JP2006198073A - Body motion detection machine and personal digital assistant device equipped with body motion detection machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a body motion detection machine used for precisely determining body motion, especially tumbing or walking, walking speed by always gripping acceleration in a vertical direction regardless of a securing direction. <P>SOLUTION: The body motion detecting machine detecting the body motion of a user comprises an acceleration detecting section 8 detecting acceleration in at least three different axial directions, stop determining section 5 determining whether or not the body motion detection machine 4 stops based on the acceleration detected by the acceleration detecting section 8 and the gravitational acceleration, a corrected value calculating section 10 calculating a corrected value converting the acceleration detected by the acceleration detecting section 8 to an acceleration in a predetermined direction based on the acceleration detected by the acceleration detecting section 8 and the gravitational acceleration when the stop determining section 5 determines that the body motion detecting machine 4 stops, a converting acceleration calculating section 13 converting the acceleration detected by the acceleration detecting section 8 based on the corrected value when the stop determining section 5 determines that the body motion detecting machine 4 does not stop, and an exercise analyzing section 11 analyzing the converted acceleration calculated by the converting acceleration calculating section 13 and determining the characteristic of the exercise of the user. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a body motion detector that is carried by a user and detects the body motion of the user, and in particular, regardless of the direction in which the body motion detector is attached to the user, the motion state of the user is highly accurate. The present invention relates to a body motion detector to be determined and a mobile terminal device including the same.

  As a conventional technique for detecting a user's body movement using acceleration, there is a technique for detecting the number of steps using an acceleration sensor. (For example, refer to Patent Document 1). FIG. 15 is a functional block diagram of a body motion detection device using the conventional technique described in Patent Document 1.

In FIG. 15, the action axis determination unit 121 selects a single sensor that indicates the maximum deflection width from a plurality of body motion sensors (111 to 114) having different acceleration directions to be detected, and the selected sensor. The direction of acceleration to be detected is set as the direction of body movement, and the number of steps is estimated using the step count counter 123 based on the sensor output.
JP 2002-191580 A (page 11, FIG. 5)

  However, in the conventional configuration, although it is impossible to attach the sensor to the human body in a state in which the direction of body movement is exactly the same, it is a single of several sensors with fixed directions. Since the direction of acceleration detected by the sensor is the direction of body movement, the direction of the sensor and the direction of body movement of the user do not necessarily match completely, and the acceleration generated in the direction of body movement cannot be detected accurately. The problem is that the user's exercise state cannot be accurately grasped.

  Furthermore, there has been a problem that it is impossible to accurately determine whether the vibration detected by the sensor is a simple body movement, a walking, a device removal, or a device fall.

  The present invention solves the above-described conventional problems, and includes a body motion detector capable of accurately determining the state of motion of the user and quantitatively evaluating each determined state. It aims at providing a portable terminal device.

In order to solve the above-described conventional problems, a body motion detector according to the present invention is a body motion detector that detects a user's body motion, and an acceleration detection unit that detects at least different triaxial accelerations. Detecting the acceleration based on the acceleration detected by the acceleration detecting means and the gravitational acceleration, and detecting the acceleration when the stationary determining means determines that the stationary motion detecting means is stationary. Correction value calculating means for calculating a correction value for converting the acceleration detected by the acceleration detecting means into acceleration in a predetermined direction based on the acceleration detected by the means and the gravitational acceleration;
When the stationary determination means determines that it is not stationary, a conversion acceleration calculation means for converting the acceleration detected by the acceleration detection means based on the correction value, and an analysis of the converted acceleration calculated by the conversion acceleration calculation means And a motion analysis means for determining the characteristics of the user's motion.

  This makes it possible to determine movements such as stillness, activity, falls, walking, etc., and to calculate general indices such as the number of steps, step length, walking speed, etc. with high accuracy, regardless of the direction the user has attached the body motion detector. can do.

  Further, the acceleration detecting means detects accelerations in three axis directions orthogonal to each other, and the stationary determination means calculates a sum of squares of the accelerations of the three axes, and further calculates a square root of the sum of squares and a gravitational acceleration. When the difference is equal to or smaller than a predetermined threshold, it may be determined that the body motion detector is stationary.

