JP3271451B2 - Dozing warning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, with the increasing number of traffic accidents, each driver has been increasingly required to drive safely. Various measures have been taken.

For example, in Japanese Utility Model Laid-Open No. 5-39506, the heart rate of a driver is detected by a heart rate sensor provided on an arm band, and when the heart rate falls below a specified value, the driver's awakening degree is reduced. There is disclosed a technique of judging that it is decreasing and giving a warning to a driver to call attention.

[0004] In general, when drowsiness occurs during driving, the driver consciously or unconsciously tries to wipe out drowsiness, such as elongating or stretching his back or sitting down again (an action that accompanies such drowsiness). Are called secondary actions).

[0005] Normally, the heart rate decreases when the user falls asleep, but in the case of a driver with many secondary actions, a temporary increase in the heart rate often mixes, and as a result, as shown in FIG. The average value of the heart rate ((a) in the figure) and the average value of the heart rate during the drowsy driving ((b) in the figure) hardly change.

Accordingly, such a driver's falling asleep cannot be detected merely by lowering the heart rate as in the above-described prior art.

The applicant of the present invention has disclosed in Japanese Patent Application No. 6-22736 a device aimed at accurately detecting dozing without using an average value of heart rate and generating a warning. The contents are as follows.

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

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

[0010] In this heartbeat fluctuation waveform, the heart does not always beat at regular intervals but constantly fluctuates and fluctuates.

In the graph of FIG. 7, since the length of the RRI is set on the vertical axis, the value of the RRI decreases as the heart rate increases,
This indicates that a slower heart rate results in a higher RRI.
Also, when the driver becomes drowsy and the heart rate slows down, the RRI rises and the average value X ₀ at the time of awakening determined in advance.
Values are often higher than

In such a heart rate variability waveform, the average value in the illustrated section is almost the same as the average value X ₀ at the time of awakening, but the integral value indicating a state in which dozing gradually progresses. Since the value of the portion painted black is larger than the value at the time of awakening, the value appears to be dozing.

In the section, this average value is clearly less than the average value X ₀ and no drowsiness can be detected. However, the area (integral value) of the black portion is determined, and this value is used as a reference. If it is checked whether the value is equal to or more than the value, the dozing detection can be performed.

Therefore, when the dozing warning device is worn (ie, when the user is awake), all RRI values for a predetermined number of beats or a predetermined time detected by the heart rate sensor are obtained, and the average value thereof is calculated and exceeds the average value. The threshold value is determined by multiplying the integral value of the RRI value by a predetermined value. The “beat rate” refers to the number of one beat composed of adjacent heartbeats,
Is different from the equivalent heart rate.

As described above, the average value of the RRI value and the threshold value are determined at the time of awakening, and thereafter, for example, when the vehicle is driven, the RRI value for a predetermined number of beats or for a predetermined time is calculated. Among these RRI values, RRI values exceeding the average value determined as described above are integrated. That is,
The area of the black portion in FIG. 7 is obtained.

When the integrated value exceeds the above-mentioned threshold value, a warning can be given to a driver or the like by driving a warning generating means from the control unit.

[0017]

The heartbeat generally fluctuates when drowsiness begins, but this fluctuation varies from individual to individual, and the manner and variance of the fluctuation changes over time. There is such a problem.

For example, in the case of the driver shown in FIG. 8, when the driver falls asleep as the number of beats (elapse of time) shown on the horizontal axis in FIG. 8, the auxiliary line (waveform center line) shown in FIG. ) Indicates that the RRI value (vertical axis) is large.

The auxiliary line indicates the outline of the RRI waveform, and the auxiliary line indicates the RRI value obtained first.
This applies to FIGS. 9 and 10 described below.

Such variation in RRI can be understood more clearly by taking the variance (vertical axis) of the RRI value as shown in FIG.

That is, since this variance can be equivalently considered to be the above-mentioned integral value, the alarm continues to sound from the point where the number of beats is around the point U, and in some cases, the alarm sounds even though the user is not sleepy.

In the case of the driver shown in FIG. 9,
As can be seen from the auxiliary line in FIG. 3A, the RRI value decreases as the user shifts to the dozing state.

In the variance of the RRI value shown in FIG. 3B, the beat rate sharply decreases from the vicinity of the point V, and the alarm does not sound from this side even though the patient is drowsy.

