CALCULATION APPARATUS, CALCULATION SYSTEM, CALCULATION METHOD, AND RECORDING MEDIUM

A calculation apparatus includes a processing section that performs determination of a swing type on the basis of information regarding an attitude or a position of an exercise appliance at a predetermined timing during a backswing.

BACKGROUND

1. Technical Field

The present invention relates to a calculation apparatus, a calculation system, a calculation method, and a recording medium.

2. Related Art

In the related art, in order to check a golf swing, it is effective to capture an image of the swing. For example, JP-A-2004-129687 discloses a technique in which a downswing is subjected to image processing by using a direct linear transformation method (DLT method) using a high-speed camera, and thus a swing pattern of a golfer is classified.

However, in the technique disclosed in JP-A-2004-129687, since a period of time spent on a downswing which is evaluated in order to classify a swing pattern is considerably shorter than a period of time spent on a backswing, obtained information is restricted, and thus a swing pattern is insufficiently classified.

SUMMARY

An advantage of some aspects of the invention is to provide a calculation apparatus, a calculation system, a calculation method, and a recording medium, capable of determining a swing type by focusing on the fact that a tendency of a downswing depends on a backswing and by analyzing an attitude or a position of an exercise appliance during backswing.

APPLICATION EXAMPLE 1

A calculation apparatus according to this application example includes a processing section that performs determination of a swing type on the basis of information regarding an attitude or a position of an exercise appliance at a predetermined timing during a backswing.

Since it is considered that a tendency for a user to perform a downswing depends on a backswing of the user, it is possible to sufficiently determine a swing type of the user simply on the basis of an attitude or a position of the exercise appliance at a predetermined timing during a backswing.

APPLICATION EXAMPLE 2

In the calculation apparatus according to the application example, the information may include information regarding a rotation angle about a rotation axis of a shaft at the predetermined timing with a longitudinal direction of the shaft of the exercise appliance as the rotation axis.

Since it is considered that features of a swing of the user appear in temporal changes of the rotation angle about the shaft axis, it is possible to perform determination with high accuracy on the basis of the rotation angle at a predetermined timing.

APPLICATION EXAMPLE 3

In the calculation apparatus according to the application example, the processing section may perform the determination according to a range in which the rotation angle is included.

It is possible to easily perform determination on the basis of a range in which the rotation angle is included.

APPLICATION EXAMPLE 4

In the calculation apparatus according to the application example, the predetermined timing may include two or more timings.

It is possible to further increase the accuracy of determination on the basis of rotation angles at two or more timings than on the basis of a rotation angle at a single timing.

APPLICATION EXAMPLE 5

In the calculation apparatus according to the application example, the predetermined timing may include at least one of a halfway back timing and a top timing.

Since it is considered that features of a swing of the user appear in a rotation angle at halfway back or at the top, it is possible to reduce an amount of necessary information and also to increase the accuracy of determination on the basis of a rotation angle at at least one of the halfway back and top timings.

APPLICATION EXAMPLE 6

In the calculation apparatus according to the application example, the swing type may be any one of an upper body type, a lower body type, and a whole body type.

Therefore, a swing type of the user can be classified as any one of the upper body type, the lower body type, and the whole body type.

APPLICATION EXAMPLE 7

In the calculation apparatus according to the application example, the information may include information regarding a position of a ball hitting portion of the exercise appliance at the predetermined timing.

Since it is considered that features of a swing of the user appear in a trajectory of the ball hitting portion, it is possible to determine a swing type with high accuracy on the basis of a position of the ball hitting portion at a predetermined timing.

APPLICATION EXAMPLE 8

In the calculation apparatus according to the application example, the processing section may perform the determination according to a region in which the position is included.

It is possible to easily perform determination on the basis of the region. A boundary of the region may be fixed, and may be variable.

APPLICATION EXAMPLE 9

In the calculation apparatus according to the application example, the processing section may set a boundary of the region on the basis of a first virtual plane specified by the longitudinal direction of the shaft of the exercise appliance at the time of starting a swing, and a target hit ball direction.

If a boundary is defined on the basis of the shaft axis direction of the exercise appliance at the time of starting a swing, it is possible to perform determination regardless of a habit of the way of the user holding the exercise appliance or a length of the exercise appliance.

APPLICATION EXAMPLE 10

In the calculation apparatus according to the application example, the processing section may set a boundary of the region on the basis of a second virtual plane specified by the longitudinal direction of the shaft of the exercise appliance at the time of starting a swing, a target hit ball direction, and physical information of a user.

If a boundary is defined on the basis of the physical information of the user, it is possible to perform determination regardless of a physique of the user.

APPLICATION EXAMPLE 11

In the calculation apparatus according to the application example, the second virtual plane may be a plane specified by a direction from a predetermined position between the head and the chest of the user toward a position of the ball hitting portion of the exercise appliance, and the target hit ball direction, at the time of starting the swing.

Therefore, a so-called Hogan plane can be used to define a boundary.

APPLICATION EXAMPLE 12

In the calculation apparatus according to the application example, the predetermined timing may include at least a halfway back timing.

Since it is considered that features of a swing of the user appear in a position of the ball hitting portion at a halfway back timing, it is possible to reduce an amount of necessary information and also to increase the accuracy of determination on the basis of a position of the ball hitting portion at halfway back.

APPLICATION EXAMPLE 13

In the calculation apparatus according to the application example, the swing type may be any one of a lower body type, an upper body type, a first whole body type, a second whole body type, and a third whole body type.

Therefore, a swing type of the user can be classified as any one of the upper body type, the lower body type, and the whole body type.

APPLICATION EXAMPLE 14

In the calculation apparatus according to the application example, the rotation angle is a relative value obtained when the shaft changes from a first state to a second state.

APPLICATION EXAMPLE 15

In the calculation apparatus according to the application example, the first state may be a standing still state before starting a swing action, and the second state may be an action state after starting the swing action.

APPLICATION EXAMPLE 16

In the calculation apparatus according to the application example, the information may be information indicating an average value or an intermediate value of the rotation angle in a predetermined period of time during the backswing.

If the average value or the intermediate value is used, it is possible to prevent the influence which a rotation angle measurement error exerts on a determination result.

APPLICATION EXAMPLE 17

In the calculation apparatus according to the application example, the information may be information indicating an average value or an intermediate value of the position in a predetermined period of time during the backswing.

If the average value or the intermediate value is used, it is possible to prevent the influence which a position measurement error exerts on a determination result.

APPLICATION EXAMPLE 18

In the calculation apparatus according to the application example, the information may be information generated on the basis of an output from an inertial sensor.

It is possible to obtain necessary information in a smaller calculation amount on the basis of the output from the inertial sensor than on the basis of a swing image or the like, and thus high efficiency is ensured.

APPLICATION EXAMPLE 19

A calculation system according to this application example includes a calculation apparatus that includes a processing section performing determination of a swing type on the basis of information regarding an attitude or a position of an exercise appliance at a predetermined timing during a backswing; and an inertial sensor that outputs data which is a basis of the information.

Since it is considered that a tendency for a user to perform a downswing depends on a backswing of the user, it is possible to sufficiently determine a swing type of the user simply on the basis of an attitude or a position of the exercise appliance at a predetermined timing during a backswing.

APPLICATION EXAMPLE 20

A calculation method according to this application example includes performing determination of a swing type on the basis of information regarding an attitude or a position of an exercise appliance at a predetermined timing during a backswing.

Since it is considered that a tendency for a user to perform a downswing depends on a backswing of the user, it is possible to sufficiently determine a swing type of the user simply on the basis of an attitude or a position of the exercise appliance at a predetermined timing during a backswing.

APPLICATION EXAMPLE 21

A calculation program according to this application example causes a computer to execute a determination procedure of performing determination of a swing type on the basis of information regarding an attitude or a position of an exercise appliance at a predetermined timing during a backswing.

Since it is considered that a tendency for a user to perform a downswing depends on a backswing of the user, it is possible to sufficiently determine a swing type of the user simply on the basis of an attitude or a position of the exercise appliance at a predetermined timing during a backswing.

APPLICATION EXAMPLE 22

A recording medium according to this application example stores therein a calculation program causing a computer to execute a determination procedure of performing determination of a swing type on the basis of information regarding an attitude or a position of an exercise appliance at a predetermined timing during a backswing.

Since it is considered that a tendency for a user to perform a downswing depends on a backswing of the user, it is possible to sufficiently determine a swing type of the user simply on the basis of an attitude or a position of the exercise appliance at a predetermined timing during a backswing.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. The embodiments described below are not intended to improperly limit the content of the invention disclosed in the appended claims. In addition, all constituent elements described below are not essential constituent elements of the invention.

1. Swing Diagnosis System

1-1. Outline of Swing Diagnosis System

FIG. 1is a diagram for explaining an outline of a swing diagnosis system (an example of a calculation system) of the present embodiment. A swing diagnosis system1of the present embodiment is configured to include a sensor unit10(an example of an inertial sensor) and a swing analysis apparatus20(an example of a calculation apparatus).