As a result, it is possible to accurately detect the stationary state of the body motion detector with a minimum configuration.
Further, the correction value calculation means may calculate a correction value corresponding to each acceleration detection axis based on an inclination angle of each acceleration detection axis of the acceleration detector with respect to a vertical direction. Further, the converted acceleration calculating means calculates the converted acceleration of each axis based on the correction value and the acceleration detected by the acceleration detector, and the motion analyzing means analyzes with the value obtained by adding the converted acceleration of each axis. It's also good. Further, the motion analysis means calculates a change rate of the conversion acceleration in an arbitrary past time period, and determines that the user has collided or falls by comparing the change rate with a predetermined reference value. It's also good.

  Thereby, since the change of the acceleration of a perpendicular direction can be detected, a user's exercise | movement state can be determined correctly.

  The portable terminal device concerning this invention is a portable terminal device provided with a communication means, Comprising: The above-mentioned body motion detector and the operation condition of the said portable terminal device are detected, The operating state of the said body motion detector is controlled. It comprises control means, determination acquisition means for acquiring the determination result of the motion analysis means of the body motion detector, and a display device for displaying the acquired determination result.

Thereby, it is possible to determine only the user's exercise state more accurately without detecting an acceleration different from the user's exercise such as during operation of the mobile terminal device.
Note that the present invention is not limited to the above-described body motion detector and portable terminal device, and the same effects can be achieved as a body motion detection method and the problems can be solved. The same applies to a program that causes a computer to execute an operation based on the method.

  According to the body motion detector of the present invention, regardless of the direction the user wears the body motion detector, the user's body motion can be accurately grasped and useful for health such as falls, collisions, steps and walking speed. Accurate information can be determined accurately. In addition, according to the mobile terminal device of the present invention, it is possible to distinguish between movement when the mobile terminal device is used and body motion when the mobile terminal device is carried, and detect only useful information related to the body motion.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a front view of a foldable mobile phone as a mobile terminal device equipped with a body motion detector according to the present invention.

  In the figure, a cellular phone 1 includes a display device 2 composed of a liquid crystal display for displaying information necessary for the cellular phone 1, and two electrical contacts provided at a coupling portion on the screen side and a coupling portion on the keyboard side constituting the hinge. 3 is provided. The electrical contact 3 detects opening / closing of the mobile phone 1 and is an energization detection unit that detects an open / closed state based on the presence / absence of energization associated with the opening / closing of the mobile phone 1.

  FIG. 2 is a mobile phone 1 equipped with a body motion detector according to the present invention, which detects acceleration associated with body motion and monitors the collision / falling of a resident who is a user in an elderly care facility. It is a figure which shows the use condition of the mobile telephone 1 at the time of doing.

  The mobile phone 1 is attached to the waist portion of the user 7 in an arbitrary state. The mobile phone 1 can detect the body movement of the user 7 and transmit the result to the care staff information terminal 6. As shown in this figure, in the present embodiment, the mobile phone 1 is operated while being worn on the right side of the waist of the user 7, and displays the collision / falling state on the information terminal 6 for care staff. .

FIG. 3 is a functional block diagram of the mobile phone 1 according to the present embodiment.
As shown in the figure, the mobile phone 1 is a terminal that can execute normal voice calls, e-mails, and other applications, and includes a body motion detector 4, a control unit 9, a display device 2, and an output unit 12. And a determination acquisition unit 14 and a communication unit 15.

  The body motion detector 4 further includes a stillness determination unit 5, an acceleration detection unit 8, a correction value calculation unit 10, a motion analysis unit 11, and a converted acceleration calculation unit 13.

  The acceleration detection unit 8 includes a three-dimensional acceleration sensor that can detect accelerations of three axes orthogonal to each other, and processes and outputs signals from these sensors.

  The stillness determination unit 5 calculates the sum of squares of the output values for each axis from the acceleration detection unit 8, and further calculates a difference of the square root of the sum of squares with respect to the gravitational acceleration, and the difference is equal to or less than a predetermined value (for example, the difference is 0). It is a processing part which judges that it is still.

