JP3195805B2 - Vehicle contact prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a distance and a relative speed between an own vehicle and an obstacle, judges a possibility of contact from the detection result, and automatically performs a contact avoidance measure such as automatic braking. The present invention relates to a vehicle contact prevention device used in a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a contact prevention device for a vehicle of this kind, for example, Japanese Patent Publication No. 39-2565 and Japanese Patent Publication No.
As disclosed in Japanese Patent Application Laid-Open No. 9-5668, the distance and the relative speed between the vehicle and an obstacle in front are continuously detected using an optical method or an ultrasonic frequency, and the detected values are detected. It is determined whether there is a danger of contact based on the distance and relative speed between the vehicle and the obstacle in front of the vehicle.If it is determined that there is a danger of contact, the actuator is actuated to brake each wheel. It is known to automatically prevent contact. In addition to the automatic braking, automatically performs steering if it is determined that there is a risk of contact is also known that so as to avoid contact (JP flat 1-124008 JP reference).

[0003]

However, in such a contact prevention device, the possibility of contact is determined not only by the distance and relative speed between the vehicle and the obstacle in front but also by the coefficient of friction of the road surface ( This is performed before taking contact avoidance measures such as automatic braking, taking into consideration the road surface μ), etc., while taking such contact avoidance measures may affect the possibility of contact with road surface μ etc. Due to changes in factors or circumstances, contact may not be avoided even if contact avoidance measures are taken. In this case, it is desirable to alert the occupant of the own vehicle in advance and to notify the driver of another vehicle that may come into contact with the danger state.

The present invention has been made in view of the foregoing, and an object of the present invention is to provide an occupant of an own vehicle when contact cannot be avoided due to a change in road surface μ while taking contact avoidance measures. It is intended to provide a vehicle contact prevention device which can draw attention to a driver of a vehicle or another vehicle and can ensure safety.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, the distance between an own vehicle and an obstacle is determined.
Distance detection means for detecting the distance between the vehicle and the obstacle
A relative speed detecting means for detecting a speed, and
Road surface friction coefficient detecting means for detecting a road surface friction coefficient,
The distance between the own vehicle and the obstacle detected by the distance detecting means
The distance between the two was detected by the road surface friction coefficient means.
The road surface friction coefficient and the relative speed
Smaller than the first predetermined distance set based on the relative speed
First alarm means for issuing a first alarm at the time of
The distance between the car and the obstacle is smaller than the first predetermined distance.
When the distance is smaller than the second predetermined distance set to the threshold value.
Automatic braking means for applying dynamic braking;
During operation, the road surface friction
There is a change in the coefficient and contact with the above obstacles cannot be avoided
Having second alarm means for issuing a second alarm sometimes
And the first warning means is provided only to the driver of the own vehicle.
1 while the second
Warning means should be used for all drivers and other occupants of the vehicle.
Specified to be configured to issue a second alarm to personnel
It is assumed that.

According to a second aspect of the present invention, there is provided the first alarm device.
The step is an alarm lamp provided on the instrument panel.
Yes, specify that the second alarm means is an alarm buzzer
It is assumed that.

Further, the invention according to claim 3 is an automatic braking system.
During operation of the means, the road surface friction coefficient
Changes in the coefficient of friction prevent contact with obstacles
Occasionally a crush with the second warning by the second warning means
To be configured to sound
is there.

[0008]

According to the above-mentioned structure, according to the first aspect of the present invention,
The distance between the vehicle and the obstacle depends on the road surface friction coefficient and the relative speed.
When the distance is smaller than the first predetermined distance set based on the degree
Means that the first alarm means only issues the first alarm
Other crews are given a first alert
And the other occupants do not feel bothered.

On the other hand, during the operation of the automatic braking means, the road surface friction
When contact with obstacles cannot be avoided due to a change in coefficient
The second warning means is not only for the driver of the car, but also for the car
Emergency alert to issue a second alert to all crew members
Warning to all occupants of the vehicle and ensuring safety
Is achieved.