The sensor unit10can measure acceleration generated in each axial direction of three axes and angular velocity generated around each of the three axes, and is attached to a golf club3(an example of an exercise appliance).

In the present embodiment, as illustrated inFIG. 2, the sensor unit10is attached to a part of a shaft of the golf club3so that one axis of three detection axes (an x axis, a y axis, and a z axis), for example, the y axis matches a longitudinal direction of the shaft. Preferably, the sensor unit10is attached to a position close to a grip to which impact during ball hitting is hardly forwarded and a centrifugal force is not applied during a swing. The shaft is a shaft portion other than a head (an example of a ball hitting portion) of the golf club3and also includes the grip. However, the sensor unit10may be attached to a part (for example, the hand or a glove) of a user2, and may be attached to an accessory such as a wristwatch.

The user2performs a swing action for hitting a golf ball4according to predefined procedures.FIG. 3is a diagram illustrating procedures of actions performed by the user2. As illustrated inFIG. 3, first, the user2performs an input operation of physical information of the user2, information (golf club information) regarding the golf club3used by the user2, and the like via the swing analysis apparatus20(step S1). The physical information includes at least one of information regarding a height, a length of the arm, and a length of the leg of the user2, and may further include information regarding a sex or other information. The golf club information includes at least one of information regarding a length (club length) of the golf club3and the type (number) of golf club3. Next, the user2performs a measurement starting operation (an operation for starting measurement in the sensor unit10) via the swing analysis apparatus20(step S2). Next, after receiving a notification (for example, a notification using a voice) of giving an instruction for taking an address attitude (a basic attitude before starting exercise) from the swing analysis apparatus20(Y in step S3), the user2takes an address attitude so that the axis in the longitudinal direction of the shaft of the golf club3is perpendicular to a target line (a target direction of a hit ball), and stands still (step S4). Next, the user2receives a notification (for example, a notification with a voice) of permitting a swing from the swing analysis apparatus20(Y in step S5), and then hits the golf ball4by performing a swing action (step S6).

In step S1inFIG. 3, the user2inputs physical information such as a height, a sex, an age, and nationality, and inputs golf club information such as a club length, a number. Information included in the physical information is not limited thereto, and, the physical information may include, for example, at least one of information regarding a length of the arm and a length of the leg instead of or along with the height. Similarly, information included in the golf club information is not limited thereto, and, for example, the golf club information may not include at least one of information regarding the club length and the number, and may include other information.

If the user2performs the measurement starting operation in step S2inFIG. 3, the sensor unit10measures three-axis accelerations and three-axis angular velocities in a predetermined cycle (for example, 1 ms), and sequentially transmits the measured data to the swing analysis apparatus20. Communication between the sensor unit10and the swing analysis apparatus20may be wireless communication, and may be wired communication. This data indicates a position or an attitude of the sensor unit10, and further indicates a position or an attitude of each portion of the golf club3.

1-2. Configuration of Swing Diagnosis System

FIG. 4is a diagram illustrating a configuration example (configuration examples of the sensor unit10and the swing analysis apparatus20) of the swing diagnosis system1of the present embodiment. As illustrated inFIG. 4, in the present embodiment, the sensor unit10is configured to include an acceleration sensor12, an angular velocity sensor14, a signal processing section16, and a communication section18.

The acceleration sensor12measures respective accelerations in three axial directions which intersect (ideally, orthogonal to) each other, and outputs digital signals (acceleration data) corresponding to magnitudes and directions of the measured three-axis accelerations.

The angular velocity sensor14measures respective angular velocities in three axial directions which intersect (ideally, orthogonal to) each other, and outputs digital signals (angular velocity data) corresponding to magnitudes and directions of the measured three-axis angular velocities.

The signal processing section16receives the acceleration data and the angular velocity data (measured data) from the acceleration sensor12and the angular velocity sensor14, respectively, adds time information thereto, stores the data in a storage portion (not illustrated), adds time information to the stored measured data (an example of attitude or position information) so as to generate packet data conforming to a communication format, and outputs the packet data to the communication section18.

Ideally, the acceleration sensor12and the angular velocity sensor14are provided in the sensor unit10so that the three axes thereof match three axes (an x axis, a y axis, and a z axis) of an orthogonal coordinate system (sensor coordinate system) defined for the sensor unit10, but, actually, errors occur in installation angles. Therefore, the signal processing section16performs a process of converting the acceleration data and the angular velocity data into data in the xyz coordinate system by using a correction parameter which is calculated in advance according to the installation angle errors.

The signal processing section16may perform a process of correcting the temperatures of the acceleration sensor12and the angular velocity sensor14. The acceleration sensor12and the angular velocity sensor14may have a temperature correction function.

The acceleration sensor12and the angular velocity sensor14may output analog signals, and, in this case, the signal processing section16may A/D convert an output signal from the acceleration sensor12and an output signal from the angular velocity sensor14so as to generate measured data (acceleration data and angular velocity data), and may generate communication packet data by using the data.

The communication section18performs a process of transmitting packet data received from the signal processing section16to the swing analysis apparatus20, or a process of receiving a control command from the swing analysis apparatus20and sending the control command to the signal processing section16. The signal processing section16performs various processes corresponding to control commands.

The swing analysis apparatus20is implemented by, for example, an information terminal (client terminal) such as a smart phone or a personal computer, and is configured to include a processing section21(an example of a processing section), a communication section22, an operation section23, a storage section24, a display section25, and a sound output section26.

The communication section22performs a process receiving packet data transmitted from the sensor unit10and sending the packet data to the processing section21, or a process of transmitting a control command from the processing section21to the sensor unit10.

The operation section23performs a process of acquiring operation data from the user2and sending the operation data to the processing section21. The operation section23may be, for example, a touch panel type display, a button, a key, or a microphone.

The storage section24is constituted of, for example, 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 section24stores a program for the processing section21performing various calculation processes or a control process, or various programs or data for realizing application functions. Particularly, in the present embodiment, the storage section24stores a swing analysis program240(an example of a calculation program) which is read by the processing section21and executes a swing analysis process (an example of a calculation method). The swing analysis program240may be stored in a nonvolatile recording medium (an example of a recording medium) in advance, or the swing analysis program240may be received from a server by the processing section21via a network, and may be stored in the storage section24.

The storage section24stores golf club information242, physical information244, sensor attachment position information246, a first determination table243, and a second determination table248as information used for the swing analysis process.

The golf club information242is information indicating a specification of the golf club3used by the user2. For example, the user2may input golf club information of the golf club3which is used, by operating the operation section23, and the input golf club information may be used as the golf club information242. Alternatively, in step S1inFIG. 3, the user2may sequentially input type numbers of the golf club3(alternatively, selects a type number from a type number list) so that specification information (for example, information regarding a length of the shaft, a central position a lie angle, a face angle, and a loft angle) for each type number is stored in the storage section24in advance. In this case, specification information of an input type number may be used as the golf club information242.

The physical information244is information indicating a physique (a height of the waist, a height of the neck, a length of the arm, and the like) of the user2. For example, the user2may input physical information by operating the operation section23, and the input physical information may be used as the physical information244.

The sensor attachment position information246is information indicating an attachment position of the sensor unit10in the golf club3. For example, in step S1inFIG. 3, the user2may input an attachment position of the sensor unit10and a distance to the grip of the golf club3by operating the operation section23, and the input distance information may be used as the sensor attachment position information246. Alternatively, the sensor unit10may be attached at a defined predetermined position (for example, a distance of 20 cm from the grip), and thus information regarding the predetermined position may be stored as the sensor attachment position information246in advance.

The first determination table243is a reference table used to determine a swing type of the user2. An argument (input) of the first determination table243is an attitude of the golf club3at a predetermined timing during a backswing, and a function (output) of the first determination table243is a swing type. In other words, if an attitude of the golf club3at a predetermined timing is input, the first determination table243outputs a swing type (determination result) according to a range in which the attitude is included. Here, it is assumed that a rotation angle of the golf club3is used as an attitude of the golf club3.

The rotation angle of the golf club3is a rotation angle about a first axis (an example of a rotation axis) of the golf club3with the longitudinal direction of the golf club3as the rotation axis (first axis), and is expressed by a relative value (relative rotation angle) with a value of a rotation angle at the time of starting a swing (or at address) as a reference. Here, in a case where the user2is a right-handed golfer, a right-handed screw tightening direction in which the tip end directs toward the head side of the golf club3is a positive direction of a rotation angle of the golf club3, and, in a case where the user2is a left-handed golfer, a left-handed screw tightening direction in which the tip end directs toward the head side of the golf club3is a positive direction of a rotation angle of the golf club3.

Here, the predetermined timing is assumed to be a halfway back timing and a top timing. In this case, arguments (inputs) of the first determination table243are a rotation angle θHWBat the halfway back timing and a rotation angle θTOPat the top timing. In other words, if the rotation angle θHWBat the halfway back timing and the rotation angle θTOPat the top timing are input, the first determination table243outputs a swing type (determination result) according to a range in which a combination of the rotation angles θHWBand θTOPis included.

