JP2013192590A - Motion analysis device and motion analysis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motion analysis device and a motion analysis method capable of performing a motion analysis in which a bias value of an angular velocity sensor is removed for only a stationary period before a motion period.SOLUTION: A motion analysis device 1 includes: angular velocity sensors 102x-102z for detecting the angular velocity of a measuring object 10; a bias estimation part 202 for obtaining a bias value that is included in output signals of the angular velocity sensors and changes with time as a bias estimated value in which the time is a function on the basis of the output signals acquired from the angular velocity sensors in a first period T1 during which the measuring object is in a stationary state; and a motion analysis part 204 for analyzing the motion of the measuring object on the basis of correction data in which the bias estimated value corresponding, on a time base, to the output signals acquired from the angular velocity sensors in a second period T2 following the first period is removed from the output signals.

Description

  The present invention relates to a motion analysis apparatus and a motion analysis method using an angular velocity sensor.

  There is a need for an apparatus for analyzing the motion of an object to be examined in various fields. For example, a tennis racket or a swing trajectory of a golf club, an exercise form such as baseball pitching or batting, etc. can be analyzed, and an improvement point can be clarified from the analysis result, thereby improving the competitiveness.

  At present, an optical motion capture device is known as a practical motion analysis device. This apparatus generally analyzes the motion by continuously capturing an object to be measured attached with a marker with an infrared camera or the like, and calculating the movement trajectory of the marker using the captured continuous image ( Patent Document 1).

  On the other hand, in recent years, a device has been proposed in which a small inertia sensor is attached to an object to be inspected, and the motion of the object to be inspected is analyzed from output data of a sensor that detects a physical quantity of a measurement object (Patent Document 2). . This apparatus has the advantage that it is easy to handle because it does not require an infrared camera.

JP 2010-110382 A JP 2008-073210 A

  Here, when analyzing the motion of the measurement object using an angular velocity sensor (gyro sensor) as an inertial sensor, it is necessary to remove the bias of the angular velocity sensor. The bias is a generic term for errors including zero bias in an initial state where the angular velocity is zero and random drift caused by external factors such as power supply fluctuation and temperature fluctuation.

  In order to obtain the bias value, for example, a stationary period may be set before and after the exercise period, and the bias value during the exercise period may be estimated based on a signal output from the angular velocity sensor during each stationary period. .

  However, this method does not allow real-time motion analysis. In addition, since a stationary period must be set before and after the exercise, it is difficult to perform a smooth measurement, and when the subject is accompanied by an exercise, many restrictions are imposed on the subject, which impairs convenience.

  Therefore, some aspects of the present invention have an object to provide a motion analysis apparatus and a motion analysis method that enable motion analysis by removing the bias value of the angular velocity sensor only by providing a stationary period before the motion period. To do.

(1) One aspect of the present invention is
An angular velocity sensor for detecting the angular velocity of the object to be measured;
Based on the output signal acquired from the angular velocity sensor during the first period in which the measurement target object is stationary, a bias value that is included in the output signal of the angular velocity sensor and changes with time is used as a function of time. A bias estimation unit to be obtained as an estimated value;
Based on the correction data obtained by removing the output signal and the estimated bias corresponding to the time axis from the output signal acquired from the angular velocity sensor in the second period following the first period, the measurement target object A motion analysis unit for analyzing the motion of
The present invention relates to a motion analysis apparatus having

  Here, since the angular velocity is zero, the output signal acquired from the angular velocity sensor during the first period in which the measurement target object is stationary is only a bias value that changes with time. In one aspect of the present invention, the bias estimation unit obtains a bias estimation value as a function of time from the bias value (angular velocity sensor) acquired in the first period. In the second period following the first period, the motion analysis unit measures the measurement object based on the correction data obtained by removing the output signal and the estimated bias corresponding to the time axis from the output signal acquired from the angular velocity sensor. Analyze the motion of an object. Therefore, just by providing the first period (stationary period) before the second period (including the exercise period), the bias estimation value used in the second period can be acquired, and the motion analysis with the bias value of the angular velocity sensor removed can be performed. It becomes possible. Moreover, motion analysis can be performed in real time without waiting for a rest period after the motion period.

