JP2966155B2 - 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 and the like, the distance and the relative speed between the vehicle and an obstacle in front are continuously detected by using an optical method or ultrasonic waves, and the detected speed is detected. Judgment is made based on the distance and relative speed between the host vehicle and the obstacle in front, and if it is judged that there is a possibility of contact, the actuator is actuated to automatically brake each wheel. It is known to avoid the contact by applying a force. In addition to this automatic braking, there is also known a system in which when it is determined that there is a possibility of contact, the steering is automatically performed to avoid the contact (Japanese Patent Application Laid-Open No. 1-124008). reference).

In such a contact prevention device, as disclosed in Japanese Patent Publication No. 55-22291,
It counts the number of times contact avoidance measures are taken, and when the number of times exceeds a predetermined value, it is possible to judge that the driver is not in a normal state, such as being very sleepy, and to issue an alarm or apply automatic braking. is there.

[0004]

However, as described above,
The alarm and automatic braking are performed only when the number of times of contact avoidance measures is equal to or greater than a predetermined value. Since attention is distracted, it is desirable from the viewpoint of enhancing safety to make it easier to take contact avoidance measures such as automatic braking.

The present invention has been made in view of the foregoing, and an object of the present invention is to increase the number of times the contact avoidance measures are performed, so that the contact avoidance measures are more likely to be performed, thereby improving safety. It is an object of the present invention to provide a vehicle contact prevention device capable of achieving the following.

[0006]

In order to achieve the above object, the invention according to claim 1 comprises a detecting means for detecting a distance and a relative speed between the own vehicle and an obstacle, and the detecting means detects the distance and the relative speed. When the distance between the determined own vehicle and the obstacle becomes smaller than a first threshold value set in accordance with the relative speed, a vehicle that automatically performs a contact avoidance measure with the obstacle The contact prevention device is assumed. When the distance between the own vehicle and the obstacle becomes smaller than a second threshold value set to a value larger than the first threshold value, an alarming means for issuing an alarm, An operating frequency calculating means for obtaining an operating frequency of the avoidance measure, and correcting the value of the first threshold value to a larger value as the operating frequency of the contact avoidance measure increases, and changing the correction to the first threshold value. Threshold value changing means for restricting the value of to a value smaller than a predetermined upper limit value.

[0007]

According to the present invention, when the distance between the host vehicle and the obstacle becomes smaller than a first threshold value set based on the relative speed, the present invention performs contact avoidance measures. Before that, the driver is alerted by issuing an alarm when the distance to the obstacle becomes smaller than a second threshold larger than the first threshold. In addition, the higher the frequency of operation of the contact avoidance measures, the more easily the contact avoidance measures are activated by correcting the value of the first threshold value to a large value, so that the driver's attention is distracted. Occasionally, the contact avoidance measures will be easier to operate. Since the first threshold value is set to the upper limit value, it is possible to prevent the contact avoidance measure from excessively operating.

[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 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 according 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 Thereafter, the brake is supplied to a brake device 6 of each wheel through an ABS (anti-skid brake device) valve unit 5.

The automatic braking valve unit 4 has a shutter valve 11, a pressure increasing valve 12, and a pressure reducing valve 13 for blocking communication between the master cylinder 3 and the brake device 6 side. Valves 11 to 13
Are each composed of an electromagnetic two-port two-position switching valve. 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, braking is applied by the brake device 6 of each wheel according to the depression force of the brake pedal 2. On the other hand, when the shutter valve 11 is in the closed position, the pressure increasing valve 12 is switched to the open position, and the pressure reducing valve 13 is switched to the closed position.
Is supplied to the brake device 6 of each wheel to apply braking, and the pressure increasing valve 12 is set to the closed position, and 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 1 including a voltage source for applying a voltage to each of them.
6 and the actuator 16 is controlled by receiving a signal from the 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 31 denotes an ultrasonic radar unit provided at the front 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 to the obstacle ahead and the relative speed based on the delay time (Doppler shift) from the transmission time of the radar reception wave. 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 that is reflected upon hitting the front obstacle by the receiving unit.
3 and 34 are received through the signal processing unit 35, and the distance 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 uses the calculation results of the distance and the relative speed by the systems of the ultrasonic radar units 31 in an auxiliary manner. These elements 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 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 both the units 45 and 32 control the control box 17 ( (See FIG. 2). Reference numeral 46 denotes an alarm display unit provided on an instrument panel in the vehicle compartment.
Is provided with an alarm buzzer 47 and a distance display section 48 which receive signals from the control unit 45, respectively.

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 (first threshold value) is a distance between the host vehicle and the obstacle in front of which there is a possibility of contact between the host vehicle and the obstacle in front and automatic braking is started to prevent contact. And the threshold value L0 for starting the automatic braking.
Is calculated using a threshold map as shown in FIG. The threshold value L2 (second threshold value) is a distance between the host vehicle and an obstacle ahead which issues an alarm prior to the start of automatic braking. It is set to be larger than the threshold value L0 for starting braking by a predetermined amount. The threshold value L3 is a distance between the host vehicle and an obstacle in front of which the possibility of contact after the start of automatic braking is eliminated and 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.
Indicates the inter-vehicle distance necessary to prevent the preceding vehicle from contacting the preceding obstacle and stopping when the preceding vehicle stops, and the preceding obstacle always stops regardless of the relative speed V1. in a case ones (that is, when the relative speed V1 is equal to the vehicle speed v0) the same value as the (numeric expression v0 ^2/2 [mu] g)
Take. A threshold line B indicates an inter-vehicle distance (numerical formula V1 / (2v0-V1) / 2 .mu.g) necessary to prevent contact with the preceding vehicle when the vehicle is fully braked, and a threshold line C Indicates the inter-vehicle distance necessary to prevent contact with the preceding vehicle when the preceding vehicle applies gentle braking with a deceleration μ / 2 g, and the threshold line D indicates the vehicle distance when the preceding vehicle maintains a constant vehicle speed. shows the inter-vehicle distance (numeric expression V1 ^2/2 [mu] g) required to prevent contact with. 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 L0 corresponding to the current relative speed V1 is obtained from the threshold line B.

