JPH11321375A - Device for judging vehicular drive while dozing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for judging drive while dozing, which properly determines a drive while dozing based on a reference value by deciding the reference value as a criterion for the presence or the absence of dozing when a driver is awake. SOLUTION: After a device for judging drive while dozing is started to work, a driver is wakened up by an alarm 30 to detect his heartbeat interval signal by a heartbeat sensor 10 before a microcomputer 20 determines whether or not he drives the car while dozing, and a reference value as a criterion for the presence or the absence of dozing is thereby decided by the microcomputer 20 based on the heartbeat interval signal. Thus as mentioned above, the reference value is turned out to be an accurate criterion because the reference value is computed based on the heartbeat interval of the driver, who is awakened by the alarm 30 right after a drive preventive device for dozing is started to work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drowsiness driving judging device suitable for use in a drowsiness prevention device for a vehicle.

[0002]

2. Description of the Related Art Conventionally, in order to prevent a driver from falling asleep during driving of an automobile, there is an apparatus that determines the presence or absence of a driver falling asleep using a biological state such as a heartbeat of the driver. In this apparatus, the driver's biological condition is detected during driving of the vehicle, and the biological condition is compared with a reference value as a determination criterion to determine whether the driver has fallen asleep.

[0003]

However, in the above-described device for determining a drowsy driving, the biological condition of the driver is affected by its physical condition, and therefore, the biological condition detected from the driver when the driver is drowsy. Even if the reference value is determined on the basis of the above, an accurate reference value cannot be obtained. Therefore,
If such a reference value is used, there is a problem that a drowsy driving cannot be correctly determined.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-178115, the behavioral state of an automobile is used instead of the above-mentioned biological state, and immediately after the automobile starts running.
There is a drowsy driving judging device for a vehicle which regards the driver's awake state for 5 minutes, detects the behavior state of the vehicle within 5 minutes immediately after the vehicle starts running, and determines the reference value based on the behavior state.

However, since the driver is not always in the awake state immediately after the start of driving of the automobile, the correct reference value is not always obtained. Regarding this problem, when the driver fell asleep by simulation and examined the heartbeat interval and the heartbeat intensity of the driver, the graph shown in FIG. 3 was obtained. This heartbeat intensity is obtained by frequency analysis of the driver's heartbeat interval.

This graph shows changes in the heartbeat interval and the heartbeat intensity both when the driver is drowsy and when the driver is not drowsy. A symbol A is a graph showing a heartbeat interval, a symbol B is a graph showing a heartbeat intensity, and a symbol C is a reference value for judging the presence or absence of dozing driving based on the heartbeat intensity. This reference value is a value obtained by multiplying the average value of the driver's heartbeat intensity for 10 minutes after the start of driving of the automobile by a constant 2.

[0007] According to these, when the driver is drowsy, the variation in the heartbeat interval is larger and the heartbeat intensity is larger than when the driver is not drowsy. Therefore, when the driver is not drowsy, if the heartbeat interval is detected from the driver and the above-mentioned reference value is determined according to the heartbeat intensity based on the data, the driver will be drowsy In addition, the heartbeat intensity indicated by reference numeral B is larger than the reference value indicated by reference numeral C (see reference numeral T in FIG. 3). For this reason, it can be understood that the drowsiness driving is correctly determined by determining the presence or absence of the drowsiness driving using such a reference value.

Therefore, the present invention has been made in view of the above problem, and a reference value which is a criterion for judging the presence or absence of dozing driving is determined when the driver is awake, and the presence or absence of dozing driving is correctly determined using the reference value. It is an object of the present invention to provide a vehicle dozing driving determining device for determining.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a biological condition detecting means (10) for detecting a biological condition of a driver of a vehicle, and the biological condition detecting means. Determining a presence or absence of a drowsiness driving based on a comparison between the detected biological condition and a reference value (10)
7) a drowsy driving determination device for a vehicle, comprising: an awakening means (30) for awakening the driver prior to the start of the determination by the determination means; And a determining means (103) for determining a reference value based on the awake biological state of the driver who has been awake.

As described above, the reference value is determined based on the biological condition of the driver awakened by the awakening means prior to the start of the determination by the determination means. Become. Therefore, if such a reference value is used, the presence or absence of the drowsy driving can be correctly determined.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a drowsy driving prevention device for a vehicle to which the present invention is applied. The drowsy driving prevention device includes a heart rate sensor 10, a microcomputer 20, and an alarm device 30. Heart rate sensor 10
Detects the driver's heartbeat interval and outputs a heartbeat interval signal to the microcomputer 20.

The microcomputer 20 executes a computer program according to a flowchart shown in FIG. During execution of the computer program, the microcomputer 20 determines whether or not the driver has fallen asleep in accordance with the heartbeat interval signal from the heartbeat sensor 10.
The alarm device 30 is controlled by the microcomputer 20 to issue an alarm to the driver.

