JPH0652500A - Travelling safety device for vehicle - Google Patents

Abstract

PURPOSE:To prevent a self vehicle from coming into contact with a front obsta cle and to secure safety even though the detectable distance of an obstacle detecting means is de creased due to the weather conditions such as fog and rain or blind curves. CONSTITUTION:An obstacle detecting means 36 detecting the front obstacle and a control section 51 discriminating the possibility of the self vehicle coming into contact with the front obstacle based on the detection are provided. The contact preventing measures such as warning or braking are taken automatically if there is a possibiliy of contact. A dirty level sensor 45 detecting the dirty level of lens is provided. When the detectable distance on the travelling traffic lane of the drivers own vehicle by means of the obstacle detecting means 36 is decreased than the normal case due to the dirt of lens, the contact possibility discrimination logic by the control section 51 is changed on a safety side. For example, both warning start distance and automatic braking start distance are shortened, the alarm is changed to be given before starting the automatic braking at all times, and the warning start distance is changed to be shorter than the detectable distance by performing decerelation through automatic braking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle running safety system configured to automatically take contact avoidance measures such as braking or warning when there is a possibility of contact between an own vehicle and an obstacle ahead. It relates to the device.

[0002]

2. Description of the Related Art Conventionally, an automatic braking device has been known as a traveling safety device for this type of vehicle. As disclosed in Japanese Patent Laid-Open No. 54-33444, for example, this automatic braking device continuously detects the distance between the host vehicle and an obstacle ahead by using a radar device and the like. Based on the detection result, it is determined whether or not the own vehicle may come into contact with an obstacle ahead, and when there is the possibility of contact, the actuator is operated to apply braking force to each wheel. . In addition, there are those that give an alarm to alert the driver before the start of this automatic braking, and those that issue an alarm instead of automatic braking when there is a possibility of contact to alert the driver. Are known.

By the way, the detectable distance of a front obstacle by the detecting means such as the radar device is remarkably reduced depending on the weather conditions such as fog and rain. Further, even in the case of a so-called blind curve where the road on which the vehicle is traveling is curved and the curved side is invisible, the detectable distance on the traveling lane of the vehicle by the detection means is reduced.

As a method for coping with such a situation, Japanese Utility Model Laid-Open No. 2-7156 discloses that control itself for taking contact avoidance measures such as automatic braking is stopped. Further, in JP-A-53-16230, when the detectable distance is reduced, the distance to the front obstacle is estimated based on the detected value up to that point and the judgment of the contact possibility is continued. It is disclosed.

[0005]

However, the former one cannot exert the function of the device for avoiding the contact with the front obstacle, which is not desirable for ensuring the traveling safety of the vehicle. The latter is effective for a short time from the time when the detectable distance decreases, but the estimation error increases as the time increases, and contact avoidance measures are taken against the appearance of a new front obstacle. I can't take it effectively.

The present invention has been made in view of the above points, and an object of the present invention is to detect obstacles on the traveling lane of an own vehicle by obstacle detecting means depending on weather conditions such as fog and rain or blind curves. By changing the contact possibility determination logic to the safe side when the distance decreases, a vehicle that can ensure the safety by avoiding the contact between the vehicle and the front obstacle regardless of the decrease in the detectable distance. It is intended to provide the driving safety device of.

[0007]

In order to achieve the above object, the invention according to claim 1 is an obstacle detecting means for detecting an obstacle existing in front of the own vehicle, and an own vehicle based on the detection. Driving safety of a vehicle that is provided with contact possibility determination means for determining the possibility of contact with a front obstacle and is configured to take contact avoidance measures when there is a possibility of contact between the vehicle and the front obstacle. In the apparatus, the detectable distance lowering detection means for detecting when the detectable distance on the traveling lane of the own vehicle by the obstacle detection means is lower than in normal time, and the detection by the signal of the detecting means When the possible distance is reduced, the determination logic changing means for changing the determination logic of the contact possibility by the contact possibility determination means to the safe side is provided.

