JPWO2017094521A1 - Wearable device, posture measurement method and program thereof - Google Patents

Abstract

The acceleration sensor 10 when the wearable device 2 is determined not to be in a stationary state by the stationary state determination unit 24 or when the posture determination unit 25 determines that the posture of the wearable device 2 with respect to the direction of gravity is not within a predetermined range. The data of the acceleration detected in the above is not used by the posture reference information acquisition unit 23 to acquire posture reference information. As a result, it is possible to automatically acquire the posture reference information under an appropriate condition in which the wearable device 2 is stationary and its posture is within a predetermined range.

Description

  The present invention relates to a wearable device that can be worn on a body or clothes, and more particularly to a wearable device including an acceleration sensor.

  Wearable devices are relatively small electronic devices that can be worn on the body, clothes, etc. For example, various devices (acceleration sensors, angular velocity sensors, etc.) and communication functions for measuring the state of the body for health management and the like. What is provided is known (see Patent Document 1 below).

JP 2008-22214A

  In the case of a wearable device equipped with an acceleration sensor, it is possible to measure the degree of body tilt relative to the direction of gravity as the body posture. The acceleration detected by the acceleration sensor while the body is stationary represents the gravitational acceleration. If the direction of gravity when the body is in a certain reference posture (for example, an upright posture) is defined as the “reference direction”, it is possible to determine how much the gravity direction indicated by the detection result of the acceleration sensor is inclined with respect to the reference direction. For example, the inclination of the body with respect to the reference posture, that is, the posture of the body can be measured.

  In order to measure the posture of the body, information on the direction of gravity (reference direction) when the body is in the reference posture is required. This reference direction is determined from the detection result of the acceleration sensor obtained when the body is in the reference posture. The detection of acceleration for determining the reference direction may be executed, for example, by a user's manual operation (button operation or the like). However, in consideration of cases used by elderly people and children who are unfamiliar with machine operation, and cases that are worn on a daily basis, it is desirable that such acceleration detection be performed automatically. .

  In order to automatically execute acceleration detection in order to determine the reference direction, it is necessary to determine by a suitable means that the body is stationary when the acceleration is detected. For example, a method may be considered in which whether or not the body is in a stationary state is determined based on the fluctuation range of the detection result of the acceleration sensor, and the reference direction is determined based on the detection result of the acceleration sensor when it is determined that the body is stationary. It is done. However, since this method does not take into account the user's posture, for example, even if the wearable device is worn and is in a lying posture, the reference direction is based on the detection result of acceleration in that posture if it is stationary. Is determined. That is, simply determining whether or not the vehicle is stationary may determine the reference direction based on the acceleration detected in an inappropriate posture. In this case, an erroneous measurement result indicating that the posture is greatly inclined from the reference posture is obtained although the posture is actually the reference posture.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wearable device capable of accurately measuring the posture with respect to the direction of gravity using an acceleration sensor while reducing the burden on the user's operation, and its posture measurement. It is to provide a method and a program.

  A wearable device according to a first aspect of the present invention includes an acceleration sensor, an acceleration data acquisition unit that repeatedly acquires acceleration data detected by the acceleration sensor, and acceleration data acquired by the acceleration data acquisition unit. A posture calculation unit that calculates a posture with respect to the direction of gravity based on the direction of gravity shown and posture reference information related to a reference direction that is a direction of gravity as a reference for the posture, and the acceleration acquired by the acceleration data acquisition unit A posture reference information acquisition unit that acquires the posture reference information corresponding to the direction of gravity indicated by the acceleration data, and a stationary state based on the acceleration data acquired by the acceleration data acquisition unit Data of acceleration acquired by the stationary state determination unit for determining whether or not there is, and the acceleration data acquisition unit Based on provided orientation relative to the direction of gravity and determining posture determination unit that determines whether within a predetermined range. The posture reference information acquisition unit is detected when the stationary state determination unit determines that the posture is not in a stationary state, or when the posture determination unit determines that the posture is not within the predetermined range. Acceleration data is excluded from data used to acquire the posture reference information.

  According to said structure, when it determined with the said stationary state determination part not being in a stationary state, or when the said attitude | position determination part determined with the attitude | position with respect to the direction of gravity not being in the said predetermined range, it detected The acceleration data is excluded from data used to acquire the posture reference information in the posture reference information acquisition unit. For example, the acceleration data detected when the user wearing the wearable device is exercising is excluded from the data used to acquire the posture reference information. The acceleration data detected when the posture of the user wearing the wearable device is not normal, or when the posture of the user is normal and the wearing state of the wearable device is not normal is also the posture reference. Excluded from data used for information acquisition. This makes it possible to automatically acquire the posture reference information under an appropriate condition that is stationary and the posture is within a predetermined range. Therefore, the burden on the user's operation is reduced, and the posture calculation unit calculates an accurate posture with respect to the direction of gravity.

Preferably, the posture determination unit may perform the posture determination based on acceleration data acquired by the acceleration data acquisition unit when the stationary state determination unit determines that the vehicle is in a stationary state.
Thereby, since the influence of acceleration other than gravity is suppressed, accurate posture determination can be performed.

Preferably, when the posture determination unit determines that the posture is within the predetermined range, the acceleration data acquisition unit determines that the posture is within the predetermined range when the posture determination unit determines that the posture is not within the predetermined range. In comparison, the repetition cycle for acquiring the acceleration data may be lengthened.
Thereby, when the posture is not within the predetermined range, the repetition cycle of the acceleration data acquisition is lengthened, thereby reducing the power consumption.

