JPH07327941A - Doze alarm device - Google Patents

Abstract

PURPOSE:To issue an alarm by accurately detecting a dozing state by finding a threshold value from the integration value of a value RRI exceeding a mean value when the variance value of the value RRI of a heartbeat in waking shows a value smaller than a prescribed value and issuing the alarm when the integration value over the mean value out of the same number of values RRI exceeds the threshold value. CONSTITUTION:In the waking, a heartbeat sensor 2 outputs a heartbeat signal to an arithmetic circuit 6, and the arithmetic circuit 6 fetches, for example, RRIs of sixty beats and stores them in memory. The mean values and variance values of the RRIs of sixty beats are found, and the integration value of the RRI over the mean value is found when the variance value is smaller than a prescribed upper limit value, and the threshold value can be found by multiplying the integration value by a prescribed coefficient. The judgement of doze at the wheel in running is performed by storing by fetching the RRI values of sixty beats in the memory, finding the integration value by sampling the value over the mean value obtained previously, driving an oscillation circuit 7 when the integration value shows the threshold value larger than the one in the waking, and supplying an alarm signal to an alarm piece 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dozing warning device,
In particular, the present invention relates to a drowsiness warning device that can be used to prevent drowsiness driving in a vehicle.

[0002]

2. Description of the Related Art In recent years, the need for safe driving has increased more and more for each driver as the number of traffic accidents has increased. However, since drowsiness driving is one of the major causes of traffic accidents, it is prevented. Various measures have been taken.

For example, in Japanese Utility Model Application Laid-Open No. 5-39506, the heart rate sensor provided on the arm band detects the heart rate of the driver, and when the heart rate falls below a specified value, the driver's arousal level is increased. A technique has been disclosed in which the driver is warned that he / she has declined to warn the driver.

Generally, when a driver feels drowsiness while driving, the driver intentionally or unconsciously tries to wipe out the drowsiness, such as a lack of stretch, a stretched back, and a sitting (such behavior that occurs with drowsiness). Is called as a secondary action).

Normally, when the person becomes sleepy, the heart rate decreases, but in the case of a driver with many secondary actions, a temporary increase in the heart rate often becomes mixed, and as a result, as shown in FIG. The average value of the heart rate of the above (Fig. (A)) and the average value of the heart rate during dozing driving (Fig. (B)) are almost unchanged.

Therefore, such a driver's drowsiness cannot be detected by merely lowering the heart rate as in the prior art as described above.

Therefore, the applicant of the present application has disclosed, in Japanese Patent Application No. 6-22736, an apparatus for accurately detecting drowsiness and issuing a warning without using the average value of the heart rate. The contents are as follows.

<Contents of Japanese Patent Application No. 6-22736> The heartbeat raw signal has a waveform as shown in the electrocardiogram of FIG. 6, and the highest mountain of this electrocardiogram is called an R wave. The interval with the R wave is called RRI (RR interval). This RRI
The value corresponds to the heartbeat interval (or heart rate) in FIG.

The RRI length is read from the heartbeat interval between the R wave and the R wave given as the output signal of the heartbeat sensor and plotted for each beat to obtain a heartbeat fluctuation waveform as shown in FIG.

In this heartbeat fluctuation waveform, the heart does not always pulsate at a constant interval but constantly fluctuates and fluctuates.

In the graph of FIG. 7, since the RRI length is plotted on the vertical axis, the faster the heartbeat, the lower the RRI value.
It shows that the slower the heartbeat, the higher the RRI.
In addition, when the driver becomes drowsy and the heartbeat becomes slow, the RRI rises and the average value X ₀ at the time of awakening that was previously obtained
More often than not.

Now, in such a heartbeat fluctuation waveform, the average value in the section shown in the figure becomes almost the same as the average value X ₀ at the time of awakening, but the integral showing the state in which drowsiness gradually progresses. The value in the black-painted area appears larger than the value when awakening, so it can be determined as a doze.

In the section, this average value is obviously less than the above-mentioned average value X ₀ and the doze cannot be detected, but the area (integrated value) of the black-painted portion is obtained, and this value is used as a reference. By checking whether the value is equal to or more than the value, it becomes possible to detect the doze.

Therefore, when this drowsiness warning device is worn (that is, when awake), a total RRI value of a predetermined number of heartbeats detected by the heartbeat sensor is calculated, an average value thereof is calculated, and an RRI value exceeding the average value is calculated. The integral value is multiplied by a predetermined value and set as a threshold value.

In this way, the average value and the threshold value of the RRI value are obtained at the time of awakening, and thereafter, for example, when the automobile is driven, a predetermined number of RRI values similar to the above are obtained,
Of these RRI values, the RRI value exceeding the average value obtained above is integrated. That is, the area of the black-painted portion in FIG. 7 is obtained.

When the integrated value exceeds the above threshold value, the warning unit can be activated from the control unit to give a warning to the driver or the like that the driver is dozing.

[0017]

However, in the above-mentioned Japanese Patent Application No. 6-22736, the driver moves his body or sighs while calculating the average value X ₀ at the time of awakening. When an action such as a conversation is taken, the RRI value suddenly decreases, and it becomes impossible to obtain an accurate average value X ₀ , which causes a problem that accurate drowsiness detection cannot be performed.