  (2) In one aspect of the present invention, the bias estimation unit linearly approximates data sampled on the time axis as an output signal from the angular velocity sensor on a two-dimensional plane including the time axis, and the bias An estimated value can be obtained.

  In this way, the estimated bias value as a function of time is a linear function, and thus the bias value divided from the angular velocity sensor output can be easily and quickly calculated by the data correction unit.

  (3) In one aspect of the present invention, when the linear approximation formula of the bias estimated value Vias (t) which is the angular velocity per second (dps) is Vias (t) = a × t + b, the bias estimating unit When the slope a becomes smaller than the threshold value, the estimated bias value can be determined.

  Based on the angular velocity sensor output obtained in a fixed stationary period or a short stationary period, the estimated bias value may not be set appropriately. Depending on the bias stability of the angular velocity sensor and external factors, an improper bias estimation value is a case where the bias drift of the angular velocity sensor is large and the slope a in the formula Vias (t) = a × t + b is excessive. is there. Therefore, it is possible to evaluate whether or not the inclination a is reliable by comparing the inclination of the bias estimated value obtained based on the angular velocity sensor output obtained in the first stationary period with a threshold value. If the slope a is smaller than the threshold value, it can be determined as a reliable bias value. If the slope a is larger than the threshold value, the length of the stationary period may be extended to reacquire the estimated bias value and evaluate it.

  (4) In one aspect of the present invention, the bias estimation unit can determine the bias estimation value when the slope a becomes a ≦ 0.010.

  In this way, it is possible to obtain a bias estimated value close to a bias estimated value obtained by providing a stationary period before and after the exercise period.

  (5) In one aspect of the present invention, the bias estimation unit can determine the bias estimation value when the slope a is a ≦ 0.005.

  In this way, it is possible to obtain an estimated bias value closer to the estimated bias value obtained by providing a stationary period before and after the exercise period.

  (6) In one mode of the present invention, it can further have a notification part which notifies the start of exercise after the bias estimation value is decided in the bias estimation part.

  Since it is necessary to obtain the bias estimated value, a stationary period is required before the exercise is started, and a notification for ending the stationary period and starting the exercise can be performed based on the determination timing of the bias estimated value.

  (7) In one aspect of the present invention, the motion analysis unit can analyze the motion of the measurement target object based on the correction data and an integrated value of the correction data.

  Among the movements of the object to be measured, it can be analyzed by the angular velocity obtained by correcting the output of the angular velocity sensor and the angle obtained by integrating it. In addition, the motion of the measurement target object can be analyzed with high accuracy by removing the bias value.

  (8) In one aspect of the present invention, the motion analysis unit can analyze the motion of the measurement target object in real time in the order in which the output signal of the angular velocity sensor is input. That is, in one embodiment of the present invention, a bias estimation value can be obtained without waiting for a stationary period after an exercise period, so that an exercise analysis can be performed in real time.

(9) In one embodiment of the present invention,
An acceleration sensor for detecting an acceleration of the measurement object;
The motion analysis unit can analyze the motion of the measurement target object based on m (m is a natural number) floor integral value of the output signal of the acceleration sensor and the output signal of the acceleration sensor.

  As motion analysis data, acceleration is obtained as an output of the acceleration sensor in addition to angular velocity or angle, and velocity and position can be obtained by integrating the acceleration m-th order, so that the motion analysis of the object to be measured can be performed precisely. it can.