The invention according to claim 2 is dependent on the invention according to claim 1, and in the running safety device of the vehicle, particularly as a contact avoidance measure, an alarm and an automatic braking for automatically applying a braking force to each wheel. The object is limited to the automatic braking device having a.

The inventions according to claims 3 and 4 are both dependent on the invention according to claim 2, and show a concrete example in which the judgment logic changing means, which is one of the constituents, changes the judgment logic. That is, in the invention according to claim 3, the judgment logic changing means, when the detectable distance decreases,
Both the alarm start distance and the automatic braking start distance are shortened, and the contact possibility determination logic is changed so that an alarm is always issued before the automatic braking is started. Further, in the invention according to claim 4, when the detectable distance decreases, the determination logic changing means performs deceleration by automatic braking to determine the contact possibility determination logic so that the alarm start distance becomes equal to or less than the detectable distance. To change.

[0010]

With the above construction, in the invention according to claim 1,
When the detectable distance on the driving lane of the host vehicle due to the obstacle detection means becomes lower than normal due to weather conditions such as fog or rain or blind curves, etc., this is detected by the detectable distance decrease detection means. The decision logic of the contact possibility is changed to the safe side by the decision logic changing means which receives the signal of the detecting means. Here, for example, when both the alarm start distance and the automatic braking start distance are shortened and the alarm is always issued before the automatic braking is started as in the invention described in claim 3, the host vehicle approaches the obstacle ahead. In this case, it is possible to prevent the driver from falling into a panic state and making a mistake in the driving operation due to the sudden automatic braking. Further, when the vehicle is decelerated by the automatic braking and the alarm start distance is changed to be equal to or less than the detectable distance as in the invention described in claim 4, the alarm and the automatic braking are normally provided when the vehicle approaches an obstacle ahead. The operation is the same as in the case of, and the contact between the own vehicle and the front obstacle is avoided.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment in which the present invention is applied to an automatic braking device for a vehicle, FIG. 1 is a hydraulic circuit diagram of the automatic braking device, and FIG. 2 is a block diagram of the automatic braking device. Is.

In FIG. 1, reference numeral 1 is a master back for increasing a pedaling force of a brake pedal 2 by a driver, and 3 is a master cylinder for generating a brake pressure according to the pedaling force increased by the master back 1. The brake pressure generated in the master cylinder 3 is first sent to the hydraulic actuator unit 4 of the automatic braking device, and then the hydraulic actuator unit 5 of the antiskid brake device (ABS).
Is supplied to each brake device 6 of four wheels (only one wheel is shown in the figure).

The hydraulic actuator section 4 of the automatic braking device has a shutter valve 11, a pressure increasing valve 12 and a pressure reducing valve 13 for cutting off the communication between the master cylinder 3 and the brake device 6 side. One valve 1
All of 1 to 13 are electromagnetic 2-port 2-position switching valves. Between the pressure increasing valve 12 and the master cylinder 3, a motor-driven oil pump 14 and the oil pump 1 are provided.
And an accumulator 15 for storing the pressure oil discharged from No. 4 and keeping it at a constant pressure. When the shutter valve 11 is in the open position, the brake device 6 for each wheel is driven according to the depression force of the brake pedal 2.
Brakes on. On the other hand, when the shutter valve 11 is in the closed position, the pressure increasing valve 12 is in the open position and the pressure reducing valve 1 is in the open position.
When 3 is switched to the closed position, the pressure oil from the accumulator 15 is supplied to the brake device 6 of each wheel to increase the brake pressure, and the pressure increasing valve 12 is closed and the pressure reducing valve 13 is opened. When they are switched, the pressure oil is returned from the brake device 6 to reduce the brake pressure.

The ABS hydraulic actuator section 5 has a 3-port 2-position switching valve 21 provided for each wheel, and is applied to each braking device 6 by switching the valve 21 when the ABS is operated. The brake pressure is controlled to prevent each wheel from locking. Although the structure of the hydraulic actuator section 5 is not described in detail, in addition to the switching valve 21, a motor-driven oil pump 22 and accumulators 23 and 24 are provided. The brake device 6 for each wheel includes a disk 26 that rotates integrally with the wheel, and a caliper 27 that receives the brake pressure from the master cylinder 3 side and clamps the disk 26.