Further , according to the third aspect of the present invention, automatic braking is provided.
During the operation of the means, the road surface friction coefficient changes and
When contact with an object cannot be avoided, a second warning
Your horn will sound, and you will be
Be careful not only for the occupants of the car but also for the drivers of other vehicles, etc.
It will be evoked to ensure safety.

[0011]

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

1 to 3 show an automatic braking device for a vehicle according to an embodiment of the present invention, FIGS. 1 and 2 show a hydraulic circuit configuration of the automatic braking device, and FIG. 3 is a block configuration of the automatic braking device. Is shown.

In FIGS. 1 and 2, reference numeral 1 denotes a master back for increasing the depression force of the brake pedal 2 by the driver;
Reference numeral 3 denotes a master cylinder that generates a braking pressure corresponding to the stepping force increased by the master back 1. The braking pressure generated by the master cylinder 3 is first supplied to the automatic braking valve unit 4, and then the ABS is transmitted. (Anti-skid brake device) The brake device 6 of each wheel is supplied through a valve unit 5.

The automatic braking valve unit 4 includes a shutter valve 11, a pressure increasing valve 12, and a pressure reducing valve 1 for interrupting communication between the master cylinder 3 and the brake device 6.
The three valves 11 to 13 are all electromagnetic two-port two-position switching valves. A motor-driven oil pump 14 and an accumulator 15 for storing pressure oil discharged from the oil pump 14 and maintaining the oil at a constant pressure are interposed between the pressure increasing valve 12 and the master cylinder 3. Has been established. When the shutter valve 11 is in the open position, the brake pedal 2
Is applied by the brake device 6 of each wheel according to the stepping force of the vehicle. On the other hand, when the shutter valve 11 is in the closed position,
When the pressure-increasing valve 12 is switched to the open position and the pressure-reducing valve 13 is switched to the closed position, the pressure oil from the accumulator 15 is supplied to the brake device 6 of each wheel to apply braking, and the pressure-increasing valve 12 is moved to the closed position When the pressure reducing valve 13 is switched to the open position, the pressure oil is returned from the brake device 6 and the braking is weakened. The switching of the three valves 11 to 13 is performed by an actuator 16 including a voltage source for applying a voltage to each of the valves, and the actuator 16 is controlled by receiving a signal from a control box 17.

The ABS valve unit 5 has a three-port two-position switching valve 21 provided for each wheel, and the braking pressure applied to each brake device 6 by switching the valve 21 during braking. Is controlled so that each wheel does not lock. Although the configuration of the ABS is not described in detail, it includes a motor-driven oil pump 22 and accumulators 23 and 24 in addition to the switching valve 21.
The brake device 6 for each wheel includes a disk 26 that rotates integrally with the wheels, and a caliper 27 that receives the braking pressure from the master cylinder 3 and clamps the disk 26.

On the other hand, in FIG. 3, reference numeral 31 denotes an ultrasonic radar unit provided at the front part of the vehicle body. The ultrasonic radar unit 31, which is not shown in detail in the drawing, transmits an ultrasonic wave from a transmitting unit as is well known. An operation for transmitting to an obstacle such as a vehicle ahead of the own vehicle and receiving a reflected wave reflected from the front obstacle at a receiving unit, and receiving a signal from the radar unit 31 The unit 32 calculates the distance and the relative speed between the host vehicle and the obstacle ahead of the vehicle based on the delay time (Doppler shift) from the transmission time of the radar reception wave. 33 and 3
Reference numeral 4 denotes a pair of radar head units provided on the left and right of the front part of the vehicle body, respectively.
The transmitting unit 34 transmits the pulsed laser light from the transmitting unit to the obstacle in front of the own vehicle, and receives the reflected light reflected on the front obstacle by the receiving unit. A signal processing unit 35 converts signals from the radar head units 33 and 34 into a signal processing unit 35.
And calculates the distance and the relative speed between the host vehicle and the obstacle ahead based on the delay time from the transmission time of the laser reception light. And the arithmetic unit 32
Gives priority to the calculation result of the distance and relative speed by the system of the radar head units 33 and 34, and uses the calculation result of the distance and relative speed by the system of the ultrasonic radar unit 31 in an auxiliary manner. These constitute a distance / relative speed detecting means 36 for detecting the distance and the relative speed between the host vehicle and the obstacle ahead.

