JPH07313477A - Nap warning device - Google Patents

Abstract

PURPOSE:To accurately detect a nap without using an RRI value with which a noise component, etc., is mixed and generate an alarm by setting a value which is a specific multiple of a mean value as an upper-limit value, and substituting the mean value for an RRI value which exceeds the mean value or upper- limit value and integrating it. CONSTITUTION:At awakening time as an initial state, a heartbeat sensor 2 outputs a heartbeat signal to an arithmetic circuit 6, which inputs a specific number of RRIs and stores them in its internal memory. The mean value of the RRIs is found and a specific multiple of the mean value is set as the upper- limit value of the RRIs. To decide nap driving, a specific number of RRI values are inputted and stored in the memory, RRI values exceeding the upper-limit value among the inputted RRI values are canceled, and the mean value is inputted instead of the RRI values. Then the values exceeding the mean value are integrated and when the integral value exceeds a threshold value, an oscillation circuit 7 is driven to supply an alarm signal to an alarm piece 3, giving the driver a light electric shock.

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 regular intervals, 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, when noise is mixed in the heartbeat signal, the erroneous R wave is detected and the RRI value becomes abnormally large, for example, 1800 msec (see FIG. 8). .

There is a problem that the integral value becomes large in such a portion, and the above drowsiness alarm is erroneously issued even when the driver is awake.

Therefore, it is an object of the present invention to provide a device for accurately detecting a drowsiness and issuing a warning without using an RRI value mixed with a noise component or the like.

[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 that exceed the average value are set as threshold values, and then predetermined And a control unit for activating the warning generating means when the RRI value exceeding the average value out of several RRI values exceeds the threshold value, and the control unit controls the A predetermined multiple value is set as the upper limit value, and the average value and the RRI value exceeding the upper limit value are replaced with the average value and integrated.

[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, the average value thereof is calculated, and the upper limit value obtained by multiplying the average value by a predetermined value and the integrated value of the RRI value exceeding the average value are multiplied by a predetermined value and determined and stored as a threshold value.

Thereafter, for example, when the automobile is driven, a predetermined number of RRI values are obtained in the same manner as described above. Among these RRI values, the RRI values exceeding the above average value and further exceeding the upper limit value are also obtained. As for the above, noise is mixed in and replaced with the above average value without using as it is.

Then, the area of the black-painted portion in FIG. 7 is obtained by integrating the RRI value exceeding the above-obtained average value.

When the integrated value exceeds the above threshold value, the warning unit can be activated by the control unit to give a warning to the driver or the like about the dozing driving.

In this way, since noise and the like in the RRI value are removed and integration is performed, an accurate drowsiness alarm can be issued even if the heartbeat signal is disturbed by noise and the like.

[0026]

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.

FIGS. 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 also 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 is obtained (step S2).

The average value X ₀ thus obtained
A predetermined value, for example 1.5 times, X _m = X ₀ × 1.5
The upper limit of the RI value is set (step S3).

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

The above-mentioned constant K is, for example, "3", which is a value that indicates by experiment or the like how much it can be judged from the time of awakening to determine that it is drowsy. It doesn't matter.

In this way, RRI at the time of initial awakening
The average value X ₀ and the threshold value K · Y ₀ are obtained and used for the determination of the dozing driving during the traveling thereafter.

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

Then, the RRI value of the 60 beats taken in is
Among them, the upper limit value X obtained in step S3 _mBeyond
The average value instead of canceling the RRI value
X₀Is input as the RRI value (step S6).

For example, when the average value X ₀ = 884.2 msec, X
_m = 1326.3 msec, and as shown in the following Table 1, step S6
Is processed.

[0040]

[Table 1]

As can be seen from Table 1, any RRI value exceeding the above upper limit value X _m = 1326.3 msec is the average value X _0.
= Forcibly replaced by 884.2msec.

Then, the RR subjected to the process of step S6
Of the I values, those exceeding the average value X ₀ obtained in step S2 are extracted, and the integrated value Y of the exceeded portion (the area of the black-painted portion in FIG. 7) is obtained (step S7).

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 S8).

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 S9).

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.

After such warning is given for a certain period of time (step S10), 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 is provided on the outside, for example, on a dashboard or the like, and refresh air is sent out by transmitting and receiving signals by radio waves. You may

[0048]

As described above, according to the drowsiness warning device of the present invention, the average value of the RRI values of a predetermined number of heartbeats at the time of awakening, the upper limit value of a predetermined multiple of this average value, and the average value are exceeded. A threshold value that is a predetermined multiple of the integrated value of the RRI value is obtained, and then, of the RRI values obtained in the same manner, those that exceed the upper limit value are replaced with the average value, and those that exceed the above average value are obtained by integration. Since the warning is generated when this integrated value exceeds the above threshold value as if a drowsiness is occurring, the heartbeat signal is applied even to a driver whose average RRI value during drowsiness is the same as when awake. It is possible to accurately detect the dozing driving in a form in which the abnormal RRI value due to the noise mixed in is excluded. Further, 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 heart rate variability waveform diagram for explaining the problems of the conventional example.

[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.

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 is calculated as a threshold value and stored.
Of the predetermined number of RRI values thereafter, the RR exceeding the average value
In a drowsiness warning device provided with a control unit for integrating the I value and energizing the warning generation means when the value exceeds the threshold, the control unit sets a value of a predetermined multiple of the average value as an upper limit value. A drowsiness warning device characterized in that an RRI value which has been set and exceeds the average value and the upper limit value is replaced with the average value and integrated.