Preferably, the posture reference information acquisition unit uses the acceleration data detected when the stationary state determination unit determines that the stationary state has not continued for a certain period of time or more to acquire the posture reference information. May be excluded from the data.
Thus, even if the posture determination unit determines that the posture is within the predetermined range, the acceleration data detected in the case of a temporary posture in which the stationary state has not continued for a certain time or more is Excluded from data used to acquire posture reference information. That is, the posture reference information is acquired based on the acceleration data detected in a stable posture while maintaining a stationary state. Therefore, the posture calculation unit calculates a more accurate posture with respect to the direction of gravity.

Preferably, the posture reference information acquisition unit is detected when the stationary state determination unit determines that the posture is in a stationary state and the posture determination unit determines that the posture is within the predetermined range. A series of the acceleration data may be averaged, and the posture reference information corresponding to the direction of gravity indicated by the averaged acceleration data may be acquired.
As a result, the posture reference information with the direction of gravity in an average posture as the reference direction is acquired.

Preferably, the wearable device according to the first aspect is determined to be in a stationary state by an angular velocity sensor, an angular velocity data acquisition unit that repeatedly acquires angular velocity data detected by the angular velocity sensor, and the stationary state determination unit. In this case, an angular velocity offset correction unit may be provided that corrects the offset of the angular velocity data based on the angular velocity data acquired by the angular velocity data acquisition unit.
As a result, the offset added to the angular velocity data is accurately corrected.

Preferably, when the posture determination unit determines that the posture is not in the predetermined range, the angular velocity data acquisition unit determines that the posture is within the predetermined range. In comparison, the repetition cycle of obtaining the angular velocity data may be lengthened.
Thereby, when the posture is not in the predetermined range, the repetition rate of the data acquisition of the angular velocity is lengthened, thereby reducing the power consumption.

Preferably, the angular velocity data acquiring unit may stop acquiring the angular velocity data when the posture determining unit determines that the posture is not within the predetermined range.
Thereby, when the posture is not in the predetermined range, the acquisition of the angular velocity is stopped, so that the power consumption is further reduced.

  A second aspect of the present invention relates to a method in which a computer measures the attitude of the wearable device with respect to the direction of gravity based on acceleration data detected by an acceleration sensor mounted on the wearable device. This posture measuring method is a reference for the direction of gravity indicated by the acceleration data acquired in the step of repeatedly acquiring the acceleration data detected by the acceleration sensor and the step of acquiring the acceleration data, and the posture reference. Based on the posture reference information related to the reference direction, which is the direction of gravity, the acceleration data acquired based on the acceleration data acquired in the step of calculating the posture with respect to the direction of gravity and the step of acquiring the acceleration data Determining whether or not the vehicle is in a stationary state based on the acceleration data acquired in the step of acquiring the posture reference information according to the direction of gravity indicated by the step of acquiring the acceleration data; Based on the acceleration data acquired in the step of acquiring the acceleration data, Orientation with respect to the direction of force and a determining whether within a predetermined range. In the step of obtaining the posture reference information, if it is determined in the step of determining the stationary state that it is not in a stationary state, or the step of determining a posture with respect to the direction of gravity is not within the predetermined range. The acceleration data detected when determined to be excluded from the data used to acquire the posture reference information.

  According to the above configuration, when it is determined that the stationary state is not the stationary state in the step of determining the stationary state, or the posture with respect to the direction of gravity is determined not to be within the predetermined range in the step of determining the posture The acceleration data detected in the step is excluded from data used for acquiring the posture reference information in the step of acquiring the posture reference information. For example, the acceleration data detected when the user wearing the wearable device is exercising is excluded from the data used to acquire the posture reference information. The acceleration data detected when the posture of the user wearing the wearable device is not normal, or when the posture of the user is normal and the wearing state of the wearable device is not normal is also the posture reference. Excluded from data used for information acquisition. This makes it possible to automatically acquire the posture reference information under an appropriate condition that is stationary and the posture is within a predetermined range. Accordingly, the burden on the user's operation is reduced, and an accurate posture with respect to the direction of gravity is calculated in the step of calculating the posture.

  A third aspect of the present invention is a program for causing a computer to execute the posture measurement method according to the second aspect.

  ADVANTAGE OF THE INVENTION According to this invention, the attitude | position with respect to the direction of gravity can be measured correctly using an acceleration sensor, reducing the burden of a user's operation.

It is a figure which shows an example of a structure of the wearable apparatus which concerns on 1st Embodiment. It is a figure which shows an example of the wearable apparatus with which the user was mounted | worn. 2A shows a case where the user is in an upright posture, and FIG. 2B shows a case where the user is in a lying posture. It is a flowchart for demonstrating the operation | movement in connection with the detection of the periodic acceleration in the wearable apparatus which concerns on 1st Embodiment. It is a flowchart for demonstrating the operation | movement in connection with acquisition of the attitude | position reference information in the wearable apparatus which concerns on 1st Embodiment. It is a flowchart for demonstrating the operation | movement in connection with acquisition of the attitude | position reference information in the wearable apparatus which concerns on 2nd Embodiment. It is a flowchart for demonstrating the operation | movement in connection with acquisition of the attitude | position reference information in the wearable apparatus which concerns on 3rd Embodiment. It is a flowchart for demonstrating the operation | movement in connection with the detection of the periodic acceleration in the wearable apparatus which concerns on 4th Embodiment. It is a figure which shows an example of a structure of the wearable apparatus which concerns on 5th Embodiment. It is a flowchart for demonstrating the operation | movement in connection with the detection of the periodic angular velocity in the wearable apparatus which concerns on 5th Embodiment. It is a flowchart for demonstrating the operation | movement in connection with acquisition of the offset information of angular velocity in the wearable apparatus which concerns on 5th Embodiment. It is a flowchart for demonstrating the operation | movement in connection with the detection of the periodic acceleration in the wearable apparatus which concerns on 6th Embodiment. It is a flowchart for demonstrating the operation | movement in connection with the detection of the periodic angular velocity in the wearable apparatus which concerns on 7th Embodiment.