The transmitting and receiving directions of the pulse laser light by the two radar head units 33 and 34 are provided so as to be changeable in the left and right horizontal directions by a motor 37, and the operation of the motor 37 is controlled by the arithmetic unit 32. 38
Is an angle sensor for detecting the transmission / reception direction of the pulse laser light from the rotation angle of the motor 37.
Is input to the arithmetic unit 32, and the radar head units 33 and 34 in the arithmetic unit 32
The transmission / reception direction of the pulsed laser light is added to the calculation of the distance and the relative speed by the system.

A steering angle sensor 41 detects a steering angle.
42 is a vehicle speed sensor for detecting the vehicle speed, 43 is a front and rear G sensor for detecting the front and rear acceleration (front and back G) of the vehicle, and 44 is a road surface friction coefficient detecting means for detecting a road surface friction coefficient (μ).
The detection signals of these various sensors 41 to 44 are input to a control unit 45 that controls the actuator 16. The control unit 45 also receives a signal of the distance and the relative speed between the own vehicle and the obstacle in front obtained by the arithmetic unit 32.
(See FIG. 2). Reference numeral 46 denotes an alarm display unit provided on an instrument panel in the vehicle compartment. The alarm display unit 46 includes an alarm buzzer 47 as a second alarm unit that receives a signal from the control unit 45, a distance display unit 48, An alarm lamp 49 is provided as first alarm means . Warning lamp 49
Is to issue an alarm (first alarm) only to the driver of the own vehicle, and the alarm buzzer 47 is to issue an alarm (second alarm) not only to the driver of the own vehicle but also to all the occupants. Reference numeral 50 denotes a horn for issuing a warning to a driver or the like of another vehicle. The horn 50 receives a signal from the control unit 45 and operates.

FIG. 4 shows a control flow of automatic braking by the control unit 45 for preventing contact. In this control flow, first, after starting, various signals are read in step S1, and various threshold values L0 are read in step S2.
, L2, L3 are calculated. The threshold value L0 is determined by the distance between the own vehicle and the preceding obstacle (the second position) at which there is a risk of contact between the own vehicle and the preceding obstacle and automatic braking is started to prevent contact .
Is a predetermined distance), the calculation of the threshold L0 of the automatic braking start is performed using the threshold value map as shown in FIG. The threshold value L2 is a distance between the own vehicle and the obstacle ahead (a first predetermined distance) that issues an alarm before the start of automatic braking.
Is away), the threshold L2 of the alarm is a predetermined amount set greater than the threshold value L0 of the automatic braking start. The threshold value L3 is a distance between the host vehicle and the obstacle in front of which the danger of contact is eliminated after the start of automatic braking and the automatic braking is released.
Is set to a value larger by a predetermined amount than the threshold value L0 for starting the automatic braking, and in some cases, to a value smaller by a predetermined amount.

Here, the threshold value map shown in FIG. 5 will be described.
When the vehicle in front contacts the obstacle in front of it and stops, it indicates the distance between vehicles required to prevent contact with this vehicle. when a stationary object (i.e. when the relative velocity V1 is equal to the vehicle speed v0) the same value (numeric expression v0 ² / 2.mu.
g). The threshold line B indicates the inter-vehicle distance (numerical formula V1 · (2v0−V1) / 2 μg) required to prevent contact with the preceding vehicle when the vehicle is fully braked,
Threshold line C indicates the inter-vehicle distance necessary to prevent contact with the preceding vehicle when gentle braking with a deceleration μ / 2 g is applied. when kept indicating the inter-vehicle distance (numeric expression V1 ^2/2 [mu] g) required to prevent contact with the vehicle. Further, the threshold line E indicates an inter-vehicle distance in which even if the own vehicle applies automatic braking, contact with the preceding vehicle cannot be prevented, but the impact force at the time of contact can be reduced. In the case of the present embodiment, the threshold line B is selected, and the threshold value L0 corresponding to the current relative speed V1 is obtained from the threshold line B.