As illustrated inFIG. 5, the first determination table243stores three ranges (a range in an upper part ofFIG. 5, a range in an intermediate part ofFIG. 5, and a range in a lower part ofFIG. 5) for combinations of the rotation angles θHWBand θTOPand swing types (“upper body type”, “lower body type”, and “whole body type”) respectively corresponding to the three ranges.

As illustrated in the upper part ofFIG. 5, the range of the relatively large rotation angles θHWBand θTOPis correlated with the “upper body type”. This range is a range of 40 degrees≦θHWBand 100 degrees≦θTOP.

As illustrated in the intermediate part ofFIG. 5, the range of the relatively small rotation angles θHWBand θTOPis correlated with the “lower body type”. This range is a range of θHWB≦0 degrees and θTOP≦10 degrees.

As illustrated in the lower part ofFIG. 5, the range of the intermediate rotation angles θHWBand θTOPis correlated with the “whole body type”. This range is a range of (25−α) degrees<θHWB<(25+α) degrees, and (50−β) degrees<θTOP<(50+β) degrees. α is a predetermined value, for example, about 15 degrees, and β is a predetermined value, for example, about 50 degrees.

The “upper body type” is a swing type in which a swing is performed by using the upper body (mainly, the arms or the wrists) more than the lower body, the “lower body type” is a swing type in which a swing is performed by using the lower body more than the upper body (mainly, the arms or the wrists), and the whole body type is a swing type in which a swing is performed by using the upper body (mainly, the arms or the wrists) and the lower body with good balance.

The number of ranges (the number of swing types), the boundary values of the range, and the like illustrated inFIG. 5are only examples.

Referring toFIG. 4again, the second determination table248is a reference table used to determine a swing type of the user2. An argument (input) of the second determination table248is a position of the golf club3at a predetermined timing during a backswing, and a function (output) of the second determination table248is a swing type. In other words, if a position of the head of the golf club3at a predetermined timing is input, the second determination table248outputs a swing type (determination result) according to a region in which the position is included. Here, it is assumed that the predetermined timing is a halfway back timing, and a position of the head of the golf club3is used as a position of the golf club3. In other words, if a position of the head at the halfway back timing is input, the second determination table248outputs a swing type (determination result) according to a range (region) in which the position is included.

As illustrated inFIG. 6, the second determination table248stores five ranges (regions A to E) for positions of the head, and swing types (“lower body type”, “upper body type”, “first whole body type”, “second whole body type”, and “third whole body type”) respectively corresponding to the five regions A to E.

As illustrated in the uppermost part ofFIG. 6, the region A is correlated with the “lower body type”. The region A is a region which is closest to the head of the user2. Details of the region A will be described later.

As illustrated in the lowermost part ofFIG. 6, the region E is correlated with the “upper body type”. The region E is a region which is closest to the feet of the user2. Details of the region E will be described later.

As illustrated in the second to fourth parts ofFIG. 6, the regions B to D are correlated with the “first whole body type” to the “third whole body type”. The regions B to D are regions located between the region A and the region E. Details of the regions B to D will be described later.

The number of regions (the number of swing types), the interfaces of the regions A to E, and the like illustrated inFIG. 6may be fixed in advance, and may be set for each swing. Hereinafter, it is assumed that the number of regions (the number of swing types) is fixed in advance, and the interfaces of the regions A to E are set for each swing. Details (determination region setting process) of a method of setting the interfaces will be described later.

Referring toFIG. 4again, the storage section24is used as a work area of the processing section21, and temporarily stores data which is input from the operation section23, results of calculation executed by the processing section21according to various programs, and the like. The storage section24may store data which is required to be preserved for a long period of time among data items generated through processing of the processing section21.

The display section25displays a processing result in the processing section21as text, a graph, a table, animation, and other images. The display section25may be, for example, a CRT, an LCD, a touch panel type display, and a head mounted display (HMD). A single touch panel type display may realize functions of the operation section23and the display section25.

The sound output section26outputs a processing result in the processing section21as a sound such as a voice or a buzzer sound. The sound output section26may be, for example, a speaker or a buzzer.

The processing section21performs a process of transmitting a control command to the sensor unit10, various computation processes on data which is received from the sensor unit10via the communication section22, and various control processes, according to various programs. By executing the swing analysis program240, the processing section21functions as a data acquisition portion210, a swing analysis portion215, an image data generation portion216, a storage processing portion217, a display processing portion218, and a sound output processing portion219.

The data acquisition portion210performs a process of receiving packet data which is received from the sensor unit10by the communication section22, acquiring time information and measured data from the received packet data, and sending the time information and the measured data to the storage processing portion217.

The swing analysis portion215performs a process of analyzing a swing of the user2by using the measured data output from the sensor unit10. Specifically, first, the swing analysis portion215computes an offset amount included in the measured data by using the measured data (acceleration data and angular velocity data) during standing still (at address) of the user2, stored in the storage section24. Next, the swing analysis portion215subtracts the offset amount from the measured data after starting of a swing, stored in the storage section24, so as to perform bias correction, and computes a position and an attitude of the sensor unit10during a swing action of the user2(during the action in step S6inFIG. 3) by using the bias-corrected measured data.

For example, the swing analysis portion215computes a position (initial position) of the sensor unit10during standing still (at address) of the user2in an XYZ coordinate system (global coordinate system) by using acceleration data measured by the acceleration sensor12, the golf club information242, and the sensor attachment position information246, and computes changes in positions from the initial position of the sensor unit10in a time series by integrating subsequent acceleration data. The user2performs the action in step S4inFIG. 3, and thus an X coordinate of the initial position of the sensor unit10is 0. As illustrated inFIG. 2, since the y axis of the sensor unit10matches the longitudinal direction of the shaft of the golf club3, and the acceleration sensor12measures only the gravitational acceleration during standing still of the user2, the swing analysis portion215can compute an inclined angle of the shaft by using y axis acceleration data. The swing analysis portion215obtains a distance LSHbetween the sensor unit10and the head on the basis of the golf club information242(a length of the shaft), and the sensor attachment position information246(a distance from the grip), and sets, as the initial position of the sensor unit10, a position at the distance LSHfrom the origin in a negative direction of the y axis of the sensor unit10, specified by the inclined angle of the shaft when a position of the head is used as the origin (0,0,0).

The swing analysis portion215computes an attitude (initial attitude) of the sensor unit10during standing still (at address) of the user2in the XYZ coordinate system (global coordinate system) by using acceleration data measured by the acceleration sensor12, and computes changes in attitudes from the initial attitude of the sensor unit10by performing rotation calculation using angular velocity data which is subsequently measured by the angular velocity sensor14. An attitude of the sensor unit10may be expressed by, for example, rotation angles (a roll angle, a pitch angle, and a yaw angle) about the X axis, the Y axis, and the Z axis, or a quaternion. Since the acceleration sensor12measures only the gravitational acceleration during standing still of the user2, the swing analysis portion215can specify angles respectively formed between the x axis, the y axis, and the z axis of the sensor unit10, and the gravitational direction, by using three-axis acceleration data. Since the user2performs the action in step S4inFIG. 3, the y axis of the sensor unit10is present on a YZ plane during standing still of the user2, and thus the swing analysis portion215can specify the initial attitude of the sensor unit10.

On the basis of a position of the sensor unit10at each time point of a swing, an attitude of the sensor unit10at the time point, the golf club information242, and the sensor attachment position information246, the swing analysis portion215computes a position of the head at the time point.

On the basis of a position of the sensor unit10at each time point of a swing, an attitude of the sensor unit10at the time point, the golf club information242, and the sensor attachment position information246, the swing analysis portion215computes a position of the grip at the time point.

The signal processing section16of the sensor unit10may compute an offset amount of measured data so as to perform bias correction on the measured data, and the acceleration sensor12and the angular velocity sensor14may have a bias correction function. In this case, it is not necessary for the swing analysis portion215to perform bias correction on the measured data.

The swing analysis portion215detects specific timings (a swing starting timing, a top timing, and a halfway back timing) during a swing action of the user2by using the time information and the measured data stored in the storage section24. For example, the swing analysis portion215computes a combined value of the measured data (acceleration data or angular velocity data) output from the sensor unit10, and specifies a swing starting and top timings (time points) on the basis of the combined value.

The swing analysis portion215specifies a halfway back timing (time point) on the basis of the position of the head and the position of the grip in a period of time (backswing) from the swing starting timing to the top timing.

The swing analysis portion215determines a swing type of the user2on the basis of at least one of a range in which the rotation angles θHWBand θTOPat the specific timings (the halfway back timing and the top timing) during the backswing and a region in which the position of the head is included at the specific timing (the halfway back timing) during the backswing, and thus generates determination result information.

The image data generation portion216performs a process of generating image data for displaying the determination result information.

The storage processing portion217performs a process of receiving the time information and the measured data from the data acquisition portion210, and storing the time information and the measured data in the storage section24in correlation with each other.

The storage processing portion217performs read/write processes of various programs or various data for the storage section24. The storage processing portion217performs not only the process of storing the time information and the measured data received from the data acquisition portion210in the storage section24in correlation with each other, but also a process of storing the determination result information or the like generated by the swing analysis portion215in the storage section24.