<First Embodiment>
Hereinafter, a wearable device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of the configuration of the wearable device 2 according to the first embodiment. FIG. 2 is a diagram illustrating an example of the wearable device 2 attached to the user 1. FIG. 2A shows a case where the user 1 is in an upright posture, and FIG. 2B shows a case where the user 1 is in a lying posture. In the example of FIG. 2, the wearable device 2 is attached to a belt buckle or the like wound around the abdomen of the user 1. When the posture of the user 1 with respect to the direction of gravity changes as shown in FIGS. 2A and 2B, the posture of the wearable device 2 with respect to the direction of gravity also changes accordingly.

  In addition, the aspect which wears the wearable apparatus 2 is not limited to the example of FIG. For example, the wearable device 2 may be mounted on a hat, a hands-free device, a headset, a hearing aid, glasses, or the like.

  The wearable device 2 illustrated in the example of FIG. 1 includes an acceleration sensor 10, a processing unit 20, a storage unit 30, and a communication unit 40.

  The acceleration sensor 10 is a sensor that detects acceleration applied to the wearable device 2 and detects acceleration in a plurality of axial directions (for example, three axial directions) orthogonal to each other. For example, the acceleration sensor 10 is a signal corresponding to acceleration by converting a distance in which a minute mechanism member formed on a semiconductor chip is displaced against a spring force into an electric signal by a MEMS (micro electro mechanical systems) technique. Is output. Specifically, the acceleration sensor 10 includes an acceleration detection element using MEMS or the like, an analog circuit such as an amplifier that processes an output signal of the detection element, and an AD converter that converts the output signal of the analog circuit into a digital signal. Consists of. The acceleration sensor 10 repeatedly detects acceleration values in the respective directions at regular time intervals according to the control of the processing unit 20.

  The communication unit 40 is a device that exchanges data with an external device (not shown) by a predetermined communication method. For example, the communication unit 40 receives a command for causing the processing unit 20 to execute a predetermined process, data used for executing the process, and the like from an external device. Further, the communication unit 40 transmits processing result data (acceleration data, calculated posture data, etc.) of the processing unit 20 to an external device. For example, the communication unit 40 includes a communication module such as Bluetooth (registered trademark) that performs relatively short-distance communication with a mobile device such as a smartphone.

  The processing unit 20 is a device that controls the overall operation of the wearable device 2, and includes, for example, a computer that executes processing according to a program stored in the storage unit 30. The program in the storage unit 30 may be stored in advance in a ROM or the like, or may be loaded from an external device by the communication unit 40. Alternatively, a program may be input from the outside through an interface device such as a USB or a recording medium reading device and written in the storage unit 30. All of the processing in the processing unit 20 may be executed by a computer, or at least a part thereof may be executed by a dedicated hardware circuit.

  The processing unit 20 includes an acceleration data acquisition unit 21, a posture calculation unit 22, a posture reference information acquisition unit 23, a stationary state determination unit 24, and a posture determination unit 25 as processing blocks relating to acceleration measurement.

  The acceleration data acquisition unit 21 repeatedly acquires the acceleration data detected by the acceleration sensor 10 at a constant period and stores it in the storage unit 30.

  The stationary state determination unit 24 determines whether the wearable device 2 is in a stationary state based on the acceleration data acquired by the acceleration data acquisition unit 21. For example, the stationary state determination unit 24 calculates an evaluation value (such as a series of acceleration dispersion) indicating a temporal fluctuation range of a series of acceleration data acquired by the acceleration data acquisition unit 21, and the evaluation value is a stationary state. Is included in a predetermined range, it is determined that the wearable device 2 is in a stationary state.

  The posture determination unit 25 determines whether the posture of the wearable device 2 with respect to the direction of gravity is included in a predetermined range based on the acceleration data acquired by the acceleration data acquisition unit 21. For example, when the acceleration in each axial direction detected by the acceleration sensor 10 is included in a predetermined range, the posture determination unit 25 determines that the posture of the wearable device 2 is included in the predetermined range.

  The “predetermined range” that is the determination criterion of the posture determination unit 25 is that the wearable device 2 is correctly attached to the user 1 and the user 1 is in a reference posture (for example, the upright posture shown in FIG. 2A). Specifies the range of acceleration when the posture is relatively close. Therefore, when the acceleration data acquired by the acceleration data acquisition unit 21 is out of the “predetermined range”, the wearable device 2 is worn incorrectly or the user 1 is greatly inclined with respect to the reference posture. (For example, the recumbent posture shown in FIG. 2B) may be present.

  For example, the posture determination unit 25 performs posture determination based on the acceleration data acquired by the acceleration data acquisition unit 21 when it is determined by the stationary state determination unit 24 that the vehicle is in a stationary state. Since the influence of acceleration other than gravity is suppressed in the stationary state, the acceleration data acquired by the acceleration data acquisition unit 21 substantially indicates the direction of gravity. Therefore, by using the acceleration data when it is determined to be in a stationary state, the posture with respect to the direction of gravity can be accurately determined.