(10) Another aspect of the present invention is:
Obtaining an output signal from an angular velocity sensor attached to the measurement target object in a first period in which the measurement target object is stationary;
Obtaining a bias value included in an output signal of the angular velocity sensor acquired in the first period and changing with time as a bias estimation value having a function of time;
Obtaining an output signal of the angular velocity sensor in a second period following the first period;
The motion of the measurement target object is analyzed based on correction data obtained by removing the bias estimation value corresponding to the output signal and the time axis from the output signal of the angular velocity sensor acquired in the second period. Process,
It is related with the motion analysis method which has.

  In another aspect of the present invention, the bias estimated value used in the second period can be obtained simply by providing the first period (stationary period) before the second period (including the exercise period), and the bias value of the angular velocity sensor It is possible to analyze the motion without removing the. Moreover, motion analysis can be performed in real time without waiting for a rest period after the motion period.

It is a figure showing the outline of the motion analysis device concerning the embodiment of the present invention. It is a figure which shows the golf club which is a measurement object, and the charger which charges the sensor unit attached to the golf club. FIG. 3 is a block diagram of the sensor unit shown in FIGS. 1 and 2. It is a figure which shows the charge state (static state) which connected the golf club and the charger with the contact. 1 is a block diagram of a motion analysis apparatus according to an embodiment of the present invention. It is a timing chart which shows the sensor output signal sampled in the 1st and 2nd period. It is a figure which shows the movement locus | trajectory of a measurement object. It is a flowchart which shows the motion analysis method sail which concerns on embodiment of this invention. It is a figure which shows the bias estimated value obtained by carrying out the linear approximation of the sampling data from an angular velocity sensor. FIG. 10 (A) shows a bias estimation value of a comparative example obtained by providing a stationary period before and after the exercise period, and FIGS. 10 (B) to 10 (E) provide different stationary periods before the exercise period. FIG. 10 (F) is a diagram showing angular velocity data from which the bias estimated value is removed.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not necessarily.

1. Outline of Motion Analysis Device As shown in FIG. 1, the motion analysis information collection device 100 includes a sensor unit 20 including an angular velocity sensor attached to a measurement target object, for example, a golf club 10, a bias estimation unit, and a motion analysis unit. Including a host terminal 200.

1.1. Sensor Unit Here, the target of the motion analysis information of the motion analysis device 1 is the golf club 10 operated by the subject shown in FIG. FIG. 1 shows a swing locus A of a club head 11 of a golf club 10 operated by a subject. The swing locus A includes a swing activation position P1, a top position P2, an impact position P3, and a follow-through top position P4.

  FIG. 2 shows a golf club 10 to which the sensor unit 20 used in the present embodiment is mounted, and a holder for the golf club 10, for example, a charger 30. The charger 30 charges a secondary battery that supplies power to a sensor built in the sensor unit 20.

  FIG. 2 schematically shows the golf club 10 in which the sensor unit 20 is mounted on the club shaft 12. The charger 30 is a stand type, and can hold the club shaft 12 in a stationary state, and can charge a secondary battery in the sensor unit 20 via a contact described later. The position where the sensor unit 20 is attached is not limited to the club shaft 12 but may be the club head 11 or the like, for example. Further, the sensor unit 20 is not necessarily limited to the one attached to the golf club 10 and may be attached to the subject.

  The sensor unit 20 can detect a given physical quantity and output a signal (data) corresponding to the magnitude of the detected physical quantity (for example, acceleration, angular velocity, speed, angular acceleration, etc.). In the present embodiment, as shown in FIG. 3, the sensor unit 20 is a triaxial detection type acceleration sensor 102x to 102z (an example of an inertial sensor, which is an example of an inertial sensor) that detects acceleration in the X-axis, Y-axis, and Z-axis directions. Axis acceleration sensor) and a three-axis detection type gyro sensor that detects angular velocities in the X-axis, Y-axis, and Z-axis directions (an example of an angular velocity sensor and an inertial sensor; hereinafter referred to as a three-axis gyro sensor) 104x˜ A 6-axis detection type motion sensor consisting of 104z is provided.