After calculating the various thresholds L0, L2, L3, at step S3, the relative speed V1 between the host vehicle and the obstacle ahead is determined.
Is greater than or equal to zero, that is, whether or not both are approaching. If this determination is YES, furthermore, in step S4, the distance between the host vehicle and the obstacle ahead (hereinafter referred to as the inter-vehicle distance).
It is determined whether or not L1 is smaller than the warning threshold L2. If the determination is YES, the warning lamp 49 is turned on to issue a warning to the driver of the own vehicle in step S5. Subsequently, in step S6, it is determined whether or not the inter-vehicle distance L1 is smaller than a threshold value L0 for starting automatic braking. If the determination is YES, the actuator 16 is set in step S7 to apply automatic braking with full braking. Activate

Subsequently, in step S8, after waiting for Δt seconds from the start of the automatic braking, the road surface μ sensor 44
To measure the friction coefficient μ of the road surface, and read the signal from the sensor 44. Thereafter, in step S9, it is determined whether or not the road surface friction coefficient μ measured after elapse of Δt seconds from the start of automatic braking is smaller than the road surface friction coefficient μ0 measured before the start of automatic braking. When this determination is YES, that is, when the road surface friction coefficient μ becomes small after the automatic braking starts and the braking distance becomes long, the alarm buzzer 47 is sounded in step S10 to warn all the occupants of the own vehicle, and the horn 50 is sounded. Then, it returns after issuing a warning to the driver of another vehicle. On the other hand, if the determination is NO, the process returns. A step S8, S9 and the road surface μ sensor 44 used for the determination detect a change in the road surface condition (road surface friction coefficient μ) which affects the possibility of contact during the operation of automatic braking as a contact or contact avoidance measure. μ change detection means (situation change detection means) 51 is configured;
The signals from the road surface μ change detecting means 51 are received by the steps S9 and S10, the alarm buzzer 47, and the horn 50, and an alarm is issued when the contact cannot be avoided due to a change in the road surface μ which affects the possibility of contact. The alarm device 52 which emits an alarm is configured. If the determination in step S4 or S6 is NO, the process immediately returns.

On the other hand, if the determination in step S3 is NO, that is, if the own vehicle is moving away from the obstacle ahead (the preceding vehicle), the inter-vehicle distance L1 is greater than the threshold value L3 for releasing automatic braking in step S11. It is determined whether it is small. If the determination is YES, the process returns in step S12 with the automatic braking applied, while if the determination is NO, the process returns after releasing the automatic braking in step S13.

Next, the operation of the above embodiment, in particular, the control of automatic braking for preventing contact by the control unit 45 in the control box 17 will be described. When it becomes smaller than the threshold value L0 for starting automatic braking, the control unit 45 activates the actuator 16 and switches the opening and closing of the valve in the automatic braking valve unit 4 via the voltage generated by the actuator 16 to perform automatic braking. Done.
That is, the shutter valve 11 is closed, and the pressure increasing valve 12 is switched to the open position, and the pressure reducing valve 13 is switched to the closed position. As a result, the pressure oil from the accumulator 15 is supplied to the brake devices 6 (calipers 27) of the respective wheels, and a full braking force is applied to the respective wheels by the operation of the brake devices 6, thereby resulting in a forward obstacle. Contact with an object can be prevented.

In a danger state where the friction coefficient μ of the road surface becomes small during the operation of the automatic braking and the braking distance becomes long, contact with the obstacle in front cannot be avoided. Detected by the detection means 51, the alarm buzzer 47 and the horn 50 are sounded before contact. For this reason, it is possible to inform all occupants of the vehicle of the danger of contact and warn them, and to alert drivers of other vehicles that may be in contact to take contact avoidance measures. Thus, safety can be ensured.

It should be noted that the present invention is not limited to the above-described embodiment, but includes various other modifications.
For example, in the above embodiment, the threshold value L0
In order to obtain the threshold value B, a threshold line B in FIG. 5 is uniquely selected, and a threshold value L0 corresponding to the current relative speed V1 is determined from the threshold line B. v0
Alternatively, the plurality of threshold lines A in FIG.
To E, one threshold line may be selectively selected, and the threshold L0 corresponding to the current relative speed may be selected from the selected threshold line.