On the other hand, in FIG. 2, reference numeral 31 is an ultrasonic radar unit provided in the front part of the vehicle body. The ultrasonic radar unit 31 is not shown in detail in the drawing, but as is well known, the ultrasonic wave is emitted from the transmitting portion. While transmitting to an obstacle such as a vehicle in front of the own vehicle, the receiving section receives the reflected wave reflected by hitting the front obstacle,
Operation unit 32 for receiving signals from this radar unit 31
Is configured to calculate the distance and relative speed between the host vehicle and an obstacle ahead of the vehicle based on the delay time from the time when the radar received wave is transmitted. Reference numerals 33 and 34 denote a pair of radar head units respectively provided on the left and right of the front part of the vehicle body, and each of the radar head units 33 and 34 transmits a pulse laser beam from an emission unit toward an obstacle in front of the vehicle. In addition, the reception unit receives the reflected light reflected by the front obstacle, and the calculation unit 32
Receives signals from these radar head units 33 and 34 through a signal processing unit 35, and calculates a distance and a relative speed between the host vehicle and a front obstacle according to a delay time from a transmission time point of the laser reception light. It has become. Then, the calculation unit 32 uses the radar head units 33, 3
Priority is given to the calculation results of distance and relative speed by the system of 4,
The calculation result of the distance and the relative speed by the system of the ultrasonic radar unit 31 is used as an auxiliary, and the distance and the relative speed between the host vehicle and a front obstacle existing in front of them are also used. Obstacle detecting means 36 for detecting is configured.

The transmission / reception direction of the pulsed laser light by both the radar head units 33, 34 is provided so that it can be changed in the horizontal direction by a motor 37.
The operation of is controlled by the arithmetic unit 32. Reference numeral 38 denotes an angle sensor for detecting the transmission / reception direction of the pulsed laser light from the rotation angle of the motor 37. The detection signal of the angle sensor 38 is input to the arithmetic unit 32, and the radar head unit 33, The transmission / reception direction of the pulsed laser light is added to the calculation of the distance and the relative speed by the system of 34.

Reference numeral 41 denotes a rudder angle sensor for detecting the rudder angle,
42 is a vehicle speed sensor that detects the vehicle speed, 43 is a longitudinal G sensor that detects longitudinal acceleration (longitudinal G) of the vehicle, 44 is a road surface μ sensor that detects a friction coefficient (μ) of the road surface, and 45 is the radar head unit 33. , 34 is a lens dirtiness sensor for detecting the dirtiness degree of the lens from its transparency, and the lens dirtiness sensor is the radar head unit 3
A function as a detectable distance lowering detection unit that detects when the detectable distance on the traveling lane of the own vehicle by the obstacle detection unit 36 due to the dirt of the lenses 3 and 34 is lower than that in the normal time. Have. The various sensors 41 to 4
The detection signal of No. 5 and the signals of the distance and the relative speed between the host vehicle and the front obstacle obtained by the calculation unit 32 are both input to the control unit 51. Reference numeral 52 denotes an alarm display unit provided on an instrument panel in the vehicle compartment, and the alarm display unit 52 includes the control unit 51.
Alarm lamp 53 and alarm buzzer 54 that receive signals from each
And a distance display section 55 are provided. The control unit 51
Has a function as a contact possibility determination unit that determines the possibility of contact between the host vehicle and the front obstacle based on the distance and the relative speed between the host vehicle and the front obstacle. When it is determined that there is a possibility of contact at 51, a signal is output from the control unit 51 to the alarm buzzer 54 to issue an alarm, or the hydraulic actuator unit 4 of the automatic braking device is operated in order to avoid the contact. The braking force is automatically applied to each wheel.

Next, the control logic of the automatic braking by the control unit 51 will be described with reference to the flow charts shown in FIGS.