On the other hand, in the case of the driver shown in FIG. 10, the RRI value hardly changes even when the driver enters the dozing state as indicated by the auxiliary line in FIG. 10A, and the RRI value shown in FIG. The variance changes randomly, and an alarm sounds in response to drowsiness.

Accordingly, it is an object of the present invention to provide a device that accurately detects a dozing state and generates a warning regardless of a dozing characteristic of a subject such as a driver.

[0026]

In order to achieve the above object, a dozing warning apparatus according to the present invention comprises a heart rate sensor,
A warning generating means, and a threshold value is calculated as a threshold value of an average value of all RRI values for a predetermined number of beats or a predetermined time detected by the sensor at the time of wearing awake and a predetermined multiple of an integral value of an RRI value exceeding the average value. A control unit for integrating the RRI value exceeding the average value among the RRI values for a predetermined number of beats or a predetermined time thereafter, and activating the warning generating means when the integrated value exceeds the threshold value. The control unit obtains a new average value of RRI values for a certain number of beats or for a certain time when the integrated value does not exceed the threshold value,
When the new average value is larger than the old average value by a certain value or more, an integral value of the RRI value exceeding the new average value is obtained, and a predetermined multiple thereof is updated as a new threshold value.

After updating to the new threshold value, the control unit takes in the RRI values for a predetermined number of beats or for a predetermined time, obtains an integrated value of the RRI value exceeding the new average value, and obtains the integrated value. The warning generating means can be activated when the new threshold value is exceeded.

[0028]

According to the present invention, similarly to the above-mentioned Japanese Patent Application No. Hei 6-22736, first, when the doze warning device is mounted (ie, at the time of awakening), the control unit operates for a predetermined number of beats detected by the heart rate sensor. The total RRI value for a predetermined time is obtained and the average value is obtained.

Then, the integral value of the RRI value exceeding the average value is multiplied by a predetermined value, determined as a threshold value, and stored.

Thereafter, even when the vehicle is driven, for example, the RRI for a predetermined number of beats or for a predetermined time is performed in the same manner as described above.
A value is obtained, and among these RRI values, RRI values exceeding the above average value are integrated.

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

Further, it is determined whether or not the above-mentioned integral value exceeds the above-mentioned threshold value, and a warning of drowsy driving can be given to a driver or the like by activating the warning generating means only when the integral value> the threshold value. .

On the other hand, when the integration value ≦ the threshold value, the RRI value for a certain number of beats (this does not have to be the same as the above-mentioned predetermined number of beats or a predetermined time) or a certain time is obtained. An average value, that is, a new average value is obtained.

When the new average is larger than the old average by a certain value or more, the RRI exceeding the new average is calculated.
The integrated value is determined, and the integrated value is multiplied by a predetermined value as described above to update the threshold value, that is, the new threshold value.

After that, of the newly obtained RRI values for the predetermined number of beats or for a predetermined time, an integrated value of the RRI value exceeding the new average value is obtained. Energize.

Therefore, even if the above threshold value is not exceeded,
When it is found that the new average value is larger than the old average value by a certain value or more, the threshold value is re-randomly determined, and the above-mentioned warning is given at any time based on the updated threshold value.

As described above, according to the present invention, erroneous detection due to the integral value being too large or too small can be detected and improved as needed.

[0038]

FIG. 1 shows an electric circuit configuration of a drowsiness warning apparatus according to the present invention.
In the figure, 1 is a control unit, 2 is a heart rate sensor, 3 is a warning piece that gives a slight electric shock as a warning generation means, and 4 is a control unit 1 and a heart rate sensor 2. A power supply section for supplying power, 5 is a switch for activating the power supply section 4, 6 is an arithmetic circuit that performs an operation by receiving an output signal of the heart rate sensor 2, and 7 is driven by an output signal of the arithmetic circuit 6. This is a transmission circuit for driving the warning piece 3.

FIGS. 2 and 3 show a state in which the dozing warning device according to the present invention shown in FIG. 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 (a) and (b), when the wrist is firmly wound by the hook-and-loop fasteners 10a provided on both sides of the arm band 10, the heart rate sensor 2 and the warning strip 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 shows a flowchart 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 flowchart of FIG.
The operation of the embodiment shown in FIG.

First, when the arm band 10 is used to prevent drowsy driving, the driver turns on the power supply unit 4 by operating the switch 5 in the control unit 1 and starts the flowchart shown in FIG. When the switch 5 is pressed, for example, the power supply unit 4 continues to operate. When the switch 5 is pressed again, the switch 5 is restored to its original state and the operation of the power supply unit 4 can be canceled.

