JPH07117517A - Detector for dozing at wheel - Google Patents

Abstract

PURPOSE:To provide a detector for dozing at the wheel which can surely detect driving asleep, at any speed by using steering data within a predetermined time after driving start. CONSTITUTION:A steering period is extracted from steering angle data detected by means of a steering angle sensor 10, and on the basis of vehicle speed data from a vehicle speed sensor 12, steering periods according to vehicle speeds are extracted. An obtaining portion 20 of an individual characteristic separated according to a vehicle speed calculates a steering period that covers 10 minutes after driving start to be counted by means of a timer 18. A steering period at an unobtained vehicle speed zone is surmized by using a steering period coefficient that is not based on a driver memorized beforehand, at an unobtained vehicle speed zone individual characteristic data surmizing portion 22, and is housed, together with obtained data, at a memory portion 24 of an individual characteristic separated according to a vehicle speed. An alarm portion 28 is operated by comparing at a consciousness lowering decision portion 26 a steering period at a free time and free vehicle speed with a steering period (a reference value) housed at the memory portion 24 of an individual characteristic separated according to a vehicle speed.

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 from a steering cycle.

[0002]

2. Description of the Related Art Conventionally, various devices have been developed and mounted for the purpose of improving the safety of vehicle traveling, and one of them is a device that detects a drowsy state of a driver and issues an alarm.

For example, in the doze driving detection apparatus disclosed in Japanese Patent Laid-Open No. 5-58192, steering data for 10 minutes from the start of driving is collected as a reference value for each vehicle speed, and the reference value and the steering data are compared to make a dozing driving operation. Is being detected.

[0004]

However, it cannot be expected to steer the vehicle in all vehicle speed zones within 10 minutes after the start of operation. Therefore, it is almost impossible to obtain steering data in all vehicle speed ranges, and in the vehicle speed range where steering data cannot be obtained, it is estimated from statistical values and used as a reference value, so it matches the driving characteristics of each driver. In some cases, it was not possible to accurately detect dozing driving.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to detect a drowsy driving at a given vehicle speed by using steering data within a predetermined time after the start of driving. To provide a device.

[0006]

In order to achieve the above object, a doze driving detection apparatus according to claim 1 is a dozing driving detection apparatus for detecting a dozing driving from a steering state of a vehicle, and detecting a steering cycle. Steering cycle detecting means, first reference steering cycle calculating means for calculating an average steering cycle within a predetermined time from the start of operation for each vehicle speed zone, storage means for storing a steering characteristic coefficient that does not depend on a driver with respect to the vehicle speed, Second reference steering cycle calculating means for calculating the steering cycle for all vehicle speeds based on the steering cycle for each vehicle speed zone and the steering characteristic coefficient, and the steering cycle detected by the steering cycle detecting means at any time and at any vehicle speed. And a determination unit that determines whether or not the driver is dozing by comparing the steering periods calculated by the second reference steering period calculation stage at the vehicle speed. To.

In order to achieve the above object, in the drowsiness driving detection apparatus according to a second aspect of the present invention, the first reference steering cycle calculating means calculates the average steering cycle by increasing the number of samples in the low vehicle speed range. Is characterized by.

[0008]

The steering cycle is greatly influenced by the vehicle speed, and the difference in the absolute value of the steering cycle due to the characteristic difference of each driver is also large. However, it is empirically known that the tendency of the steering cycle to increase or decrease with vehicle speed is almost the same regardless of the driver. The present invention pays attention to this fact, and regarding the vehicle speed range in which the steering cycle data is not obtained within a predetermined time after the start of driving (for example, 10 minutes after the start of driving), steering that does not depend on the driving characteristics of the driver stored in advance. The estimation is performed using the characteristic coefficient and the steering cycle data of the other vehicle speed range obtained by actual detection.
That is, although the absolute value is different, the absolute value of the steering characteristic coefficient whose increase / decrease tendency hardly changes depending on the driver is corrected by the actual driver's steering cycle data to obtain the reference steering cycle. Even at a vehicle speed for which no cycle data has been obtained, it is possible to reliably detect dozing driving.