In this flowchart, after starting, first, in step S1, signals such as the distance L1 between the host vehicle and a front obstacle, the relative speed V1, and the host vehicle speed v0 are read, and then step S2. With various thresholds L0
, L2, L3 are calculated. The threshold value L0 is the distance between the host vehicle and the front obstacle, at which there is a possibility of contact between the host vehicle and the front obstacle, and automatic braking is started to avoid the contact. The calculation of the threshold L0 is shown in FIG.
The threshold map as shown in FIG. The threshold value L2 is a distance between the host vehicle and an obstacle ahead of the vehicle, which gives an alarm prior to the start of automatic braking. The threshold value L2 for starting the alarm is greater than the threshold value L0 for starting the automatic braking. Is also set to a value larger by a predetermined amount. The threshold L3 is
This is the distance between the host vehicle and the front obstacle that releases the possibility of contact after the start of automatic braking and the automatic braking is released. The threshold L3 for releasing the automatic braking is the threshold L0 for starting the automatic braking. Is set to a value larger by a predetermined amount than the above, and in some cases, a value smaller by a predetermined amount.

The threshold map shown in FIG. 5 will now be described. In this map, the threshold line A is
When a vehicle ahead comes into contact with the obstacle ahead of the vehicle and stops, it indicates the inter-vehicle distance required to avoid contact with this vehicle, and the obstacle ahead always appears regardless of the magnitude of the relative speed V1. The same value as when the vehicle is stationary (that is, when the relative speed V1 is the same as the vehicle speed v0) (numerical expression v0 ² / 2μ)
g) is taken. The threshold line B indicates the inter-vehicle distance (numerical expression V1. (2v0-V1) / 2 .mu.g) required to avoid contact with this vehicle when the front vehicle is fully braked,
Threshold line C indicates the inter-vehicle distance required to avoid contact with the front vehicle when the front vehicle is subjected to slow braking of deceleration μ / 2g, and threshold line D indicates that the front vehicle maintains a constant vehicle speed. when kept indicating the inter-vehicle distance (numeric expression V1 ^2/2 [mu] g) required to avoid contact between the vehicle. Further, the threshold line E indicates an inter-vehicle distance in which the contact with the preceding vehicle cannot be avoided even when the host vehicle applies automatic braking, but the impact force at the time of contact can be mitigated. In the case of the present embodiment, the threshold line B is selected, and the threshold line B is used to obtain the threshold value L0 corresponding to the current relative speed V1.

After the calculation of the various threshold values L0, L2, L3, in step S3, the lenses of the radar head units 33, 34 are contaminated based on the signal from the lens contamination degree sensor 45, and by extension, the obstacle detection means 36. It is determined whether or not the detectable distance of is lower than that in the normal time.
If this determination is YES, the alarm lamp 53 is turned on in step S4 to warn the lens of contamination, and in step S5, predetermined values are set for the alarm start threshold L2 and the automatic braking start threshold L0. Subtract α2 and α0. As shown in FIG. 6, the predetermined values α2 and α0 are set to increase in a quadratic curve as the vehicle speed v0 increases. Then, the process proceeds to step S11.

The significance of subtracting the predetermined values α2 and α0 from the alarm start threshold L2 and the automatic braking start threshold L0 will be described with reference to FIG. FIG. 7 is a graph in which the vertical axis represents the distance and the horizontal axis represents the vehicle speed v0. In this figure, curves L2 and L0 respectively indicate the threshold value for alarm start and the threshold value for automatic braking start. . The curves L2 and L0 are set to be lower than the normal detectable distance A where the lenses of the radar head units 33 and 34 are not dirty in the obstacle detecting means 36, but can be detected due to the dirt of the lenses. When the distance decreases to the B value, it becomes higher than the B value depending on the magnitude of the vehicle speed v0. In this case, the point v at which the curve L2 and the B value intersect
When the vehicle speed v0 is higher than B, the threshold value for alarm start is set to the B value and the threshold value for automatic braking start is set to the C value. The C value is the value of the curve L0 when the vehicle speed v0 is vB, and is smaller than the B value by a predetermined amount. And the curves L2 and B
The difference from the value is α2, and the difference between the curve L0 and the C value is α0. Therefore, subtracting the predetermined values .alpha.2 and .alpha.0 from the alarm start threshold value L2 and the automatic braking start threshold value L0 is such that both threshold values L2 and L0 are less than the detectable distance B of the obstacle detecting means 36. It is designed to be short and to always give an alarm before the start of automatic braking. Further, in steps S3 to S5, when the detectable distance of the obstacle detecting means 36 decreases due to the dirt of the lens, the alarm start distance (threshold value L2) and the automatic braking start distance (threshold value L).
The determination logic changing means 61 is configured to change the contact possibility determination logic to the safe side by changing (0).