  Here, as the three-axis gyro sensors (angular velocity sensors) 104x to 104z, vibration-type angular velocity sensors can be used. The vibration type angular velocity sensor vibrates the vibrating body at a constant frequency. When an angular velocity is applied to the vibrating body, a Coriolis force is generated, and the vibrating body vibrates in different directions due to the Coriolis force. The angular velocity can be detected by detecting the displacement due to the Coriolis force. For example, by sealing the angular velocity sensor element under reduced pressure, the Q value of the vibration type angular velocity sensor element is increased, and an angular velocity with excellent bias stability can be detected (for example, JP 2010-203990 A).

  The control unit 110 illustrated in FIG. 3 is connected to the sensors 102x to 102z and 104x to 104z, the communication unit 120, and the secondary battery 130. The control unit 110 can be further connected to the charger 30.

  The control unit 110 includes a data processing unit 110A that outputs the output signals of the sensors 102x to 102z and 104x to 104z together with time information, for example, as a packet and outputs the packet to the communication unit 120. The communication unit 118 illustrated in FIG. 3 performs processing for transmitting the packet data received from the data processing unit 110A to the host terminal 300. The control unit 110 can include a charge control unit 110B that controls charging of the secondary battery 130.

  FIG. 4 shows a basic configuration example of the charger 30 and the exercise apparatus (golf club) 10 to be measured shown in FIG. The charger 30 functioning as a holder includes a grounding portion 31, a shaft holding portion 32 extending upward from the grounding portion 31, a charging circuit 33 provided in the grounding portion 31, and 2 provided in the shaft holding portion 32. Two charging terminals 34 and 35 are provided. The golf club 10 has to-be-charged terminals 13 and 14 in contact with the charging terminals 34 and 35 of the charger 30 on the club shaft 12. The sensor unit 20 provided in the golf club 10 is not shown in FIG.

1.2. Host Terminal FIG. 5 shows a host terminal 200. The host terminal 200 includes a processing unit (CPU) 201, a communication unit 210, an operation unit 220, a ROM 230, a RAM 240, a nonvolatile memory 250, a display unit 260, and a notification unit 270.

  The communication unit 210 performs a process of receiving a signal transmitted from the sensor unit 20 and sending the signal to the processing unit 201. The operation unit 220 performs a process of acquiring operation data from the user and sending it to the processing unit 201. The ROM 230 stores programs for the processing unit 201 to perform various calculation processes and control processes, various programs and data for realizing application functions, and the like. The RAM 240 is used as a work area of the processing unit 201, and temporarily stores programs and data read from the ROM 230, data input from the operation unit 220, calculation results executed by the processing unit 201 according to various programs, and the like. It is a storage unit. In the present embodiment, in particular, known data about the initial position P0 and the impact position P3 shown in FIG. 7 to be described later can be stored in the ROM 230 or the RAM 240. The non-volatile memory 250 is a storage unit that records data that needs to be stored for a long time among the data generated by the processing of the processing unit 201. The display unit 260 displays the processing result of the processing unit 201 as characters, graphs, or other images. The display unit 260 is, for example, a CRT, LCD, touch panel display, HMD (head mounted display), or the like. In addition, you may make it implement | achieve the function of the operation part 220 and the display part 260 with one touchscreen type display. The notification unit 270 notifies the subject that exercise may be started.

  The processing unit 201 performs various calculation processes on the data received from the sensor unit 20 via the communication unit 210 and various control processes (display control for the display unit 260, etc.) in accordance with a program stored in the ROM 230. In particular, in the present embodiment, the processing unit 201 includes the bias estimation unit 202 and the motion analysis unit 204, and the motion analysis unit 204 can function as the data correction unit 206 and the calculation unit 208.

