 and a region opposite to the V zone including the Hogan's plane 40. For example, the image generation unit 215 may generate the image data in which the predetermined colors are set to a first region outside the V zone and present counterclockwise from the shaft plane 30 and a second region outside the V zone and present clockwise from the Hogan's plane 40 in FIG. 11. At this time, the image generation unit 215 may include information indicating that the first region is a slice zone and the second region is a hook zone in the image data. Thus, the user 2 can recognize whether his or her swing tendency is a slice tendency or a hook tendency.
The image generation unit 215 may change a display form of the trajectory in a rhythm of a predetermined section. For example, in FIG. 13, the image generation unit 215 changes the display form of the trajectory from the address to the impact, but may change the display form of a trajectory from the address to the end of a swing. The image generation unit 215 may change the display form of the trajectory in regard to a trajectory of only a downswing.
The image generation unit 215 may generate the image data in which the V zone is colored. For example, the image generation unit 215 may generate the image data in which a region interposed between the shaft plane 30 and the Hogan's plane 40 is all painted with a predetermined color. In this case, the image generation unit 215 may display a trajectory of which the above-described display form is changed in the image data in which the V zone is colored. The image generation unit 215 may display the trajectory without changing the display form according to whether the trajectory is inside or outside the V zone (for example, the trajectory may be displayed with one color).
The image generation unit 215 may generate the image data which includes a region outside a V zone including a line segment obtained by multiplying the first line segment 51 by the scale factor S and the Hogan's plane 40.
FIG. 14 is a diagram illustrating an example of a screen in which a region outside a V zone including a line segment and a Hogan's plane is displayed. As illustrated in FIG. 14, a line segment 91 obtained by multiplying the first line segment 51 by the scale factor S is displayed in a screen 90. A region 92 outside a V zone including the Hogan's plane 40 as a part of a side surface is displayed in the screen 90. The region 92 is all painted with a predetermined color.
The image generation unit 215 may indicate the V zone by the line segment 91 and the region 92, as illustrated in FIG. 14. As described above, the image generation unit 215 displays a trajectory of which a display form is changed according to whether the trajectory is inside or outside the V zone.
The image generation unit 215 may display the first line segment 51 in the screen 90 instead of the line segment 91. The image generation unit 215 may generate the image data which includes a region outside a V zone including a line segment obtained by multiplying the second line segment 53 by the scale factor H and the shaft plane 30.
As described above, the second imaginary plane specifying unit 212 specifies the second line segment 53 using the body information and the measurement data output by the sensor unit 10. However, a process of specifying the second line segment 53 connecting the positions 63 and 62 of the head (the blow portion) of the golf club 3 may be performed using the first line segment 51 specified by the first imaginary plane specifying unit 211 and the predetermined angle θ relative to the first line segment 51.
As described above, the Hogan's plane 40 is specified by the output of the sensor unit 10 fitted in the golf club 3, but the invention is not limited thereto. For example, a sensor unit may be fitted in an arm or the like of the user 2 and the Hogan's plane 40 may be specified based on an output of the sensor unit.
As described above, the acceleration sensor 13 and the angular velocity sensor 14 are embedded in the sensor unit 10 to be integrated, but the acceleration sensor 13 and the angular velocity sensor 14 may not be integrated.
Alternatively, the acceleration sensor 13 and the angular velocity sensor 14 may not be embedded in the sensor unit 10, but may be mounted directly on the golf club 3 or the user 2. In the foregoing embodiments, the sensor unit 10 and the exercise analysis device 20 are separated, but the sensor unit 10 and the exercise analysis device 20 may be integrated to be mounted on the golf club 3 or the user 2.
In the foregoing embodiments, the exercise analysis device 20 calculates the Z coordinate A_Zof the predetermined position 63 on the line segment connecting both shoulders of the user 2 to one another as the sum of the Y coordinate G_Yof the position 62 of the grip end and the length L₂of the arm of the user 2 as in equation (9), but another equation may be used. For example, the exercise analysis device 20 may multiply L₂by a coefficient K and adds G_Yto calculate A_Zas in A_Z=G_Y+K·L₂.
The exercise analysis system (the exercise analysis device) analyzing a golf swing has been exemplified above. However, the invention can be applied to an exercise analysis system (exercise analysis device) analyzing swings of various exercises of tennis, baseball, and the like.
The functional configuration of the exercise analysis system described above is classified according to main processing content in order to facilitate understanding of the configuration of the exercise analysis system. The invention is not limited by the method of classifying the constituent elements or the names of the constituent elements. The configuration of the exercise analysis system can be classified into further many constituent elements according to the processing content. One constituent element can be classified to perform more processes. The process of each constituent element may be performed by one piece of hardware or may be performed by a plurality of pieces of hardware.
Units of processes in the flowcharts described above are divided according to main processing content in order to facilitate understanding of the process of the exercise analysis device. The invention is not limited by a method of dividing the units of processes or the names of the units of processes. The process of the exercise analysis device can be divided in more units of processes according to the processing content. One unit of process can be divided to include more processes. The processing procedure of the foregoing flowchart is not limited to the example illustrated in the drawing.
The embodiments of the invention have been described above, but the technical scope of the invention is not limited to the scope described in the foregoing embodiments. It should be apparent to those skill in the art that various modifications or improvements of the foregoing embodiments are made. It should be apparent from the description of the appended claims that the modifications or the improvements are also included in the technical scope of the invention. The invention can also be provided as an exercise analysis method, a program for the exercise analysis device, or a recording medium storing the program. In the foregoing embodiments, the sensor unit 10 and the exercise analysis device 20 have been described as separate elements, but the function of the exercise analysis device 20 may be mounted on the sensor unit 10.
The entire disclosure of Japanese Patent Application No. 2014-256579, filed Dec. 18, 2014 is expressly incorporated by reference herein.

