JPH05155269A - Asleep driving detecting device - Google Patents

Abstract

PURPOSE:To detect asleep driving at real time without distinction of drivers in an asleep driving detecting device to detect driving while dozing based on the steering angle and cross directional deviation of a vehicle. CONSTITUTION:The steering angle data detected by a steering angle sensor 10 are processed at an FFT signal processing section 12 to calculate a frequency vector detecting driver's characteristic frequency. Characteristic frequencies are detected by frequencies appearing often during normal driving. Frequencies lower than the characteristic frequency by 0.1Hz to 0.2Hz are abstracted by a filter 14, and when the frequencies become not less than a specified threshold level, it is judged that driver is dozing at the wheel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drowsy driving detection device, and more particularly to a device for detecting a drowsy driving by using a change in a vehicle motion amount such as a steering angle.

[0002]

2. Description of the Related Art Conventionally, a drowsy driving detection device for detecting a drowsy state of a driver has been developed in order to ensure safety in driving on a highway.

In such a drowsy driving detection device, a configuration is adopted in which the steering angle of a normal vehicle is monitored and a decrease in the driver's consciousness, that is, a drowsiness is determined from the change in the steering angle.

For example, in the drowsy driving detection device disclosed in Japanese Patent Laid-Open No. 60-76424, it is detected that the steering wheel has rotated by a certain angle, and the rotation signals are integrated to reach a predetermined value. When it is detected that the vehicle is a dozing drive, an alarm is generated.

Further, in the vehicle alarm device disclosed in Japanese Patent Laid-Open No. 60-157927, when the monitoring value obtained from the high frequency component from the steering angle detector exceeds a reference value within a predetermined monitoring period. It is determined that a drowsiness driving has occurred and an alarm is given.

[0006]

However, in a configuration in which it is detected that the steering wheel has turned by a certain angle and the turning signals are integrated to determine whether or not the vehicle has fallen asleep, a driver on a curved track is required. There is a possibility that the driver may be determined to fall asleep even when the normal steering operation is performed, and thus there is a problem that the vehicle basically only operates effectively on a straight track.

Further, the turning angle of the steering wheel is often dependent on the individual difference of the driver, and there is a tendency that some drivers tend to take a large steering wheel even during normal driving, so that it can be applied to all drivers. There was a problem of lack of sex.

Further, even in the configuration in which it is determined that the drowsiness driving has occurred when the monitoring value obtained from the high frequency component from the steering angle detector exceeds the reference value within the predetermined monitoring period, the drowsiness driving of the driver can be performed. Depending on the mode, the high frequency component does not always increase as compared with that during normal operation, and thus it is difficult to reliably detect the occurrence of drowsiness with the high frequency component.

In view of such circumstances, the applicant of the present application previously extracted a low-frequency component of a vehicle operation amount such as a steering angle and a lateral displacement amount in Japanese Patent Application No. 3-222967, and used this as a sample during normal operation. We have proposed a doze driving detection device that determines that the vehicle is a dozing driving when it increases more than a predetermined value.

However, when performing a fast Fourier transform (FFT) process on the steering angle, the lateral displacement, etc., data of a certain length (for several minutes) is stored and processed, so that there is a problem that the real-time property is lost. However, the FFT signal processing has a problem that the data length becomes long because the steering frequency of the driver is analyzed with high resolution.

The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to make it possible to reliably detect the dozing driving in real time on any running road regardless of individual differences of the driving. It is to provide a detection device.

[0012]

In order to achieve the above object, a doze driving detection apparatus according to the present invention comprises an operation amount detecting means 1 for continuously detecting a vehicle operation amount as shown in FIG. A detection means 2 for detecting a characteristic frequency peculiar to the driver from the frequency spectrum of the vehicle motion amount during normal driving;
Filter means 3 for extracting a frequency component 0.1 Hz to 0.2 Hz lower than the characteristic frequency from the frequency spectrum of the vehicle motion amount after a predetermined time has elapsed from the start of traveling.
And a comparing means 4 for comparing the level of the frequency component extracted by the filter means 3 with a predetermined threshold level, which is equal to or higher than the predetermined threshold level of the frequency component extracted by the filter means 3. It is characterized in that the occurrence of drowsiness driving is detected from the increase in the number of driving.

[0013]

The dozing driving detection device of the present invention has such a configuration, and extracts the specific frequency by the filter means,
By comparing the levels of the extracted frequencies, the occurrence of drowsy driving is detected in real time.

The driver's driving operation can be regarded as a repetition of a series of operations of recognition, judgment, and operation. During normal driving, each of these steps is instantaneously performed under the normal consciousness of the driver. When the consciousness begins to decrease, these steps are not performed smoothly, and therefore the change in the steering angle, which is the output, also becomes slow, so that the low frequency component increases.

The applicant of the present application pays attention to such an increase in the low frequency component, and particularly a frequency component lower by 0.1 Hz to 0.2 Hz than the characteristic frequency in which the individual difference of the driver is remarkable is particularly suitable for the detection of the dozing driving. It was found that this frequency component was taken out by the filter means, and it was possible to detect the dozing driving surely in real time.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a doze driving detection apparatus according to the present invention will be described below with reference to the drawings.