  Based on the output signals acquired from the angular velocity sensors 104x to 104z when the golf club 10 is in a stationary state, the bias estimation unit 202 includes a bias value that varies with time included in the output signals 104x to 104z of the angular velocity sensors. Let the bias estimate be a function of time. In the motion analysis unit 204, from the output signals acquired from the angular velocity sensors 104 x to 104 z during the motion period following the stationary period of the golf club 10, the data correction unit 206 calculates the bias estimate corresponding to the output signal on the time axis. The correction data is generated by removal, and the calculation unit 208 analyzes the motion of the golf club 10 based on the correction data. Note that the arithmetic unit 208 can analyze the motion of the golf club 10 based on output signals from the acceleration sensors 104x to 104z.

2. Motion Analysis Method Hereinafter, the motion analysis method will be described with reference to FIGS. At the start of FIG. 6, the golf club 10 is mounted on the charger 30 shown in FIG. 4 and is stationary. At this time, the sensor unit 20 is at a known starting point P0 (position of the charger 30) shown in FIG. 7, and both acceleration and angular velocity are zero. These are known data at the start point P0.

2.1. Step S1 in FIG. 8 In step S1 in FIG. 8, an output signal is acquired from the sensor unit 20 in a stationary state in which the golf club 10 is mounted on the charger 30 from the start time t0 in FIG. That is, from the start time t0 in FIG. 8, sensor output data is sampled and acquired at a predetermined sampling frequency in a stationary state. In particular, angular velocity data is acquired from, for example, sampling time information from the three-axis gyro sensors 104x to 104z. In this stationary state, the angular velocity is zero, but the acquired angular velocity data is not zero and includes a bias value that changes with time.

  In step S <b> 2 of FIG. 8, the bias estimation unit 202 of FIG. 5 obtains a bias estimation value as a function of time based on the output signals from the three-axis gyro sensors 104 x to 104 z acquired during the stationary period.

  The bias estimation unit 202 can obtain a bias estimation value by linearly approximating data sampled on the time axis as output signals from the three-axis gyro sensors 104x to 104z on a two-dimensional plane including the time axis, for example.

  FIG. 9 shows a technique for obtaining a bias estimated value by linear approximation. In FIG. 9, the horizontal axis represents time t, and the vertical axis represents the angular velocity as an angle per second (dps). FIG. 9 shows that the angular velocities y1 to yn are acquired at the time of sampling n times from time x1 to xn.

The bias estimation unit 202 outputs n data (x1, y1), (x2, y2),... (Xn, yn) sampled on the time axis as output signals from the three-axis gyro sensors 104x to 104z. Y = a × x + b, which is linearly approximated by a two-dimensional plane (xy) including the axis, is obtained as a bias estimation value using time as a function. In other words, since the output signals y1 to yn from the three-axis gyro sensors 104x to 104z in the stationary state indicate the bias values corresponding to the times x1 to xn, the above equation expresses the bias estimated value as Vias (t ) And t is the time, the bias estimated value Vias (t), which is the angular velocity per second (dps), is
Vias (t) = a × t + b (1)
It can be expressed as. The estimated bias value Vias (t) is obtained for each of the X, Y, and Z axes.

  Here, the coefficients a and b in Expression (1) are obtained as follows in the least square method based on n pieces of data (x1, y1), (x2, y2),... (Xn, yn). .

  Here, it can be seen that the coefficients a and b in Expression (1) depend on the number of samplings (sampling time). Therefore, the present inventor obtained the bias estimation value of the equation (1) for each of different sampling times. The experimental data are shown in FIGS. 10 (A) to 10 (F). In FIG. 10A to FIG. 10F, the horizontal axis represents time, and 0 to 10000 msec (10 sec) is shown. The vertical axis represents angular velocity (dps).