As described above, when the power is turned on, that is, at the time of awakening as an initial state, the heartbeat sensor 2 outputs a heartbeat raw signal as shown in FIG. 6 to the arithmetic circuit 6 of the control unit 1.

The arithmetic circuit 6 has a predetermined number, for example, 60 beats (6 beats).
The RRI for 0 beat) is fetched and stored in a built-in memory (not shown) (step S1).

Then, the average value X of the RRI for the 60 beats
₀ is obtained (step S2).

Then, the average value X obtained in this manner is further obtained.
Obtains the integral value Y ₀ of RRI beyond the ₀ and determine the threshold K · Y ₀ obtained by multiplying a predetermined coefficient to the integrated value Y ₀ (step S3).

The above constant K is, for example, “3”, which is a value that indicates how long it can be determined to fall asleep when it is determined from awakening. No problem.

In this way, the RRI during the initial awakening
The average value X ₀ and the threshold values K · Y ₀ are obtained in advance, and the actual drowsy driving at the time of subsequent traveling or the like is determined.

That is, first, in the same manner as above, R for 60 beats
The RI value is fetched and stored in the memory (step S
4).

Then, of the obtained RRI values,
Average value X obtained in step S2 ₀Extract the ones that exceed
The integration value Y is determined (step S5).

Thereafter, the magnitude relationship between the integral value Y at the time of running or the like and the threshold value K · Y ₀ at the time of initial awakening is determined (step S6).

That is, when it is found that the integrated value Y at the time of running or the like is equal to or less than the threshold value K · Y ₀ at the time of awakening, step S
8, when it is determined that the integrated value Y is larger than the threshold value K · Y ₀ , it is determined that the vehicle is in a drowsy driving state and the arithmetic circuit 6
Drives the transmission circuit 7 for a predetermined time (step S7).

Therefore, the transmission 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 for a certain time.

Then, returning to step S4, the above operation is repeated.

On the other hand, in step S6, Y ≦ KY
When found to be _0, as well as further obtains the RRI value as a constant beat several minutes, for example, 300 beats a few minutes or a certain time, the average value of the RRI values, i.e. determining the new average value X ₁ (step S8).

Then, the new average value X ₁ is equal to the old average value X _0.
Fixed value than, for example, greater it is judged whether or not the above 50 msec (step S9), and if X ₁ ≦ X ₀ + 50msec,
Returning to step S4, if it is found that X ₁ > X ₀ +50 msec, the RR exceeding the new average value X ₁
With obtaining the integral value Y ₁ of the I value, the threshold value of this integral value Y ₁ by a predetermined times as described above, i.e., the new threshold K · Y ₁
(Step S10).

Thereafter, the process returns to step S4, and again
Captures the RRI value of beats, still among the loaded RRI value in step S5, and extracts the exceeding new average value X ₁ calculated in step S8 in the the integrated value Y
Ask for.

[0057] Then, determine the magnitude relationship between the new threshold K · Y ₁ updated in the integral value Y a step S10 (step S
6) Only when Y> K · Y ₀ , the warning generating means is activated.

In the above embodiment, the alarm piece 3 is attached to the wristband 10, but it may be provided on an external device such as a dashboard to receive all signals by radio waves. Good.

[0059]

As described above, according to the dozing warning apparatus of the present invention, when awakened, the threshold value that is a predetermined multiple of the integrated value of the RRI value exceeding the average value of the RRI value for a predetermined number of beats or for a predetermined time is set. RR for a predetermined number of beats or for a predetermined time thereafter
Among the I values, the RRI value exceeding the average value is integrated, and the warning generating means is activated when the integrated value exceeds the threshold value. Alternatively, a new average value of the RRI values for a certain period of time is obtained, and when the new average value is larger than the old average value by a certain value or more, an integrated value of the RRI values exceeding the new average value is obtained, and a predetermined multiple thereof is updated as a new threshold value. Thus, the effects shown in FIGS. 11 to 14 can be obtained.

That is, FIG. 11 (a) corresponds to the RRI waveform of the driver shown in FIG. 8, and the RRI value increases as the number of beats elapses. As shown in FIG. 7B, the threshold value of the fluctuation waveform is updated when the number of beats is point A and point B (each about 20 points).
As a result, the average value is “809.0 ms” from the start of measurement to the update time point A in FIG.
c) is the same as FIG. 9A, but after updating at point A and point B, the average values are “875.9 msec” and “926.4 ms,” respectively.
It can be seen that the RRI value exceeding this average value has decreased from FIG. "Average value"
Indicates an average value for 300 beats (step S8) after the start of measurement.

