JP7680730B2 - Wobble measurement device, wobble measurement system, and wobble measurement program - Google Patents

Description

The present invention relates to a wobble measurement device, a wobble measurement system, and a wobble measurement program.

Patent document 1 shows a measuring device equipped with an acceleration sensor.

When using this measuring device, the subject first attaches the measuring device to their wrist and sits in a chair. The subject then presses the operating button on the measuring device. The measuring device then starts the process of measuring the subject's muscle strength.

In this state, the subject stands up from the chair with all his might. The measuring device then obtains the data output from the acceleration sensor at that time and calculates the subject's muscle strength index.

JP 2017-000239 A

However, the above-mentioned measuring device assumes that the person standing up is performing the standing motion and standing up with all their strength in order to measure, so it is not suitable for measuring data that is relevant to everyday life.

The present invention was made in consideration of the above problems, and aims to provide a sway measurement device, a sway measurement system, and a sway measurement program that are capable of measuring data suited to everyday life.

According to one aspect of the present invention, the device includes an acquisition means for acquiring acceleration data indicating the movement of a user, and a determination means for determining the unsteady movement of the user based on the acceleration data acquired by the acquisition means after the acceleration data indicates the standing up movement of the user.

According to this aspect, when the acceleration data acquired by the acquisition means indicates a standing up motion of the user, this standing up motion is used as a trigger to determine whether the user is staggering based on the acceleration data.

This makes it possible to reduce the number of operation buttons compared to when measurement is started by operating an operation button, and allows the measurement of unsteadiness without the user being aware that a measurement has started.

This makes it possible to measure data that is relevant to everyday life.

FIG. 1 is a diagram showing a wobble measuring device according to a first embodiment of the present invention. FIG. 2 is a block diagram showing an example of a hardware configuration of the wobble measuring device according to the first embodiment. FIG. 3 is a functional block diagram showing an example of the functional configuration of the wobble measuring device of the first embodiment. FIG. 4 is a flowchart showing an example of the operation of the wobble measuring device according to the first embodiment. FIG. 5 is a flowchart showing an example of the start-up determination process according to the first embodiment. FIG. 6 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when a wobbling motion occurs after a rising motion. FIG. 7 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when a sitting motion is performed. FIG. 8 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when walking is performed. FIG. 9 is a flowchart showing an example of the wobble determination process according to the first embodiment. FIG. 10 is a diagram showing a change in the waveform of acceleration data, specifically, a line diagram showing the waveform when the foot-planting motion is performed twice. FIG. 11 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when a jump is performed from a standing up motion. FIG. 12 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when the person starts standing up and then runs. FIG. 13 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when the acceleration data comes to a standstill after a rising motion. FIG. 14 is a diagram showing a change in the waveform of acceleration data, specifically, a line diagram showing the waveform when a standing motion is followed by a forward foot-planting motion. FIG. 15 is a diagram showing a change in the waveform of acceleration data, specifically, a line diagram showing the waveform when a standing motion is followed by a sideways foot placement motion. FIG. 16 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when a foot-placing motion is performed. FIG. 17 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when an action such as a jump is performed. FIG. 18 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when the foot-planting motion is performed twice. FIG. 19 is a diagram showing a change in the waveform of acceleration data, and is a line diagram showing the waveform when a movement such as walking is performed. FIG. 20 is a flowchart illustrating an example of the wobble magnitude correction process according to the first embodiment. FIG. 21 is a diagram showing a changing waveform of acceleration data, and is a diagram used to explain magnitude correction for correcting the magnitude of unsteady motion based on rising motion. FIG. 22 is a flowchart illustrating an example of the notification process according to the first embodiment. FIG. 23 is a diagram showing a display example of the first embodiment. FIG. 24 is a diagram showing a wobble measurement system according to the second embodiment.

Each embodiment of the present invention will be described below with reference to the attached drawings.

First Embodiment
FIG. 1 is a diagram showing a stagger measuring device 10 according to a first embodiment. The stagger measuring device 10 is a device that detects a staggering motion caused by a user when worn by the user.

The unsteady motion that is the target of detection is likely to occur when a person stands up from a seated position. In this embodiment, the unsteady motion is defined as the staggering motion that occurs when a user using the unsteadiness measuring device 10 stands up, and as an example of this, the motion of staggering and putting one's feet down is described as being unsteady motion.

The stagger measuring device 10 comprises a device body 10A and a belt 10B for fastening the device body 10A to the user. The base end of the belt 10B is fixed to the device body 10A, and the tip end is configured so that it can be inserted into the device body 10A.

The belt 10B has a length that allows it to be wrapped around the waist of the user, and the device main body 10A into which the belt 10B is inserted has a function for fixing the inserted belt 10B. This allows the device main body 10A to be fixed closely to the user's waist by wrapping the belt 10B around the user's waist and inserting it into the device main body 10A, and then adjusting and fixing the amount of insertion of the belt 10B.

In this embodiment, the device body 10A is fixed to the user's waist, but the fixing position of the device body 10A is not limited to this, and if the device body 10A is fixed to the user's torso, it will be possible to move the device body 10A in accordance with the user's movements. Also, the fixing position of the device body 10A is not limited to the torso, and it may be fixed to the hand, etc., and as an example, if the device body 10A is fixed to the hand, the device body 10A can be moved in accordance with the user's movements by pressing the hand against the torso.

(Hardware configuration)
2 is a block diagram showing an example of a hardware configuration of the stagger measurement device 10 according to the first embodiment. The stagger measurement device 10 is configured with a computer for detecting the staggering motion of a user wearing the stagger measurement device 10.

The stagger measuring device 10 includes a processor 14, a memory unit 18, an input unit 20, a display unit 22, a communication unit 24, and an acceleration sensor 26, which are interconnected via a bus line 12.

The processor 14 may be a general-purpose processor such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a DSP (digital signal processor). The processor 14 may also be a dedicated processor such as a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array).

The storage unit 18 constitutes a storage means. This storage unit 18 is a computer-readable storage medium, and includes a ROM (Read Only Memory), a RAM (Random Access Memory), and a storage device. The storage device is realized by a HDD (Hard Disk Drive), an SSD (Solid State Drive), a flash memory, or the like.

The ROM constituting the memory unit 18, for example, stores a sway measurement program indicating the processing procedure of the sway measurement device 10, and data indicating thresholds used in the sway measurement program. The processor 14 executes each process according to the sway measurement program stored in the memory unit 18. The memory unit 18 functions as a storage medium that stores the sway measurement program that realizes the functions of the information processing device of this embodiment.

In addition, a ring buffer is constructed in the RAM constituting the memory unit 18, for example, to accumulate ten seconds' worth of acceleration data from the acceleration sensor 26. The ring buffer sequentially stores the latest acceleration data in association with the time of acquisition, while sequentially deleting acceleration data from ten seconds prior.

The input unit 20 constitutes an input device to the processor 14, and examples of the input device include a switch.

The display unit 22 is composed of a display device, such as a liquid crystal display panel.

The communication unit 24 constitutes an interface for transmitting and receiving data, and enables data to be transmitted and received between the processor 14 and an external device. Examples of the communication unit 24 include a USB (universal serial bus) or an Internet connection device. Through the communication unit 24, the processor 14 can receive the wobble measurement program and the necessary data required to execute the wobble measurement program from the external device, and can transmit measurement data and measurement results to the external device.

When the communication unit 24 is configured as an Internet connection device, the communication unit 24 receives the wobble measurement program and the necessary data required to execute the wobble measurement program from an external device such as a server via a network such as the Internet or a telephone network. The communication unit 24 can also transmit measurement data and measurement results to an external device such as a server via a network such as the Internet or a telephone network.

The acceleration sensor 26 detects the acceleration applied to the sway measurement device 10 and outputs it as acceleration data. The acceleration sensor 26 is equipped with an X-axis sensor that detects the acceleration in the left-right direction of the user wearing the sway measurement device 10 on their waist, a Y-axis sensor that detects the acceleration in the up-down direction, and a Z-axis sensor that detects the acceleration in the front-back direction.

As a result, by acquiring acceleration data from the X-axis sensor of the acceleration sensor 26, it is possible to detect the user's left-right movement and the magnitude of that movement. Also, by acquiring acceleration data from the Y-axis sensor of the acceleration sensor 26, it is possible to detect the user's up-down movement and the magnitude of that movement. And by acquiring acceleration data from the Z-axis sensor of the acceleration sensor 26, it is possible to detect the user's forward-backward movement and the magnitude of that movement.

(Function block diagram)
3 is a functional block diagram showing an example of the functional configuration of the sway measuring device 10 according to the first embodiment. The sway measuring device 10 includes an acquisition unit 30, a determination unit 32, a level determination unit 34, a counting unit 36, a notification unit 38, and a transmission unit 40.

The determination unit 32 has a sway estimation unit 50, a sway time estimation unit 52, an expected waveform extraction unit 54, a sway period estimation unit 56, a multiple determination unit 58, a rise motion estimation unit 60, an estimated waveform extraction unit 62, and an upper limit estimation unit 64. The determination unit 32 also has a rise period estimation unit 66, an end value estimation unit 68, an acceleration difference estimation unit 70, a previous waveform extraction unit 72, and a pre-rise estimation unit 74.

