JP3320752B2 - Automatic vehicle braking system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic vehicle for detecting the distance and relative speed between an own vehicle and an obstacle, judging the possibility of contact based on the detected result, and automatically applying a brake to each wheel. It relates to a braking device.

[0002]

2. Description of the Related Art Conventionally, as an automatic braking device for this kind of vehicle, 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 relative speed between an own vehicle and a preceding obstacle are continuously detected using an optical method or an ultrasonic frequency, and the detected self- The system determines whether there is a danger of collision based on the distance and relative speed between the vehicle and the obstacle in front, and if it is determined that there is a danger of collision, activates the actuators to automatically apply brakes on each wheel to cause a collision. It is known to prevent this.

[0003] In such an automatic braking device, automatic braking is not always applied while the vehicle is running. For safety reasons, when an input from a steering wheel is applied or when the vehicle speed of the host vehicle is set to a predetermined value, the automatic braking device is controlled. Generally, automatic braking is not applied when the value falls below the value (Japanese Utility Model Laid-Open No. 1-62961 and Japanese Patent Laid-Open No. 2-1937).
No. 41, etc.).

[0004]

However, in the above-mentioned conventional automatic braking device, since the distance and the relative speed between the own vehicle and the obstacle ahead are detected only by ultrasonic waves or the like, the own vehicle cannot be moved straight. When entering the turning road from the road,
A vehicle on the opposite lane may be erroneously determined as a vehicle on the lane on which the vehicle is traveling. At the point when the vehicle enters the turning road from this straight road, there is still no steering wheel input and the vehicle speed may not be reduced so much, so that the automatic braking is erroneously applied without being restricted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle which can prevent automatic braking by an obstacle on an oncoming lane and improve reliability. It is intended to provide an automatic braking device.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a distance and a relative speed between an own vehicle and an obstacle are detected, and a risk of collision with the obstacle is detected based on the detected result. In an automatic braking system for a vehicle that determines the nature of the vehicle and applies automatic braking, the distance between the vehicle and the obstacle is the distance from the vehicle to the intersection where the straight line connecting the vehicle and the obstacle intersects the center separation line of the road. If the obstacle is on the oncoming lane, a judgment means for judging that the obstacle is on the oncoming lane; and automatic braking for restricting automatic braking when the judging means judges that the obstacle is on the oncoming lane. And a regulating means. Note that regulating the automatic braking means not only preventing the automatic braking from being applied at all, but also including shortening the threshold value of the automatic braking start to make the automatic braking hard to be applied. The risk of collision means not only the possibility (danger) of collision with an obstacle in front of the vehicle but also the possibility of collision with an obstacle behind the vehicle.

[0007]

According to the above-mentioned structure, according to the first aspect of the present invention,
If the distance between the host vehicle and the obstacle is greater than the distance from the host vehicle to the intersection where the straight line connecting the host vehicle and the obstacle intersects the center separation line on the road, the obstacle is on the opposite lane. The automatic braking restricting means regulates the automatic braking based on the determination, and it is possible to prevent the automatic braking from being erroneously applied.

[0008]

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 shows a block configuration of the automatic braking device. Show.

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 brake 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 a 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 71 denotes a projection device provided at the front of the vehicle body, and 72 denotes an image processing unit.
The image processing unit 72 calculates the distance L1 between the host vehicle and the obstacle ahead of the host vehicle from the image in front of the host vehicle captured by the projection device 71.
And the relative speed, and the distance La to the intersection where the straight line connecting the vehicle and the obstacle ahead of the vehicle intersects the center separation line of the road. The signal of the image processing unit 72 is input to the control unit 45 through the arithmetic unit 32. The control unit 45 accommodates a determination unit 73 and an automatic braking restriction unit 74 described later. A pair of radar head units 33 and 34 are provided on the left and right sides of the front part of the vehicle body, and each of the radar head units 33 and 34 transmits a pulse laser beam from a transmitting unit to an obstacle in front of the own vehicle. In addition, the receiving unit receives the reflected light reflected by the front obstacle, and the arithmetic unit 32 receives the signals from the radar head units 33 and 34 through the signal processing unit 35. The distance L1 to the obstacle ahead and the relative speed are calculated based on the delay time from the transmission time of the laser reception light. The arithmetic unit 32 gives priority to the calculation results of the distance and the relative speed by the systems of the radar head units 33 and 34, and supplements the calculation results of the distance and the relative speed by the systems of the projection device 71 and the image processing unit 72. The distance / relative speed detecting means 36 for detecting the distance and the relative speed between the host vehicle and the obstacle in front of the host vehicle is configured.

