JPH0558237A - Contact preventing device for vehicle - Google Patents

Abstract

PURPOSE:To carry out the contact suppressing procedure such as automatic brake application as early as possible by varying the threshold value in the contact possibility to the larger value as the operation frequency of the contact suppressing procedure is higher, when the contact suppressing procedure is carried out when the possibility of contact exists, on the basis of the distance between an own vehicle and an obstacle and the relative speed. CONSTITUTION:A calculation unit 32 calculates the distance from an obstacle at the front and the relative speed on the basis of each signal supplied from an ultrasonic wave radar unit 31 and each laser unit 33, 34 for pulse laser beam, and a distance.relative speed detecting means 36 is constituted. While, a control unit 45 controls the actuator 16 of an automatic control valve unit for a brake device and an alarm display unit 46 on the basis of each signal supplied from a variety of sensors 41-44. In this case, the control unit 45 calculates the operation frequency of a contact suppressing device. As the operation frequency of the contact suppressing device is high, the threshold value of the contact possibility is changed to the larger value. Accordingly, the contact suppressing procedure such as automatic brake application is carried out as early as possible.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a contact preventing device for this type of vehicle, for example, Japanese Patent Publication No. 39-2565 and Japanese Patent Publication No.
As disclosed in Japanese Laid-Open Patent Publication No. 9-5668, the distance and the relative speed between the vehicle and an obstacle in front of the vehicle are continuously detected by using an optical method or ultrasonic waves, and the detected distance is detected. Judging whether there is a possibility of contact based on the distance and relative speed between the vehicle and the obstacle ahead, and if it is determined that there is a possibility of contact, activate the actuator to automatically brake each wheel. It is known that a contact is avoided by making a contact. In addition to the automatic braking, there is also known a system in which when it is determined that there is a possibility of contact, steering is automatically performed to avoid contact (JP-A-1-124008). reference).

In such a contact prevention device, as disclosed in Japanese Patent Publication No. 55-22291,
When the number of times contact avoidance measures have been taken is counted, and when the number of times exceeds a prescribed value, it may be judged that the driver is not in a normal state such as being very sleepy, and an alarm may be issued or automatic braking may be applied. is there.

[0004]

[Problems to be Solved by the Invention] However, in this way,
Only when the number of times contact avoidance measures are performed exceeds a specified value, an alarm or automatic braking is issued.However, even if the number of times contact avoidance measures are performed is below a specified value, the higher the number, the more Since attention is distracted, it is desirable from the viewpoint of enhancing safety that it is easy to take contact avoidance measures such as automatic braking.

The present invention has been made in view of the above points, and an object thereof is to make the contact avoidance treatment easier as the number of times of the contact avoidance treatment is performed, thereby improving the safety. A vehicle contact prevention device capable of achieving the above is provided.

[0006]

In order to achieve the above object, the invention according to claim 1 is, as a vehicle contact prevention device, a detecting means for detecting a distance and a relative speed between the vehicle and an obstacle. A contact possibility determining means for determining whether or not there is a possibility of contact based on the distance and relative speed between the vehicle and the obstacle detected by the detecting means, and the contact is possible by the determining means. It is assumed that contact avoidance measures are automatically taken when it is determined that there is a possibility. Further, further, an operation frequency calculating means for obtaining the operation frequency of the contact avoidance treatment, and a signal from the operation frequency calculating means,
Threshold change means for changing the contact possibility threshold in the contact possibility determination means to a larger value as the operation frequency of the contact avoidance measure is higher.
Note that the possibility of contact includes not only the possibility of contact with an obstacle in front of the vehicle but also the possibility of contact with an obstacle in the rear of the vehicle.

[0007]

With the above-described structure, in the present invention, the operating frequency of the contact avoidance measure is obtained by the operating frequency calculating means, and the higher the operating frequency, the more the possibility of contact in the contact possibility judging means by the threshold changing means. The threshold value is changed to a large value so that contact avoidance measures such as automatic braking can be taken earlier.

[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. Indicates.

In FIGS. 1 and 2, reference numeral 1 is a master back for increasing the depression force of the brake pedal 2 by the driver,
Reference numeral 3 is 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 then, , ABS (anti-skid brake device) is supplied to the brake device 6 of each wheel through the valve unit 5.