  The posture calculation unit 22 is based on the direction of gravity indicated by the acceleration data acquired by the acceleration data acquisition unit 21 and the posture reference information regarding the reference direction, which is the direction of gravity serving as the reference for the posture. Calculate the posture.

For example, in the posture reference information, a vector represented by a group of acceleration values detected in a plurality of axial directions of the acceleration sensor 10 is referred to as a coordinate system having coordinate axes parallel to the reference direction (hereinafter referred to as “reference coordinate system”). .) For converting to a vector.
The acceleration vector detected by the acceleration sensor 10 is a vector of a fixed coordinate system (hereinafter referred to as “sensor coordinate system”) defined by the detection axis of the acceleration sensor 10. For example, the posture reference information includes information of coordinate conversion (such as a rotation matrix) for converting the vector of the sensor coordinate system into the vector of the reference coordinate system. The posture calculation unit 22 uses the posture reference information to coordinate-convert the acceleration vector in the sensor coordinate system detected by the acceleration sensor 10 into a vector in the reference coordinate system.

  Here, the coordinate axis of the reference coordinate system parallel to the reference direction is referred to as “Z axis”, and the coordinate axes of the reference coordinate system orthogonal to the Z axis are referred to as “X axis” and “Y axis”. Further, the posture when the direction of gravity indicated by the acceleration data detected by the acceleration sensor 10 matches the reference direction is referred to as a “reference posture”. The vector of the reference coordinate system obtained by the coordinate conversion of the posture calculation unit 22 is parallel to the Z axis when the wearable device 2 is the “reference posture”, but the wearable device 2 is inclined with respect to the “reference posture”. In the case of a different posture, this vector has an inclination with respect to the Z axis. Therefore, the inclination of the acceleration vector after the coordinate conversion from the sensor coordinate system to the reference coordinate system with respect to the Z axis represents the inclination of the attitude with respect to the “reference attitude”. The posture calculation unit 22 uses, as data representing the inclination of the vector with respect to the Z axis, for example, an angle around the X axis of an image obtained by projecting the vector onto the YZ plane, or an image obtained by projecting the vector onto the XZ plane. Is calculated around the Y axis.

  The posture reference information acquisition unit 23 acquires posture reference information corresponding to the direction of gravity indicated by the acceleration data based on the acceleration data acquired by the acceleration data acquisition unit 21. However, the posture reference information acquisition unit 23 detects the acceleration detected when the stationary state determination unit 24 determines that the posture is not in the stationary state or when the posture determination unit 25 determines that the posture is not within the predetermined range. Is excluded from the data used for obtaining the posture reference information.

  For example, the posture reference information acquisition unit 23 may acquire the posture reference information at a periodic timing, or at a timing when a specific operation state occurs (for example, when a transition to the standby operation mode occurs). May be. Even if it is the timing which acquires attitude | position reference information, the attitude | position reference information acquisition part 23 is detected at the said timing, when it determines with it not being in a still state, or when it determines with an attitude | position not being in the predetermined range. Acceleration data is not used for acquisition of posture reference information, and the acquisition of posture reference information is forgotten.

  The storage unit 30 is a computer program in the processing unit 20, constant data used for processing of the processing unit 20, variable data temporarily stored in the course of processing, processing result data (acceleration data, calculated (Attitude data, etc.) are stored. The storage unit 30 includes, for example, a ROM, a RAM, a nonvolatile memory, and the like.

  Here, the operation of the wearable device 2 according to the present embodiment having the above-described configuration will be described.

  FIG. 3 is a flowchart for explaining an operation related to periodic acceleration detection in the wearable device 2 according to the first embodiment.

ST100, ST105:
The acceleration data acquisition unit 21 acquires data of acceleration detected by the acceleration sensor 10 and stores it in the storage unit 30 when a preset periodic acceleration detection timing is notified by a timer or the like (ST100). (ST105).

ST110:
The stationary state determination unit 24 determines whether or not the wearable device 2 is in a stationary state based on the acceleration data acquired in step ST105. For example, the stationary state determination unit 24 calculates the variance of acceleration from a series of data including the data acquired in step ST105. If the variance is smaller than a predetermined threshold value, the stationary state and the variance are threshold values. If it exceeds, it is determined as a non-stationary state.

ST115:
The posture determination unit 25 determines whether the posture of the wearable device 2 with respect to the direction of gravity is within a predetermined range based on the acceleration data acquired in step ST105. For example, the posture determination unit 25 determines whether or not a plurality of axial acceleration values are included in the normal range determined for each axis, and if all the axial acceleration values are included in the normal range, the wearable is determined. It is determined that the posture of the device 2 is included in the predetermined range. When there is an acceleration value that is not included in the normal range, the posture determination unit 25 determines that the posture of the wearable device 2 is not included in the predetermined range.

ST120:
The posture calculation unit 22 is based on the direction of gravity indicated by the acceleration data acquired in step ST105 and the latest posture reference information acquired by the posture reference information acquisition unit 23. The posture is calculated, and the calculation result is stored in the storage unit 30.

  When the posture calculation unit 22 stores the calculation result of the posture in the storage unit 30, the determination result of the stationary state in step ST110 or the determination result of the posture in step ST115 is used as information related to the reliability of the calculation result. May be stored in the storage unit 30 together. Thereby, it can be confirmed that the reliability of the calculation result of the posture is low when it is determined that it is in the non-still state or when the posture is determined not to be within the predetermined range.

ST140:
When a predetermined end condition is not satisfied, such as when a command instructing the end of the measurement operation is input from the communication unit 40 or the like, the processing unit 20 returns to step ST100 and repeats the above processing.