That is, as shown in the graph of heart rate vs. RRI value shown in FIG.
Since the I value fluctuates greatly (the variance value σ ² is large at this time), the accurate average value X ₀ during awakening cannot be obtained.
On the other hand, in the section, the fluctuation of the RRI value is small (the variance value is small), and the average value X _{0 at} this time is reliable.

Therefore, the present invention is based on the RRI of the heartbeat during awakening.
It is an object of the present invention to provide a device that accurately detects a drowsy state and issues a warning without always ensuring that the average value is correct.

[0020]

In order to achieve the above object, a doze warning device according to the present invention comprises a heartbeat sensor,
A warning generation means and a predetermined multiple of the average value of all RRI values of a predetermined number of heartbeats detected by the sensor when the user is awake and wearing, and a predetermined multiple of the integrated value of the RRI values exceeding the average value are set as threshold values, and then the predetermined values are set. A control unit that integrates RRI values exceeding the average value among the plurality of RRI values and activates the warning generating means when the RRI value exceeds the threshold value, and the control unit determines the average value. The characteristic is that the variance value of the RRI value is also obtained during the calculation, and the average value and the variance value are recalculated when the variance value exceeds a predetermined value.

[0021]

In the present invention, like the above-mentioned Japanese Patent Application No. 6-22736, first, when this drowsiness warning device is worn (that is, when awakened)
R for a specified number of heartbeats detected by the heartbeat sensor
The RI value is calculated and the average value X ₀ thereof is calculated. At the same time, the variance value σ ^{2 of the} RRI value is also calculated.

When the variance value σ ² exceeds a predetermined value, the driver takes actions such as moving the body, sighing, or talking as described above, and as a result, the above average value is obtained. Assuming that X ₀ is a fluctuating and unreliable value (see FIG. 8), the average value X ₀ and the variance value σ ² are calculated again without using the average value X ₀ at this time.

If the variance value σ ² does not exceed the predetermined value, the recalculated average value X ₀ is a reliable value.
Further, an upper limit value obtained by multiplying the average value X ₀ by a predetermined value and the average value X ₀
The integrated value of the RRI value that exceeds is multiplied by a predetermined value, determined as a threshold value, and stored.

Thereafter, for example, when the automobile is driven, a predetermined number of RRI values are obtained in the same manner as described above, and of these RRI values, the RRI value exceeding the above average value X ₀ is integrated.

Then, the RRI value exceeding the average value calculated above is integrated to obtain the area of the black-painted portion in FIG.

When the integrated value exceeds the above threshold value, the warning unit can be activated from the control unit to give a warning to the driver or the like that the driver is dozing.

In this way, since the integration using only the reliable average value X ₀ of the RRI value is performed, an accurate drowsiness alarm can be issued.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an electric circuit configuration of a drowsiness warning device according to the present invention, which is basically the above-mentioned Japanese Patent Application No. 6-22736.
In the figure, 1 is a control unit, 2 is a heartbeat sensor, 3 is a warning piece for giving a slight electric shock as a warning generation means, and 4 is a control unit 1 and a heartbeat sensor 2. A power supply unit for supplying power, 5 is a switch for activating the power supply unit 4, 6 is an arithmetic circuit that receives the output signal of the heartbeat sensor 2 and performs arithmetic operation, and 7 is driven by the output signal of the arithmetic circuit 6. It is a transmission circuit for driving the warning piece 3.

2 and 3 show a state in which the drowsiness warning device according to the present invention shown in FIG. 1 is mounted on the wrist band 10, which is basically the same as the above-mentioned Japanese Patent Application No. 6-. 22736
The control unit 1 is provided on the surface of the arm band 10, but the heart rate sensor 2 and the warning piece 3 are attached to the back side of the arm band 10 as shown in FIG. As shown in (a) and (b), when it is tightly wrapped around the wrist by the surface fasteners 10a provided on both sides of the arm band 10, the heartbeat sensor 2 and the warning piece 3 come into direct contact with the wrist, and the control unit 1 The switch 5 can be operated from the outside of the arm band 10.

FIG. 4 is a flow chart of a program stored and executed in the arithmetic circuit 6 in the control unit 1 shown in FIGS.
1 to 3 with reference to the flow chart of FIG.
The operation of the embodiment shown in FIG.

First, when the arm band 10 is used for drowsy driving prevention, the driver operates the switch 5 in the control unit 1 to turn on the power supply section 4 and start the flowchart shown in FIG. It should be noted that, for example, when the switch 5 is pressed, the power supply unit 4 continues to operate, and when it is pressed again, the power supply unit 4 is restored and the operation of the power supply unit 4 can be released.

In this way, when the power is turned on, that is, at the time of awakening as the initial state, the heartbeat sensor 2 outputs the heartbeat raw signal as shown in FIG. 6 to the arithmetic circuit 6.

The arithmetic circuit 6 takes in a predetermined number, for example, 60 beats of RRI, and stores it in a built-in memory (not shown) (step S1).