  FIG. 10A shows a comparative example. 10A, unlike the present invention, when the exercise period is within 1000-9000 msec, for example, the first stationary period 1 second (1-1000 mesc) set before the exercise period and the post-exercise period are set. The second stationary period of 1 second (9000-10000 mesc) is set. In FIG. 10A, the average value of the output signals acquired from the triaxial gyro sensors 104x to 104z during the first stationary period and the average value of the output signals acquired from the triaxial gyro sensors 104x to 104z during the second stationary period. Are connected by a straight line to obtain an estimated bias value. In this case, since the estimated bias value cannot be obtained unless the second stationary period after the exercise period is waited for, real-time exercise analysis cannot be performed. In addition, since the first and second stationary periods must be set before and after the exercise period, it is difficult to perform smooth measurement, and many restrictions are imposed on the subject when accompanied by the subject's exercise, which impairs convenience.

  10B to 10E, the bias estimation value is obtained by changing the length of the stationary period before the exercise period. In FIG. 10B, the bias of equation (1) is based on the output signals acquired from the triaxial gyro sensors 104x-104z during the rest period of 1 second (1-1000 mesc) set before the exercise period. This is an estimated value. In the sampling period of 1 second, the slope “a” of Expression (1) may become large as shown in FIG. Therefore, the stationary period set before the exercise period as shown in FIG. 10 (C) is set to 2 seconds (1-2000 mesc), or the stationary period set before the exercise period as shown in FIG. 10 (D). When the period was 3 seconds (1 to 3000 mesc), the bias drift was stable, and the slope a in the equation (1) could be reduced. In FIG. 10E, the stationary period is set to 1 second and the position of the stationary period is moved to 2000 to 3000 msec as in FIG. 10B. However, as in FIG. The slope a may increase.

  As described above, if a bias estimation value is obtained by securing a stationary period set before the exercise period for at least 2 seconds or more, an appropriate bias estimation value can be obtained without setting the stationary period after the exercise period. I understand.

  The length of the stationary period (bias estimation time) set before the exercise period depends on the bias stability of the three-axis gyro sensors 104x to 104z. As the triaxial gyro sensors 104x to 104z, as described above, for example, vibration-type angular velocity sensors with high bias stability in which angular velocity sensor elements are sealed under reduced pressure can be used.

  Here, the length of the stationary period (bias estimation time) set before the exercise period depends on the bias stability of the three-axis gyro sensors 104x to 104z, etc., or depends on external factors, and is therefore variable. May be.

  For this purpose, the obtained estimated bias value can be evaluated, for example, by comparing the magnitude of the slope a in the equation (1) with a threshold value. By doing in this way, the reliability of a bias estimated value can be improved.

  Here, the threshold value is considered from the slope a of the formula (1) of the estimated bias value obtained in FIGS. 10 (A) to 10 (D). The slope a of the bias estimated value equation (1) obtained in FIGS. 10A to 10D was the following value for each of the X, Y, and Z axes.

XYZ
FIG. 10 (A) −0.0008 −0.0013 −0.0008
FIG.10 (B) -0.0448 -0.0008 +0.0147
FIG.10 (C) -0.0120 -0.0073 +0.0010
FIG.10 (D) +0.0001 +0.0029 -0.0032
When the inclination a of the formula (1) of the bias estimation value obtained in FIGS. 10A to 10D is evaluated, when FIGS. 10C and 10D are valid, a ≦ 0. 010. In this case, as shown in FIG. 10B, the estimated bias value obtained in the stationary period of 1 second is not adopted, and the estimated bias value obtained by setting the stationary period as 2 seconds as shown in FIG. It becomes a definite value. When the threshold value is set in this way, a bias estimated value close to the bias estimated value of the comparative example obtained by providing a stationary period before and after the exercise period as shown in FIG. 10A can be obtained.

  When FIG. 10D is valid, a ≦ 0.005 can be satisfied. In this case, as shown in FIGS. (B) and (C), the estimated bias values obtained in the 1-second and 2-second stationary periods are not adopted, and the stationary period is set to 3 seconds as shown in FIG. 10 (D). The obtained bias estimated value becomes a definite value. When the threshold value is set in this way, a bias estimated value closer to the bias estimated value of the comparative example obtained by providing a stationary period before and after the exercise period as shown in FIG. 10A can be obtained.