  FIG. 4 is a flowchart for explaining an operation related to acquisition of posture reference information in the wearable device 2 according to the first embodiment.

ST200:
The posture reference information acquisition unit 23 is a timer or other notification that notifies the timing of acquiring predetermined periodic posture reference information, and other processing blocks that notify that a specific operation state for which posture reference information should be acquired has occurred. If a notification is received from step ST205, the process proceeds to steps ST205 and ST210. If there is no such notification, the process proceeds to step ST220.

ST205, ST210:
When the stationary state determination unit 24 determines that the vehicle is stationary and the posture determination unit 25 determines that the posture is within the predetermined range, the posture reference information acquisition unit 23 proceeds to step ST215, otherwise. The process proceeds to step ST220.

ST215:
The posture reference information acquisition unit 23 acquires posture reference information corresponding to the direction of gravity indicated by the acceleration data, based on the latest acceleration data acquired in step ST105. For example, the posture reference information acquisition unit 23 converts a gravitational acceleration vector indicated by the latest acceleration data acquired in step ST105 into a vector parallel to a predetermined coordinate axis (Z axis) of the reference coordinate system, or the like. Get information.

ST220:
When a predetermined end condition is not satisfied, such as when a command instructing the end of the measurement operation is input from the communication unit 40 or the like, the processing unit 20 returns to step ST200 and repeats the above processing.

  As described above, according to the wearable device 2 according to the present embodiment, when the wearable device 2 is determined not to be in the stationary state by the stationary state determination unit 24 or when the posture determination unit 25 determines the wearable device for the direction of gravity. The acceleration data detected by the acceleration sensor 10 when it is determined that the second posture is not within the predetermined range is not used by the posture reference information acquisition unit 23 to acquire the posture reference information. For example, acceleration data detected when a user wearing the wearable device 2 is exercising is not used to acquire posture reference information. When the user wearing the wearable device 2 is not in a normal posture (such as in a lying posture), or when the user is in a normal posture and the wearable device 2 is not in a normal state (wearing upside down) Also, the acceleration data detected in the case) is not used for obtaining the posture reference information. As a result, it is possible to automatically acquire the posture reference information under an appropriate condition in which the wearable device 2 is stationary and its posture is within a predetermined range. Therefore, the burden on the user's operation can be reduced compared to the case where a manual operation for obtaining posture reference information is required, and the gravity is compared with the case where only the stationary state is determined to obtain posture reference information. It is possible to calculate an accurate posture with respect to the direction.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.
The wearable device 2 according to the second embodiment is obtained by changing the operation of acquiring the posture reference information in the wearable device 2 according to the first embodiment described above, and the other configuration according to the first embodiment. The same as the wearable device 2.

  FIG. 5 is a flowchart for explaining an operation related to acquisition of posture reference information in the wearable device 2 according to the second embodiment. The flowchart shown in FIG. 5 is obtained by replacing step ST205 in the flowchart shown in FIG. 4 with step ST205A, and the other steps are the same as the flowchart shown in FIG.

  In the present embodiment, the posture reference information acquisition unit 23 determines that the stationary state continues for a predetermined time or more in the stationary state determination unit 24 (ST205A), and the posture determination unit 25 determines that the posture is within a predetermined range. When it is determined (ST210), the posture reference information is acquired (ST215). The posture reference information acquisition unit 23 accelerates when the posture determination unit 25 determines that the stationary state has not continued for a predetermined time or more even when the posture determination unit 25 determines that the posture is within a predetermined range. The acceleration data detected by the sensor 10 is not used to acquire posture reference information. That is, the posture reference information acquisition unit 23 acquires posture reference information based on acceleration data detected in a stable posture in which the stationary state is maintained for a certain time or more. Thereby, since the posture reference information is acquired in a stable posture that tends to be close to the reference posture, a more accurate posture with respect to the direction of gravity can be calculated.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
The wearable device 2 according to the third embodiment is also obtained by changing the operation of acquiring the posture reference information in the wearable device 2 according to the first embodiment described above, and the other configuration according to the first embodiment. The same as the wearable device 2.

  FIG. 6 is a flowchart for explaining an operation related to acquisition of posture reference information in the wearable device 2 according to the third embodiment.

ST250:
The posture reference information acquisition unit 23 checks whether or not new acceleration data has been acquired by the acceleration data acquisition unit 21, and moves to steps ST255 and ST260 if new acceleration data is acquired, and otherwise. The process proceeds to step ST270.

ST255, ST260:
When the stationary state determining unit 24 determines that the camera is stationary, and the posture determining unit 25 determines that the posture is within the predetermined range, the posture reference information acquiring unit 23 proceeds to step ST265, otherwise. The process proceeds to step ST270.

ST265:
The posture reference information acquisition unit 23 calculates the average value of acceleration using the latest acceleration data acquired by the acceleration data acquisition unit 21. For example, the posture reference information acquisition unit 23 calculates a new average value of acceleration by a weighted moving average that adds a predetermined weight to the current average value and the latest acceleration value.

ST270:
The posture reference information acquisition unit 23 is a timer or other notification that notifies the timing of acquiring predetermined periodic posture reference information, and other processing blocks that notify that a specific operation state for which posture reference information should be acquired has occurred. If a notification is received from step ST275, the process proceeds to step ST275, and if there is no such notification, the process proceeds to step ST280.