As shown in FIG. 2, the functions of each part of the sway measuring device 10 are realized by the processor 14 executing the sway measuring program read from the memory unit 18. Alternatively, at least one of the parts of the sway measuring device 10 may be realized by individual hardware such as an ASIC.

The acquisition unit 30 acquires acceleration time series data indicating the movement of the user wearing the stagger measurement device 10 as acceleration data from the acceleration sensor 26 (see Figure 2).

When the acceleration data acquired by the acquisition unit 30 indicates the user's standing up motion, the determination unit 32 determines whether the user is unsteady based on the acceleration data after the standing up motion is indicated.

Specifically, the determination unit 32 has a sway estimation unit 50, which determines whether the acceleration data acquired by the acquisition unit 30 is equal to or greater than a first threshold value that is reached when swaying occurs.

One example of this first threshold is the foot-down threshold that is reached when the person stumbles and puts his or her feet down, and the unsteadiness estimation unit 50 determines whether the acceleration data acquired by the acquisition unit 30 is equal to or greater than the foot-down threshold that is reached when the person stumbles and puts his or her feet down.

The unsteadiness estimation unit 50 estimates that the user is unsteady when the acceleration data acquired by the acquisition unit 30 is equal to or greater than the foot placement threshold, and estimates that the user is not unsteady when the acceleration data is less than the foot placement threshold.

The foot-on threshold is a threshold that is determined based on the standard of the change in acceleration when a person stumbles and puts his/her feet on the ground after standing up. For example, the foot-on threshold is determined in advance based on the results of an experiment or a simulation.

The determination unit 32 further includes a wobbling time estimation unit 52 that estimates that the user has become unsteady. When the acceleration data after the standing up motion is equal to or greater than the foot placement threshold, the wobbling time estimation unit 52 determines whether the period from the first minimum value to the next minimum value in the region of the acceleration data equal to or less than a predetermined threshold value smaller than the foot placement threshold is equal to or less than a second threshold value. When the period from the first minimum value to the next minimum value is equal to or less than the second threshold value, the wobbling time estimation unit 52 estimates that the user has become unsteady. In other words, the wobbling time estimation unit 52 estimates that the user has become unsteady when the first minimum value and the next minimum value in the acceleration data time series are equal to or less than the predetermined threshold value.

One example of the second threshold is an intensity threshold determined based on the standard of the strength of the impact when the person stumbles and puts their feet down. The wobble time estimation unit 52 estimates that wobble has occurred when the period from the first minimum value to the next minimum value in the region of the acceleration data below a predetermined threshold value smaller than the foot-down threshold value is below the intensity threshold value. The predetermined threshold value is set, for example, to a value in the range from the acceleration value in a seated position to the above-mentioned foot-down threshold value.

The determination unit 32 also has an expected waveform extraction unit 54 and a swaying period estimation unit 56. The expected waveform extraction unit 54 extracts an expected waveform that is expected to indicate the occurrence of a swaying movement from the change waveform of the acceleration data acquired by the acquisition unit 30. The swaying period estimation unit 56 predicts the period that is expected to indicate the occurrence of a swaying movement from the change in the acceleration data acquired by the acquisition unit 30, and if the predicted period is equal to or shorter than a reference time defined by the criteria for a swaying movement, it estimates that the user has swayed. In other words, the swaying period estimation unit 56 estimates that the user has swayed if the time from the start point to the end point of the expected waveform extracted by the expected waveform extraction unit 54 is equal to or shorter than the reference time defined by the criteria for a swaying movement.

The expected waveform extraction unit 54 extracts, as an expected waveform, the range from the first minimum value that appears first to the second minimum value that appears next in the region below a predetermined threshold value that is smaller than the foot placement threshold value in the acceleration data acquired by the acquisition unit 30 after the standing up motion is performed. Specifically, the expected waveform extraction unit 54 includes an extraction unit that extracts the range from the first minimum value that appears first in a time series to the next minimum value that appears next in the acceleration data acquired by the acquisition unit 30 after the standing up motion is performed. If the range extracted by this extraction unit is less than a reference time determined by the criteria for unsteady motion, the estimation unit estimates that the user has experienced unsteady motion.

Furthermore, the determination unit 32 has a multiple determination unit 58 that determines that wobbling has occurred when there are multiple maximum values of acceleration indicated in the acceleration data in the above-mentioned expected waveform. The multiple determination unit 58 determines that wobbling has occurred when the ratio of adjacent maximum values to minimum values between adjacent maximum values among the multiple maximum values in the expected waveform is equal to or greater than a third threshold. Specifically, the multiple determination unit 58 will be described for the case where there are multiple maximum values of acceleration indicated in the acceleration data in a period in which wobbling motion is assumed to have occurred. In this case, it is determined that wobbling has occurred when the ratio of the minimum value between adjacent maximum values among the multiple maximum values to adjacent maximum values is equal to or greater than a third threshold value that distinguishes between walking or running motion and wobbling motion.

An example of the third threshold value is a discrimination threshold value that distinguishes between walking or running motion and unsteady motion. The multiple determination unit 58 determines that unsteady motion has occurred when the ratio of adjacent maximum values to minimum values between adjacent maximum values among multiple maximum values in the expected waveform is equal to or greater than the discrimination threshold value.

The determination unit 32 also has a standing up movement estimation unit 60, which estimates that a standing up movement has been performed when the acceleration data acquired by the acquisition unit 30 is equal to or greater than a fourth threshold value.

The fourth threshold value, for example, is an increase threshold value for detecting an increase in acceleration accompanying a standing up movement when the standing up movement is performed, and the standing up movement estimation unit 60 estimates that a standing up movement has been performed when the acceleration data acquired by the acquisition unit 30 is equal to or greater than the increase threshold value.

This increase threshold is a threshold that is determined based on the standard for the amount of increase in acceleration when a person stands up, and is determined in advance based on the results of an experiment or simulation, for example.

The determination unit 32 further includes an estimated waveform extraction unit 62 and an upper limit estimation unit 64. The estimated waveform extraction unit 62 extracts an estimated waveform estimated to be a rising motion from the changing waveform of the acceleration data acquired by the acquisition unit 30. The upper limit estimation unit 64 estimates that a rising motion has been performed when the maximum value of the estimated waveform extracted by the estimated waveform extraction unit 62 is equal to or less than the maximum acceleration that can occur when a rising motion is performed. In other words, the upper limit estimation unit 64 predicts a period during which a rising motion is estimated to have been performed from the change in the acceleration data acquired by the acquisition unit 30, and estimates that a rising motion has been performed when the maximum value in the predicted period is equal to or less than the maximum acceleration that can occur when a rising motion is performed.

The determination unit 32 also has a rise period estimation unit 66, which estimates that a rise operation has occurred when the time from the start point to the end point of the estimated waveform is within a rise width time indicating a rise operation. The rise period estimation unit 66 estimates that a rise operation has occurred when the time from when the acceleration data acquired by the acquisition unit 33 rises from a stable state to when it returns to the original state is within a rise width time indicating a rise operation.

The estimated waveform extraction unit 62 extracts, as an estimated waveform, a range from a first minimum value that becomes a minimum just before the acceleration shown in the acceleration data acquired by the acquisition unit 30 exceeds a rising threshold to a second minimum value that becomes a minimum just after the acceleration falls below the rising threshold. In other words, the estimated waveform extraction unit 62 includes a rise time extraction unit. The rise time extraction unit extracts a rise range from a first minimum value that becomes a minimum just before the acceleration shown in the acceleration data acquired by the acquisition unit 30 exceeds a fourth threshold for detecting an increase in acceleration associated with a rising motion to a second minimum value that becomes a minimum just after the acceleration falls below the fourth threshold.

The determination unit 32 has an end value estimation unit 68, which estimates that a rising motion has been performed when the second minimum value of the estimated waveform extracted by the estimated waveform extraction unit 62 is equal to or less than a fifth threshold value for detecting a drop in acceleration shown in the acceleration data when the rising motion is terminated. In other words, the end value estimation unit 68 estimates that a rising motion has been performed when the second minimum value identified by the rise time extraction unit is equal to or less than a fifth threshold value for detecting a drop in acceleration shown in the acceleration data when the rising motion is terminated.

One example of the fifth threshold is a drop threshold for detecting a drop in acceleration indicated in the acceleration data when the standing up movement is terminated. The end value estimation unit 68 estimates that the standing up movement has been performed when the second minimum value of the estimated waveform extracted by the estimated waveform extraction unit 62 is equal to or less than the drop threshold for detecting a drop in acceleration indicated in the acceleration data when the standing up movement is terminated.

This descent threshold is a threshold that is determined based on the standard for the amount of descent that occurs when acceleration increases and then decreases when a person stands up, and is determined in advance, for example, based on the results of an experiment or simulation. As a specific example, the descent threshold is set to a value smaller than the value of acceleration in a seated position.

The determination unit 32 has an acceleration difference estimation unit 70, which estimates that a standing up movement has been performed when the first minimum value of the estimated waveform is greater than the second minimum value. Specifically, the acceleration difference estimation unit 70 extracts a first minimum value that is a minimum immediately before the acceleration indicated in the acceleration data acquired by the acquisition unit 30 exceeds a fourth threshold value for detecting an increase in acceleration associated with the standing up movement. The acceleration difference estimation unit 70 also extracts a second minimum value that is a minimum immediately after the acceleration falls below the fourth threshold value. Then, the acceleration difference estimation unit 70 estimates that a standing up movement has been performed when the first minimum value is greater than the second minimum value.