On the other hand, if the judgment in step S3 is NO, it is judged in step S6 whether or not a warning due to the lighting of the warning lamp 53 is issued. If a warning is issued, in step S7. After dismissing that warning,
Control goes to step S11.

As shown in FIG. 4, in step S11, it is determined whether the relative speed V1 between the host vehicle and the front obstacle is equal to or greater than zero, that is, the two are approaching. This judgment is YES
If it is, it is further determined in step S12 whether or not the distance L1 between the host vehicle and the front obstacle (hereinafter referred to as inter-vehicle distance) is smaller than the above-mentioned warning start threshold value L2, and this determination is YES. If so, the alarm buzzer 54 is sounded in step S13. Subsequently, in step S14, it is determined whether or not the inter-vehicle distance L1 is smaller than the threshold value L0 for starting automatic braking. If the determination is YES, the actuator unit is controlled to apply automatic braking with full braking in step S15. Activate 4 and return. Step S12 or S14
If the determination is NO, the process immediately returns.

When the determination in step S11 is NO, that is, when the host vehicle and the front obstacle (front vehicle) are moving away from each other, in step S16 the inter-vehicle distance L1 is greater than the automatic braking release threshold L3. Determine if it is small. When the determination is YES, the routine directly returns, while when the determination is NO, the automatic braking is released in step S17 and then the routine returns.

When the automatic braking device is controlled according to the above-mentioned flowchart, when the detectable distance of the obstacle detecting means 36 becomes shorter than usual due to the dirt of the lens, an alarm is started. Both the threshold value L2 and the threshold value L0 for starting automatic braking are reduced below the detectable distance, and the threshold value L0 for starting automatic braking is always smaller than the threshold value L2 for starting alarm. Since the change is made, the warning buzzer 54 is always sounded before the automatic braking to call the driver's attention. For this reason, it is possible to prevent the driver from falling into a panic state due to a sudden operation of automatic braking, and it is possible to improve safety.

FIG. 8 is a flowchart showing a modification of the control logic for automatic braking. In the case of this modification, the automatic braking device is provided with a rainfall sensor (not shown) for detecting the presence or absence of rainfall and the rain pressure at the time of rainfall, instead of the lens dirtiness sensor 45 shown in FIG. The detection signal of is input to the control unit 51.

In the flowchart shown in FIG. 8, after starting, first in step S21, the distance L1 between the host vehicle and the obstacle ahead, the relative speed V1, and the host vehicle speed v.
A signal such as 0 is read and various threshold values L are set in step S22.
Calculate 0, L2, and L3.

Subsequently, after the presence or absence of rainfall and the rainfall pressure at the time of rainfall are detected by the rainfall sensor in step S23, it is determined in step S24 whether or not it is rainfall. When it is raining with this determination being YES, in step S26, the detectable distance Lmax of the obstacle detecting means 36 (radar head units 33, 34) during rain is calculated using the map shown in FIG. As can be seen from FIG. 9, the rain pressure and the detectable distance Lmax of the obstacle detection means 36 are in inverse proportion.