ST275:
The posture reference information acquisition unit 23 acquires posture reference information corresponding to the direction of gravity indicated by the average value of acceleration based on the average value of acceleration calculated in step ST265. For example, the posture reference information acquisition unit 23 converts information such as a rotation matrix that converts the gravitational acceleration vector indicated by the average acceleration acquired in step ST265 into a vector parallel to a predetermined coordinate axis (Z axis) of the reference coordinate system. To get.

ST280:
If a predetermined end condition is not satisfied, such as when a command instructing the end of the measurement operation is input from the communication unit 40 or the like, the processing unit 20 returns to step ST250 and repeats the above processing.

  As described above, according to the wearable device 2 according to the present embodiment, when the wearable device 2 is determined not to be in the stationary state by the stationary state determination unit 24 or when the posture determination unit 25 determines the wearable device for the direction of gravity. The acceleration data detected by the acceleration sensor 10 when it is determined that the posture 2 is not within the predetermined range is excluded from the data used for the posture reference information acquisition by the posture reference information acquisition unit 23. This makes it possible to automatically acquire posture reference information under an appropriate condition in which the wearable device 2 is stationary and its posture is within a predetermined range, thereby reducing the burden on the user's operation. At the same time, an accurate posture with respect to the direction of gravity can be calculated.

  Further, according to the wearable device 2 according to the present embodiment, it is detected when the stationary state determination unit 24 determines that the vehicle is in the stationary state and the posture determination unit 25 determines that the posture is within a predetermined range. The series of acceleration data is averaged in the attitude reference information acquisition unit 23, and attitude reference information corresponding to the direction of gravity indicated by the averaged acceleration data is acquired in the attitude reference information acquisition unit 23. As a result, posture reference information with the direction of gravity in the average posture as the reference direction is acquired. Therefore, it is possible to suppress a change in the reference direction of the posture reference information due to the influence of the temporary posture change. Therefore, accurate and stable posture calculation can be performed.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described.
The wearable device 2 according to the fourth embodiment is obtained by changing the operation of the acceleration data acquisition unit 21 in the wearable device 2 according to the first embodiment described above, and the other configuration according to the first embodiment. The same as the wearable device 2.

  FIG. 7 is a flowchart for explaining operations related to detection of periodic acceleration in the wearable device 2 according to the fourth embodiment. The flowchart shown in FIG. 7 is obtained by adding steps ST125, ST130, and ST135 to the flowchart shown in FIG. 3, and the other steps are the same as the flowchart shown in FIG.

  When the posture determination unit 25 determines the posture in step ST115, the acceleration data acquisition unit 21 changes the acceleration detection cycle according to the determination result. That is, when the posture determination unit 25 determines that the posture of the wearable device 2 is within a predetermined range (ST125), the acceleration data acquisition unit 21 sets the data acquisition cycle from the acceleration sensor 10 to a normal value ( ST130). On the other hand, when the posture determination unit 25 determines that the posture of the wearable device 2 is not within the predetermined range (ST125), the acceleration data acquisition unit 21 makes the period of data acquisition from the acceleration sensor 10 longer than the normal value. To do.

  When the posture of the wearable device 2 is not within a predetermined range, the posture reference information acquisition unit 23 cannot obtain acceleration data that should be used for acquisition of the posture reference information. Becomes lower. In this case, since it is not necessary to frequently calculate the posture in the posture calculation unit 22, the acceleration data acquisition unit 21 can increase the acceleration data acquisition cycle. Therefore, the power consumption can be reduced by extending the acceleration data acquisition cycle as in this embodiment.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described.
The wearable device according to the fifth embodiment includes an angular velocity sensor.

  FIG. 8 is a diagram illustrating an example of the configuration of a wearable device 2A according to the fifth embodiment. The wearable device 2A shown in FIG. 8 is obtained by replacing the processing unit 20 in the wearable device 2 shown in FIG. 1 with a processing unit 20A and adding an angular velocity sensor 50. Other configurations are the same as the wearable device 2 shown in FIG. The same.

  The angular velocity sensor 50 is a sensor that detects an angular velocity when the wearable device 2 moves, and detects angular velocities around a plurality of axial directions (for example, three axial directions) orthogonal to each other. For example, the angular velocity sensor 50 moves a minute mechanism member (moving body) formed on the semiconductor chip by MEMS technology, and outputs an angular velocity detection signal corresponding to the Coriolis force generated in the mechanism member by the rotational motion. Specifically, the angular velocity sensor 50 includes an angular velocity detection element such as a MEMS, an analog circuit such as an amplifier that processes an output signal of the detection element, and an AD converter that converts the output signal of the analog circuit into a digital signal. Consists of. The angular velocity sensor 50 repeatedly detects angular velocity values in the respective directions at regular time intervals according to the control of the processing unit 20A.

  The processing unit 20A includes an angular velocity data acquisition unit 26, an offset information acquisition unit 27, and an angular velocity offset correction unit 28 in addition to the processing blocks similar to those of the processing unit 20 already described.

  The angular velocity data obtaining unit 26 repeatedly obtains angular velocity data detected by the angular velocity sensor 50 at a constant period and stores the data in the storage unit 30.

  The offset information acquisition unit 27 acquires, as offset information, the angular velocity data acquired by the angular velocity data acquisition unit 26 when the stationary state determination unit 24 determines that the vehicle is in a stationary state.

  The angular velocity offset correction unit 28 corrects the offset of the angular velocity data based on the offset information acquired by the offset information acquisition unit 27. Since the angular velocity is zero in the stationary state, the angular velocity data acquired as offset information by the offset information acquisition unit 27 indicates an offset that is a fixed error from the original angular velocity (zero) in the stationary state. The angular velocity offset correction unit 28 subtracts the offset indicated by the offset information from the angular velocity value indicated by the angular velocity data.