The determination unit 32 has a pre-waveform extraction unit 72 and a pre-rise estimation unit 74. The pre-waveform extraction unit 72 extracts a pre-rise waveform from the change waveform of the acceleration data acquired by the acquisition unit 30 prior to the estimated waveform. The pre-rise estimation unit 74 estimates that a rise-up movement has been performed when the average value of the acceleration indicated in the acceleration data in the pre-rise waveform extracted by the pre-waveform extraction unit 72 is equal to or less than the seated state threshold value indicating the acceleration in the seated state. In other words, the pre-rise estimation unit 74 estimates that a rise-up movement has been performed when the amount of change in acceleration indicated in the acceleration data prior to the rise-up movement is equal to or less than the seated state change amount indicating the acceleration change in the seated state.

The level determination unit 34 determines the sway level based on the relationship between the maximum value of acceleration indicated in the acceleration data in the estimated waveform and the maximum value of the expected waveform. Note that the detailed determination method will be described later. In other words, the level determination unit 34 determines the sway level based on the relationship between the maximum value of acceleration indicated in the acceleration data during the period in which it is estimated that a rise-up movement was performed and the maximum value of acceleration indicated in the acceleration data during the period in which it is estimated that a swaying movement occurred.

The counting unit 36 calculates the number of times the wobbling state occurs as the wobbling count. When the wobbling count calculated by the counting unit exceeds a sixth threshold value determined in advance, the notification unit 38 notifies the user that the wobbling count has exceeded the count threshold value.

The sixth threshold can be rephrased as a count threshold, for example, and when the number of wobble occurrences calculated by the counting unit exceeds a predetermined count threshold, the notification unit 38 notifies the user that the number of wobble occurrences has exceeded the count threshold.

The transmission unit 40 transmits the acceleration data acquired by the acquisition unit 30 and the determination made by the determination unit 32 to an external device.

(Operation description)
Next, the operation of the sway measuring device 10 will be described with reference to FIGS. 4 to 6 and in accordance with the processing procedure executed by the processor.

Figure 4 is a flowchart showing the operation of the wobble measuring device 10 according to this embodiment, and Figure 5 is a flowchart showing an example of the start-up determination process according to this embodiment.

Figure 6 shows a waveform 100 of the change in acceleration indicated by the acceleration data, which shows a waveform in the case where a swaying motion 104 appears after a rising motion 102. In this waveform 100, the rising motion 102 is shown as an estimated waveform 106, and the swaying motion 104 is shown as an assumed waveform 108. In addition, a pre-rising waveform 110 is shown for the pre-motion 107 before the estimated waveform 106.

In the example shown in FIG. 5, the memory unit 18 has areas reserved for the flags and counters described below, and in the initial process executed immediately after the start of the stagger measurement process, each flag is cleared to "0" and each counter is reset to "0". The stagger measurement device 10 is worn by the user in a state where it is wrapped around the user's waist with a belt 10B, and the acceleration data output from the acceleration sensor 26 changes according to the user's movements.

First, the processor 14 executes the wobble measurement process stored in the memory unit 18, and then the processor 14 executes the start-up determination process (step S1).

(Start-up judgment)
The standing-up determination process (step S1) is a process for determining whether or not the user has performed a standing-up motion. In this standing-up determination process, as shown in Fig. 5, acceleration data indicating the user's motion is obtained from the acceleration sensor 26 (step S21).

Here, the acceleration sensor 26 acquires acceleration data from the X-axis sensor, the Y-axis sensor, and the Z-axis sensor, and the composite value obtained by combining the acceleration data from the sensors of each axis is used as the acceleration data to be used hereinafter.

In this embodiment, a composite value of acceleration data from each sensor constituting the acceleration sensor 26 is used as the acceleration data used in the determination process, but this is not limited to this. For example, in each determination process, only acceleration data from a sensor suitable for that determination process may be used.

It is determined whether the acceleration indicated by the acquired acceleration data is equal to or greater than an increase threshold Ta that is applied when the acceleration increases when a standing-up motion is performed (step S22). Here, the acceleration data is data that indicates the acceleration value in a time series. For this reason, the explanation of replacing acceleration data or acceleration with "acceleration value" is omitted.

Here, the increasing threshold value Ta is, for example, 1.05 G, where G is the gravitational acceleration [9.8 m/s ² ].

The reason for this is that experiments have shown that the amount of change (change amount) in acceleration when stationary, i.e., the error, is at most 0.04 G or less, and when taking into account measurement error, it is preferable to set the increase threshold Ta to 1.05 G. Then, when the acceleration data is equal to or greater than the increase threshold Ta, the processor 14 estimates that the user's movement is a standing up motion.

If the acquired acceleration data is less than the increase threshold Ta in step S22, the processes of steps S21 and S22 are repeated until the acceleration data is equal to or greater than the increase threshold Ta. Also, if it is determined in step S22 that the acquired acceleration data is equal to or greater than the increase threshold Ta, it can be estimated that the user has performed a standing up motion 102. Therefore, this estimation is used as a trigger to extract an estimated waveform 106 that is estimated to indicate the standing up motion 102 from the change waveform 100 of the acquired acceleration data (step S23).

Figure 6 shows a waveform when a staggering motion 104 occurs after a rise motion 102, and the extraction of an estimated waveform 106 will be explained using this Figure 6.

First, ten seconds of acceleration data is stored in the ring buffer of the memory unit 18 in association with the time at which it was acquired. As an example, a waveform 100 of the change in the acceleration data stored in the memory unit 18 is shown in FIG. 6.

In the change waveform 100 of the acceleration data stored in the memory unit 18, the point at which the acceleration data becomes a first minimum value A corresponding to a minimum value immediately before the acquired acceleration data exceeds the rising threshold value Ta is defined as a previous minimum point 120. Also, the point at which the acceleration data becomes a second minimum value B corresponding to a minimum value immediately after the acquired acceleration data exceeds the rising threshold value Ta is defined as a subsequent minimum point 122. In such a case, the processor 14 extracts the range from the previous minimum point 120 to the subsequent minimum point 122 as the estimated waveform 106.

It is determined whether the acceleration at the estimated waveform maximum point 124, where the acceleration reaches the maximum value C in the extracted estimated waveform 106, is equal to or less than the maximum acceleration Tb (not shown) that can occur when the standing up movement 102 is performed (step S24). As such, there is a limit to the speed at which the user can stand up. For this reason, if the acceleration exceeds the maximum acceleration Tb, it is determined to be a movement other than the standing up movement 102.

Here, the maximum acceleration Tb is set to 3.0 G as an example.

For example, it has been found through experiments that when the acceleration sensor 26 is subjected to an impact by being hit against an object or dropped, the maximum acceleration value measured is three times or more the maximum value measured during the rise-up motion 102. Taking this into consideration, the maximum acceleration Tb is set to approximately twice the average value of the maximum acceleration values measured during the wobbling motion 104.

In step S24, if the acceleration of the estimated waveform maximum point 124 exceeds the maximum acceleration Tb, the extracted estimated waveform 106 is not a waveform indicating the rising motion 102, so it is determined that the rising motion 102 has not been performed, and the process branches to step S21. Also, in step S24, if the acceleration of the estimated waveform maximum point 124 is equal to or less than the maximum acceleration Tb, it is estimated that the extracted estimated waveform 106 is a waveform indicating the rising motion 102, so it is estimated that the rising motion 102 has been performed, and the process moves to the next step S25.

In step S25, it is determined whether the time D from the estimated waveform start point 126 to the estimated waveform end point 128 in the extracted estimated waveform 106 is equal to or greater than the rise width time threshold Tc indicating the rise motion 102 (step S25).

When determining the estimated waveform start point 126 and the estimated waveform end point 128, the waveform of a certain period that appears before the estimated waveform 106 is set as the pre-rise waveform 110, and the average value of the acceleration in the pre-rise waveform 110 is calculated and this average value is set as the estimated waveform end criterion 132. The point at which the estimated waveform end criterion 132 is reached just before the estimated waveform 106 exceeds the rise threshold Ta is set as the estimated waveform start point 126. In addition, the point at which the estimated waveform end criterion 132 is reached just after the estimated waveform 106 falls below the rise threshold Ta is set as the estimated waveform end point 128.

Here, the rise width time threshold Tc is set to 0.1 seconds as an example.

For example, it has been found through experiments that when the acceleration sensor 26 is hit against an object or dropped and subjected to an impact, the time from the estimated waveform start point 126 to the estimated waveform end point 128 in the estimated waveform 106 is as follows: In other words, the experimental result of the above time when an impact is applied by hitting or dropping against an object is less than 1/5 the average value of the time D measured in the rise motion 102. Taking this into consideration, the rise width time threshold Tc is set to 1/4 the average value (0.25 seconds) of the time indicating the width on the waveform measured in the rise motion 102.

If it is determined in step S25 that the time D from the estimated waveform start point 126 to the estimated waveform end point 128 is below the rising width time threshold Tc, the process branches to step S21. Also, if it is determined in step S25 that the time D from the estimated waveform start point 126 to the estimated waveform end point 128 is equal to or greater than the rising width time threshold Tc, the generated estimated waveform 106 is presumed to be a waveform indicating the rising motion 102. Therefore, it is presumed that the rising motion 102 has been performed, and the process proceeds to the next step S26.