FIGS. 12A and 12B show RRI values in FIGS. 11A and 11B, respectively, and FIG.
As in the case of (b), the integration value Y (step S in FIG. 4) is equivalently obtained.
It is represented by the variance corresponding to 5), and before correction (a)
Gradually increases in accordance with FIG. 11 (a),
After the correction (b), the average value is randomly updated at the points A and B, so that it can be seen that the variance is reduced from this point. Therefore, the number of cases where a warning is generated without exceeding the threshold value is reduced.

FIG. 13 (a) corresponds to the RRI waveform of the driver shown in FIG. 9, and the RRI value decreases with the lapse of the heartbeat, but the corrected RRI fluctuation when applied to the present invention. As shown in FIG. 7B, when the number of beats is at points C and D, the threshold is updated (about 15
Minute and 45 minutes later), the average value “897.6 ms” from the start of measurement to the update time point B in FIG.
“c” is the same as FIG. 9A, but after the update at point C, the average value drops to “822.3 msec”, and after the update at point D, the average value drops to “807.8 msec”. The RRI value exceeding this average value is smaller than that shown in FIG. 11A, so that the number of cases in which a warning is generated is reduced.

FIGS. 14A and 14B show the variance of the RRI values in FIGS. 13A and 13B, respectively. The variance is larger at each of the points C and D, so that the number of cases where a warning is generated without exceeding the threshold too much increases.

[Brief description of the 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 a doze warning device according to the present invention and Japanese Patent Application No. 6-22736 is provided on an arm band.

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

FIG. 4 is a flowchart of a program stored and executed in a control unit used in the drowsiness warning device according to the present invention.

FIG. 5 is a waveform diagram showing a time change of a heart rate at the time of awakening and at the time of drowsy driving, respectively.

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

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

FIG. 8 is a graph showing an RRI heart rate variability waveform and a moving integral value of a certain driver measured by a dozing warning device according to Japanese Patent Application No. 6-22736.

FIG. 9 is a graph showing an RRI heart rate variability waveform and a moving integral value of another driver measured by the dozing warning device according to Japanese Patent Application No. 6-22736.

FIG. 10 is a graph showing an RRI heart rate variability waveform and a moving integral value of still another driver measured by a dozing warning device according to Japanese Patent Application No. 6-22736.

FIG. 11 is a graph showing the RRI heart rate variability waveform of the driver in FIG. 8 measured by the dozing warning device according to the present invention.

FIG. 12 is a graph showing the movement integral value of the driver in FIG. 8 measured by the dozing warning device according to the present invention.

FIG. 13 is a graph showing the RRI heart rate variability waveform of the driver in FIG. 9 measured by the dozing warning device according to the present invention.

FIG. 14 is a graph showing the integrated movement value of the driver in FIG. 9 measured by the drowsiness warning device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control unit 2 Heart rate sensor 3 Warning piece 4 Power supply unit 5 Power switch 6 Arithmetic circuit 7 Oscillation circuit 10 Arm band

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 5/00-5/03

Claims (2)

(57) [Claims] 1. A heart rate sensor, a warning generating means, and an average value of all RRI values for a predetermined number of beats or a predetermined time detected by the sensor when the sensor is woken up and an integrated value of RRI values exceeding the average value. A predetermined multiple is calculated as a threshold value, and of the RRI values for a predetermined number of beats or a predetermined time thereafter,
A drowsiness warning device, comprising: a control unit that integrates an RRI value exceeding the average value and activates the warning generation means when the integrated value exceeds the threshold value. When the threshold value does not exceed the threshold value, a new average value of the RRI value for a certain number of beats or for a predetermined time is obtained, and when the new average value is larger than the old average value by a certain value or more, the integrated value of the RRI value exceeding the new average value is calculated. A dozing warning device characterized by updating the predetermined threshold value as a new threshold value. 2. The control unit, after updating to the new threshold value, fetches an RRI value for a predetermined number of beats or for a predetermined time, obtains an integrated value of an RRI value exceeding the new average value, and calculates the integrated value. The drowsiness warning device according to claim 1, wherein the warning generation means is activated when the new threshold value is exceeded.