Further, in the above embodiment, the road surface friction coefficient μ was measured before and after the start of automatic braking by full braking, respectively.
When the coefficient of friction μ decreases after the start of automatic braking, a warning is immediately issued assuming that there is a possibility of contact with an obstacle in front of the vehicle. threshold calculation formula of the automatic braking start the road surface friction coefficient μ measured after initiation (e.g. V1 ^2/2
μg) to calculate the threshold value L5, determine whether the actual inter-vehicle distance L1 is smaller than the threshold value L5, and issue an alarm when it is determined to be smaller. .

[0028]

As described above, according to the vehicle contact prevention device of the present invention , the distance between the host vehicle and the obstacle is reduced by the road surface.
First predetermined distance set based on friction coefficient and relative speed
If it is smaller than the first warning means,
To the first warning only to other passengers,
No alarm was issued, and the other crew members felt annoyed.
Can be prevented.

On the other hand, during the operation of the automatic braking means,
When there is a change and contact with obstacles cannot be avoided,
Before the contact, the second alarm means
To issue a second warning to all occupants in advance,
To alert all occupants of the vehicle
And safety can be ensured.

When contact with an obstacle cannot be avoided
A horn sounds with a second alarm
In emergency situations, not only the occupant of the vehicle but also other vehicles
Drivers can be alerted to
Integrity can be ensured.

[Brief description of the drawings]

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

FIG. 2 is a layout diagram of components of a hydraulic circuit of the automatic braking device.

FIG. 3 is a block diagram of the automatic braking device.

FIG. 4 is a flowchart showing a control flow of automatic braking by a control unit for preventing contact.

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

[Explanation of symbols]

6 Brake device 16 Actuator 36 Distance / relative speed detecting means 44 Road surface μ sensor (Road surface friction coefficient detecting unit) 47 Warning buzzer (Second warning unit) 49 Warning lamp (First warning unit) 50 Klaxon 51 Road surface μ change detecting unit ( Situation change detection means) 52 alarm device

Continued on the front page (72) Inventor Ken Kawamura 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (72) Inventor Akinori Utsunomiya 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (56) References JP-A-1-124008 (JP, A) JP-A-51-31422 (JP, A) JP-A-58-53544 (JP, A) JP-A-58-33363 (JP, U) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) B60T 7/12 B60R 21/00 620 G05D 1/02 G08G 1/16

Claims (3)

(57) [Claims] 1. A distance for detecting a distance between an own vehicle and an obstacle.
Separation detection means, and relative speed detection for detecting the relative speed between the vehicle and the obstacle
Road friction detecting means, the friction coefficient of a road surface on which the vehicle is traveling
Coefficient detecting means, and the distance between the own vehicle and the obstacle detected by the distance detecting means.
The distance between the two was detected by the road surface friction coefficient means.
The road surface friction coefficient and the relative speed
Smaller than the first predetermined distance set based on the relative speed
The first warning means for issuing a first warning at a time, and the distance between the host vehicle and the obstacle is smaller than the first predetermined distance.
Smaller than the second predetermined distance set to a value smaller than
Automatic braking means for applying automatic braking when the road surface friction coefficient means is operating while the automatic braking means is operating.
From the detection results, there is a change in the road surface friction coefficient
A second alarm that issues a second alarm when contact cannot be avoided
Alarm means , wherein the first alarm means only issues a first alarm to the driver of the vehicle.
And the second alarm hand
The steps are given to the driver of the vehicle and all other crew members.
2. A contact prevention device for a vehicle, wherein the device is configured to issue the second alarm . 2. An alarm system according to claim 1, wherein said first alarm means is provided on an instrument panel.
A vehicle which is an information lamp and wherein the second alarm means is an alarm buzzer.
Contact prevention device. 3. The detection result of the road surface friction coefficient means according to claim 1, wherein the automatic braking means operates.
Of road surface friction coefficient to avoid contact with obstacles
When it is not possible, the second alarm means
It is characterized by being configured to sound traction
Vehicle contact prevention device.