The display processing portion218performs a process of displaying various images (including text, symbols, and the like in addition to an image corresponding to the image data generated by the image data generation portion216) on the display section25. For example, the display processing portion218displays an image corresponding to the image data generated by the image data generation portion216, or text or the like indicating a determination result in the swing analysis portion215automatically or in response to an input operation performed by the user2after a swing action of the user2is completed. Alternatively, a display section may be provided in the sensor unit10, and the display processing portion218may transmit image data to the sensor unit10via the communication section22, and various images, text, or the like may be displayed on the display section of the sensor unit10.

The sound output processing portion219performs a process of outputting various sounds (including voices, buzzer sounds, and the like) from the sound output section26. For example, the sound output processing portion219may read the various pieces of information stored in the storage section24automatically or when a predetermined input operation is performed after a swing action of the user2is completed, and may output a swing analysis sound or voice from the sound output section26. Alternatively, a sound output section may be provided in the sensor unit10, and the sound output processing portion219may transmit sound data or voice data to the sensor unit10via the communication section22, and may output various sounds or voices from the sound output section of the sensor unit10.

A vibration mechanism may be provided in the swing analysis apparatus20or the sensor unit10, and various pieces of information may be converted into vibration information by the vibration mechanism so as to be presented to the user2.

1-3. Swing Analysis Process

FIG. 7is a flowchart illustrating procedures of the swing analysis process performed by the processing section21. The processing section21performs the swing analysis process according to the procedures shown in the flowchart ofFIG. 7by executing the swing analysis program240stored in the storage section24. Hereinafter, the flowchart ofFIG. 7will be described.

First, the processing section21starts acquisition of measured data from the sensor unit10(step S10).

Next, the processing section21notifies the user2of permission of swing starting (step S18) in a case where a standing still state is continuously detected for a predetermined period of time (Y in step S12) by using the measured data from the sensor unit10during a standing still action (address action) of the user2(the action in step S4inFIG. 3), and returns the process in step S12in a case where the standing still state is not detected (N in step S12). The processing section21outputs, for example, a predetermined image or sound, or an LED is provided in the sensor unit10, and the LED is lighted, so that the user2is notified of permission of swing starting. The user2confirms the notification and then starts a swing.

Next, the processing section21performs processes in step S20and the substantially steps in real time during the swing action of the user2or after the swing is completed.

First, the processing section21computes an initial position and an initial attitude of the sensor unit10by using the measured data acquired by the sensor unit10at address (step S20).

Next, the processing section21detects a timing at which the user2starts the swing, a top timing, a ball hitting timing (impact timing) by using the measured data acquired from the sensor unit10(step S22).

The processing section21computes a position and an attitude of the sensor unit10during the swing action of the user2in parallel to the process in step S22, or before and after the process in step S22(step S24).

Next, the processing section21detects a halfway back timing on the basis of a position of the head and a position of the grip during a backswing (step S25).

As illustrated inFIG. 8, the halfway back timing is a timing (a timing at which the shaft of the golf club3is along the ground surface) at which the axis of the golf club3in the longitudinal direction is horizontal in the backswing (a period of time from the swing starting timing to the top timing).

Next, the processing section21computes a rotation angle θHWBof the golf club3at the halfway back timing (a measurement time point tbof the halfway back) and a rotation angle θTOPof the golf club3at the top timing (a measurement time point t2of the top) on the basis of angular velocity data ωy(t) about the y axis in the backswing (step S26).

The rotation angle θHWB(tb) of the golf club3at the measurement time point tbof the halfway back may be obtained by time-integrating the angular velocity data ωy(t) over an interval from a measurement time point t1of the swing starting to the measurement time point tbof the halfway back. However, here, in order to use the time of the swing starting as a reference, a rotation angle at the time of the swing starting is set to zero.

The rotation angle θTOP(t2) of the golf club3at the top timing t2may be obtained by time-integrating the angular velocity data ωy(t) over an interval from the measurement time point t1of the swing starting to the measurement time point t2of the top.

Next, the processing section21determines whether or not a combination of the rotation angle θHWBof the golf club3at the halfway back and the rotation angle θTOPof the golf club3at the top is included in the range (any one of the range in the upper part, the range in the intermediate part, and the range in the lower part ofFIG. 5) prepared in the first determination table243(step S28).

In a case where the combination of the rotation angle θHWBof the golf club3at the halfway back and the rotation angle θTOPof the golf club3at the top is included in the range (Y in step S28), the processing section21inputs the combination of the rotation angles θHWBand θTOPto the first determination table243, determines a swing type output from the first determination table243according to the combination as a swing type of the user2(step S30), and proceeds to step S37. The procedure in step S30is an example of a determination procedure.

On the other hand, in a case where the combination of the rotation angle θHWBof the golf club3at the halfway back and the rotation angle θTOPof the golf club3at the top is not included in the range (N in step S28), the processing section21sets regions A to E in the second determination table248(step S32).

Next, the processing section21computes a position of the head at the halfway back (step S34). The position of the head at the halfway back may be obtained on the basis of the position of the sensor unit at the measurement time point tbof the halfway back, the attitude of the sensor unit at the measurement time point tbof the halfway back, the golf club information242, and the sensor attachment position information246.

Next, the processing section21inputs the position of the head at the halfway back to the second determination table248, determines a swing type output from the second determination table248according to the position as a swing type of the user2(step S36), and proceeds to step S37. The procedure in step S36is an example of a determination procedure.

Next, the processing section21generates information (determination result information) indicating the swing type of the user2, displays the determination result information on the display section25(step S37), and finishes the process.

In the flowchart ofFIG. 7, order of the respective steps may be changed as appropriate within an allowable range.

1-3-1. Process of Detecting Swing Starting and Top

FIG. 9is a flowchart illustrating examples of procedures of a process (the process in step S22inFIG. 7) of detecting swing starting and a top. Hereinafter, the flowchart ofFIG. 9will be described.

First, the processing section21performs bias correction on the measured data (acceleration data and angular velocity data) stored in the storage section24(step S200).

Next, the processing section21computes a combined value n0(t) of angular velocities at each time point t by using the angular velocity data (angular velocity data for each time point t) having undergone the bias correction in step S200(step S210). For example, if the angular velocity data items at the time point tare respectively indicated by x(t), y(t), and z(t), the combined value n0(t) of the angular velocities is computed according to the following Equation (1).

FIG. 10illustrates examples of three-axis angular velocity data items x(t), y(t) and z(t) obtained when the user2hits the golf ball4by performing a swing. InFIG. 10, a transverse axis expresses time (msec), and a longitudinal axis expresses angular velocity (dps).

Next, the processing section21converts the combined value n0(t) of the angular velocities at each time point t into a combined value n(t) which is normalized (scale-conversion) within a predetermined range (step S220). For example, if the maximum value of the combined value of the angular velocities in an acquisition period of measured data is max (n0), the combined value n0(t) of the angular velocities is converted into the combined value n (t) which is normalized within a range of 0 to 100 according to the following Equation (2).

FIG. 11is a diagram in which the combined value n0(t) of the three-axis angular velocities is computed according to Equation (1) by using the three-axis angular velocity data items x(t), y(t) and z(t) inFIG. 10, and then the combined value n(t) normalized to 0 to 100 according to Equation (2) is displayed in a graph. InFIG. 11, a transverse axis expresses time (msec), and a longitudinal axis expresses a combined value of the angular velocity.

Next, the processing section21computes a derivative dn(t) of the normalized combined value n(t) at each time point t (step S230). For example, if a cycle for measuring three-axis angular velocity data items is indicated by Δt, the derivative (difference) dn(t) of the combined value of the angular velocities at the time point t is calculated by using the following Equation (3).

FIG. 12is a diagram in which the derivative dn(t) is calculated according to Equation (3) on the basis of the combined value n(t) of the three-axis angular velocities inFIG. 11, and is displayed in a graph. InFIG. 12, a transverse axis expresses time (msec), and a longitudinal axis expresses a derivative value of the combined value of the three-axis angular velocities. InFIGS. 10 and 11, the transverse axis is displayed at 0 seconds to 5 seconds, but, inFIG. 12, the transverse axis is display at 2 seconds to 2.8 seconds so that changes in the derivative value before and after impact can be understood.

Next, of time points at which a value of the derivative dn (t) of the combined value becomes the maximum and the minimum, the processing section21specifies the earlier time point as an impact measurement time point t3(step S240) (refer toFIG. 12). It is considered that a swing speed is the maximum at the moment of impact in a typical golf swing. In addition, since it is considered that a value of the combined value of the angular velocities also changes according to a swing speed, a timing at which a derivative value of the combined value of the angular velocities is the maximum or the minimum (that is, a timing at which the derivative value of the combined value of the angular velocities is a positive maximum value or a negative minimum value) in a series of swing actions can be captured as a timing of impact. Since the golf club3vibrates due to the impact, a timing at which a derivative value of the combined value of the angular velocities is the maximum and a timing at which a derivative value of the combined value of the angular velocities is the minimum may occur in pairs, and, of the two timings, the earlier timing may be the moment of the impact.