The correction value calculation unit 10, the conversion acceleration calculation unit 13, and the motion analysis unit 11 will be described later.
The control unit 9 can be energized by contact with each other when the electrical contact 3 as an energization detection unit provided at the hinge of the cellular phone 1 is in contact, that is, when the cellular phone 1 is opened and used. This is a processing unit that measures the resistance value between the contact points of the electrical contact 3 that cannot be energized when not closed and controls the body motion detector 4 to operate when the resistance value is infinite.

  The determination acquisition unit 14 is a processing unit that acquires the determination of the motion analysis unit 11 described later from the body motion detector 4.

  The output unit 12 displays the analysis result obtained by the motion analysis unit 11 acquired by the determination acquisition unit 14 on the liquid crystal display 2 that is a display device provided in the mobile phone 1, and outputs the result to the communication unit 15 to externally It is a processing part which performs communication.

  Next, the correction value calculation unit 10, the conversion acceleration calculation unit 13, and the motion analysis unit 11 of the body motion detector 4 provided in the mobile phone 1 worn on the right side of the waist of the user 7 will be described.

  First, the user 7 closes the mobile phone 1 and wears it as shown in FIG. At this time, the normal cellular phone function, which is a function other than the body motion detector, is stopped, and the operation of the body motion detector 4 is started. This is controlled by the control unit 9 based on the energized state of the electrical contact 3 described above.

  The acceleration detection unit 8 detects accelerations of three axes orthogonal to each other while the stationary determination unit 5 determines that the stationary unit is stationary, and outputs acceleration information for each axis to the correction value calculation unit 10.

The correction value calculation unit 10 determines a correction value for each axis based on the value of each axis and the gravitational acceleration.
Hereinafter, the calculation method of the correction value will be described in detail.

  FIG. 4 is a diagram showing the relationship between the direction of the acceleration detection axis of the triaxial acceleration sensor and the vertical gravitational acceleration.

  The action point 17 of acceleration is on the horizontal plane 16, and the three-way accelerations (Az21, Ax22, Ay23) obtained by the acceleration detector 8 are indicated by a solid line vector extending from the action point 17. At this time, the angle θz formed by the acceleration Az21 with the vertical direction 18, the angle θx formed by the acceleration Ax22 with the front-rear direction 19 and the angle θy formed by the acceleration Ay23 with the left-right direction 20 have the following relationship. Based on this relational expression, the correction value calculation unit 10 calculates a value obtained from the cosine function on the right side as a correction value. g is the gravitational acceleration.

g = Az × cos (θz) (Equation 1)

g = Ax × cos (θx) (Equation 2)

g = Ay × cos (θy) (Equation 3)

  Next, when there is a body motion, that is, while the stillness determination unit 5 determines that it is not still, the conversion acceleration calculation unit 13 calculates the conversion acceleration Z based on the following equation.

Z = Az × cos (θz) + Ax × cos (θx) + Ay × cos (θy) (Formula 4)

  The motion analysis unit 11 uses the converted acceleration Z calculated by the converted acceleration calculation unit 13 to execute an algorithm for determining the collision / falling of the user. The collision / falling determination algorithm executed at this time will be described with reference to FIGS. 5 and 6.

FIG. 5 is a conceptual diagram of the fall. In the figure, the triangular area indicates the body axis component existing area 24 after the fall, and the large white arrows indicate gravity accelerations 25 and 26 (1 g = 9.8 m / s ² ). Show. The front-rear direction 27 indicates the front-rear direction of the user 7, and the up-down direction 28 indicates the direction from the foot to the head of the user 7, and coincides with the vertical direction when the user stands still.

  The figure shows the feature that the axis of the acceleration sensor that has detected the gravitational acceleration deviates from the vertical direction before the fall, and falls with the fall. In the motion analysis unit 11 in the present embodiment, an algorithm is calculated that calculates the time change rate in the converted acceleration Z in the past one second and outputs the fall information when the value is 0.75 G or more per 20 msec. ing.

  FIG. 6 is a graph showing the characteristics of the change over time of the conversion acceleration before and after the fall when the user 7 actually falls.