Then, the average value X of the RRI for these 60 beats
₀ and the variance value σ ² are obtained (step S2).

This variance value σ ² is a predetermined upper limit value A (for example,
It is determined whether or not it exceeds 5000 msec ² (step S
3). This is to determine whether or not the average value X ₀ calculated at the same time is reliable, and only when σ ² ≦ A, the average value X ₀ is regarded as accurate and the next step S4 is performed. move on.

In step S4, an integral value Y _{0 of} RRI exceeding the average value X ₀ thus obtained is further obtained, and a threshold value K · Y ₀ is obtained by multiplying the integral value Y ₀ by a predetermined coefficient. .

The above-mentioned constant K is, for example, "3", which is any value as long as it is a value that indicates how much it can be judged to be drowsy when judged from awakening. I don't mind.

In this way, the RRI during the initial awakening
The average value X ₀ and the threshold value K · Y ₀ are obtained in advance, and the dozing driving is determined during the traveling thereafter.

That is, first, R for 60 beats is performed in the same manner as above.
The RI value is captured and stored in the memory (step S
5).

Then, of the fetched RRI values, those exceeding the average value X ₀ obtained in step S2 are extracted and the integrated value Y thereof is obtained (step S6).

As a result, the magnitude relation between the integrated value Y during traveling and the threshold value K · Y ₀ at the time of initial awakening is determined (step S7).

That is, when it is determined that the integrated value Y during running or the like is less than or equal to the threshold value K · Y ₀ during awakening, step S5.
However, when it is found that the integrated value Y is larger than the threshold value K · Y ₀ , the arithmetic circuit 6 drives the transmitter circuit 7 as if it is in the dozing driving state (step S8).

Therefore, the transmitting circuit 7 can give a warning signal to the warning piece 3, and the warning piece 3 can give a slight electric shock to the driver. The warning can be given not only by such electric shock but also by sound or vibration.

After such warning is given for a certain period of time (step S9), the process returns to step S5 to repeat the above operation.

Although the alarm piece 3 is attached to the wrist band 10 in the above embodiment, it may be provided on the outside, for example, on a dashboard or the like so as to receive all signals by radio waves. Good.

[0046]

As described above, according to the doze warning device according to the present invention, the average value and the variance value of the RRI values of the predetermined number of heartbeats at the time of awakening and the average value when the variance value is equal to or less than the predetermined value. A threshold value of a predetermined multiple of the integrated value of the RRI value that exceeds the above is obtained in advance, and then those of the RRI values obtained in the same manner that exceed the above average value are obtained by integration, and this integrated value exceeds the above threshold value. Since it is configured to generate a warning that drowsiness occurs when the driver is asleep, the RRI value during drowsiness and driving may suddenly decrease due to the movement of the driver's body (see Fig. 8), or sudden movement of the vehicle. For example, even if noise is mixed in the heartbeat signal and the R wave is erroneously detected and the RRI value becomes abnormally large or small, the average value of that portion can be canceled and only the accurate average value can be used. Exactly dozing It is possible to detect the rotation. Also,
Since the calibration for obtaining the average value of each individual is performed at the time of awakening, it becomes possible to accurately detect the drowsiness corresponding to the individual difference.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electric circuit configuration of a dozing warning device according to the present invention and Japanese Patent Application No. 6-22736.

FIG. 2 is an external view when the drowsiness warning device according to the present invention and Japanese Patent Application No. 6-22736 is provided on an arm band.

FIG. 3 is a diagram when the doze warning device according to the present invention and Japanese Patent Application No. 6-22736 is attached to a wrist when an arm band is provided.

FIG. 4 is a flow chart diagram of a program stored and executed in a control unit used in the doze warning device according to the present invention.

FIG. 5 is a waveform diagram showing changes with time in heart rate during awakening and during drowsy driving.

FIG. 6 is an electrocardiographic waveform diagram showing a heartbeat raw signal obtained by a heartbeat sensor.

FIG. 7 is a diagram showing an RRI heartbeat fluctuation waveform obtained by a heartbeat sensor.

FIG. 8 is a waveform chart showing a relationship between an average value and a variance value of RRI values.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 control unit 2 heartbeat sensor 3 warning piece 4 power supply section 5 power supply switch 6 arithmetic circuit 7 transmission circuit 10 arm band In the figure, the same reference numerals indicate the same or corresponding parts.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location A61M 21/00 B60K 28/06 A A61M 21/00 330 B

Claims (1)

[Claims] 1. A heartbeat sensor, a warning generating means, an average value of all RRI values of a predetermined number of heartbeats detected by the sensor when awakened, and an RRI exceeding the average value.
A predetermined multiple of the integrated value of the values is calculated as a threshold value, and the RRI value exceeding the average value is integrated among the predetermined number of RRI values thereafter, and the warning generating means is added when the RRI value exceeds the threshold value. In a drowsiness warning device having a control unit for energizing, the control unit also obtains a variance value of the RRI value when calculating the average value, and when the variance value exceeds a predetermined value, the average value is calculated. And a drowsiness warning device characterized by recalculating the variance value.