  FIG. 9 is a flowchart for explaining an operation related to detection of a periodic angular velocity in the wearable device 2A according to the fifth embodiment.

ST300:
When the angular velocity data acquisition unit 26 is notified of the preset detection timing of the periodic angular velocity by a timer or the like, the angular velocity data acquisition unit 26 proceeds to step ST310.

ST310:
The angular velocity data acquisition unit 26 acquires angular velocity data detected by the angular velocity sensor 50 and stores it in the storage unit 30.

ST315:
The angular velocity offset correction unit 28 corrects the offset of the angular velocity data acquired by the angular velocity data acquisition unit 26 in step ST310 based on the offset information acquired by the offset information acquisition unit 27.
ST320:
When a predetermined end condition is not satisfied, such as when a command instructing the end of the measurement operation is input from the communication unit 40 or the like, the processing unit 20A returns to step ST300 and repeats the above processing.

  FIG. 10 is a flowchart for explaining operations related to acquisition of angular velocity offset information in the wearable device 2A according to the fifth embodiment.

ST400:
The offset information acquisition unit 27 receives a notification from a timer or the like that informs the timing for obtaining periodic offset information that has been set in advance, or from another processing block that informs that a specific operation state for which offset information should be obtained has occurred. If a notification is received, the process proceeds to steps ST405 and ST410. If there is no such notification, the process proceeds to step ST415.

ST405, ST410:
When the stationary state determination unit 24 determines that the wearable device 2A is in a stationary state (ST405), the offset information acquisition unit 27 acquires the latest acceleration data acquired by the angular velocity data acquisition unit 26 as offset information. And stored in the storage unit 30 (ST410). When the stationary state determination unit 24 determines that the state is a non-stationary state, the offset information acquisition unit 27 defers the acquisition of offset information.

ST415:
When a predetermined end condition is not satisfied, such as when a command instructing the end of the measurement operation is input from the communication unit 40 or the like, the processing unit 20 returns to step ST400 and repeats the above processing.

  As described above, according to the wearable device 2A according to the present embodiment, it is possible to detect angular velocity and acquire offset information in parallel with detection of acceleration and acquisition of posture reference information. Further, since the angular velocity data in the stationary state is acquired as the offset information, the offset of the acceleration data can be accurately corrected.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described.
The wearable device 2A according to the sixth embodiment is obtained by changing the operations of the acceleration data acquisition unit 21 and the angular velocity data acquisition unit 26 in the wearable device 2A according to the fifth embodiment described above. This is the same as the wearable device 2A according to the fifth embodiment.

  FIG. 11 is a flowchart for explaining operations related to detection of periodic acceleration in the wearable device 2A according to the sixth embodiment. The flowchart shown in FIG. 11 is obtained by adding steps ST125, ST130A, and ST135A to the flowchart shown in FIG. 3, and the other steps are the same as the flowchart shown in FIG.

  When the posture determination unit 25 determines the posture in step ST115, the acceleration data acquisition unit 21 and the angular velocity data acquisition unit 26 change the acceleration detection cycle and the angular velocity detection cycle according to the determination result. That is, when the posture determination unit 25 determines that the posture of the wearable device 2 is within a predetermined range (ST125), the acceleration data acquisition unit 21 and the angular velocity data acquisition unit 26 acquire the data from the acceleration sensor 10 and the angular velocity sensor. The period of data acquisition from 50 is set to a normal value (ST130A). On the other hand, when the posture determination unit 25 determines that the posture of the wearable device 2 is not within the predetermined range (ST125), the acceleration data acquisition unit 21 and the angular velocity data acquisition unit 26 acquire the cycle of data acquisition from the acceleration sensor 10 and The period of data acquisition from the angular velocity sensor 50 is set longer than the normal value (ST135A).

  According to the wearable device 2A according to the present embodiment, when the posture of the wearable device 2A is not within a predetermined range, the acceleration data acquisition cycle is lengthened, so that the wearable device 2 according to the fourth embodiment The power consumption can be reduced.

  In addition, when the posture of the wearable device 2A is not within a predetermined range, that is, when the posture is abnormal or when the wearing mode of the wearable device 2A is incorrect, the angular velocity is not frequently measured because it is not a normal use state. There are cases where it is good. In such a case, power consumption can be reduced by increasing the angular velocity data acquisition period in the angular velocity data acquisition unit 26.

<Seventh Embodiment>
Next, a seventh embodiment of the present invention will be described.
The wearable device 2A according to the seventh embodiment is obtained by changing the operations of the angular velocity data acquisition unit 26 and the angular velocity offset correction unit 28 in the wearable device 2A according to the fifth embodiment described above. This is the same as the wearable device 2A according to the fifth embodiment.

  FIG. 12 is a flowchart for explaining operations related to detection of a periodic angular velocity in the wearable device 2A according to the seventh embodiment. The flowchart shown in FIG. 12 is obtained by adding step ST305 to the flowchart shown in FIG. 9, and other steps are the same as the flowchart shown in FIG.

  In the wearable device 2A according to the present embodiment, even when the angular velocity detection timing is set in advance (ST300), when the posture determination unit 25 determines that the posture of the wearable device 2A is not within the predetermined range ( ST305), the angular velocity data acquisition by the angular velocity data acquisition unit 26 (ST310) and the angular velocity data offset correction (ST315) by the angular velocity offset correction unit 28 are stopped.