  In the figure, the horizontal axis represents time (msec) and the vertical axis represents acceleration. In other words, as this graph shows, as the user falls, the conversion acceleration fluctuation amount per approximately 40 msec shows a fluctuation of 1.5 G (0.75 G per 20 msec) or more, and the axis of the sensor detecting the gravitational acceleration is , Showing the change. The motion analysis unit 11 that has received such a signal in the present embodiment outputs “falling” as the determination result. The output unit 12 according to the present invention displays the fall information on the staff terminal 6 through the communication function of the mobile phone 1. Further, in the present embodiment, the fall information can be displayed on the mobile phone 1 worn by the user.

  FIGS. 7A and 7B show the display contents of the display screen 31 of the care staff information terminal 6 and the liquid crystal display 2 of the mobile phone 1 at this time, and illustrate the human body that has fallen as fall information. .

  As described above, the mobile phone 1 equipped with the body motion detector according to the present embodiment can detect the user's fall, and the person who discovers the fallen user 7 as well as being notified to the care staff. By viewing the display content of the mobile phone 1, it becomes possible to contact a necessary place.

  In this embodiment, the contact of the hinge part is provided as the control means. However, the energization situation of the display device of the mobile phone and the energization situation of the keyboard part may be used.

(Embodiment 2)
FIG. 8 is a block diagram showing in detail the configuration of the motion analysis unit 11 according to the second embodiment of the present invention.

  This embodiment is the same as the first embodiment except for the details of the motion analysis unit 11, and the same components as those in FIGS. 1, 2, 3, and 4 are denoted by the same reference numerals and description thereof is omitted.

  As shown in the figure, the motion analysis unit 11 includes an acquisition unit 32 that acquires the conversion acceleration from the conversion acceleration calculation unit 13, a frequency analysis unit 33 that analyzes the conversion acceleration obtained by the acquisition unit 32, and a frequency specification unit. 34 and a logarithmic conversion unit 35.

  In the motion analysis unit 11 included in the mobile phone 1 in the present embodiment, the conversion acceleration data fetched from the conversion acceleration calculation unit 13 is performed by a carried program (hereinafter referred to as a motion analysis program).

  The motion analysis unit 11 according to the present embodiment has a function of a walking state analysis, that is, a gait analysis, as a motor function evaluation method.

FIG. 9 shows a walking speed calculation method executed in the motion analysis unit 11.
First, the conversion acceleration only in the vertical direction (vertical direction) calculated by the conversion acceleration calculation unit 13 is acquired (S901), then the walking speed is detected (S902), and these detection results are output (S903). .

  FIG. 10 shows the waveform of the corrected conversion acceleration data in the up-down direction input to the motion analysis unit 11. The calculation of the walking speed is characterized in that the walking speed of the user 7 is detected from the vertical conversion acceleration waveform detected as shown in FIG. In this embodiment, this walking speed is defined as follows.

[Walking speed] = [Walking cycle] x [Step length] (Formula 5)

  The walking cycle in Equation 5 corresponds to the time interval (T (i) -T (i-1)) between adjacent zero cross points (T) of vertical acceleration in FIG. However, the zero cross point is a point where zero crossing occurs in the direction from the negative region to the positive region in the acceleration waveform of the present embodiment.

  The block diagram of FIG. 8 reflects the above principle, and the acquisition unit 32 acquires the conversion acceleration in the vertical direction measured within a predetermined time interval in the conversion acceleration acquisition step (S901), and performs this conversion. In response to the acceleration, in the walking speed detection step (S902), the frequency analysis unit 33 extracts all zero cross points in the predetermined time interval, and calculates an average time interval between all zero cross points as a walking frequency. Further, in the frequency specifying unit 34 and the walking speed detecting step (S902), frequency analysis using Fourier transform is performed in the predetermined time interval to obtain the maximum value of the frequency power. The logarithmic conversion unit 35 calculates the stride by logarithmically converting the frequency power.

  FIG. 11 shows detection of a local maximum value having a minimum frequency excluding 0 as in the walking stance with respect to the power spectrum generated in step S902 from the acceleration data, and the number of steps per second as the reciprocal of the local maximum value. It is the figure which showed that is calculated.

  FIG. 12 shows the power spectrum of the acceleration waveform in the vertical direction collected by changing the stride during walking, and for each stance, the power value indicating the lowest frequency among the respective frequencies having the maximum value is used as the stride index. It is the graph which extracted and showed the correspondence with an actual stride. The horizontal axis indicates the stride, and the vertical axis indicates the stride index in which the maximum value is expressed in common logarithm. This figure shows a linear relationship between the stride and the maximum value.