Thereafter, in step S26, it is determined whether or not the detectable distance Lmax is smaller than the alarm start distance L2. If the determination is YES, automatic braking is applied in step S27. After this automatic braking, the own vehicle speed v0 is reduced, and after waiting for the alarm start distance L2 to become the detectable distance Lmax or less, the automatic braking is released in step S28. After that, control is performed according to the flow of steps S11 to S17 in FIG. Further, when the determination in step S24 is NO, that is, when there is no rainfall, control is immediately performed according to the flow of steps S11 to S17. Step S24 ~
In S28, when the detectable distance Lmax of the obstacle detection means 36 is reduced due to rainfall, the contact possibility determination logic is set so that the alarm start distance L2 is less than the detectable distance Lmax by decelerating by automatic braking. The judgment logic changing means 71 for changing to the safe side is configured. Also,
The rainfall sensor has a function as a detectable distance lowering detecting unit that detects when the detectable distance Lmax of the obstacle detecting unit 36 is lower than in a normal time due to the rainfall.

When the automatic braking device is controlled according to the above-mentioned flowchart, when the detectable distance of the obstacle detecting means 36 becomes shorter than the normal time (non-rainfall) due to the rainfall, the automatic braking is automatically performed. Braking and own vehicle speed v0
As a result, the alarm start distance L2 becomes less than the detectable distance Lmax. Then, when the host vehicle approaches the front obstacle, the alarm and the automatic braking are sequentially activated as in the non-rainfall, so that the contact between the host vehicle and the front obstacle can be surely avoided.

FIG. 10 is a flowchart showing another modification of the control logic for automatic braking. In this flowchart, after starting, first, in step S
At 31 the distance L1 between the vehicle and the obstacle ahead, the relative speed V
Signals such as 1 and the vehicle speed v0 are read, and various threshold values L0, L2, L3 are calculated in step S22.

Subsequently, in step S33, it is determined whether or not the road on which the vehicle is traveling is curved and the curved side is so invisible that it is a so-called blind curve. This determination is made based on external information obtained from a marker or the like provided on the road surface, or a group of front obstacles (a guide rail reflector group or a preceding group) is detected by an obstacle detection means 36 (see FIG. 2) mounted on the vehicle. Vehicle groups, etc.) that are operated, and judge based on the detection result. Then, when the judgment is YES in the blind corner, the detectable distance Lmax on the traveling lane of the own vehicle by the obstacle detection means 36 (see FIG. 2) is calculated in step S34. Here, assuming that the radius of curvature of the blind corner is R and the distance between the road edge and the running center line of the road is b, the above-described detectable distance Lmax is expressed by the following formula.

Lmax = (2Rb) ^1/2 Then, in step S35, it is determined whether or not the detectable distance Lmax is smaller than the alarm start distance L2. If this determination is YES, automatic braking is performed in step S36. multiply.
Then, after the vehicle speed V0 decreases due to the automatic braking and the alarm start distance L2 becomes equal to or less than the detectable distance Lmax, the automatic braking is released in step S37. After that,
The control is performed according to the flow of steps S11 to S17 in FIG. If the judgment in step S33 is not a blind corner, the steps S11-S are immediately executed.
Control is performed according to the flow consisting of 17. Step S above
33 to S37, the detectable distance L on the traveling lane of the own vehicle by the obstacle detection means 36 due to the blind corner
When max decreases, the judgment logic changing means 81 is arranged to change the contact possibility judgment logic to the safe side so that the alarm start distance L2 is reduced by the automatic braking and the alarm start distance L2 becomes equal to or smaller than the detectable distance Lmax.

When the automatic braking device is controlled according to the above flow chart, when the vehicle travels in the blind corner, the obstacle detection means 36 can detect the distance Lmax on the traveling lane of the vehicle on a straight road. However, the vehicle speed v0 decreases due to automatic braking, and the alarm start distance L2 becomes less than the detectable distance Lmax. Therefore, when the own vehicle approaches the front obstacle, the alarm and the automatic braking are sequentially activated, so that the contact between the own vehicle and the front obstacle can be reliably avoided.