Next, the processing section21specifies a time point of a minimum point at which the combined value n(t) is close to 0 before the measurement time point t3of the impact, as a measurement time point t2of the top (step S250) (refer toFIG. 11). It is considered that, in a typical golf swing, an action temporarily stops at the top after starting the swing, then a swing speed increases, and finally impact occurs. Therefore, a timing at which the combined value of the angular velocities is close to 0 and becomes the minimum before the impact timing may be captured as the top timing.

Next, the processing section21specifies an interval in which the combined value n(t) is equal to or smaller than a predetermined threshold value before and after the measurement time point t2of the top, as a top interval (step S260). It is considered that, since an action temporarily stops at the top in a typical golf swing, a swing speed is reduced before and after the top. Therefore, an interval, including the top timing, in which the combined value of the angular velocities is continuously equal to or smaller than a predetermined threshold value may be recognized as the top interval.

Next, the processing section21specifies a last time point at which the combined value n(t) is equal to or smaller than the predetermined threshold value before a starting time point of the top interval, as a measurement time point t1of the swing starting (step S270) (refer toFIG. 11), and finishes the process. It is hardly considered that, in a typical golf swing, a swing action is started from a standing still state, and the swing action is stopped at the top. Therefore, the last timing at which the combined value of the angular velocities is equal to or smaller than the predetermined threshold value before the top timing may be captured as a timing of starting the swing action. The time point of the minimum point at which the combined value n(t) is close to 0 before the time point t2of the top may be specified as a measurement time point of the swing starting.

In the flowchart ofFIG. 9, order of the respective steps may be changed as appropriate within an allowable range. In the flowchart ofFIG. 9, the processing section21specifies impact or the like by using the three-axis angular velocity data, but may specify impact or the like by using three-axis acceleration data in the same manner.

In the flowchart ofFIG. 9, the processing section21detects a timing (impact) at which the user2has hit a ball by using the square root of the square sum, as shown in Equation (1) as a combined value of three-axis angular velocities measured by the sensor unit, but, as a combined value of three-axis angular velocities, for example, a square sum of three-axis angular velocities, a sum or an average of three-axis angular velocities, or the product of three-axis angular velocities may be used. Instead of a combined value of three-axis angular velocities, a combined value of three-axis accelerations such as a square sum or a square root of three-axis accelerations, a sum or an average value of three-axis accelerations, or the product of three-axis accelerations may be used.

1-3-2. Halfway Back Detection Process

FIG. 13is a flowchart illustrating examples of procedures of a halfway back detection process (the process in step S25inFIG. 7). Hereinafter, the flowchart ofFIG. 13will be described.

First, the processing section21computes a position of the head and a position of the grip at each time point in the backswing on the basis of the position and the attitude of the sensor unit10at each time point in a period of time (backswing) from the measurement time point t1of the swing starting to the measurement time point t2of the top, the golf club information242, and the sensor attachment position information246(step S280).

Next, the processing section21computes a difference ΔZ(t) between a Z coordinate component ZG(t) of the position of the grip at a time point t and a Z coordinate component ZH(t) of the position of the head at the same time point t, with respect to each time point t in the backswing (step S290). The difference ΔZ(t) at the time point t is expressed by an equation of ΔZ(t)=ZG(t)−ZH(t).

Next, the processing section21specifies a time point at which a sign of the difference ΔZ(t) during the backswing changes from negative to positive, as the measurement time point tbof the halfway back (step S300), and finishes the process.

1-3-3. Process of Setting Determination Region

FIG. 14is a flowchart illustrating examples of procedures of a process (the process in step S32ofFIG. 7) of setting a determination region. Hereinafter, the flowchart ofFIG. 14will be described.

First, the processing section21performs a process of specifying a shaft plane (an example of a first virtual plane) (step S321). When a line segment obtained by cutting the shaft plane in the YZ plane is viewed from a negative side of the X axis, the line segment is as indicated by the reference numeral30inFIGS. 15 and 16. A coordinate system illustrated inFIGS. 15 and 16is an XYZ coordinate system (global coordinate system) which has a target line indicating a target direction of a hit ball as an X axis, an axis on a horizontal plane which is perpendicular to the X axis as a Y axis, and a vertically upward direction (a direction opposite to the gravitational acceleration direction) as a Z axis. The process of specifying the shaft plane30will be described later in detail.

First, the processing section21performs a process of specifying a Hogan plane (an example of a second virtual plane) (step S322). When a line segment obtained by cutting the Hogan plane in the YZ plane is viewed from a negative side of the X axis, the line segment is as indicated by the reference numeral40inFIGS. 15 and 16. The process of specifying the Hogan plane40will be described later in detail.

Next, the processing section21computes an angle Δθ(acute angle) formed between the shaft plane30and the Hogan plane40on the YZ plane, and determines an angle pitch Δθ′ of each of the determination regions A to E by multiplying the angle Δθ by a predetermined coefficient (for example, “½”) (step S323). Here, a region interposed between the shaft plane30and the Hogan plane40is a so-called V zone, and the angle Δθ indicates an open angle of the V zone. Therefore, as the open angle Δθ of the V zone increases, the angle pitches Δθ′ of the determination regions A to E also increase.

Next, the processing section21sets interfaces40A to40D of the regions A to E on the basis of the shaft plane30or the Hogan plane40and the angle pitch Δθ′ (step S324), and finishes the process. Consequently, setting of the regions A to E is completed.

As illustrated inFIG. 15, the interface40A is an interface between the region A and the region B, the interface40B is an interface between the region B and the region C, the interface40C is an interface between the region C and the region D, and the interface40D is an interface between the region D and the region E. Above all, the region B between the interface40A and the interface40B is the Hogan plane40and a peripheral region thereof, and the region D between the interface40C and the interface40D is the shaft plane30and a peripheral region thereof.

Meanwhile, the interface40A is a plane obtained by rotating the Hogan plane40by an angle of +Δθ′/2 about the X axis (or a plane obtained by rotating the shaft plane30by +5Δθ′/2 about the X axis). Here, when viewed from the negative side of the X axis, a clockwise direction is assumed to be a positive direction of an angle about the X axis.

The interface40B is a plane obtained by rotating the Hogan plane40by an angle of −Δθ′/2 about the X axis (or a plane obtained by rotating the shaft plane30by an angle of +3Δθ′/2 about the X axis).

The interface40C is a plane obtained by rotating the Hogan plane40by an angle of −3Δθ′/2 about the X axis (or a plane obtained by rotating the shaft plane30by an angle of +Δθ′/2 about the X axis).

The interface40D is a plane obtained by rotating the Hogan plane40by an angle of −5Δθ′/2 about the X axis (or a plane obtained by rotating the shaft plane30by an angle of −Δθ′/2 about the X axis).

1-3-4. Outline of Shaft Plane and Hogan Plane

FIG. 16is a diagram illustrating a shaft plane and a Hogan plane at address of the user2. Here, the XYZ coordinate system (global coordinate system) is defined which has a target line indicating a target direction of a hit ball as the X axis, an axis on a horizontal plane which is perpendicular to the X axis as the Y axis, and a vertically upward direction (a direction opposite to the gravitational acceleration direction) as the Z axis.FIG. 16displays the X axis, the Y axis, and the Z axis.

As illustrated inFIG. 16, the shaft plane30at address of the user2is a virtual plane including a first axis51in the longitudinal direction of the shaft of the golf club3, and a third axis52indicating a target direction of a hit ball. InFIG. 16, the origin O (0,0,0) of the XYZ coordinate system is set at a position61of the head (ball hitting portion) of the golf club3at address.

The Hogan plane40is a virtual plane including the third axis52and a second axis53. The second axis53is an axis passing through a predetermined position63(for example, a position of the base of the neck, or a position of one of left and right shoulders) on a line segment connecting both of the shoulders of the user2to each other, and a position62(an example of a ball hitting position) of the head (ball hitting portion) of the golf club3. However, the second axis53may be an axis passing through the predetermined position63and a position (an example of a ball hitting position) of the golf ball4.

1-3-5. Shaft Plane Specifying Process

FIG. 17is a flowchart illustrating examples of procedures of a process (the process in step S321inFIG. 14) of specifying the shaft plane (first virtual plane) performed by the processing section21. Hereinafter, the flowchart ofFIG. 17will be described.

First, as illustrated inFIG. 18, the processing section21computes coordinates (0,GY,GZ) of a position62of a grip end by using acceleration data measured at address by the sensor unit10and the golf club information242with the position61of the head of the golf club3as the origin O (0,0,0) of the XYZ coordinate system (global coordinate system) (step S100).FIG. 18is a plan view in which the golf club3and the sensor unit10during standing still (at address) of the user2are viewed from the negative side of the X axis, the origin O (0,0,0) is set at the position61of the head of the golf club3, and coordinates of the position62of the grip end are (0, GY, GZ). As illustrated inFIG. 18, the gravitational acceleration G is applied to the sensor unit10during standing still of the user2, and thus a relationship between a y axis acceleration y(0) and an inclined angle (an angle formed between the axis of the shaft in the longitudinal direction and the horizontal plane (XY plane)) α of the shaft of the golf club3is expressed by Equation (4).