  In the present embodiment, the stride can be estimated from the maximum value of the frequency power. The estimation formula used at this time is shown in Formula 6. The unit of stride is [cm].

[Step length] = 143 × (maximum frequency power) −271 (Expression 6)

  FIG. 12 shows the correspondence between the stride and the maximum frequency power. In the walking speed detection step (S12), the stride based on this estimation formula is substituted into the formula 6 to detect the walking speed.

In the output step (S903), the result is output.
FIG. 13 is an example of a screen in which the transition of walking speed is scored and displayed.

  As shown in the figure, the change in walking speed is scored and displayed on the liquid crystal display of the mobile phone 1 or displayed on the information terminal by communication, thereby improving the motivation of the user 7 for rehabilitation. Can do.

FIG. 14 is a diagram showing a change with time of the walking speed of the user 7.
In the present embodiment, the walking cycle is obtained from the adjacent zero cross points of the vertical acceleration in the walking speed detection step (S902). However, in the walking speed detection step (S902), any one in the horizontal plane is obtained. You may obtain | require a walk cycle from the zero crossing point of the acceleration of a direction (for example, left-right direction, the front-back direction). However, in this case, the walking cycle corresponds to a value obtained by halving the average value between all zero cross points in a predetermined time interval.

  According to the mobile phone 1 provided with the body motion detector 4 in the above embodiment, the user's vertical (vertical direction) can be determined from the acceleration obtained from the multi-axis acceleration sensor even if the user wears it in any direction. , The accuracy of walking speed measurement can be extracted, health-related information such as falls, collisions, stride length and left and right leg strength differences can be used, and health management in general life situations It can also be applied to uses such as rehabilitation in medical situations.

  The present invention can be applied to a body motion detector that detects the motion of a human body or the like, and in particular, can be applied to a body motion detector provided in a mobile terminal device such as a mobile phone.

It is a top view shown in the state where a cellular phone in an embodiment of the present invention was developed. It is a figure which shows PC of the user and manager who attached the mobile phone. It is a functional block diagram in the mobile phone of this embodiment. It is a three-dimensional graph which shows the concept for the correction value calculation in this embodiment. It is a conceptual diagram which shows the axis | shaft etc. of the acceleration sensor at the time of a fall. It is a graph which shows waveforms, such as conversion acceleration at the time of a fall. It is a figure which shows the output screen of an analysis result. It is a functional block diagram explaining a motion analysis part in detail. It is a flowchart which shows the detection operation | movement of walking speed. It is a graph which shows the waveform of the conversion acceleration of an up-down direction. It is a figure which shows the power spectrum obtained from the waveform of conversion acceleration. It is a figure which shows the output example in this embodiment. It is a figure which shows the output example in this embodiment. It is a functional block diagram of the conventional body motion detection apparatus. It is a functional block diagram of the body movement detection apparatus using the conventional technique.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile phone 2 Liquid crystal display, display apparatus 3 Electrical contact 4 Body motion detector 5 Stationary judgment part 6 Information terminal 7 User 8 Acceleration detection part 9 Control part 10 Correction value calculation part 11 Motion analysis part 12 Output part 13 Conversion acceleration calculation Unit 14 determination acquisition unit 15 communication unit 17 action point 18 vertical direction 19 front-rear direction 20 left-right direction 21, 22, 23 acceleration 24 body axis existence region 25, 26 gravitational acceleration 32 acquisition unit 33 frequency analysis unit 34 frequency identification unit 35 logarithmic conversion Part

Claims (15)