The present invention is not limited to the above embodiment, but includes various other modifications.
For example, in the above-mentioned embodiment or its modified example, the case where the cause of the detection distance Lmax of the own vehicle on the traveling lane by the obstacle detection means 36 is reduced is the case where the lens is dirty, rain or a blind corner. Of course, the present invention is not limited to this, and can be similarly applied to the case where the detection distance Lmax on the traveling lane of the own vehicle by the obstacle detection means 36 is decreased due to other causes.

Further, in the above embodiment, the case of the automatic braking device having the alarm and the automatic braking is described as the contact avoidance measure to be taken when there is a possibility of contact between the host vehicle and the front obstacle. The invention can be similarly applied to a case where an automatic steering device that automatically steers or a device that issues only an alarm is provided as a contact avoidance measure when there is a possibility of contact.

[0039]

As described above, according to the vehicle traveling safety device of the present invention, the distance that can be detected by the obstacle detecting means on the traveling lane of the own vehicle is usually determined by weather conditions such as fog and rain or blind curves. When it becomes lower than the time, the logic for determining the possibility of contact is changed to the safe side, so contact avoidance measures can be effectively taken regardless of the decrease in the detectable distance, and safety can be ensured. .

In particular, according to the third aspect of the invention, both the alarm start distance and the automatic braking start distance are shortened when the detectable distance is decreased, and the alarm is always issued before the automatic braking is started. Therefore, it is possible to prevent the driver from falling into a panic state and making a mistake in the driving operation due to the sudden application of the automatic braking.

Further, according to the invention as set forth in claim 4, since the alarm start distance is changed so as to be equal to or less than the detectable distance by performing deceleration by automatic braking when the detectable distance decreases, Similarly, the alarm and the automatic braking operation can surely avoid the contact between the vehicle and the obstacle ahead.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an automatic braking device according to an embodiment of the present invention.

FIG. 2 is a block configuration diagram of the automatic braking device.

FIG. 3 is a flowchart showing a control logic of automatic braking.

FIG. 4 is a flowchart of the same.

FIG. 5 is a diagram showing a map for calculating a contact avoidance threshold value.

FIG. 6 is a diagram showing functions of predetermined values α2 and α0.

FIG. 7 is a diagram for explaining a relationship between an alarm start distance and an automatic braking start distance, and a detectable distance of an obstacle detection unit.

FIG. 8 is a flowchart showing a modified example of a control logic for automatic braking.

FIG. 9 is a characteristic diagram showing the relationship between the detectable distance of the obstacle detection means and rain pressure.

FIG. 10 is a flowchart showing another modification of the control logic for automatic braking.

[Explanation of Codes] 36 Obstacle Detecting Means 45 Lens Dirt Degree Sensor (Detecting Means at Detectable Distance Reduction) 51 Control Unit (Contact Possibility Judging Unit) 61, 71, 81 Judgment Logic Changing Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ayumu Doi, No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) Kenichi Okuda, No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Corporation (72) Inventor Naoji Masuda 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Motor Corporation

Claims (4)

[Claims] 1. An obstacle detection means for detecting an obstacle existing in front of the host vehicle, and a contact possibility determination means for determining the possibility of contact between the host vehicle and the front obstacle based on the detection. A traveling safety device for a vehicle, which is configured to take contact avoidance measures when there is a possibility of contact between the host vehicle and an obstacle ahead of the host vehicle. When the detectable distance decreases, the detection means for detecting when the detectable distance decreases, and when the detectable distance decreases, the contact possibility determination means determines the contact possibility. A traveling safety device for a vehicle, comprising: a judgment logic changing means for changing a logic to a safe side. 2. The vehicle running safety device according to claim 1, further comprising an alarm and automatic braking for automatically applying a braking force to each wheel as the contact avoidance measure. 3. The determination logic changing means, when the detectable distance is reduced, shortens both the alarm start distance and the automatic braking start distance and always outputs an alarm before the automatic braking is started. The traveling safety device for a vehicle according to claim 2, wherein 4. The determination logic changing means changes the contact possibility determination logic such that when the detectable distance decreases, deceleration is performed by automatic braking and the alarm start distance becomes equal to or less than the detectable distance. The vehicle safety device according to claim 2.