If the time period indicating the width of the estimated waveform 106 from the estimated waveform start point 126 to the estimated waveform end point 128 is short, it is considered that the wobble measuring device 10 has been hit against an object. If the time period indicating the width of the estimated waveform 106 is long, it is predicted that the operation is other than the rising operation 102.

In step S26, it is determined whether the second minimum value B of the extracted estimated waveform 106 is equal to or less than the descending threshold value Td that is applied when the acceleration indicated in the acceleration data decreases when the rising motion 102 ends. The fact that the second minimum value B of the estimated waveform 106 is equal to or less than the descending threshold value Td is considered to be a characteristic of the waveform indicating the rising motion 102.

Here, the drop threshold Td is set to 1.0 G as an example.

The reason for this is that it has been found through experiments that when the start-up operation 102 is performed, the second minimum value B of the estimated waveform 106 becomes a value smaller than 1.0 G.

In step S26, if the second minimum value B exceeds the descending threshold value Td, the process branches to step S21. Also, in step S26, if the second minimum value B is equal to or less than the descending threshold value Td, the extracted estimated waveform 106 is estimated to be a waveform indicating the rising motion 102, so it is estimated that the rising motion 102 has been performed, and the process moves to the next step S27.

In step S27, it is determined whether the first minimum value A of the front minimum point 120 of the extracted estimated waveform 106 is greater than the second minimum value B of the rear minimum point 122. Based on this determination, it is determined whether the motion is a standing up motion 102 or a sitting down motion.

In step S27, if the first minimum value A of the front minimum point 120 is equal to or less than the second minimum value B of the rear minimum point 122, the estimated waveform 106 is considered to be a waveform indicating a sitting motion, and the process branches to step S21. Also, in step S27, if the first minimum value A of the front minimum point 120 is greater than the second minimum value B of the rear minimum point 122, the extracted estimated waveform 106 is considered to be a waveform indicating a standing up motion 102, and it is therefore assumed that a standing up motion 102 has been performed.

Here, FIG. 7 shows a change waveform 100 of acceleration data, and as an example shows a sitting waveform 142 when a sitting motion 140 is performed. This sitting waveform 142 is similar to the rising waveform that appears when a standing motion 102 is performed. However, it differs in that the first minimum value A of the front minimum point 120 is equal to or lower than the second minimum value B of the rear minimum point 122.

Therefore, by making judgments based on each of the steps described above, it is possible to distinguish between the rising waveform (estimated waveform 106) that appears when the rising motion 102 is performed and the sitting waveform 142.

Then, as shown in FIG. 6, a pre-rising waveform 110 is extracted from the change waveform 100 of the acceleration data acquired by the acceleration sensor 26 prior to the estimated waveform 106 (step S28). Specifically, the waveform for a certain period of time prior to the pre-minimum point 120 of the estimated waveform indicating the rising motion is taken as the pre-rising waveform 110. Here, in this embodiment, the certain period of time is set to, for example, 3 seconds, and the waveform for 3 seconds prior to the estimated waveform start point 126 is extracted as the pre-rising waveform 110.

Next, it is determined whether the extracted pre-onset waveform 110 is, for example, a walking waveform (step S29). In this embodiment, it is determined whether the extracted pre-onset waveform 110 is a waveform indicating a seated state, which is an example of a waveform other than a walking waveform, thereby determining whether the pre-onset waveform 110 is a walking waveform.

Specifically, it is determined whether the change in acceleration 146 indicated in the acceleration data in the extracted pre-rise waveform 110 is equal to or less than the seated state change amount Tf, which indicates the change in acceleration in a seated state.

In step S29, if the acceleration change amount 146 of the extracted pre-rise waveform 110 exceeds the seating state change amount Tf, the rise flag stored in the memory unit 18 is cleared to "0" (step S30), and the process returns to the wobble measurement process that called the rise determination process.

In addition, in step S29, if the change in acceleration 146 of the extracted pre-rise waveform 110 is equal to or less than the seated state change amount Tf, it is estimated that the extracted pre-rise waveform 110 is a waveform that indicates a seated state. Therefore, it can be estimated that the user was seated, i.e., not walking, before performing the stand-up motion 102.

Here, FIG. 8 shows a change waveform 100 of acceleration data, and as an example shows a walking waveform 150 when walking movement 148 is performed. This walking waveform 150 is similar to the sitting waveform that appears in a sitting state, but the amount of change 146 of the waveform differs between the walking waveform 150 and the sitting waveform. Therefore, by making the judgment in step S29, it is possible to distinguish between the sitting waveform that appears in a sitting state and the walking waveform 150.

Then, the rising flag stored in the memory unit 18 is set to "1" (step S31), the number stored in the rising counter stored in the memory unit 18 is counted up (step S32), and the process returns to the wobble measurement process that called the rising judgment process.

As a result, when the standing up flag is "1", it can be determined that the user wearing the stagger measuring device 10 has performed the standing up motion 102 from a seated position. In addition, the number stored in the standing up counter can be used to determine the number of times the user has performed the standing up motion 102 from a seated position.

In the wobble measurement process, as shown in FIG. 4, it is determined whether a standing up action has been performed from a seated state based on whether the standing up flag is "1" or "0" (step S2). If it is determined in step S2 that a standing up action 102 has not been performed from a seated state, the process branches to step S1 without performing the wobble determination process (step S3). If it is determined in step S2 that a standing up action 102 has been performed from a seated state, the wobble determination process is executed (step S3).

(Wandering judgement)
The unsteadiness determination process (step S3) is a process for determining an unsteadiness motion 104 of the user based on acceleration data after a standing up motion 102 is performed, and the unsteadiness determination process will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a flow chart showing an example of the unsteadiness determination process. Fig. 10 is a diagram showing a change waveform 100 of the acceleration data, showing the waveform when the foot-down motion is performed twice.

That is, in the wobble determination process, as shown in Fig. 9, it is determined whether the acceleration data acquired from the acceleration sensor 26 is equal to or greater than a foot-down threshold Tg, which is an example of a first threshold that is reached when the user stumbles and puts his/her feet down, as shown in Fig. 10 (step S51). Here, the foot-down threshold Tg is a standard for the change in acceleration when the user stumbles and puts his/her feet down.

If the acceleration data acquired from the acceleration sensor 26 in step S51 is less than the foot placement threshold Tg, the unsteadiness flag stored in the memory unit 18 is cleared to "0" (step S52), and the process returns to the unsteadiness measurement process that called the unsteadiness determination process. Also, if the acceleration data acquired from the acceleration sensor 26 in step S51 is equal to or greater than the foot placement threshold Tg, it is presumed that the user has become unsteady. For this reason, an assumed waveform 108 that is assumed to indicate the occurrence of a unsteady movement 104 is extracted from the change waveform 100 of the acceleration data acquired by the acceleration sensor 26 (step S53).

As an example, the foot placement threshold Tg is set to 1.7 G. Experimental data shows that the change in acceleration of the walking waveform is at most 0.5 G, so taking into account measurement error, it is preferable to set 1.7 G as the threshold for determining wobble.

To be more specific, the acceleration data acquired from the acceleration sensor 26 after the rising motion 102 is detected is set to the expected waveform start point 164 at the first minimum point in the region below a predetermined threshold Th that is smaller than the foot placement threshold Tg. The acceleration data is set to the expected waveform end point 166 at the next minimum point in the region below a predetermined threshold Th that is smaller than the foot placement threshold Tg, and the range from the expected waveform start point 164 to the expected waveform end point 166 is extracted as the expected waveform 108.

Here, the predetermined threshold Th is a threshold for extracting an assumed waveform 108 that is assumed to indicate the occurrence of a swaying movement 104 from the waveform shown in the acceleration data. Note that, as an example, this predetermined threshold Th is the estimated waveform end criterion 132 that indicates the average value of the pre-rising waveform 110.

Then, the time from the expected waveform start point 164 to the expected waveform end point 166 is set as the expected waveform width time F, and it is determined whether the expected waveform width time F is equal to or less than the reference time Tj determined by the criteria for the wobbling movement (step S54). Here, the footing waveform 170 for determining the wobbling movement 104 is a narrow waveform. However, if multiple footing movements are performed in one wobbling movement 104, a wide waveform is detected.

In step S54, if the expected waveform width time F is equal to or less than the reference time Tj, the expected waveform 108 is assumed to be a waveform indicating a swaying movement 104, so it is presumed that the user is swaying, and the process proceeds to the next step S55.

As an example, the reference time Tj is set to 0.15.

Figure 11 shows a change waveform 100 of acceleration data, which is a waveform measured when a jump is made from a rising motion 102. When a jump is made from a rising motion 102, the expected waveform width time F from the expected waveform start point 164 to the expected waveform end point 166 of the expected waveform 108 that appears after the estimated waveform 106 exceeds the reference time Tj.

Figure 12 shows a waveform 100 of the change in acceleration data, and as an example shows a waveform measured when starting to run immediately after the rising motion 102. When running is started immediately after the rising motion 102, the expected waveform width time F from the expected waveform start point 164 to the expected waveform end point 166 of the expected waveform 108 that appears after the estimated waveform 106 exceeds the reference time Tj.