  As described above, step S2 may be repeatedly performed until the estimated bias value is determined in step S3 of FIG. Or as above-mentioned, the bias estimated value obtained during the fixed stationary period can also be made into a definite value.

2.2. Exercise Analysis Step In step S4 of FIG. 8, the notification unit 270 shown in FIG. 5 can notify the start of exercise after the bias estimation value is determined by the bias estimation unit 202. This notification can be made by display or sound.

  In step S <b> 5 of FIG. 8, it is monitored whether or not the golf club 10 is detached from the charger 30. The fact that the golf club 10 has been removed from the charger 30 is determined by the control unit 110 in FIG. 3 monitoring the voltage at the contacts 13 and 14 of the golf club 10 shown in FIGS. 3 and 4. If it is acquired by the control unit 110 that the golf club 10 has been removed from the charger 30 (YES in step S5 in FIG. 8), the process proceeds to step S6. In step S6 of FIG. 8, the collection of the first output data in the first period (stationary period) T1 in FIG. 6 ends, and the movement analysis is performed by collecting the second output data in the second period (movement period) T2. Be started.

  First, motion analysis based on output signals from the three-axis gyro sensors 104x to 104z will be described. In the motion analysis unit 204 in FIG. 5, the data correction unit 206 uses the bias estimation value Vias () corresponding to the output signal on the time axis from the output signal acquired from the three-axis gyro sensors 104x to 104z in the second period T2. t) is removed. The estimated bias value Vias (t) corresponding to the output signal on the time axis is obtained by substituting the time t at which the output signal was sampled into the equation (1). At this time, if the estimated bias value as a function of time is a linear function as shown in Equation (1), the data correction unit 206 can easily and quickly calculate the bias value divided from the angular velocity sensor output. it can. The sensor unit signal sent from the sensor unit 20 to the host terminal 200 contains the sampling time and the output signals of the three-axis gyro sensors 104x to 104z acquired at the sampling time in one packet.

  At this time, the data correction unit 206 initializes with the known data (angular velocity is zero) for the position P0 acquired in the first period T1 in FIG. 6, and in the second period T2 in FIG. 6 based on the initial value. The collected data can be corrected together.

  FIG. 10F shows data corrected as described above. As shown in FIG. 10F, in the period in which the golf club 10 is stationary before and after the exercise period, the angular velocity is zero and the bias value is removed. Since the bias value is similarly removed during the exercise period, correction data with less error is obtained.

  Next, in the motion analysis unit 204 in FIG. 5, the calculation unit 208 analyzes the motion of the golf club 10 based on the correction data from the data correction unit 206. The calculation unit 208 can analyze the posture of the golf club 10 by calculating the angle from the angular velocity data by integrating the correction data.

  On the other hand, the sensor unit signal transmitted from the sensor unit 20 to the host terminal 200 includes output signals from the acceleration sensors 102x to 102z. Therefore, the calculation unit 208 can analyze the motion of the golf club 10 by performing m-order integration (m is a natural number) on the output signals from the acceleration sensors 102x to 102z. When the output signals from the acceleration sensors 102x to 102z are first-order integrated, the speed can be obtained from the acceleration. When the output signals from the acceleration sensors 102x to 102z are second-order integrated, the position can be obtained from the velocity. At this time, the output from the acceleration sensors 102x to 102z is based on the known data at the positions P0 and P3 shown in FIG. 7 (the positions P0 and P3 are known and the velocity and acceleration at the position P0 are zero). The signal and its integrated value can be corrected.

  In this way, the swing motion of the golf club 10 starting from the position P0 shown in FIG. 7 and from the address position P1 to the finish position P5 can be accurately analyzed by removing the bias value. In addition, in this embodiment, the motion analysis can be performed in real time without waiting for a stationary period after the exercise period.