A body motion detector for detecting a user's body motion,
Acceleration detecting means for detecting acceleration in at least three different axis directions;
Stationary determination means for determining whether the body motion detector is stationary based on the acceleration detected by the acceleration detection means and the gravitational acceleration;
When the stillness determining means determines that it is stationary, a correction value for converting the acceleration detected by the acceleration detecting means into an acceleration in a predetermined direction is calculated based on the acceleration detected by the acceleration detecting means and the gravitational acceleration. Correction value calculating means;
Converted acceleration calculating means for converting the acceleration detected by the acceleration detecting means based on the correction value when the stationary determining means determines that the stationary is not stationary;
A body motion detector comprising: motion analysis means for analyzing the conversion acceleration calculated by the conversion acceleration calculation means and determining the characteristics of the user's motion. The acceleration detecting means detects accelerations in three axial directions orthogonal to each other,
The stationary determination means calculates the sum of squares of the accelerations of the three axes, and the body motion detector is stationary when the difference between the square root of the sum of squares and the gravitational acceleration is equal to or less than a predetermined threshold. The body motion detector according to claim 1, wherein the body motion detector is determined.   3. The body movement according to claim 2, wherein the correction value calculation means calculates a correction value corresponding to each acceleration detection axis based on an inclination angle of each acceleration detection axis of the acceleration detector with respect to a vertical direction. Detector. Conversion acceleration calculation means calculates conversion acceleration of each axis based on the correction value and the acceleration detected by the acceleration detector,
4. The body motion detector according to claim 3, wherein the motion analysis means analyzes the value obtained by adding the converted accelerations of the respective axes.   The motion analysis means calculates a change rate of the conversion acceleration in an arbitrary past time interval, and determines that the user has collided or falls by comparing the change rate with a predetermined reference value. The body motion detector according to claim 1, wherein   6. The body motion detector according to claim 5, wherein the predetermined reference value has a rate of change per 20 milliseconds of 0.7 times or more of gravitational acceleration.   The motion analysis means calculates the amplitude of variation in conversion acceleration and the existence range of the midpoint of the amplitude, and compares the amplitude and each midpoint with a predetermined reference value to determine the characteristics of the motion. The body motion detector according to claim 1, wherein walking is determined as follows. The motion analysis means;
A frequency analysis unit that generates a frequency spectrum based on a change over time in a predetermined time interval of the conversion acceleration;
A frequency corresponding to the maximum value is identified from the generated frequency spectrum, and further includes a frequency identifying unit that identifies a lowest frequency excluding a DC component from the frequency spectrum,
The body motion detector according to claim 1, wherein at least one of the number of steps and the walking speed in the predetermined time interval is output based on the identified frequency. A mobile terminal device comprising communication means,
The body motion detector according to any one of claims 1 to 8,
Control means for detecting the operation status of the mobile terminal device and controlling the operating state of the body motion detector;
Determination acquisition means for acquiring the determination result of the motion analysis means of the body motion detector;
A display device for displaying the obtained determination result;
A portable terminal device comprising: The control means further includes
With an energization detection unit that detects the energization situation in a predetermined part of the mobile terminal device,
The mobile terminal device according to claim 9, wherein an operation state of the body motion detector is controlled in accordance with a change in current in the predetermined part or power consumption. The portable terminal device further includes
The portable terminal device according to claim 9, further comprising: an output unit that outputs a graph associated with a date and time to the display device based on a determination result acquired by the determination acquisition unit.   The portable terminal device according to claim 11, wherein the output unit outputs the determination result to the communication unit. A method for determining a movement state of a user with a body motion detector comprising an acceleration detection means for detecting acceleration in at least three different axial directions,
A stationary determination step of determining whether or not the body motion detector is stationary based on the acceleration detected by the acceleration detection means and the gravitational acceleration;
A correction for calculating a correction value for converting the acceleration detected by the acceleration detection means into an acceleration in a predetermined direction based on the acceleration detected by the acceleration detection means and the gravitational acceleration when the stationary determination means determines to be stationary. A value calculation step;
A conversion acceleration calculation step for converting the acceleration detected by the acceleration detection means based on the correction value and a conversion acceleration calculated in the conversion acceleration calculation step when analyzing that the stationary determination step is not stationary. A body motion detection method comprising: a motion analysis step of determining a motion characteristic of the user. It is a method applied to a portable terminal device provided with the body movement detector according to any one of claims 1 to 8,
A control step of detecting an operation state of the mobile terminal device and controlling an operating state of the body motion detector;
A method comprising: a determination acquisition step of acquiring a determination result of the motion analysis means of the body motion detector; and a display step of displaying the acquired determination result.   The program which makes a computer perform each step of the said Claim 13 or Claim 14.

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