In this way, by determining whether the expected waveform width time F from the expected waveform start point 164 to the expected waveform end point 166 of the expected waveform 108 is less than or equal to the reference time Tj, it is possible to determine whether the expected waveform 108 is a waveform that indicates a swaying motion 104.

Next, the acceleration of maximum point 172 where assumed waveform 108 is at its maximum is acquired as assumed waveform maximum value E1 (step S55), and it is determined whether acquired assumed waveform maximum value E1 is equal to or greater than the target value Tk reached when the person stumbles and puts his or her feet on the ground (step S56). The fact that acquired assumed waveform maximum value E1 is equal to or greater than the target value Tk is a characteristic of a swaying waveform.

Here, the expected waveform maximum value E1 reaches a value Tk of 2.0 G, as an example.

The reason for doing this is that experiments have shown that the maximum acceleration measured while walking is, on average, 1.5G. Taking this into consideration, the reached value Tk is determined by adding twice the magnitude of 0.5G, which is the difference from 1G, to 1G.

If the expected waveform maximum value E1 is less than the reached value Tk in step S56, it is assumed that the expected waveform 108 is not a waveform that indicates the swaying motion 104. Therefore, the sway flag is cleared to "0" (step S52), and the process returns to the sway measurement process that called the sway determination process. If the expected waveform maximum value E1 is equal to or greater than the reached value Tk in step S56, the expected waveform 108 is a waveform that indicates the swaying motion 104, and the sway flag is set to "1" as sway has occurred.

Figure 13 shows a change waveform 100 of acceleration data, and as an example shows a waveform measured when the body stops after a rising motion 102. When the body stops after the rising motion 102 without a swaying motion 104, the expected waveform maximum value E1 of the maximum point 172 of the expected waveform 108 is less than the reached value Tk.

Therefore, by determining whether the expected waveform maximum value E1 of the expected waveform 108 is equal to or greater than the reached value Tk, it is possible to determine whether the expected waveform 108 is a waveform that indicates a swaying motion 104.

Figure 14 is a diagram showing a waveform 100 of change in acceleration data, and as an example, shows a waveform measured when a standing up movement 102 is followed by a foot-planting movement in a forward direction. Also, Figure 15 is a diagram showing a waveform 100 of change in acceleration data, and as an example, shows a waveform measured when a standing up movement 102 is followed by a foot-planting movement in a lateral direction.

When a forward or lateral foot placement motion indicating unsteadiness is performed from the standing up motion 102, the acceleration becomes equal to or exceeds the foot placement threshold Tg.

When a forward or lateral foot placement motion that indicates wobbling is performed from the rising motion 102, the expected waveform width time F from the expected waveform start point 164 to the expected waveform end point 166 becomes less than the reference time Tj. Also, it has been found through experiments that when a forward or lateral foot placement motion that indicates wobbling is performed from the rising motion 102, the expected waveform maximum value E1 becomes greater than or equal to the reached value Tk.

Therefore, by determining whether the conditions of steps S51, S54, and S56 are satisfied, it is possible to determine whether the expected waveform 108 is a waveform that indicates a swaying operation.

Then, the number of wobble counters stored in the memory unit 18 is counted up to count the number of wobble occurrences (step S58), and the process returns to the wobble measurement process that called the wobble determination process.

On the other hand, if the expected waveform width time F exceeds the reference time Tj in step S54, as shown in FIG. 10, it is determined whether the expected waveform 108 has an expected waveform minimum point 174 where the acceleration is minimal (step S60). This determines whether the foot contact occurs multiple times in the expected waveform 108 (step S60).

If the expected waveform 108 does not have an expected waveform minimum point 174 in step S60, the expected waveform 108 is not a waveform that occurs when multiple footings occur. However, the expected waveform width time F of the expected waveform 108 exceeds the reference time Tj. Therefore, the wobble flag is cleared to "0" (step S61), and the process returns to the wobble measurement process that called the wobble determination process.

In addition, in step S60, if there is an expected waveform minimum point 174 in the expected waveform 108, it is considered that there are multiple acceleration maximum values indicated in the acceleration data in the expected waveform 108, and that multiple foot placements have occurred in the expected waveform 108. Therefore, the time indicating the width on the foot placement waveform 170 indicating the first foot placement motion is obtained as the foot placement time G (step S70).

Here, the foot waveform 170 indicating the first foot action starts from the expected waveform start point 164. Also, the expected waveform minimum point 174 that appears first in the expected waveform 108 is the foot waveform end point, which is the end point of the foot waveform, and the time from the expected waveform start point 164 to the expected waveform minimum point 174, which is the end point of the foot waveform, is the foot time G.

Then, it is determined whether the expected waveform maximum value E1, which is the maximum value of the footing waveform 170, is equal to or greater than the footing threshold value Tg (step S71). If the expected waveform maximum value E1 is less than the footing threshold value Tg in step S71, it is considered that the waveform does not indicate a footing motion, so the wobble flag is cleared to "0" (step S61) and the process returns to the wobble measurement process that called the wobble determination process.

In step S71, if the expected waveform maximum value E1 is equal to or greater than the reached value Tk, the waveform may indicate a foot-on-ground motion. For this reason, it is determined whether the foot-on-ground time G is equal to or less than the reference time Tj, which is a strength threshold determined based on the standard for the strength of the impact when the person stumbles and places the foot on the ground (step S72). The fact that the expected waveform maximum value E1 is equal to or greater than the foot-on-ground threshold value Tg and the foot-on-ground time G is equal to or less than the reference time Tj are characteristics of a swaying waveform.

Here, the reference time Tj is 0.15 seconds, as mentioned above.

The reason for this is that it has been found through experiments that the minimum value of the time that indicates the width of the gait waveform measured while walking is 0.2 seconds. Taking this into consideration, the reference time Tj is set to 3/4 times 0.2 seconds.

Here, FIG. 16 shows a change waveform 100 of acceleration data, and shows the waveform when a foot-on-ground movement is performed as an example. The waveform width 178 of the foot-on-ground waveform 170 that appears when a foot-on-ground movement is performed is shown in time, and its maximum value is found by experiment, and a reference time Tj indicating the waveform width is determined from the experimental results.

On the other hand, FIG. 17 shows a change waveform 100 of acceleration data, and shows a jump waveform 180 in the case of jumping as an example of jumping, walking, or running. It has been found by experiment that the minimum value of the time indicated by the waveform width 182 of this jump waveform 180 is greater than the reference time Tj. It has been found by experiment that this minimum value is the same for the walking waveform that appears in walking and the running waveform that appears in running.

Therefore, if the footing time G in the expected waveform 108 is less than or equal to the reference time Tj, it is possible to determine that the expected waveform 108 indicates a swaying motion 104.

In this embodiment, we will explain a case where the wobbling motion is determined based on the time indicating the width on the foot-down waveform 170 indicating the first foot-down motion in the assumed waveform 108 where the foot-down motion has been performed multiple times, but this is not limited to this.

For example, if there is one foot-on-foot movement in the expected waveform 108, the wobbling movement 104 can be determined based on whether the expected waveform width time F from the expected waveform start point 164, which is the start point of the expected waveform 108, to the expected waveform end point 166, which is the end point, is less than or equal to the reference time Tj. Here, the reference time Tj indicates a time determined by the standard for the wobbling movement 104.

If, in step S72, the footing time G exceeds the reference time Tj, it is deemed that the waveform does not indicate a footing motion, so the wobble flag is cleared to "0" (step S61) and the process returns to the wobble measurement process that called the wobble determination process.

In step S72, if the footing time G is equal to or less than the reference time Tj, even if the assumed waveform width time F from the assumed waveform start point 164 to the assumed waveform end point 166 of the assumed waveform 108 exceeds the reference time Tj, there is a possibility that the assumed waveform 108 is a waveform that indicates a footing motion. For this reason, it is determined whether the ratio of the minimum value between adjacent maximum values among the multiple maximum values in the assumed waveform 108 to the adjacent maximum values is equal to or greater than a discrimination threshold that distinguishes between walking or running motion and unsteady motion.

Specifically, the second maximum value E2 of the second maximum point 184 of the assumed waveform 108 is divided by the assumed waveform minimum value H indicated by the assumed waveform minimum point 174 between the maximum point 172 and the maximum point 184, and also by the second maximum value E2 to calculate the valley depth J (step S73). Expressed as a formula, J = E2 / H / E1. In other words, a shallow valley in the assumed waveform 108 indicates a walking or running state, and a deep valley in the assumed waveform 108 indicates a staggering movement 104.

Then, it is determined whether the valley depth J, i.e., the proportion of valley waveforms that appear between successive foot-on-ground waveforms 170 when successive foot-on-ground movements are performed, is less than the discrimination threshold Tm (step S74).

Here, the discrimination threshold Tm is set to 0.5 as an example.

The reason for this is that experiments have shown that the minimum values that appear in running waveforms measured while running are small. For this reason, the discrimination threshold was determined by comparing with the running waveform.

Figure 18 shows a waveform 100 of change in acceleration data, and as an example shows a waveform in which a foot planting motion is performed twice. It has been found through experiments that when a foot planting motion is performed multiple times, a minimum value 188 appears in the assumed waveform 108, and the ratio between the minimum value 188 and the maximum values 190, 192 on either side of the minimum value 188 is equal to or greater than a certain value.