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 an 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, 44 is a road surface μ sensor for detecting a road surface friction coefficient (μ), and these various sensors 41 to 44 Is input to the control unit 45 that controls the actuator 16. The control unit 45 also receives signals of the distance and the relative speed between the own vehicle and the obstacle ahead obtained by the arithmetic unit 32, and the two units 45 and 32 are connected to the control box 17 (FIG. 2). See).
Reference numeral 46 denotes an alarm display unit provided on an instrument panel in the vehicle compartment. The alarm display unit 46 is provided with an alarm buzzer 47 for receiving signals from the control unit 45 and a distance display unit 48.

FIG. 4 shows a control flow of automatic braking by the control unit 45 for preventing collision. In this control flow, first, after starting, various signals are read in step S51, and in step S52, the distance L1 between the own vehicle and the obstacle ahead is calculated from the signal of the image processing unit 72 to the intersection on the road center separation line. It is determined whether the distance is greater than the distance La. In this determination, it is ultimately determined whether or not the obstacle ahead is on the oncoming lane. In step S52, the projection device 71 and the image processing unit 72 determine whether the obstacle ahead is on the oncoming vehicle. A judging means 73 for judging that the object is on the line is configured.

Here, the threshold value map shown in FIG. 5 will be described.
When the vehicle in front collides with the obstacle in front of it and stops, it indicates the inter-vehicle distance necessary to prevent collision 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 / 2μ
g). The threshold line B indicates the inter-vehicle distance (numerical formula V1 · (2v0−V1) / 2 μg) required to prevent a collision with the preceding vehicle when the vehicle is fully braked,
Threshold line C indicates the inter-vehicle distance required to prevent a collision with the preceding vehicle when the preceding vehicle applies gentle braking with a deceleration μ / 2g, and threshold line D indicates a constant vehicle speed for the preceding vehicle. maintaining the time headway distance required to prevent a collision with the vehicle (numeric expression V1 ² / 2 μg). Further, the threshold line E indicates an inter-vehicle distance at which a collision with a preceding vehicle cannot be prevented even when the own vehicle applies automatic braking, but an impact force at the time of the collision can be reduced.

The determination in step S52 is YE
In the case of S, that is, when the front obstacle is on the oncoming lane, the threshold line E in FIG. 5 is selected in step S53, and then the process proceeds to step S55. On the other hand, when the determination is NO, that is, when the forward obstacle is not on the opposite lane but on the same lane as the own vehicle, step S
At step 54, the threshold line D in FIG. 5 is selected, and then the process proceeds to step S55. In step S55, various threshold values L0
, L2, L3 are calculated. The threshold value L0 is the distance between the host vehicle and the obstacle in front of which there is a danger of collision between the host vehicle and the obstacle in front and the automatic braking is started to prevent the collision. The calculation of the value L0 is performed using a threshold map as shown in FIG. The threshold value L2 is the distance between the host vehicle and an obstacle in front of which an alarm is issued prior to the start of automatic braking.
It is set to be larger by a predetermined amount than the threshold value L0 for starting the automatic braking. The threshold value L3 is the distance between the host vehicle and the obstacle in front of the vehicle, which eliminates the risk of collision after the start of automatic braking and releases the automatic braking.
Is set to be larger by a predetermined amount than the threshold value L0 for starting the automatic braking. In the case of the present embodiment, a threshold value L0 corresponding to the current relative speed V1 is obtained from the threshold lines E and D. In FIG. 5, since the threshold line E has a smaller threshold value L0 than the threshold line D, the selection of the threshold line E requires a shorter automatic braking start distance. , It becomes difficult to apply automatic braking. Therefore, step S
The automatic braking restricting means 74, which regulates automatic braking when the determining means 73 determines that the obstacle ahead is on the opposite lane, is constituted by 52 and 53.