FIG. 2 shows a block diagram of the configuration of this embodiment, and FIG. 3 shows an operation flowchart of this embodiment. In the figure, a steering angle sensor 10 as an operation amount detecting means is attached to a steering shaft of a vehicle. As the steering angle sensor 10, for example, a slit plate press-fitted into a steering shaft and two sets of photointerrupters attached to a column tube can be used, and the photointerrupter is shielded from light by the slit plate as the steering shaft rotates. The turning direction and the turning angle of the steering can be detected by turning on and off depending on whether the steering wheel is turned on or off.

Then, the detection signal from the steering angle sensor 10 is input to the FFT signal processing unit 12, and the fast Fourier transform is performed to calculate the frequency spectrum of the steering angle. Specifically, the steering angle signals sequentially supplied from the steering angle sensor 10 are input to the memory in the FFT signal processing unit 12, and the steering angle data for 20 minutes are sequentially updated and stored. Then, the steering angle data for the past several seconds, for example, 540 seconds from the present is subjected to the fast Fourier transform every 10 seconds to obtain the past five seconds.
A frequency spectrum for 40 seconds is calculated (S101 in FIG. 3).
-S103).

After the frequency spectrum is calculated in this manner, the FFT signal processing section 12 further detects a characteristic frequency peculiar to the driver from this frequency spectrum. This characteristic frequency is a change in steering during normal operation, for example, 10 minutes before the start of the operation (specifically, the frequency spectrum of the steering angle data 10 minutes before the start of the operation has a particularly high level, That is, it is detected from the steering frequency that frequently appears. This characteristic frequency is a physical quantity peculiar to the driver. Therefore, if the driver changes, the characteristic frequency also changes, which enables highly versatile determination according to the driver.

After the characteristic frequency is detected in this way, the cutoff frequency of the filter 14 is set to a frequency band lower than the characteristic frequency by 0.1 Hz to 0.2 Hz (S105).

FIG. 4 (A) shows an example of the frequency spectrum of the steering angle of the driver during normal driving,
The steering spectrum is concentrated around 0.4 Hz, and this 0.4 Hz becomes the characteristic frequency f _T. In the figure, the spectrum with a frequency of 0.1 Hz or less is high because the vehicle runs on a curved track.

After the filter is set in this way,
Next, dozing driving is detected 10 minutes after the start of driving. That is, the steering angle data from the steering angle sensor 10 has the cut-off frequency set as described above (since the characteristic frequency is 0.4 Hz in the present embodiment, it is 0.1 Hz-0.2 Hz lower than that. 2Hz-
0.3Hz range) Input to filter 14 and 0.2Hz
Only the components in the −0.3 Hz frequency band are extracted. Then, the level of the extracted frequency component and the predetermined threshold level are compared in real time by the comparator 16, and when the level is equal to or higher than the threshold value, it is determined that the drowsiness driving has occurred, and the alarm device 18 is activated. (S106-S107).

FIG. 4 (B) shows an example of the frequency spectrum of the steering angle when a drowsy driving actually occurs, which is 0.2 Hz-0 lower than the characteristic frequency f _T by 0.1 Hz-0.2 Hz. In the frequency band of 3 Hz, the level is remarkably increased as compared with the normal state, and therefore, for example, by setting the threshold level to about 1.5 times the level in the normal state, it is possible to reliably detect the dozing driving. Is understood.

As described above, in the present embodiment, attention is paid to a frequency band lower by a predetermined frequency than the characteristic frequency in which the driver's driving characteristics appear, and it is determined whether or not a drowsy driving occurs by increasing the level in this frequency band. Therefore, it becomes possible to reliably detect the dozing driving in real time irrespective of the driver and the traveling road.

Although the steering angle is used as the vehicle operation amount in this embodiment, another vehicle operation amount such as a lateral displacement amount may be used.

[0026]

As described above, according to the doze driving detection device of the present invention, it is possible to detect the dozing driving in real time regardless of the driver.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of the present invention.

FIG. 2 is a configuration block diagram of an embodiment of the present invention.

FIG. 3 is an operation flowchart diagram of the embodiment.

FIG. 4 is a steering angular frequency spectrum diagram during normal driving and during dozing driving in the same embodiment.

[Explanation of symbols]

 10 Steering Angle Sensor 12 FFT Signal Processor 14 Filter 16 Comparator 18 Alarm

Claims (1)

[Claims] 1. A motion amount detecting means for continuously detecting a vehicle motion amount, a detecting means for detecting a characteristic frequency peculiar to a driver from a frequency spectrum of the vehicle motion amount during normal operation, and a predetermined time from the start of traveling. Filter means for extracting a frequency component 0.1 Hz to 0.2 Hz lower than the characteristic frequency from the frequency spectrum of the vehicle motion amount after the passage, the level of the frequency component extracted by the filter means, and a predetermined threshold level A drowsiness driving detection device for detecting the occurrence of a drowsiness driving from the increase of the frequency component extracted by the filter means at a predetermined threshold level or more.