On the other hand, FIG. 19 shows a waveform 100 of changes in acceleration data, and as an example shows a walking waveform when walking is performed, out of walking and running. Experiments have shown that in this walking waveform, the ratio between the minimum value 188 and the maximum values 190, 192 on either side of it is less than a certain value. The same is true for the running waveform that shows running.

From these experimental results, it can be determined that the expected waveform 108 exhibits a swaying motion 104 when the aforementioned valley depth J in the expected waveform 108 is equal to or greater than the discrimination threshold Tm.

In step S74, if the valley depth J is less than the discrimination threshold Tm, the assumed waveform 108 is considered to be a waveform indicating walking or running, so the wobble flag is cleared to "0" (step S61), and the process returns to the wobble measurement process that called the wobble determination process.

Also, in step S74, if the valley depth J is equal to or greater than the discrimination threshold Tm, it is considered that the assumed waveform 108 indicates a wobble motion 104. Therefore, it is determined that wobble has occurred, so the wobble flag is set to "1" (step S57), the wobble counter is counted up (step S58), and the process returns to the wobble measurement process that called the wobble determination process.

Note that the comparison value used in the judgment in step S56 and the comparison value used in the judgment in step S71 are the same value, so the comparison value in both steps S56 and S71 is set to the reached value Tk, but the comparison value in step S56 and the comparison value in step S71 may be different values.

In addition, since the comparison value used in the judgment in step S54 and the comparison value used in the judgment in step S72 are the same value, the comparison value in both steps S54 and S72 is set as the reference time Tj, but the comparison value in step S54 and the comparison value in step S72 may be different values.

In the wobble determination process, as shown in FIG. 4, it is determined whether wobble has occurred by determining whether the wobble flag is "1" (step S4). If wobble has not occurred in step S4, the process returns to step S1. If wobble has occurred in step S4, a wobble magnitude correction process is executed (step S5).

(Wobble magnitude correction process)
Next, a wobble magnitude correction process for correcting the wobble magnitude will be described with reference to FIGS.

Figure 20 is a flow chart showing an example of a sway magnitude correction process, in which the magnitude of acceleration of the sway waveform indicating the swaying motion 104 is corrected based on the magnitude of acceleration of the rising waveform indicating the rising motion 102. Also, Figure 21 is a diagram showing a change waveform 100 of acceleration data, in which the rising waveform indicating the rising motion 102 appears in the estimated waveform 106, and the sway waveform indicating the swaying motion 104 appears in the assumed waveform 108.

First, in the wobble magnitude correction process shown in FIG. 20, the wobble magnitude is acquired (step S100). Specifically, the expected waveform maximum value E1, which is the maximum value of acceleration shown in the acceleration data in the expected waveform 108 showing the wobble movement 104, is acquired.

Next, the rising magnitude is obtained (step S101). Specifically, the maximum acceleration value C shown in the acceleration data of the estimated waveform 106 indicating the rising motion 102 is obtained.

Then, the estimated waveform maximum value E1 indicating the magnitude of the wobbling motion 104 is corrected based on the maximum value C of the estimated waveform 106 indicating the magnitude of the rising motion 102, thereby correcting the wobbling magnitude with the rising magnitude (step S102).

Specifically, the expected waveform maximum value E1 is divided by the maximum value C of the estimated waveform 106 to obtain a correction value K for correcting the fluctuation magnitude (K = E1 ÷ C), and the process returns to the fluctuation measurement process that called the fluctuation magnitude correction process.

Then, in the wobble measurement process, a notification process is executed (step S6) as shown in FIG. 4.

(Notification process)
Fig. 22 is a flowchart showing an example of the notification process, in which the measurement results are displayed on the display unit 22 to notify the user. Fig. 23 is a diagram showing an example of a display on the display unit 22.

In this notification process, as shown in FIG. 22, the number stored in the wobble counter is displayed as the number of times on the display unit 22 (step S110).

For example, if "10" is stored in the wobble counter, as shown in FIG. 23, the wobble count field 302 on the display screen 300 of the display unit 22 displays the number of wobble counts as "10 times." When a user sees this display, they can know that there have been 10 wobble counts since the start of measurement by the wobble measurement device 10.

Then, it is determined whether the number of wobble occurrences stored in the wobble counter is greater than a count threshold value previously stored in the storage unit 18 (step S111). If the number of wobble occurrences is equal to or less than the count threshold value in step S111, the process branches to step S113, and if the number of wobble occurrences exceeds the count threshold value, a message indicating that the number of wobble occurrences has exceeded the count threshold value is displayed on the display unit 22 (step S112).

For example, if the number of wobble occurrences is "10" and the number threshold is stored as "5," the wobble occurrences field 302 on the display unit 22 displays "Over specified value." When a user sees this display, they can recognize that the wobble occurrences are greater than the specified value.

In step S113, the wobble rate is calculated and the calculated wobble rate is displayed (step S114). The wobble rate indicates the ratio of wobble motions 104 occurring to the rise motions 102, and is calculated by dividing the number stored in the wobble counter by the number stored in the rise counter.

For example, if "10" is stored in the wobble counter and "20" is stored in the standing up counter, the wobble rate is "50%" and as shown in FIG. 23, the wobble rate column 304 on the display unit 22 displays "50%." A user who sees this display can recognize that there is a 50% chance that wobbling will occur when performing a standing up action.

Then, the sway level is calculated (step S115). The sway level is a value calculated based on the relationship between the maximum value of acceleration indicated in the acceleration data in the estimated waveform and the maximum value of acceleration indicated in the acceleration data in the assumed waveform.

To be more specific, the average of the estimated waveform maximum values is calculated as the estimated waveform average value by adding up the maximum values C of all estimated waveforms 106 in each waveform determined to be in a swaying state and dividing by the number of swayings. In addition, the average of the estimated waveform maximum values is calculated as the estimated waveform average value by adding up all expected waveform maximum values E1 in each waveform determined to be in a swaying state and dividing by the number of swayings. The expected waveform average value is then divided by the estimated waveform average value to calculate the sway level.

For example, if the expected waveform average value is "2G" and the estimated waveform average value is "2G", the wobble level will be "1".

The maximum value C and the expected waveform maximum value E1 for each waveform are stored in the memory unit 18 at any time.

Next, the calculated wobble level is judged (step S116), the judgment result is displayed (step S117), and the process returns to the wobble measurement process that called the notification process.

To be more specific, when the wobble level is judged, if the wobble level is less than "0.5", the judgment result is "small", and if the wobble level is between "0.5" and "2", the judgment result is "medium". Also, if the wobble level is more than "2", the judgment result is "large".

For example, if the expected waveform average value is "2", the estimated waveform average value is "2", and the wobble level is "1", the judgment result is "medium", and "medium" is displayed in the wobble level column 305 of the display unit 22. A user who sees this display can recognize that the wobble level is "medium".

(Action and Effects)
Next, the effects of this embodiment will be described.

The stagger measuring device 10 in this embodiment includes an acquisition unit 30 that acquires acceleration data indicating the user's movement. The stagger measuring device 10 also includes a determination unit 32 that, when the acceleration data acquired by the acquisition unit 30 indicates the user's standing up motion 102, determines the user's staggering motion 104 based on the acceleration data after the standing up motion 102 is displayed.

According to this configuration, when the acceleration data acquired by the acquisition unit 30 indicates a standing up motion 102 of the user, this standing up motion 102 is used as a trigger to determine the user's unsteady motion 104 based on the acceleration data.

This makes it possible to reduce the number of operation buttons compared to when measurement is started by operating an operation button, and allows the measurement of unsteadiness without the user being aware that a measurement has started. This makes it possible to measure data in line with everyday life.

In addition, with typical measuring devices, the user must use all their strength to stand up from a seated position, which is a burden for elderly people. In contrast, with the unsteadiness measuring device 10 of this embodiment, the user does not need to exert force or stand up quickly during measurement. This makes it possible to determine the condition of the lower limbs, such as unsteadiness, with a low load, without the user having to use all their strength to stand up.

Furthermore, it is said that unsteadiness when getting up from a sitting or lying position is related to the risk of falling. For this reason, the unsteadiness measuring device 10 can be used by the person himself or by those around him to determine whether or not unsteadiness is occurring in daily life, thereby helping to prevent falls.

In addition, the number of operation buttons to be operated when starting measurement can be reduced, which makes it possible to reduce the cost of the stagger measurement device 10. Furthermore, by reducing the number of operation buttons, it is possible to reduce the size of the stagger measurement device 10.

In addition, in this embodiment, the determination unit 32 has a wobble estimation unit 50 that estimates that the user is wobbling when the acceleration data acquired by the acquisition unit 30 is equal to or greater than the foot placement threshold Tg that is reached when the user stumbles and places the foot on the ground.

With this configuration, the foot placement state caused by stumbling is correctly detected from the acceleration data, making it possible to accurately determine the stumbling movement 104.

Furthermore, in this embodiment, the determination unit 32 has a swaying time estimation unit 52. When the acceleration data becomes equal to or greater than the foot placement threshold Tg, the swaying time estimation unit 52 acquires the period from the first minimum value to the next minimum value in the time series in the region where the acceleration data is equal to or less than a predetermined threshold Th that is smaller than the foot placement threshold Tg. When this period is equal to or less than the intensity threshold, the swaying time estimation unit 52 estimates that the user has swayed.