Therefore, if a length of the shaft of the golf club3included in the golf club information242is indicated by L1, GYand GZare respectively computed by using the length L1of the shaft and the inclined angle α according to Equations (5) and (6).

Next, the processing section21multiplies the coordinates (0,GY,GZ) of a position62of the grip end of the golf club3by a scale factor S so as to compute coordinates (0,SY,SZ) of a midpoint S3of a vertex S1and a vertex S2of the shaft plane30(step S110). In other words, SYand SZare respectively computed according to Equations (7) and (8).

FIG. 19is a view in which a sectional view of the shaft plane30inFIG. 18which is cut in the YZ plane is viewed from the negative side of the X axis. As illustrated inFIG. 19, a length (a width of the shaft plane30in a direction orthogonal to the X axis) of a line segment connecting the midpoint S3of the vertex S1and the vertex S2to the origin O is S times the length L1of the first line segment51. The scale factor S is set to a value at which a trajectory of the golf club3during a swing action of the user2enters the shaft plane30. For example, if a length of the arm of the user2is indicated by L2, the scale factor S may be set as in Equation (9) so that the width S×L1of the shaft plane30in the direction orthogonal to the X axis is twice the sum of the length L1of the shaft and the length L2of the arm.

The length L2of the arm of the user2is associated with a height L0of the user2. The length L2of the arm is expressed by a correlation expression such as Equation (10) in a case where the user2is a male, and is expressed by a correlation expression such as Equation (11) in a case where the user2is a female, on the basis of statistical information.

Therefore, the length L2of the arm of the user is calculated according to Equation (10) or Equation (11) by using the height L0and a sex of the user2included in the physical information244.

Next, the processing section21computes coordinates (−TL/2, 0, 0) of a vertex T1of the shaft plane30, coordinates (TL/2, 0, 0) of a vertex T2, coordinates (−TL/2, SY, SZ) of the vertex S1, and coordinates (TL/2, SY, SZ) of the vertex S2by using the coordinates (0, SY, SZ) of the midpoint S3and a width (the length of the third line segment52) TL of the shaft plane30in the X axis direction (step S120). The width TL in the X axis direction is set to a value at which a trajectory of the golf club3during a swing action of the user2enters the shaft plane30. For example, the width TL in the X axis direction may be set to be the same as the width S×L1in the direction orthogonal to the X axis, that is, twice the sum of the length L1of the shaft and the length L2of the arm.

The shaft plane30is specified on the basis of the coordinates of the four vertices T1, T2, S1and S2, computed in the above-described way.

1-3-6. Hogan Plane Specifying Process

FIG. 20is a flowchart illustrating examples of procedures of a process (the process in step S322inFIG. 14) of specifying a Hogan plane (second virtual plane) performed by the processing section21. Hereinafter, the flowchart ofFIG. 20will be described.

First, the processing section21estimates the predetermined position63on the line segment connecting both of the shoulders of the user2by using the coordinates (0, GY, GZ) of the position62of the grip end of the golf club3, and the physical information244of the user2, and computes coordinates (AX,AY,AZ) thereof (step S200).

FIG. 21is a view in which a sectional view of the Hogan plane40which is cut in the YZ plane is viewed from the negative side of the X axis. InFIG. 21, a midpoint of the line segment connecting both of the shoulders of the user2is the predetermined position63, and the predetermined position63is present on the YZ plane. Therefore, an X coordinate AXof the predetermined position63is 0. As illustrated inFIG. 21, the processing section21estimates, as the predetermined position63, a position obtained by moving the position62of the grip end of the golf club3by the length L2of the arm of the user2in a positive direction along the Z axis. Therefore, a Y coordinate AYof the predetermined position63is the same as the Y coordinate GYof the position62of the grip end, and a Z coordinate AZof the predetermined position63is computed as a sum of the Z coordinate GZof the position62of the grip end and the length L2of the arm of the user2as in Equation (12).

The length L2of the arm of the user2is calculated according to Equation (7) or (8) by using the height L0and a sex of the user2included in the physical information244.

Next, the processing section21multiplies the Y coordinate AYand the Z coordinate AZof the predetermined position63by a scale factor H, so as to compute coordinates (0,HY,HZ) of a midpoint H3of a vertex H1and a vertex H2of the Hogan plane40(step S210). In other words, HYand HZare respectively computed according to Equation (13) and Equation (14).

As illustrated inFIG. 21, a length (a width of the Hogan plane40in a direction orthogonal to the X axis) of a line segment connecting the midpoint H3of the vertex H1and the vertex H2to the origin O is H times the length L3of the second line segment53. The scale factor H is set to a value at which a trajectory of the golf club3during a swing action of the user2enters the Hogan plane40. For example, the Hogan plane40may have the same shape and size as the shape and the size of the shaft plane30. In this case, since the width H×L3of the Hogan plane40in the direction orthogonal to the X axis matches the width S×L1of the shaft plane30in the direction orthogonal to the X axis, and is twice the sum of the length L1of the shaft of the golf club3and the length L2of the arm of the user2, the scale factor H may be set as in Equation (15).

The length L3of the second line segment53is computed according to Equation (16) by using the Y coordinate AYand the Z coordinate AZof the predetermined position63.

Next, the processing section21computes coordinates (−TL/2,0,0) of a vertex T1of the Hogan plane40, coordinates (TL/2,0,0) of a vertex T2, coordinates (−TL/2,HY,HZ) of the vertex H1, and coordinates (TL/2,HY,HZ) of the vertex H2by using the coordinates (0,HY,HZ) of the midpoint H3and a width (the length of the third line segment52) TL of the Hogan plane40in the X axis direction (step S220). The width TL in the X axis direction is set to a value at which a trajectory of the golf club3during a swing action of the user2enters the Hogan plane40. In the present embodiment, the width TL of the Hogan plane40in the X axis direction is the same as the width of the shaft plane30in the X axis direction, and may thus be set to be twice the sum of the length L1of the shaft and the length L2of the arm, as described above.

The Hogan plane40is specified on the basis of the coordinates of the four vertices T1, T2, H1and H2, computed in the above-described way.

1-4. Display Screen of Determination Result

FIG. 22is a diagram illustrating an example of a display screen of a determination result (diagnosis result) displayed on the display section25.

As illustrated inFIG. 22, a text image77indicating a swing type of the user2, and a text image78indicating advice (practice method or the like) suitable for the swing type of the user2are displayed on the display screen of a determination result (diagnosis result). In the example illustrated inFIG. 22, a case is shown in which a swing type of the user is determined as being the “upper body type”. In this case, a text image “upper body type” indicating that a swing type of the user2is an upper body type is displayed as the text image77. In addition, in this case, a text image indicating advice information suitable for the upper body type is displayed as the text image78.

As indicated by the reference numeral78inFIG. 22, the advice information suitable for the upper body type includes, for example, information for specifically explaining the upper body type, and information for causing a swing of the upper body type approach a swing of the whole body type. The information for explaining the upper body type includes, for example, information such as the content that “you have a strong tendency to raise the club, and thus hand-swing somewhat easily occurs”. The information for causing a swing of the upper body type to approach a swing of the whole body type includes, for example, information such as the content that “power can be efficiently transmitted to a ball by using the whole body with good balance; for this, further note a backswing in which the upper body and the lower body are synchronized with each other; and draw an image of first moving the right shoulder at starting of the backswing, and successively perform a swing of moving the arms, the club, and the lower body”.

The advice information is stored in the storage section24in advance for each swing type, for example. For example, when a determination result (diagnosis result) is displayed, the processing section21reads advice information suitable for a swing type of the user2from the storage section24, and displays the text image78indicating the advice information on the display section25along with the text image77indicating the swing type.

2. Modification Examples

2-1. Modification Example of Interface

In the above description, the processing section21uses the physical information of the user2when the Hogan plane40is specified on the basis of the shaft plane30, but may not use the physical information. For example, a plane obtained by rotating the shaft plane30by a predetermined angle (for example, +30 degrees) around the X axis may be used as the Hogan plane40.

The processing section21sets the interfaces40A to40D of the determination regions A to E (that is, the interfaces40A to40D are variable) on the basis of the shaft plane30specified by using an attitude of the golf club at address, but may set predetermined planes fixed to XYZ coordinates as the interfaces40A to40D (that is, the interfaces40A to40D may be fixed). However, also in this case, preferably, each of the interfaces40A to40D is a rotational symmetric plane with respect to the X axis, and the angle pitches Δθ′ of the interfaces40A to40D are uniformly set.

In the above-described swing analysis apparatus20, the number of determination regions (a total number of regions A to E) is “five”, but may be “six or greater”, and may be “four or smaller”. As the number of determination regions increases, the number of swing types which can be determined also increases.

2-2. Data Input Screen

In the above-described swing analysis apparatus20, used to determine a swing type is acquired from the sensor unit10, but the user2may manually input (manual input) the data.