After calculating the various thresholds L0, L2, L3, the counter N is read in step S3, and
4. The value obtained by multiplying the automatic braking start threshold L0 previously obtained in step 4 by the safety factor K is used as the new automatic braking start threshold L0.
And Here, the counter N is the number of times of the automatic braking operation. Further, the safety factor K is obtained by the following equation.

K = 1 + (N / 1000) However, the safety factor K takes a value sufficiently smaller than the safety margin A (for example, 1.5) (1.5>K> 1).

Subsequently, in step S5, it is determined whether or not the relative speed V1 between the own vehicle and the obstacle ahead is equal to or greater than zero, that is, whether or not both are approaching. If this determination is YES, furthermore, at step S6, the distance L1 between the host vehicle and the obstacle ahead (hereinafter referred to as the inter-vehicle distance) is set to the threshold value L for generating the alarm.
It is determined whether it is smaller than 2 and if this determination is YES, the alarm buzzer 47 is sounded in step S7. Subsequently, in step S8, 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 S, the actuator 16 is operated so as to apply the automatic braking with the full braking in step S9, and 1 is added to the counter N in step S10, and then the routine returns. If the determination in step S6 or S8 is NO, the routine immediately returns.

On the other hand, when the determination in step S5 is NO, that is, when 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.

In the above control flow, in particular, step S
6 and S7, an alarm is issued when the distance between the host vehicle and the obstacle in front becomes smaller than the alarm generation threshold L2 set to a value larger than the threshold L0 for starting automatic control. The alarm means 51 is configured. Step S
The operation frequency calculating means 52 for obtaining the number of times or the frequency of the operation of the automatic braking as the contact avoidance measure is constituted by 10 and the operation frequency calculating means 5 by steps S3 and S4.
2, the value of the threshold value L0 for starting automatic braking is corrected to a larger value as the number of times of automatic braking is increased, and the correction is made when the value of the threshold value L0 for starting automatic braking becomes a predetermined value. A threshold value changing means 53 for regulating the value to be smaller than the upper limit value is provided.

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. Is smaller than the threshold value L0 for starting automatic braking, the control unit 45 activates the actuator 16,
The automatic braking is performed by switching the opening and closing of the valve in the automatic braking valve unit 4 via the voltage generated in the above. That is, while closing the shutter valve 11,
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 this case, the threshold value L for starting the automatic braking is
In the case of 0, the number of times of automatic braking is counted, and the higher the number of times, the larger the value is changed, so that the more distracted the driver, the easier it is to apply automatic braking earlier, With this, contact with a forward obstacle can be prevented, and safety can be further improved.

In the above-described embodiment, when determining the threshold value L0 for starting automatic braking, the threshold line B in FIG. 5 is uniquely selected, and the relative speed V1 at the present time is determined from the threshold line B. Is determined from the plurality of threshold lines A to E in FIG. 5 according to the vehicle speed v0 or road conditions. A configuration may be adopted in which a value line is selected, and a threshold value L0 corresponding to the current relative speed is selected from the selected threshold value line.

In the above embodiment, the case where the automatic braking is employed as the contact avoidance measure has been described. However, the present invention is similarly applicable to the case where the automatic steering is employed instead of or in combination with the automatic braking. Of course.

[0027]

As described above, according to the vehicle contact prevention device of the present invention, the higher the frequency of operation of the contact avoidance measures, the easier the contact avoidance measures are activated, and the more the driver's attention is distracted. As the contact avoidance measure becomes easier to operate, the threshold value of the contact avoidance measure can be set to an upper limit to prevent the contact avoidance measure from being excessively activated.
Contact avoidance measures can be appropriately taken according to the driving state of the driver, and safety 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 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 34 Distance / relative speed detecting means 51 Alarm means 52 Operating frequency calculating means 53 Threshold value changing means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B60R 21/00 624E 626B (72) Inventor Takeshi Takagi 3-1, Fuchu-cho, Shinchu, Aki-gun, Hiroshima Prefecture Inside Mazda Motor Corporation (72) Inventor Satoshi Morioka 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (72) Inventor Satoru Matsuoka 3-1 Shinchi-chichi, Fuchu-cho, Aki County, Hiroshima Prefecture Inside Mazda Co., Ltd. (72) Inventor Hikita Naoyuki 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (56) References JP-A-2-254030 (JP, A) JP-A-54-27136 (JP, A) JP-A-2-254030 (JP, A) JP-A-3-176799 (JP, A) JP-B-55-22291 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60R 21/00 B60T 7 / 14 G08G 1/16 B60K 28/06

Claims (1)

(57) [Claims] 1. A detecting device for detecting a distance and a relative speed between a host vehicle and an obstacle, wherein a distance between the host vehicle and the obstacle detected by the detecting device is:
Than the first threshold value set according to the relative speed
In a vehicle contact prevention device that automatically takes measures to avoid contact with an obstacle when the distance becomes smaller, the distance between the own vehicle and the obstacle is smaller than the first threshold value.
Becomes smaller than a second threshold value set to a large value.
And when the alarm means and the operation frequency calculating means for determining an operating frequency of the contact avoidance measures, as the first high operating frequency of the contact avoidance action threshold for issuing an alarm
Value is corrected to a large value, and the correction is
The threshold value of 1 will be smaller than the predetermined upper limit
A vehicle contact prevention device comprising: a threshold value changing means for restricting a vehicle.