Claims

What is claimed is:

1. An exercise analysis device comprising:

a first specifying unit that specifies a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of an inertial sensor;

a second specifying unit that specifies a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis;

an analysis unit that calculates a trajectory of a swing of the user based on an output of the inertial sensor; and

a determination unit that determines whether the trajectory passes through a predetermined region specified based on the first and second axes.

2. The exercise analysis device according to claim 1,

wherein the determination unit determines a portion of the trajectory which passes through the predetermined region and a portion of the trajectory which does not pass through the predetermined region.

3. The exercise analysis device according to claim 2, further comprising:

an image generation unit that generates image data in which a display form of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

4. The exercise analysis device according to claim 3,

wherein the image generation unit generates the image data in which a color of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

5. The exercise analysis device according to claim 3,

wherein the image generation unit generates the image data in which the trajectory continuously lights and blinks to distinguish the portion which passes through the predetermined region from the portion which does not pass through the predetermined region.

6. The exercise analysis device according to claim 3,

wherein the image generation unit generates the image data in which a kind of line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

7. The exercise analysis device according to claim 3,

wherein the image generation unit generates the image data in which a thickness of a line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

8. The exercise analysis device according to claim 1,

wherein the first specifying unit specifies a first imaginary plane including the first axis and the hitting direction,

wherein the second specifying unit specifies a second imaginary plane including the second axis and the hitting direction, and

wherein the predetermined region is a region interposed between the first and second imaginary planes.

9. The exercise analysis device according to claim 8,

wherein the image generation unit defines first and second regions interposing the predetermined region outside the predetermined region, and generates image data in which the predetermined region, the first region, and the second region are distinguished and displayed.

10. An exercise analysis method comprising:

specifying a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of an inertial sensor;

specifying a second axis forming a predetermined angle along with the first axis, using a hitting direction as a rotation axis;

calculating a trajectory of a swing of the user based on an output of the inertial sensor; and

determining whether the trajectory passes through a predetermined region specified based on the first and second axes.

11. The exercise analysis method according to claim 10,

wherein in the determining of the trajectory, a portion of the trajectory which passes through the predetermined region and a portion of the trajectory which does not pass through the predetermined region are determined.

12. A program causing a computer to perform:

13. A recording medium that records a program causing a computer to perform:

14. An exercise analysis system comprising:

an inertial sensor;

a first specifying unit that specifies a first axis which lies in a longitudinal direction of a shaft of an exercise tool at an address posture of a user, using an output of the inertial sensor;

15. An exercise analysis device that determines whether a trajectory of a swing of a user passes through a V zone.

16. The exercise analysis device according to claim 15,

wherein a display form of the trajectory differs between a portion of the trajectory which passes through the V zone and a portion of the trajectory which does not pass through the V zone.

17. The exercise analysis device according to claim 16, further comprising:

an image generation unit that generates image data in which the display form of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

18. The exercise analysis device according to claim 16,

wherein the image generation unit generates image data in which a color of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

19. The exercise analysis device according to claim 16,

wherein the image generation unit generates image data in which the trajectory continuously lights and blinks to distinguish the portion which passes through the predetermined region from the portion which does not pass through the predetermined region.

20. The exercise analysis device according to claim 16,

wherein the image generation unit generates image data in which a kind of line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.

21. The exercise analysis device according to claim 16,

wherein the image generation unit generates image data in which a thickness of a line of the trajectory differs between the portion which passes through the predetermined region and the portion which does not pass through the predetermined region.