The automatic braking valve unit 4 has a shutter valve 11, a pressure increasing valve 12 and a pressure reducing valve 1 which block the communication between the master cylinder 3 and the brake device 6 side.
3 and each of these three valves 11 to 13 is an electromagnetic 2-port 2-position switching valve. A motor-driven oil pump 14 and an accumulator 15 for storing the pressure oil discharged from the oil pump 14 and maintaining it at a constant pressure are interposed between the pressure increasing valve 12 and the master cylinder 3. It is set up. When the shutter valve 11 is in the open position, the brake pedal 2
Braking is applied by the brake device 6 of each wheel in accordance with the pedaling force of. 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 for 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, pressure oil is returned from the brake device 6 to weaken the braking. The switching of the three valves 11 to 13 is performed by an actuator 16 including a voltage source or the like for applying a voltage to each of them, and the actuator 16 is controlled by receiving a signal from a control box 17.

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

On the other hand, in FIG. 3, reference numeral 31 denotes 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. It is configured such that it transmits to an obstacle such as a vehicle in front of its own vehicle and receives a reflected wave reflected by hitting the front obstacle at a receiving unit, and a calculation for receiving a signal from this radar unit 31. The unit 32 is adapted to calculate the distance and the relative speed with respect to the obstacle ahead by the delay time (Doppler shift) from the transmission time point of the radar reception wave. 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. The radar head units 33 and 34 transmit pulsed laser light from a transmitter to an obstacle ahead of the vehicle. In addition, the reception unit receives the reflected light reflected by the front obstacle, and the arithmetic unit 32 includes the radar head unit 3
Signals from the motors 3 and 34 are received through the signal processing unit 35, and the distance and relative speed to the obstacle ahead are calculated based on the delay time from the transmission point of the laser reception light. Then, the arithmetic unit 32 prioritizes the calculation result of the distance and the relative speed by the system of the radar head units 33 and 34, and uses the calculation result of the distance and the relative speed by the system of the ultrasonic radar unit 31 as an auxiliary. Further, these constitute distance / relative speed detection means 36 for detecting the distance and relative speed between the vehicle and the obstacle ahead.

The transmission / reception direction of the pulsed laser light by the radar head units 33 and 34 is provided so as to be horizontally changeable 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 pulsed laser light from the rotation angle of the motor 37.
Detection signal of the radar head units 33, 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.

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 the longitudinal acceleration (longitudinal G) of the vehicle, 44 is a road surface μ sensor that detects the friction coefficient (μ) of the road surface, and these various sensors 41 to 44 The detection signal is input to the control unit 45 that controls the actuator 16. The control unit 45 also receives the signals of the distance and the relative speed between the vehicle and the front obstacle obtained by the arithmetic unit 32, and these units 45 and 32 are connected to the control box 17 ( (See FIG. 2). Reference numeral 46 denotes an alarm display unit provided on the 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.

FIG. 4 shows a control flow of automatic braking for preventing contact by the control unit 45. 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 the distance between the vehicle and the front obstacle at which there is a possibility of contact between the vehicle and the front obstacle, and automatic braking is started to prevent the contact. The threshold value L0 is calculated using a threshold value map as shown in FIG. The threshold value L2 is the distance between the vehicle and an obstacle ahead of the vehicle that issues an alarm prior to the start of automatic braking. The threshold value L2 for generating this alarm is greater than the threshold value L0 for starting automatic braking. Is also set larger by a predetermined amount. Further, the threshold value L3 is a distance between the vehicle and the front obstacle that releases the possibility of contact after the start of automatic braking and the automatic braking is released. The value is set to a value larger by a predetermined amount than the threshold value L0 for starting automatic braking, 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 the front vehicle comes into contact with the front obstacle and stops, it indicates the inter-vehicle distance required to prevent contact with this vehicle. The front obstacle is always displayed 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 prevent contact with this vehicle when the front vehicle is fully braked,
Threshold line C indicates the inter-vehicle distance required to prevent contact with the preceding vehicle when the preceding vehicle is subjected to deceleration μ / 2g slow braking, and threshold line D indicates that the preceding vehicle maintains a constant vehicle speed. 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 the inter-vehicle distance that can prevent the contact with the vehicle in front even if the own vehicle is automatically braked, but can reduce the impact force at the time of contact. In the case of this embodiment, the threshold line B is selected, and the threshold line B is used to determine the threshold value L0 corresponding to the current relative speed V1.

After calculating the various threshold values L0, L2, and L3, the counter N is read in step S3, and step S3 is read.
The value obtained by adding the safety factor K to the threshold value L0 for the automatic braking start previously obtained in step 4 is added to the new threshold value L0 for the automatic braking start.
And Here, the counter N is the number of automatic braking operations. Further, the safety factor K is obtained by the following formula.