For example, if the period from the first minimum value to the next minimum value is short, the user may be jumping, walking, or running, and by determining this period, it is possible to distinguish between these non-wandering movements and wandering movements.

In addition, in this embodiment, the determination unit 32 has an expected waveform extraction unit 54 that extracts an expected waveform 108 that is expected to indicate the occurrence of a swaying movement 104 from the changing waveform of the acceleration data acquired by the acquisition unit 30. The determination unit 32 also has a swaying period estimation unit 56 that estimates that the user has experienced swaying when the time from the start point to the end point of the expected waveform 108 extracted by the expected waveform extraction unit 54 is less than or equal to a reference time determined by the criteria for the swaying movement 104.

Furthermore, in this embodiment, the expected waveform extraction unit 54 sets the range from the first minimum value to the next minimum value in the region below a predetermined threshold value Th that is smaller than the foot placement threshold value Tg in the acceleration data acquired by the acquisition unit 30 after the standing up movement 102 is performed as the expected waveform 108. In other words, the determination unit 32 has an extraction unit that extracts the range from the first minimum value to the next minimum value in the time series in the acceleration data acquired by the acquisition unit 30 after the standing up movement is performed. The determination unit 32 also has an estimation unit that estimates that the user has experienced unsteadiness when the range extracted by the extraction unit is equal to or shorter than a reference time defined by the criteria for unsteady movement.

This configuration makes it possible to stably and accurately extract the expected waveform 108.

In addition, in this embodiment, the determination unit 32 has a multiple determination unit 58 that determines that swaying has occurred when there are multiple maximum acceleration values indicated in the acceleration data in the assumed waveform 108. The multiple determination unit 58 determines that swaying has occurred when the ratio of the minimum value between adjacent maximum values among the multiple maximum values to the adjacent maximum values is equal to or greater than a discrimination threshold that distinguishes between walking or running motion and swaying motion 104.

For example, if the valley of the expected waveform 108 is shallow, the expected waveform 108 is considered to indicate a walking or running motion by the user, and it becomes possible to distinguish between a waveform indicating a walking or running motion by the user and a waveform indicating a staggering motion 104.

In addition, in this embodiment, the determination unit 32 has a stand-up movement estimation unit 60 that estimates that a stand-up movement 102 has been performed when the acceleration data acquired by the acquisition unit 30 becomes equal to or greater than an increase threshold Ta for detecting an increase in acceleration associated with a stand-up movement.

According to this configuration, when the acceleration data reaches or exceeds the increase threshold value Ta, it becomes possible to estimate a standing up motion 102. In this way, by detecting the increase in acceleration accompanying the standing up motion 103, it is possible to accurately estimate the standing up motion 102 of the user.

In this embodiment, the determination unit 32 also has an estimated waveform extraction unit 62 that extracts an estimated waveform 106 that is estimated to have been performed when the rise-up movement 102 has been performed from the changing waveform of the acceleration data acquired by the acquisition unit 30. The determination unit 32 also has an upper limit estimation unit 64 that estimates that the rise-up movement 102 has been performed when the maximum value of the estimated waveform 106 extracted by the estimated waveform extraction unit 62 is equal to or less than the maximum acceleration that can occur when the rise-up movement 102 is performed.

With this configuration, by using the maximum value of the estimated waveform 106 as a parameter for identifying the user's standing up movement 102, it is possible to prevent erroneous detection of movements other than the standing up movement 102.

Furthermore, in this embodiment, the determination unit 32 has a rise period estimation unit 66 that estimates that a rise operation 102 has been performed when the time D from the start point to the end point of the estimated waveform 106 is within the rise width time threshold Tc indicating the rise operation 102.

With this configuration, by using time D as a parameter for identifying the user's standing up motion 102, it is possible to prevent erroneous detection due to contact with the acceleration sensor 26.

In this embodiment, the estimated waveform extraction unit 62 determines as the first minimum value A the value at which the acceleration shown in the acceleration data acquired by the acquisition unit 30 becomes minimum immediately before exceeding the increase threshold value Ta. The estimated waveform extraction unit 62 determines as the second minimum value B the value at which the acceleration becomes minimum immediately after falling below the increase threshold value Ta. The estimated waveform extraction unit 62 then extracts the range from the first minimum value A to the second minimum value B as the estimated waveform 106. The determination unit 32 has an end value estimation unit 68 that estimates that the rise-up movement 102 has been performed when the second minimum value B of the estimated waveform 106 extracted by the estimated waveform extraction unit 62 is equal to or less than the decrease threshold value Td for detecting a decrease in acceleration shown in the acceleration data when the rise-up movement is ended.

This configuration makes it possible to distinguish between rising and falling waveforms.

Furthermore, in this embodiment, the determination unit 32 has an acceleration difference estimation unit 70 that estimates that a standing up movement 102 has been performed when the first minimum value A of the estimated waveform 106 is greater than the second minimum value B. In other words, the determination unit 32 extracts a first minimum value that is a minimum immediately before the acceleration indicated in the acceleration data acquired by the acquisition unit 30 exceeds a fourth threshold value for detecting an increase in acceleration associated with the standing up movement. The determination unit 32 also extracts a second minimum value that is a minimum immediately after the acceleration falls below the fourth threshold value. Then, the determination unit 32 estimates that a standing up movement has been performed when the first minimum value is greater than the second minimum value.

This configuration improves the accuracy of distinguishing between rising and falling waveforms.

In addition, in this embodiment, the determination unit 32 has a pre-rise waveform extraction unit 72 that extracts a pre-rise waveform 110 from the change waveform of the acceleration data acquired by the acquisition unit 30 prior to the estimated waveform 106. The determination unit 32 also has a pre-rise estimation unit 74 that estimates that a rise motion 102 has been performed when the change amount 146 of acceleration indicated in the acceleration data in the pre-rise waveform 110 extracted by the pre-rise waveform extraction unit 72 is equal to or less than the seated state change amount indicating the acceleration in the seated state.

With this configuration, the determination unit 32 can determine whether or not the motion is a standing up motion 102 from a seated position by identifying the amount of change in acceleration 146 indicated in the acceleration data.

Furthermore, in this embodiment, a level determination unit 34 is further provided that determines the wobble level based on the relationship between the maximum acceleration value C shown in the acceleration data in the estimated waveform 106 and the maximum acceleration value E1 shown in the acceleration data in the assumed waveform 108.

With this configuration, it is possible to determine the risk of falling by determining the degree of unsteadiness.

In this embodiment, the wobble measuring device 10 includes a counting unit 36 that calculates the number of occurrences of the wobble state as the wobble count. The wobble measuring device 10 further includes a notification unit 38 that notifies the user that the wobble count has exceeded a predetermined count threshold when the wobble count calculated by the counting unit 36 exceeds a predetermined count threshold.

This configuration allows the user to intuitively recognize the number of times they are swaying.

In this embodiment, the determination result, such as the fact that the number of swayings has exceeded the threshold number of times, is displayed on the display unit 22 to notify the user, but this is not limited to the above. For example, the determination result may be notified by a sound such as a voice.

In this embodiment, the device further includes a transmission unit 40 that transmits the acceleration data acquired by the acquisition unit 30 and the determination made by the determination unit 32 to an external device.

Therefore, the acceleration data acquired by the acceleration sensor 26 and the determination result, such as the fact that the number of swayings has exceeded the number threshold, can be transmitted to an external device such as a smartphone via the communication unit 24. In this case, the determination result, such as the fact that the number of swayings has exceeded the number threshold, can be notified by the external device.

This makes it possible to send acceleration data to an external device, such as a caregiver's smartphone, and share the acceleration data with each other.

Second Embodiment
Next, a wobble measuring system according to a second embodiment will be described with reference to FIG.

Figure 24 shows a sway measurement system 500 according to the second embodiment. Explanations of parts that are the same as or equivalent to the first embodiment will be omitted, and only the differences will be explained.

This wobble measurement system 500 includes a first device 502 and a second device 504.

The first device 502 is a device worn by the user and includes an acceleration sensor 510 that acquires acceleration data indicative of the user's movements, and a transmission unit 512 that transmits the acceleration data acquired by the acceleration sensor 510 to the second device 504.

The second device 504 is, for example, a terminal such as a smartphone. The second device 504 includes a receiving unit 514 that receives acceleration data transmitted from a transmitting unit 512 of the first device 502, and an acquiring unit 516 that acquires acceleration data acquired by an acceleration sensor 510 of the first device 502 via the receiving unit 514.

The second device 504 also includes a determination unit 518 that, when the acceleration data acquired by the acquisition unit 516 indicates the user's standing up motion 102, determines the user's unsteady motion 104 based on the acceleration data after the standing up motion 102 is indicated. The second device 504 also includes a notification unit 520 that notifies the user of the result of the determination by the determination unit 518.

This type of wobble measurement system 500 can also achieve the same effects as the first embodiment.

In addition, since the determination process can be performed by the second device 504, it is possible to improve the determination accuracy without complicating the processing of the first device 502 worn by the user.

In the second embodiment, the second device 504 includes the units 514, 516, 518, and 520, but the present invention is not limited to this. For example, the functions of the units 514, 516, 518, and 520 may be realized by storing a wobble measurement program in the second device 504 and executing the measurement program in a processor that constitutes the computer of the second device 504.