  Such a motion analysis can be ended by returning the golf club 10 to the charger 30, for example. Therefore, in FIG. 6, it is determined whether or not the golf club 10 has been returned to the charger 30 in step S7, and the determination in step S7 is YES, so that the motion analysis can be terminated. The fact that the golf club 10 has been returned to the charger 30 is determined by the control unit 110 in FIG. 3 monitoring the voltage at the contacts 13 and 14 of the golf club 10 shown in FIGS. 3 and 4.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention.

  For example, the measurement target object of the present invention can be preferably applied to an exercise apparatus such as a golf club or a tennis racket, but is not limited thereto.

  Further, the bias estimation unit 202, the data correction unit 206, or the notification unit 270 may be provided in the sensor unit 20 instead of the host terminal 200.

  DESCRIPTION OF SYMBOLS 1 Motion analysis apparatus, 10 measurement object, 20 sensor unit, 30 charger (holding tool), 102x-102z acceleration sensor, 104x-104z angular velocity sensor (gyro sensor), 110 control part, 110A data processing part, 110B charge control Unit, 120 communication unit, 130 secondary battery, 200 host terminal, 202 bias estimation unit, 204 motion analysis unit, 206 data correction unit, 208 calculation unit, 270 notification unit, T1 first period, T2 second period

Claims (10)

An angular velocity sensor for detecting the angular velocity of the object to be measured;
Based on the output signal acquired from the angular velocity sensor during the first period in which the measurement target object is stationary, a bias value that is included in the output signal of the angular velocity sensor and changes with time is used as a function of time. A bias estimation unit to be obtained as an estimated value;
Based on the correction data obtained by removing the output signal and the estimated bias corresponding to the time axis from the output signal acquired from the angular velocity sensor in the second period following the first period, the measurement target object A motion analysis unit for analyzing the motion of
A motion analysis apparatus comprising: In claim 1,
The bias estimation unit obtains the bias estimation value by linearly approximating data sampled on the time axis as an output signal from the angular velocity sensor on a two-dimensional plane including the time axis. Analysis device. In claim 2,
When the linear approximation formula of bias estimated value Vias (t), which is the angular velocity per second (dps), is Vias (t) = a × t + b, the bias estimating unit has a slope a smaller than a threshold value. A kinematic analysis device characterized in that the estimated bias value is determined when the time becomes. In claim 3,
The motion estimation apparatus, wherein the bias estimation unit determines the bias estimation value when the inclination a becomes a ≦ 0.010. In claim 3,
The motion estimation apparatus, wherein the bias estimation unit determines the bias estimation value when the slope a becomes a ≦ 0.005. In any one of Claims 3 thru | or 5,
The motion analysis apparatus further comprising a notification unit for notifying the start of exercise after the bias estimation value is determined by the bias estimation unit. In any one of Claims 1 thru | or 6,
The motion analysis unit analyzes the motion of the measurement target object based on the correction data and an integrated value of the correction data. In claim 7,
The motion analysis device analyzes the motion of the measurement target object in real time in the order in which the output signals of the angular velocity sensor are input. In any one of Claims 1 thru | or 8,
An acceleration sensor for detecting an acceleration of the measurement object;
The motion analysis unit analyzes the motion of the measurement target object based on m (m is a natural number) floor integral value of the output signal of the acceleration sensor and the output signal of the acceleration sensor. Obtaining an output signal from an angular velocity sensor attached to the measurement target object in a first period in which the measurement target object is stationary;
Obtaining a bias value included in an output signal of the angular velocity sensor acquired in the first period and changing with time as a bias estimation value having a function of time;
Obtaining an output signal of the angular velocity sensor in a second period following the first period;
The motion of the measurement target object is analyzed based on correction data obtained by removing the bias estimation value corresponding to the output signal and the time axis from the output signal of the angular velocity sensor acquired in the second period. Process,
A motion analysis method characterized by comprising:

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