In the doze driving detection apparatus according to the second aspect of the invention, attention is paid to the fact that the steering cycle tends to vary in the low vehicle speed range, and the number of samples is increased in the low vehicle speed range to obtain an accurate steering cycle.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of the configuration of this embodiment, and FIG. 2 shows a processing flowchart of this embodiment. The doze driving detection device of the present embodiment includes a rough steering angle sensor, a vehicle speed sensor, an electronic control unit ECU, and an alarm unit. The steering angle sensor 10 is composed of a photo interrupter attached to a steering shaft of a vehicle. The steering cycle extraction unit 14 is connected to the steering angle sensor 10, and the steering cycle is calculated by FFT from the detected steering angle data (S10 in FIG. 2).
1). As a method for calculating the steering cycle by FFT from the steering cycle, the method described in Japanese Patent Laid-Open No. 58192/1993 is used. The steering cycle extraction unit 14 is connected to a vehicle speed-based steering cycle extraction unit 16, and the extracted steering cycles are sequentially output. On the other hand, the vehicle speed sensor 12 is also connected to the vehicle speed-based steering cycle extraction unit 16, and the detected vehicle speeds are sequentially output. The vehicle-speed-based steering cycle extraction unit 16 calculates a steering cycle for each vehicle speed from the input steering cycle data and vehicle speed data (S102). The vehicle speed-specific steering cycle extraction unit 16 is connected to a vehicle speed-specific personal characteristic acquisition unit 20 and sequentially outputs data of (vehicle speed, steering cycle). Personal characteristic acquisition part 2 by vehicle speed
A timer 18 is connected to 0 and calculates a steering cycle for each vehicle speed band for a predetermined time, for example, 10 minutes after the start of operation. That is, the timer 18 determines whether or not a predetermined time has elapsed (S103), and the vehicle speed is set to 10 by using the data (vehicle speed, steering cycle) input 10 minutes after the start of operation.
It is divided into vehicle speed zones for each km / h, for example, 40 km / h to 5
When the steering cycle data of 0 km / h is T1, T2, ... Tn, the average value of these is calculated and the vehicle speed range is 40 km / h.
The steering cycle is from h to 50 km / h. This steering cycle indicates the driving characteristics of the driver within 10 minutes after the start of driving (the time when the driver is sufficiently awake and is considered to perform normal driving).

If the steering cycle in all the vehicle speed zones is obtained 10 minutes after the start of driving, it is the most suitable as the reference cycle in the dozing driving determination, but it is not always possible to obtain the data in all the vehicle speed zones in 10 minutes. Absent. In particular, in the low vehicle speed range, the variation in the steering cycle becomes large, so it is necessary to take a lot of time to acquire the data, but that time may not be taken. FIG. 5 shows the time required for data acquisition for each vehicle speed. The slower the speed, the longer the time required to obtain highly reliable data, that is, the larger the number of samples. In the figure, the shaded areas are areas where it can be determined that data has been acquired, and the other areas are areas where it is determined that no data was obtained from the viewpoint of reliability. For the vehicle speed range for which no data has been acquired, it is necessary to estimate a reliable value that reflects the driving characteristics of the driver by some method. Therefore, in this embodiment, the vehicle speed range for which data has not been acquired is estimated as follows. That is, the steering cycle for each vehicle speed band calculated by the vehicle speed-specific personal characteristic acquisition unit 20 is output to the unacquired vehicle speed band individual characteristic data estimation unit 22. A memory is provided in the unacquired vehicle speed band personal characteristic data estimation unit 22, and the steering cycle coefficient for the vehicle speed is stored in advance as a map or a function. Figure 3
Shows an example of the steering cycle coefficient, and the horizontal axis shows the vehicle speed (k
m / h), the vertical axis represents the cycle at a vehicle speed of 80 km / h as 1
Is the relative period coefficient. The steering cycle decreases as the vehicle speed increases, and the steering cycle tends to decrease relatively steeply in the vicinity of 70 to 80 km / h. This steering cycle coefficient is statistically obtained, and any driver shows the same tendency regardless of the driving characteristics of the driver. Therefore, the unacquired vehicle speed zone individual characteristic data estimation unit 22 of the present embodiment calculates the steering cycle of all vehicle speed zones using this steering cycle coefficient. FIG. 4 shows a method of calculating the steering cycle. In the figure, the horizontal axis represents the vehicle speed (km / h), and the vertical axis represents the estimated steering cycle (second). The black circles are the steering cycle data that can be acquired 10 minutes after the start of operation, and the broken line is the graph (function value) of the steering cycle coefficient shown in FIG. It is optimal if all the measured steering cycle data are on the graph of the steering cycle coefficient, but since the detected values include errors, not all data are on the graph in general. . Therefore, the unacquired vehicle speed zone personal characteristic data estimation unit 22 first determines whether or not there is at least one vehicle speed zone that satisfies the personal data acquired determination area shown in FIG. 5 (S104). When there is one or more vehicle speed zones that can be acquired (the number of vehicle speed zones is three in this embodiment).
First, as shown in FIG. 4, the steering cycle coefficient is estimated using the steering cycle coefficient (S105, broken lines a, a, and c in FIG. 4). In general, since a, a, and u do not match, each estimated value for each vehicle speed range (a, a,
The average value of the three values (a, c) is calculated and used as the estimated steering cycle (S106). The white circle in FIG. 4 is the estimated steering cycle of the unacquired vehicle speed range obtained in this way, and the solid line connecting the actually-obtained steering cycle (black circle) and the estimated steering cycle (white circle) is unique to the driver. The steering cycle reflects the driving characteristics. The unacquired vehicle speed zone individual characteristic data estimation unit 22 calculates the steering cycle in this manner and stores it in the vehicle speed individual characteristic memory unit 24 as the individual characteristic of the driver (S107).