Specifically, by executing the measurement program, the processor of the second device 504 may function as an acquisition means for acquiring acceleration data indicating the user's movement obtained by the first device 502 from the first device 502, and as a determination means for determining the user's unsteady movement based on the acceleration data acquired by the acquisition means after the acceleration data indicates the user's standing up movement.

In this embodiment, the second device 504 is configured as a terminal such as a smartphone, but this is not limited to this. For example, the second device 504 may be configured as a server.

In addition, in each embodiment, the unsteadiness when standing up from a seated position is judged, but this is not limited to this. For example, unsteadiness when sitting may be judged. Also, unsteadiness when getting up from a bed or floor may be judged. Furthermore, dizziness or orthostatic hypotension occurring in the user may be judged.

In addition, in each embodiment, a case has been described in which each judgment and other processing is performed using each waveform, but this is not limited to this, and each judgment and other processing may be performed without extracting the waveform.

In addition, in each embodiment, the case where each threshold value is fixed is described, but this is not limited to this. For example, each threshold value may be configured to be changeable, as in the following embodiment.

The third embodiment has a setting mode in which each threshold value is set before starting to use the stagger measurement device.

Before starting measurement, this unsteadiness measuring device displays a message to encourage the user to stand up in stages. Specifically, the display unit 22 displays announcements such as "slowly," "a little faster," and "quickly" to encourage the user to stand up in stages. Then, each threshold value is set based on the presence or absence of unsteadiness and its acceleration.

In the fourth embodiment, before starting to use the unsteadiness measuring device, the user is asked to quickly stand up from a chair several times, the average value of the maximum acceleration peaks at that time is obtained, and each threshold value is set from the average value of each maximum peak.

In addition, in the fifth embodiment, each threshold is calibrated using machine learning even after the stagger measurement device is first used.

REFERENCE SIGNS LIST 10 Wobble measuring device 14 Processor 18 Memory unit 22 Display unit 24 Communication unit 26 Acceleration sensor 30 Acquisition unit 32 Determination unit 34 Level determination unit 36 Counting unit 38 Notification unit 40 Transmission unit 50 Wobble estimation unit 52 Wobble time estimation unit 54 Expected waveform extraction unit 56 Wobble period estimation unit 58 Multiple determination unit 60 Rising motion estimation unit 62 Estimated waveform extraction unit 64 Upper limit estimation unit 66 Rising period estimation unit 68 End value estimation unit 70 Acceleration difference estimation unit 72 Pre-waveform extraction unit 74 Pre-rising estimation unit 100 Changing waveform 102 Rising motion 104 Wobble motion 106 Estimated waveform 108 Expected waveform 110 Pre-rising waveform 120 Pre-minimum point 122 Rear minimum point 124 Estimated waveform maximum point 126 Estimated waveform start point 128 Estimated waveform end point 132 Estimated waveform end reference 164 Expected waveform start point 166 Expected waveform end point 300 Display screen 500 Wobble measurement system 502 First device 504 Second device 510 Acceleration sensor 512 Transmitting unit 514 Receiving unit 516 Acquiring unit 518 Determining unit 520 Notification unit Tg Foot contact threshold (first threshold)
Tj Reference time (intensity threshold, second threshold)
Tm Discrimination threshold (third threshold)
Ta rising threshold (fourth threshold)
Td Falling threshold (fifth threshold)

Claims (18)

an acquisition means fixed to a user's body to acquire acceleration data indicative of the user's movement;
a determination means for determining whether the user has staggered and put his/her feet on the ground based on the acceleration data acquired by the acquisition means for a predetermined period after the acceleration data indicates a transition that is inferred to indicate that the user has performed a standing up motion;
A wobble measuring device comprising: The wobble measuring device according to claim 1,
The determination means includes a staggering estimation means for estimating that the user has caused the staggering motion when the acceleration data acquired by the acquisition means is equal to or greater than a first threshold value.
Wobble measuring device. The wobble measuring device according to claim 1 or 2,
The determination means includes a swaying time estimation means for estimating that the user has caused the swaying motion when a period from a minimum value immediately before the acceleration data after the standing up motion exceeds a first threshold to a minimum value immediately after the acceleration data falls below the first threshold is equal to or shorter than a second threshold.
Wobble measuring device. The wobble measuring device according to claim 3,
the wobbling time estimation means estimates that the user has caused the wobbling motion when the immediately preceding minimum value and the immediately succeeding minimum value are equal to or smaller than a predetermined threshold value.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 4,
The determination means includes a swaying period estimation means for estimating a period during which the swaying motion is assumed to have occurred from a change in the acceleration data acquired by the acquisition means, and, if the predicted period is equal to or shorter than a reference time determined by a criterion for the swaying motion, estimating that the swaying motion has occurred in the user.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 5,
The determination means is
an extracting means for extracting a range from a first minimum value to a second minimum value that appears in a time series in the acceleration data acquired by the acquiring means after the standing-up motion is performed;
and an estimation means for estimating that the user has caused the unsteady motion when the range extracted by the extraction means is equal to or shorter than a reference time defined by a criterion for the unsteady motion.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 6,
The determination means has a multiple determination means for determining that the unsteady motion has occurred when there are multiple maximum values of acceleration indicated in the acceleration data during the period in which the unsteady motion is assumed to have occurred, and when a ratio of a minimum value between adjacent maximum values among the multiple maximum values to the adjacent maximum values is equal to or greater than a third threshold value for distinguishing between walking or running motion and the unsteady motion.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 7,
The determination means includes a stand-up movement estimation means for estimating that the stand-up movement has been performed when the acceleration data acquired by the acquisition means becomes equal to or greater than a fourth threshold value for detecting an increase in acceleration accompanying the stand-up movement.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 8,
The determination means includes an upper limit estimation means for estimating a period during which the standing-up movement is estimated to have been performed from a change in the acceleration data acquired by the acquisition means, and estimating that the standing-up movement has been performed when a maximum value in the predicted period is equal to or less than a maximum acceleration that can be generated when the standing-up movement is performed.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 9,
The determination means includes a rise-up period estimation means for estimating that the rise-up movement has been performed when a time period from when the acceleration data acquired by the acquisition means rises from a stable state to when the acceleration data returns to a normal state is equal to or longer than a rise-up width time indicating the rise-up movement.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 10,
The determination means is
a rise time extraction means for extracting a rise range from a first minimum value that is a minimum immediately before the acceleration indicated in the acceleration data acquired by the acquisition means exceeds a fourth threshold for detecting an increase in acceleration accompanying the rise-up motion to a second minimum value that is a minimum immediately after the acceleration falls below the fourth threshold;
and an end value estimation means for estimating that the rise-up movement has been performed when the second minimum value specified by the rise-up time extraction means is equal to or less than a fifth threshold value for detecting a decrease in acceleration indicated in the acceleration data when the rise-up movement is to be ended.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 11,
The determination means includes an acceleration difference estimation means for estimating that the stand-up movement has been performed when a first minimum value that becomes a minimum immediately before the acceleration indicated in the acceleration data acquired by the acquisition means exceeds a fourth threshold for detecting an increase in acceleration accompanying the stand-up movement is greater than a second minimum value that becomes a minimum immediately after the acceleration falls below the fourth threshold.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 12,
The determination means includes a pre-stand-up estimation means for estimating that the stand-up motion has been performed when an amount of change in acceleration indicated in the acceleration data before indicating the stand-up motion is equal to or less than an amount of change in a seated state indicating an acceleration change in a seated state.
Wobble measuring device. The wobble measuring device according to any one of claims 1 to 13,
The sway measuring device further comprises a level determination means for determining a sway level based on a relationship between a maximum value of acceleration indicated in the acceleration data during a period during which the standing-up movement is estimated to have been performed and a maximum value of acceleration indicated in the acceleration data during a period during which the swaying movement is estimated to have occurred. The wobble measuring device according to any one of claims 1 to 14,
A counting means for calculating the number of occurrences of the wobbling motion as a wobbling count;
a notification means for notifying the user that the number of swaying movements calculated by the counting means has exceeded a sixth threshold value when the number of swaying movements has exceeded a sixth threshold value;
The wobble measuring device further comprises: The wobble measuring device according to any one of claims 1 to 15,
The stagger measuring device further comprises a transmitting means for transmitting the acceleration data acquired by the acquiring means and the determination content by the determining means to an external device. A first device having an acceleration sensor fixed to a body of a user to acquire acceleration data indicative of a movement of the user;
a second device including: an acquisition means for acquiring the acceleration data acquired by the acceleration sensor of the first device; and a determination means for determining, when the acceleration data acquired by the acquisition means shows a transition that is presumed to indicate that the user has performed a standing up motion, whether the user has performed a staggering motion, which is a motion of the user stumbling and putting his/her feet down, based on the acceleration data for a predetermined period after showing the transition that is presumed to indicate that the user has performed the standing up motion;
A wobble measurement system comprising: Computer,
an acquisition means fixed to a user's body to acquire acceleration data indicative of the user's movement;
a determination means for determining a staggering motion, which is a motion of the user staggering and putting his/her feet down, based on the acceleration data for a predetermined period after the acceleration data acquired by the acquisition means shows a transition that is estimated to be a standing up motion of the user;
This is a wobble measurement program that acts as a

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