When the user2manually inputs the data, the processing section21of the swing analysis apparatus20may display, for example, a data input screen as illustrated inFIG. 23on the display section25.

As illustrated inFIG. 23, for example, a region selection screen88for designating to which one of regions A, B, C, D and E a position of the head at halfway back belongs is disposed on the data input screen.

The region selection screen88displays a line segment image Im30indicating a shaft plane, a line segment image Im40indicating a Hogan plane, and marks (“A”, “B”, “C”, “D”, and “E”) indicating rough positions of the regions A, B, C, D and E. If the user2designates one of the marks A, B, C, D and E (for example, the user taps the marks), a designated mark is highlighted.

For example, a numerical value input screen89for inputting a value of a rotation angle θTOP(shaft axis rotation (Top)) of the golf club3at top is disposed on the data input screen. The user2may directly input any numerical value to the numerical value input screen89.

A button image (diagnosis starting button)99or the like for the user2notifying the swing analysis apparatus20of information indicating that input is completed and an instruction for starting determination (an instruction for starting diagnosis) is displayed on the data input screen. The user2may press (tap) the diagnosis starting button99so as to cause the swing analysis apparatus20to start determination of a swing type.

If the diagnosis starting button99is pressed, the swing analysis apparatus20regards indexes displayed on the data input screen at that time as indexes input by the user, and determines a swing type on the basis of the indexes. The “indexes” mentioned here indicate the type of region to which a position of the head at halfway back belongs, a numerical value of the rotation angle θHWBof the golf club3at halfway back, and a numerical value of the rotation angle θTOPof the golf club3at top.

Therefore, if the user2designates any one of the marks A to E on the data input screen, inputs numerical values of the rotation angles θHWBand θTOP, and then presses the diagnosis starting button99, the user can understand a swing type caused by a combination of the indexes.

2-3. Input Data Editing Screen

The processing section21may display an input data editing screen illustrated inFIG. 24after the user2performs a swing. The input data editing screen illustrated inFIG. 24displays indexes actually measured in the swing in a state in which the indexes can be edited at the respective portions of the data input screen illustrated inFIG. 23.

In this case, if the user2presses the diagnosis starting button99without editing the indexes, the user can understand a swing type of the swing which has been actually performed by the user as a determination result. If the user presses the diagnosis starting button99after editing the indexes, the user can understand how a swing type is changed according to the way to change indexes related to the user as a determination result.

2-4. Modification Example Using Average Value or Intermediate Value

The above-described processing section21performs determination of a swing type on the basis of a rotation angle at a predetermined timing during a backswing, but may perform the determination on the basis of an average value or an intermediate value of rotation angles in a predetermined period of time during a backswing.

For example, the predetermined period of time may be set as a period of time of a predetermined length with the time of starting a swing as a start time, may be set as a period of time in which an angle of the shaft axis with the time of starting a swing as a reference is included in a predetermined range, and may be set as a period of time until a position of the head is deviated from a predetermined region after starting a swing. The predetermined region may be, for example, a region interposed between a virtual plane obtained by rotating the XY plane by a predetermined angle (for example, +30 degrees) about the X axis so that the XY plane is directed substantially in a vertical direction, and the XY plane, and may be the region E closest to the feet of the user2among the regions A to E illustrated inFIG. 15.

The above-described processing section21performs determination of a swing type on the basis of a position of the head at a predetermined timing during a backswing, but may perform the determination on the basis of an average value or an intermediate value of positions of the head in a predetermined period of time during a backswing.

The predetermined period of time may be set as a period of time of a predetermined length with the time of starting a swing as a start time, and may be set as a period of time in which an angle of the shaft axis with the time of starting a swing as a reference is included in a predetermined range.

2-5. Modification Example of System Configuration

In the above-described embodiment, some or all of the functions of the swing analysis apparatus20may be mounted on the sensor unit10side, and some or all of the functions of the swing analysis apparatus20may be mounted on a server side which processes requests from the swing analysis apparatus20.

In this case, for example, the user2accesses the server via the swing analysis apparatus20(or a terminal connected to a network), and uploads swing analysis data (the above-described indexes and the like regarding a swing) to the server. If the server determines a swing type on the basis of the uploaded swing analysis data (indexes and the like), the server provides information regarding the determination result (diagnosis result) to the swing analysis apparatus20(or the terminal connected to the network). The swing analysis apparatus20(or the terminal connected to the network) displays the provided determination result (diagnosis result) on a display section of the terminal.

FIG. 25is a diagram illustrating an example of a swing diagnosis system using a server. As illustrated inFIG. 25, a swing diagnosis system100(an example of a calculation system) is configured to include a sensor unit10(an example of an inertial sensor), a swing analysis apparatus20, and a swing diagnosis apparatus300(an example of a calculation apparatus).

The swing analysis apparatus20is implemented by an information terminal (client terminal) such as a smart phone or a personal computer, and the swing diagnosis apparatus300is implemented by a server which processes requests from the swing analysis apparatus20.

Hardware configurations of the swing analysis apparatus20and the sensor unit10are fundamentally the same as those in the above-described embodiment. However, the swing analysis apparatus20may further include a communication section (not illustrated) which performs communication with the swing diagnosis apparatus300via a network400. The swing diagnosis apparatus300may include, for example, a processing section (not illustrated), a storage section (not illustrated), and a communication section (not illustrated) which performs communication with the swing analysis apparatus20via the network400.

The network400may be a wide area network (WAN) such as the Internet, and may be a local area network (LAN). The swing analysis apparatus20and the swing diagnosis apparatus300may communicate with each other through, for example, near field wireless communication or wired communication, without using the network400. Here, it is assumed that the network400is used.

The processing section of the swing analysis apparatus20generates swing analysis data according to a swing of the user2, and transmits the swing analysis data to the swing diagnosis apparatus300via the network400.

The swing analysis data includes, for example, information indicating a position of the V zone (positions of the shaft plane and the Hogan plane) in XYZ coordinates, information indicating the rotation angle θHWBat halfway back, information indicating the rotation angle θTOPat top, and information indicating a position of the head at halfway back. Specific procedures of calculating the position of the V zone, the rotation angle θHWB, the rotation angle θTOP, and the position of the head are the same as described above.

If the swing analysis data transmitted by the swing analysis apparatus20is received via the network400, the processing section of the swing diagnosis apparatus300determines a swing type of the user2on the basis of the information indicating the rotation angles θHWBand θTOPincluded in the swing analysis data. The processing section of the swing analysis apparatus20sets the determination regions A to E on the basis of the information indicating the position of the V zone included in the swing analysis data, and performs determination on the basis of the set determination regions A to E, and the information indicating the position of the head included in the swing analysis data, as necessary. Specific procedures of setting the determination regions or specific procedures of the determination are the same as described above.

The processing section of the swing diagnosis apparatus300generates determination result information, and transmits the determination result information to the swing analysis apparatus20via the network400.

If the determination result information is received via the network400, the processing section of the swing analysis apparatus20displays the determination result (diagnosis result) on the display section25on the basis of the determination result information.

Therefore, in the swing diagnosis system100, among the functions of the swing analysis apparatus20in the above-described embodiment, the function regarding determination of a swing type is mainly mounted on the server (swing diagnosis apparatus300) side.

Specifically, in the swing diagnosis system100, among the functions of the swing analysis process, the function of calculating indexes (a rotation angle of the golf club and a position of the head at a predetermined timing) and the function of calculating the V zone are mounted on the swing analysis apparatus20side, and the function of setting determination regions on the basis of the V zone and the function of determining a swing type are mounted on the swing diagnosis apparatus300side.

However, allocation of the functions mounted on the swing analysis apparatus20side and the functions mounted on the swing diagnosis apparatus300side is not limited thereto. For example, the function of calculating the V zone may be mounted on the swing diagnosis apparatus300side.

In a case where the function of calculating the V zone is mounted on the swing diagnosis apparatus300side, information (measured data generated at address, golf club information, physical information, and the like) required to calculate the V zone is included in the swing analysis data.

In a case where some or all of the functions of the swing analysis apparatus20in the above-described embodiment are mounted on the swing diagnosis apparatus300side, program data and the like (data such as determination tables as necessary) required to realize the functions in the swing diagnosis apparatus300are stored in the storage section (not illustrated) of the swing diagnosis apparatus300in advance.

2-6. Modification Example Using HMD

In the above-described embodiment, a head mounted display (HMD) may be used as a display destination of a determination result (diagnosis result) or the like.

FIG. 26is a diagram illustrating an example of a head mounted display (HMD).

As illustrated inFIG. 26, an HMD500includes a spectacle main body501mounted on the head of the user2. The spectacle main body501is provided with a display section502. The display section502integrates light beams emitted from an image display portion503with light beams directed toward the eyes of the user2from the external world, and thus overlaps a virtual image from the image display portion503with a real image of the external world viewed by the user2.

The display section502is provided with, for example, the image display portion503such as a liquid crystal display (LCD), a first beam splitter504, a second beam splitter505, a first concave reflection mirror506, a second concave reflection mirror507, a shutter508, and a convex lens509.