After calculating the various thresholds L0, L2, L3, the risk of collision with the target vehicle is determined in the flow from step S56, and automatic braking or release is performed according to the presence or absence of the collision. That is, in step S56, the relative speed V1 is less than zero.
It is determined above, that is, whether or not both are approaching.

The determination in step S56 is YE
In the case of S, it is determined in step S57 whether or not the distance L1 between the host vehicle and the obstacle ahead (hereinafter, referred to as an inter-vehicle distance) is smaller than the threshold value L2 for generating an alarm.
In step S58, the alarm buzzer 47 is sounded in step S58. Subsequently, in step S59, it is determined whether or not the inter-vehicle distance L1 is smaller than a threshold value L0 for starting automatic braking.
In the case of ES, the actuator 16 is operated to apply automatic braking with full braking in step S60, and thereafter returns. If the determination in step S57 or S59 is NO, the process immediately returns.

On the other hand, if the determination in step S56 is NO, that is, if the own vehicle and the front obstacle (front vehicle) are moving away from each other, in step S61 the inter-vehicle distance L1 becomes smaller than the threshold value L3 for releasing automatic braking. Is also determined. If the determination is YES, the process returns with the automatic braking applied in step S62, while if the determination is NO, the process returns after canceling the automatic braking in step S63.

Next, the operation of the above embodiment, in particular, the control of automatic braking for preventing collision by the control unit 45 in the control box 17 will be described. When the obstacle ahead is on the same lane as the own vehicle, When the vehicle approaches the obstacle ahead and the distance L1 between them becomes smaller than the threshold value L0 at which there is a risk of collision, the control unit 45 activates the actuator 16 and, via the voltage generated by the actuator 16, Automatic braking is performed by switching the opening and closing of the valves in the automatic braking valve unit 4 (step S60). 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 acts on the respective wheels by the operation of the brake devices 6,
As a result, collision with a forward obstacle can be prevented.

On the other hand, when the obstacle in front is a vehicle on the oncoming lane, the automatic braking is restricted by reducing the threshold value L0 for starting automatic braking. Accidental application of braking can be prevented, and the reliability of operation can be improved.

[0024]

As described above, according to the automatic braking system for a vehicle according to the present invention, when an obstacle is on an oncoming lane, the fact is detected and automatic braking is regulated. Erroneous operation can be prevented, and the reliability of operation can be improved.

[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 illustrating a control flow of automatic braking by a control unit for preventing collision.

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 51, 61, 73 Judging means 52, 62, 74 Automatic braking restricting means

Continuing from the front page (72) Inventor Takeshi Takagi 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (72) Inventor Satoshi Morioka 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (72) Inventor Satoru Matsuoka 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Naoyuki Hikita 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-51-31422 (JP, A) JP-A-64-52531 (JP, A) JP-A-4-193641 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name ) B60T 7/12 B60R 21/00

Claims (1)

(57) [Claims] 1. An automatic braking device for a vehicle which detects a distance and a relative speed between an own vehicle and an obstacle, determines a risk of collision with the obstacle based on a result of the detection, and performs automatic braking. If the distance to the obstacle is greater than the distance from the vehicle to the intersection where the straight line connecting the vehicle and the obstacle intersects the median separation line on the road, the obstacle must be on the oncoming lane. And an automatic braking restricting means for restricting automatic braking when the obstacle is determined to be on the oncoming lane by the determining means.