  When the posture of the wearable device 2A is not within a predetermined range, that is, when the posture is abnormal or when the wearing state of the wearable device 2A is incorrect, the angular velocity measurement may not be frequently performed because the wearable device 2A is not in a normal use state. There is a case. In such a case, power consumption can be further reduced by stopping the angular velocity data acquisition by the angular velocity data acquisition unit 26.

  Although several embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. That is, those skilled in the art may make various modifications, combinations, and alternatives with respect to the configuration of the above-described embodiment within the technical scope of the present invention or an equivalent scope thereof.

  For example, the constituent elements in the above-described embodiments may be replaced with constituent elements in another embodiment. Moreover, you may add the component of another embodiment to each embodiment mentioned above.

  In the embodiment described above, an example of a wearable device that is worn (weared) on a human body is given, but the present invention is not limited to this example. The present invention is widely applicable to various electronic devices that are worn (weared) on animals other than humans, robots, and the like.

DESCRIPTION OF SYMBOLS 1 ... User, 2, 2A ... Wearable apparatus, 10 ... Acceleration sensor, 20, 20A ... Processing part, 21 ... Acceleration data acquisition part, 22 ... Attitude calculation part, 23 ... Attitude reference information acquisition part, 24 ... Still state determination part , 25 ... posture determination unit, 26 ... angular velocity data acquisition unit, 27 ... offset information acquisition unit, 28 ... angular velocity offset correction unit, 30 ... storage unit, 40 ... communication unit, 50 ... angular velocity sensor

Claims (10)

An acceleration sensor;
An acceleration data acquisition unit that repeatedly acquires acceleration data detected by the acceleration sensor;
Posture calculation for calculating the posture with respect to the direction of gravity based on the direction of gravity indicated by the acceleration data acquired in the acceleration data acquisition unit and the posture reference information regarding the reference direction, which is the direction of gravity serving as the reference for posture. And
A posture reference information acquisition unit that acquires the posture reference information according to the direction of gravity indicated by the acceleration data, based on the acceleration data acquired in the acceleration data acquisition unit;
Based on the acceleration data acquired in the acceleration data acquisition unit, a stationary state determination unit that determines whether or not the stationary state,
A posture determination unit that determines whether or not the posture with respect to the direction of gravity is within a predetermined range based on the acceleration data acquired in the acceleration data acquisition unit;
The posture reference information acquisition unit is detected when the stationary state determination unit determines that the posture is not in a stationary state, or when the posture determination unit determines that the posture is not within the predetermined range. A wearable device, characterized in that acceleration data is excluded from data used to acquire the posture reference information. The posture determination unit performs the posture determination based on acceleration data acquired by the acceleration data acquisition unit when the stationary state determination unit determines that the vehicle is in a stationary state. Item 2. The wearable device according to Item 1. The acceleration data acquisition unit, when the posture determination unit determines that the posture is not in the predetermined range, compared to the case where the posture determination unit determines that the posture is within the predetermined range. The wearable device according to claim 2, wherein a repetition cycle of acceleration data acquisition is lengthened. The posture reference information acquisition unit excludes the acceleration data detected when the stationary state determination unit determines that the stationary state has not continued for a certain time or more from the data used to acquire the posture reference information. The wearable device according to claim 1, wherein the wearable device is a wearable device. The posture reference information acquisition unit determines that the stationary state determination unit determines that the posture is in a stationary state, and the posture determination unit determines that the posture is within the predetermined range. The wearable device according to any one of claims 1 to 4, wherein acceleration data is averaged, and the posture reference information corresponding to the direction of gravity indicated by the averaged acceleration data is acquired. An angular velocity sensor;
Angular velocity data acquisition unit for repeatedly acquiring angular velocity data detected by the angular velocity sensor;
An angular velocity offset correction unit that corrects the offset of the angular velocity data based on the angular velocity data acquired by the angular velocity data acquisition unit when the stationary state determination unit determines that the stationary state is established. The wearable device according to claim 1, wherein the wearable device is a feature. The angular velocity data acquisition unit, when the posture determination unit determines that the posture is not within the predetermined range, compared to the case where the posture determination unit determines that the posture is within the predetermined range. The wearable device according to claim 6, wherein a repetition cycle of data acquisition of angular velocity is lengthened. The wearable device according to claim 6, wherein the angular velocity data acquisition unit stops acquiring the angular velocity data when the posture determination unit determines that the posture is not within the predetermined range. A method in which a computer measures the attitude of the wearable device with respect to the direction of gravity based on acceleration data detected by an acceleration sensor mounted on the wearable device,
Repeatedly acquiring data of acceleration detected by the acceleration sensor;
Based on the direction of gravity indicated by the acceleration data acquired in the step of acquiring the acceleration data and the posture reference information related to the reference direction, which is the direction of gravity serving as the posture reference, the posture with respect to the direction of gravity is calculated. And steps to
Acquiring the posture reference information according to the direction of gravity indicated by the acceleration data based on the acceleration data acquired in the step of acquiring the acceleration data;
Determining whether or not the vehicle is in a stationary state based on the acceleration data acquired in the step of acquiring the acceleration data;
Determining whether the posture with respect to the direction of gravity is within a predetermined range based on the acceleration data acquired in the step of acquiring the acceleration data;
In the step of obtaining the posture reference information, if it is determined in the step of determining the stationary state that it is not in a stationary state, or the step of determining a posture with respect to the direction of gravity is not within the predetermined range. The attitude measurement method characterized by excluding the acceleration data detected when it is determined that the data is used for acquiring the attitude reference information.   A program for causing a computer to execute the posture measurement method according to claim 9.

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