The first beam splitter504is disposed on the front side of the left eye of the user2, and partially transmits therethrough and partially reflects light emitted from the image display portion503.

The second beam splitter505is disposed on the front side of the right eye of the user2, and partially transmits therethrough and partially reflects the light which is partially transmitted from the first beam splitter504.

The first concave reflection mirror506is disposed on the front side of the first beam splitter504, and partially reflects the partially reflected light from the first beam splitter504so as to transmit the light through the first beam splitter504, thereby guiding the light to the left eye of the user2.

The second concave reflection mirror507is disposed on the front side of the second beam splitter505, and partially reflects the partially reflected light from the second beam splitter505so as to transmit the light through the second beam splitter505, thereby guiding the light to the right eye of the user2.

The convex lens509guides the partially transmitted light from the second beam splitter505to the outside of the HMD500when the shutter508is open.

According to the HMD500, the user2can understand necessary information such as a swing type thereof without holding the swing analysis apparatus20with the user's hand.

3. Operations and Effects of Embodiment

(1) The calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment includes the processing section21which performs determination (steps S30and S36) of a swing type on the basis of information (a rotation angle about a first axis (rotation axis) in a longitudinal direction of a shaft, a position of a ball hitting portion, and the like) regarding an attitude or a position of an exercise appliance (golf club3) at a predetermined timing during a backswing.

Since it is considered that a tendency for the user2to perform a downswing depends on a backswing of the user2, it is possible to sufficiently determine a swing type of the user2(it is possible to classify a swing type into an upper body type, a lower body type, a whole body type, and the like) simply on the basis of an attitude or a position of the exercise appliance at a predetermined timing during a backswing.

(2) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the information includes information regarding a rotation angle (for example, rotation angle θHWBor θTOP) about the rotation axis of the shaft at the predetermined timing (a top timing, a halfway back timing, or the like) with the longitudinal direction of the shaft of the exercise appliance as the rotation axis.

Since it is considered that features of a swing of the user2appear in temporal changes of the rotation angle (for example, the rotation angle θHWBor θTOP) about the shaft axis, it is possible to perform determination with high accuracy on the basis of the rotation angle (for example, the rotation angle θHWBor θTOP) at the predetermined timing (a top timing, a halfway back timing, or the like).

(3) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the processing section21performs determination according to a range (for example, the ranges shown in the upper part, the intermediate part, and the lower part ofFIG. 5) in which the rotation angle (for example, the rotation angle θHWBor θTOP) is included.

It is possible to easily perform determination (classification of a swing) on the basis of a range in which the rotation angle (for example, the rotation angle θHWBor θTOP) is included.

(4) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the predetermined timing includes two or more timings (a top timing, a halfway back timing, and the like).

It is possible to more increase the accuracy of determination on the basis of rotation angles (a combination of the rotation angles θHWBand θTOP) at two or more timings than on the basis of a rotation angle (for example, one of the rotation angles θHWBand θTOP) at a single timing.

(5) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the predetermined timing includes at least one of a halfway back timing tband a top timing t2.

Since it is considered that features of a swing of the user2appear in a rotation angle (the rotation angle θHWBor the rotation angle θTOP) at halfway back or at top, it is possible to reduce an amount of necessary information and also to increase the accuracy of determination on the basis of at least one rotation angle (at least one of the rotation angles θHWBand θTOP) at at least one of the halfway back and top timings (tband t2).

(6) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the swing type may be any one of an upper body type, a lower body type, and a whole body type.

Therefore, a swing type of the user can be classified as any one of the upper body type, the lower body type, and the whole body type.

(7) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the information regarding an attitude or a position is information regarding a position of a ball hitting portion (head) of the exercise appliance (golf club3) at a predetermined timing (a halfway back timing or the like).

Since it is considered that features of a swing of the user2appear in a trajectory of the ball hitting portion (head), it is possible to determine a swing type with high accuracy on the basis of a position of the ball hitting portion (head) at a predetermined timing (a halfway back timing or the like).

(8) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the processing section21performs determination according to a region (for example, the determination regions A to E) in which a position of the ball hitting portion (head) is included.

It is possible to easily perform determination on the basis of the region. A boundary (for example, the interfaces40A to40D) of the region (for example, the determination regions A to E) may be fixed, and may be variable.

(9) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the processing section21sets a boundary (for example, the interfaces40A to40D) of the region (for example, the determination regions A to E) on the basis of a first virtual plane (shaft plane30) specified by a longitudinal direction (y axis direction) of the shaft of the exercise appliance (golf club3) and a target hit ball direction (X axis direction) at the time of starting a swing (step S32).

If a boundary is defined on the basis of the shaft axis direction of the exercise appliance (golf club3) at the time of starting a swing, it is possible to perform determination regardless of a habit (a habit of an address attitude) of the way of the user2holding the exercise appliance or a length of the exercise appliance.

(10) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the processing section21sets a boundary (for example, the interfaces40A to40D) of the region (for example, the determination regions A to E) on the basis of a second virtual plane (Hogan plane40) specified by a shaft axis direction of the exercise appliance (golf club3), a target hit ball direction, and the physical information244of the user2, at the time of starting a swing (step S32).

If a boundary is defined on the basis of the physical information244of the user2, it is possible to perform determination regardless of a physique of the user2.

(11) In the calculation apparatus according to the present embodiment, the second virtual plane may be a plane (Hogan plane) specified by a direction from a predetermined position between the head and the chest of the user toward a position of the ball hitting portion of the exercise appliance, and the target hit ball direction (X axis direction).

Therefore, a so-called Hogan plane can be used to define a boundary.

(12) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the predetermined timing includes at least a halfway back timing tb.

Since it is considered that features of a swing of the user2appear in a position of the ball hitting portion (head), it is possible to reduce an amount of necessary information and also to increase the accuracy of determination on the basis of a position of the ball hitting portion (head) at halfway back.

(13) In the calculation apparatus according to the present embodiment, the swing type is any one of a lower body type, an upper body type, a first whole body type, a second whole body type, and a third whole body type.

Therefore, a swing type of the user can be classified as any one of the upper body type, the lower body type, and the whole body type.

(14) In the calculation apparatus according to the present embodiment, the rotation angle is a relative value obtained when the shaft changes from a first state to a second state.

(15) In the calculation apparatus according to the present embodiment, the first state is a standing still state (at the time of starting a swing or at address) before starting a swing action, and the second state is an action state (a top or halfway back timing) after starting the swing action.

(16) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the information may be information indicating an average value or an intermediate value of the rotation angles in a predetermined period of time during a backswing.

If the average value or the intermediate value is used, it is possible to prevent the influence which a rotation angle measurement error exerts on a determination result.

(17) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the information regarding an attitude or a position may be information indicating an average value or an intermediate value of a position in a predetermined period of time during a backswing.

If the average value or the intermediate value is used, it is possible to prevent the influence which a position measurement error exerts on a determination result.

(18) In the calculation apparatus (the swing analysis apparatus20or the swing diagnosis apparatus300) according to the embodiment, the information regarding an attitude or a position is information generated on the basis of an output (for example, angular velocity data or acceleration data) from an inertial sensor (sensor unit10).

It is possible to obtain necessary information in a smaller calculation amount on the basis of the output (for example, angular velocity data or acceleration data) from the inertial sensor (sensor unit10) than on the basis of a swing image or the like, and thus high efficiency is ensured.

4. Other Modification Examples

The invention is not limited to the present embodiment, and may be variously modified within the scope of the spirit of the invention.

In the above-described embodiment, the acceleration sensor12and the angular velocity sensor14are built into and are thus integrally formed as the sensor unit10, but the acceleration sensor12and the angular velocity sensor14may not be integrally formed. Alternatively, the acceleration sensor12and the angular velocity sensor14may not be built into the sensor unit10, and may be directly mounted on the golf club3or the user2. In the above-described embodiment, the sensor unit10and the swing analysis apparatus20are separately provided, but may be integrally formed so as to be attached to the golf club3or the user2. Some or all of the functions of the swing analysis apparatus20may be mounted on the sensor unit10side.

In the above-described embodiment, the swing diagnosis system (swing analysis apparatus) analyzing a golf swing has been exemplified, but the invention is applicable to a swing diagnosis system (swing analysis apparatus) analyzing a swing in various sports such as tennis or baseball.

The above-described embodiment and modification examples are only examples, and the invention is not limited thereto. For example, the embodiment and the respective modification examples may be combined with each other as appropriate.

For example, the invention includes substantially the same configuration (for example, a configuration in which functions, methods, and results are the same, or a configuration in which objects and effects are the same) as the configuration described in the embodiment. The invention includes a configuration in which an inessential part of the configuration described in the embodiment is replaced with another part. The invention includes a configuration which achieves the same operation and effect or a configuration capable of achieving the same object as in the configuration described in the embodiment. The invention includes a configuration in which a well-known technique is added to the configuration described in the embodiment.

The entire disclosure of Japanese Patent Application No. 2015-148703 filed Jul. 28, 2015 is expressly incorporated by reference herein.