After the personal characteristics of the driver are stored in the memory as described above, the dozing driving of the driver is determined using the personal characteristics as a reference value. The consciousness deterioration determining unit 26 is connected to the vehicle speed-based steering cycle extraction unit 16 described above, and the steering cycle for each vehicle speed extracted 10 minutes after the start of operation is sequentially output. The consciousness deterioration determining unit 26 has a comparator, and compares the input steering cycle with a value obtained by multiplying the gain of the reference value stored in the vehicle speed-specific individual characteristic memory unit 24 according to the determination level. Monitor the awareness level of. Then, when the driver's consciousness level is lowered, that is, when the current steering cycle is larger than the reference value multiplied by the gain, the alarm unit 2
8 is activated to wake up the driver.

As described above, in the present embodiment, the steering cycle estimated from the actual measurement value is operated by using the steering cycle obtained by actual measurement and the steering cycle coefficient showing a similar increase / decrease tendency regardless of the driver. Since the dozing driving is determined as the reference value peculiar to the driver, compared with the conventional dozing driving detection device that uses a constant value obtained statistically in the vehicle speed range that has not been acquired as a reference value, the driving characteristics of the driver are better matched. It is possible to make a reliable determination of drowsiness, and it is possible to eliminate the annoyance that a false alarm is generated when the consciousness is high, the delay of the alarm, and the like.

Further, in the present embodiment, as shown in FIG. 5, the time for determining acquisition or non-acquisition is changed for each vehicle speed, and it is set so that more time is required for a lower speed. It is possible to obtain the steering cycle and obtain the personal characteristic data of the driver more accurately and more quickly than in the case where it takes a certain time to determine that the data has been acquired regardless of the vehicle speed. Further, although the method using the FFT for measuring the steering cycle has been illustrated, the present invention is not limited to this, and a method of obtaining a steering turning point and estimating it from the turning pattern may be used.

[0016]

As described above, in the doze driving detection apparatus according to the first aspect of the invention, the dozing driving can be reliably detected at any vehicle speed by using the steering data within a predetermined time after the start of driving.

In the doze driving detection apparatus according to the second aspect of the invention, the time for determining acquisition or non-acquisition is changed for each vehicle speed, that is, the slower the speed, the more time is required. The cycle can be obtained.

[Brief description of drawings]

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

FIG. 2 is a processing flowchart of the embodiment.

FIG. 3 is a graph showing a steering cycle coefficient of the same embodiment.

FIG. 4 is an explanatory diagram of an estimated steering cycle calculation of the embodiment.

FIG. 5 is a graph showing a data acquisition time with respect to a vehicle speed in the embodiment.

[Explanation of symbols]

 10 Steering angle sensor 12 Vehicle speed sensor 28 Alarm unit

Claims (2)

[Claims] 1. A drowsy driving detection device for detecting a drowsy driving from a steering state of a vehicle, wherein a steering cycle detecting means for detecting a steering cycle, and an average steering cycle within a predetermined time from the start of driving are calculated for each vehicle speed band. A first reference steering cycle calculation means, a storage means for storing a steering characteristic coefficient that does not depend on the driver for the vehicle speed, a steering cycle for each vehicle speed zone, and a steering cycle for all vehicle speeds based on the steering characteristic coefficient The reference steering cycle calculation means compares the steering cycle detected by the steering cycle detection means at an arbitrary time and at an arbitrary vehicle speed with the steering cycle calculated at the second reference steering cycle calculation stage at that vehicle speed to fall asleep. A drowsy driving detection device, comprising: a determination unit that determines whether or not the vehicle is driven. 2. The drowsy driving detection device according to claim 1, wherein the first reference steering cycle calculation means calculates the average steering cycle by increasing the number of samples in a low vehicle speed range. apparatus.