The operation of the embodiment constructed as described above will be described. When the ignition switch is turned on, the microcomputer 20 starts executing the computer program according to the flowchart shown in FIG.
In step 100, an alarm process of the alarm device 30 is performed. As a result, the alarm device 30 is connected to the microcomputer 2
Controlled by 0 to give an alarm. Thereby, the driver is awakened.

Next, in step 101, the heart rate sensor 1
Sampling is performed based on the heartbeat interval signal from zero. Then, in step 102, frequency analysis is performed based on the sampling data obtained by the sampling,
The heartbeat intensity of the driver is calculated based on the frequency analysis.

Then, in step 103, data obtained by multiplying the average value of the driver's heart rate intensities for 5 minutes by a constant 2 is calculated as a reference value which is a criterion for judging the presence or absence of the drowsy driving. Then, at step 104, the reference value is stored in the RAM of the microcomputer 20. Next, in step 105, sampling is performed based on the heartbeat interval signal from the heartbeat sensor 10.

Then, in step 106, step 1
The frequency analysis is performed based on the sampling data obtained by the sampling in step 05, and the heart rate of the driver is calculated based on the frequency analysis. Thus, in step 107, it is determined whether or not the heartbeat intensity is larger than the reference value. Here, if the heartbeat intensity is larger than the reference value, it is determined to be YES and step 10
At 8, an alarm process of the alarm device 30 is performed. as a result,
The alarm device 30 is controlled by the microcomputer 20 to issue an alarm. As a result, the driver will be awake.

As described above, in the drowsy driving prevention device, the alarm device 30 wakes up the driver immediately after the start of its operation, and in the awakening state of the driver, the heart rate sensor 1
0 detects a heartbeat interval signal prior to the start of the determination of the presence of the dozing operation, and a reference value as a criterion for determining the presence of the dozing operation is calculated based on the heartbeat interval signal. in this way,
Since the reference value is calculated based on the heartbeat interval of the driver who awakened the driver by the alarm device 30 immediately after the start of the operation of the dozing driving prevention device, this reference value is an accurate determination reference. Therefore, if such a reference value is used, the presence or absence of the drowsy driving can be correctly determined.

In step 107, if the heartbeat intensity is smaller than the reference value, step 105
Is performed with NO. In practicing the present invention, the alarm device 30 of the above embodiment may be any device that stimulates the human senses, such as cold air, vibration, and irritating odor. Further, in the above-described embodiment, an example is described in which the heart rate sensor 10 is employed as means for detecting the heartbeat interval of the driver. However, the present invention is not limited to this, and an electrocardiograph may be employed.

In implementing the present invention, data obtained by multiplying the average value of the driver's heart rate intensity for five minutes by a constant 2 is adopted as the reference value in the above embodiment, but the present invention is not limited to this.
The above constant 2 may be appropriately changed so as to correspond to the individual difference of the heartbeat intensity. In addition, data obtained by multiplying the average value of both the maximum value and the minimum value of the heartbeat intensity by a predetermined constant may be employed instead of the average value of the heartbeat intensity as the reference value. Further, instead of the average value of the heartbeat intensity, data obtained by calculating the variance of the heartbeat intensity for a predetermined number of nights may be employed as the reference value.

In the above embodiment, as described above,
Although the example in which the processing of steps 105 to 107 is performed once has been described, the present invention is not limited to this.
The processing of steps 5 to 107 may be repeated. This can prevent an erroneous determination due to disturbance in the determination of the presence or absence of the drowsy driving. Further, in the above-described embodiment, an example is described in which the heartbeat interval is used as the biological state of the driver. However, the present invention is not limited to this, and skin temperature, skin potential, brain waves, or the like may be used.

In the above-described embodiment, the example in which the drowsiness prevention device starts its operation at the start of the operation of the automobile has been described. However, the present invention is not limited to this, and a switch for starting the operation of the drowsiness prevention device is provided. Then, the drowsy driving prevention device may start its operation based on the operation of the switch. Further, the drowsy driving prevention device may start its operation based on signals from various devices in the vehicle.

In implementing the present invention, each step in the flow chart of the above embodiment is
The function executing means may be executed by a hardware logic configuration. Further, in the above-described embodiment, the example in which the dozing driving prevention device is applied to an automobile has been described. However, the invention is not limited thereto, and may be applied to various vehicles.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the microcomputer of FIG.

FIG. 3 is a graph showing a heartbeat interval and a heartbeat intensity of the driver both when the driver is drowsy and when the driver is not drowsy.

[Explanation of symbols]

10 heart rate sensor, 20 microcomputer, 30
... alarm device.

Claims (1)

[Claims] A biological condition detecting means for detecting a biological condition of a driver of the vehicle; and determining whether or not to fall asleep based on a comparison between the biological condition detected by the biological condition detecting device and a reference value. Means (1
07), wherein the awakening means (30) for awakening the driver prior to the start of the determination by the determining means, and the biological state detecting means comprising: Deciding means (103) for determining the reference value based on the awakened biological condition of the driver who has been awakened by the awakening means, when detecting the awakened biological condition of the driver. .