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).

Then, in step S5, it is determined whether or not the relative speed V1 between the vehicle and the obstacle ahead of the vehicle is zero or more, that is, the two are approaching each other. If this determination is YES, the distance L1 between the vehicle and the front obstacle (hereinafter referred to as the inter-vehicle distance) L1 is further determined in step S6 as the threshold value L for the alarm generation.
It is determined whether or not it is smaller than 2. 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 to apply automatic braking with full braking in step S9, 1 is added to the counter N in step S10, and then the process returns. If the determination in step S6 or S8 is NO, the process immediately returns.

On the other hand, when the determination in step S5 is NO, that is, when the host vehicle and the front obstacle (front vehicle) are moving away from each other, the inter-vehicle distance L1 is greater than the threshold L3 for releasing the automatic braking in step S11. Determine if it is small. When the determination is YES, the process returns with the automatic braking applied in step S12, while when the determination is NO, the automatic braking is released in step S13 and then the process returns.

Of the above control flow, particularly step S
If it is determined that there is a possibility of contact based on the distance and relative speed between the own vehicle and the obstacle in front, and if it is determined that there is a possibility of contact, according to 1, S2, S5 to S13. A contact possibility determination unit 51 that controls the operation of the actuator 16 to apply automatic braking is configured. Further, the step S10 constitutes the operation frequency calculating means 52 for obtaining the number of times or the operation frequency of the automatic braking as the contact avoidance measure, and the steps S3 and S4 receive the signal from the operation frequency calculating means 52 to perform the automatic braking. The threshold value changing means 53 is configured to change the threshold value L0 for starting automatic braking to a larger value as the number of operations of is higher.

Next, the operation of the above-described embodiment, in particular, the control of automatic braking for preventing contact by the control unit 45 in the control box 17, will be explained. Becomes smaller than the threshold value L0 for starting automatic braking, the control unit 45 activates the actuator 16 and 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 at. 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 device 6 (caliper 27) of each wheel, and the braking device 6 operates to exert a full braking force on each wheel. It is possible to prevent contact with objects.

In this case, the threshold value L for starting the automatic braking is
A value of 0 counts the number of times automatic braking is performed, and the higher the number of times the automatic braking is performed, the larger the value is changed. With this, it is possible to prevent contact with a front obstacle, and further improve safety.

In the above embodiment, the threshold line B in FIG. 5 is uniquely selected to obtain the threshold value L0 for starting automatic braking, and the relative speed V1 at this time is selected from the threshold line B. Although the threshold value L0 corresponding to the threshold value is obtained, the present invention selectively selects one threshold value from the plurality of threshold lines A to E in FIG. 5 according to the vehicle speed v0 or road conditions. The value line may be selected, and the threshold value L0 corresponding to the current relative speed may be selected from the selected threshold value line.

Further, in the above embodiment, the case where the automatic braking is adopted as the contact avoidance measure is described, but the present invention also applies to the case where the automatic steering is adopted instead of the automatic braking or in combination with the automatic braking. Of course, it can be applied to.

[0027]

As described above, according to the vehicle contact prevention device of the present invention, the threshold value of the possibility of contact is changed to a larger value as the operation frequency of the contact avoidance treatment is higher, so that automatic braking or the like is performed. Since the contact avoidance procedure is adopted earlier, the contact avoidance procedure can be appropriately adopted according to the driving state of the driver, and the safety can be improved.

[Brief description of 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 view of components of a hydraulic circuit of the automatic braking device.

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

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

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

[Explanation of symbols]

 6 Brake Device 16 Actuator 34 Distance / Relative Velocity Detection Means 51 Contact Possibility Judgment Means 52 Actuation Frequency Calculation Means 53 Threshold Change Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Takagi, No. 3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) No. 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Stock In-house (72) Inventor Satoru Matsuoka 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) In-house Naoyuki Hikita 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Corporation

Claims (1)

[Claims] 1. A detection means for detecting a distance and a relative speed between a vehicle and an obstacle, and a possibility of contact based on a distance and a relative speed between the vehicle and the obstacle detected by the detection means. In the contact prevention device for a vehicle, which comprises contact possibility determination means for determining whether or not there is a contact, and automatically performs contact avoidance measures when the determination means determines that there is a possibility of contact. An actuation frequency calculation means for determining the actuation frequency of the treatment, and a signal from the actuation frequency calculation means, and the higher the actuation frequency of the contact avoidance treatment, the larger the threshold value of the possibility of contact in the contact possibility determination means. A vehicle contact prevention device, comprising: