JP3308292B2 - Vehicle safety equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a vehicle, and more particularly, to a vehicle which detects a relative speed between a vehicle and a preceding vehicle, determines a possibility of contact from the detection result, and performs a danger avoiding operation. Related to safety devices.

[0002]

2. Description of the Related Art Conventionally, as a safety device for a vehicle of this kind, for example, JP-B-39-2565 and JP-B-39
As disclosed in Japanese Patent No. -5668, etc., the distance and relative speed between the vehicle and an obstacle in front are continuously detected using an optical method or ultrasonic waves, and the detected The system determines whether there is a possibility of contact based on the distance and the relative speed between the vehicle and the obstacle in front, and if it is determined that there is a possibility of contact, activates the automatic braking device and activates each wheel. 2. Description of the Related Art There is a known brake that automatically applies a brake to prevent contact.

[0003]

On the other hand, when the vehicle is following a vehicle with a relatively low relative speed, the flow of the vehicle is often obstructed, and in such a situation, the vehicle ahead may be overtaken. In this case, in the conventional automatic braking device for a vehicle, there is a possibility that the brake is inadvertently operated and a rear-end collision from a following vehicle may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle safety device which can ensure safety by properly performing a danger avoiding operation when overtaking during a following running with a small relative speed.

[0005]

Means for Solving the Problems To achieve the above object, a vehicle safety device according to the present invention comprises: a relative speed detecting means for detecting a relative speed between a host vehicle and a preceding vehicle; Acceleration detecting means, distance detecting means for detecting the distance between the own vehicle and the preceding vehicle, and automatic braking when the distance between the own vehicle and the preceding vehicle is smaller than a first predetermined distance set according to the relative speed. Automatic braking means for performing, when the distance between the host vehicle and the preceding vehicle is smaller than a second predetermined distance set to a value larger than the first predetermined distance, alarm means for issuing an alarm, the automatic braking means is provided When the relative speed is equal to or less than a predetermined value larger than zero and the acceleration of the own vehicle is equal to or more than the predetermined acceleration, the automatic braking is not performed regardless of the distance between the own vehicle and the preceding vehicle. It is characterized by.

[0006]

[0007]

[0008]

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a safety device of the present invention. In FIG. 1, reference numeral 1 denotes an ultrasonic radar unit provided at a front portion of a vehicle body. The ultrasonic radar unit 1 transmits an ultrasonic wave from a transmitting unit of a vehicle, which is not shown in detail in the drawing, as is well known. The arithmetic unit 2 receives signals from the radar unit 1 while transmitting toward an obstacle such as a vehicle ahead and receiving a reflected wave reflected by the front obstacle at a receiving unit. The distance and the relative speed between the host vehicle and the obstacle ahead are calculated based on the delay time (Doppler shift) from the transmission time of the radar reception wave. Reference numerals 3 and 4 denote a pair of radar head units provided on the left and right sides of the front part of the vehicle, respectively. Each of the radar head units 3 and 4 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 wave reflected by the front obstacle, and the arithmetic unit 2 receives the signals from the radar head units 3 and 4 through the signal processing unit 5. The distance and the relative speed between the own vehicle and the obstacle ahead are calculated based on the delay time from the transmission time of the laser reception light. The arithmetic unit 2 gives priority to the calculation results of the distance and the relative speed by the systems of the radar head units 3 and 4, and uses the calculation results of the distance and the relative speed by the systems of the ultrasonic radar unit 1 in an auxiliary manner. Has become. These also constitute a distance / relative speed detecting means 6 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 radar head units 3 and 4 are provided so as to be changeable in the horizontal direction by a motor 7, and the operation of the motor 7 is controlled by the arithmetic unit 2. Numeral 8 denotes an angle sensor for detecting the transmission / reception direction of the pulse laser beam from the rotation angle of the motor 7. The detection signal of the angle sensor 8 is input to the arithmetic unit 2, and the radar head unit 3 and the The transmission and reception directions of the pulse laser light are added to the calculation of the distance and the relative speed by the four systems.

A vehicle speed sensor 11 detects a vehicle speed.
12 is a road surface μ sensor for detecting a road surface friction coefficient (μ),
Reference numeral 13 denotes an acceleration sensor for detecting acceleration. Detection signals from these sensors 11, 12, and 13 are input to the control unit 21. The control unit 21 also receives signals of the distance and the relative speed between the host vehicle and the preceding vehicle, which is an obstacle in front, obtained by the arithmetic unit 2. 22
Is an alarm display unit provided on an instrument panel in the passenger compartment. The alarm display unit 22 has a distance display unit 2 for receiving signals from the control unit 21.
3 and an alarm buzzer 24 are provided. The control unit 21 outputs a signal to the automatic brake device 31.

FIG. 2 is a threshold value calculation map. When performing automatic braking for preventing contact, various threshold values L ₀ , L
_2, L ₃ needs to be calculated. The threshold value L ₀ is a distance between the own vehicle and the preceding vehicle, which is likely to be in contact with the preceding vehicle, which is the preceding vehicle, and starts automatic braking for preventing contact. The calculation of the threshold value L ₀ is performed using a threshold value calculation map as shown in FIG. The threshold L ₂ issues a warning prior to the start of the automatic braking,
A vehicle distance between the vehicle and the vehicle in front, the alarm threshold L ₂ is a predetermined amount set greater than the threshold value L ₀ of the automatic braking start. The threshold L ₃ releases the automatic braking eliminates the possibility of the automatic braking start after contact, a following distance between the vehicle and the vehicle in front, the threshold L ₃ of the automatic brake release, said a predetermined amount set greater than the threshold value L ₀ of the automatic braking start.

Here, the threshold value calculation map shown in FIG. 2 will be described. In this map, the threshold line A indicates the inter-vehicle distance necessary to prevent contact with the preceding vehicle when the preceding vehicle comes into contact with the obstacle ahead and stops. Irrespective of the size of _{1, when} the obstacle ahead (front vehicle) is a stationary object (that is, the relative speed V
_{(When 1} is the same as the own vehicle speed V ₀ ) (numerical expression V ₀ ²⁾
/ 2 μg). The threshold line B indicates the inter-vehicle distance (numerical formula V ₁ · (2V ₀ −V ₁ ) / 2 μg) required to prevent contact with the preceding vehicle when the preceding vehicle fully applies braking. 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 threshold line D indicates the constant vehicle speed of the preceding vehicle. when kept indicating the inter-vehicle distance (numerical formula V ₁ ² / 2μg) necessary to prevent contact with the preceding vehicle. Further, the threshold line E
Indicates the inter-vehicle distance at which contact with the preceding vehicle cannot be prevented even when the vehicle is automatically braked, 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 L ₀ corresponding to the current relative speed V ₁ is obtained from the threshold line B. Furthermore the threshold L ₂ and the threshold L ₃ is obtained from the threshold L _0.

Next, the contents of control by the safety device of the present invention will be described with reference to the flowchart of FIG. S in the following description
Indicates each step. First, in S1, the inter-vehicle distance L ₁ between the own vehicle and the preceding vehicle, the vehicle speed V ₀ , and the relative speed V ₁ between the own vehicle and the preceding vehicle are read. Next, in S2, the threshold values L ₀ , L ₀ , and B _{0 for} starting automatic braking are calculated from the read values of L ₁ , V ₀ , and V ₁ using the threshold calculation map shown in FIG.
The threshold value L _{2 for} alarm generation and the threshold value L ₃ for automatic brake release are calculated.

[0015] In S3, determines the relative velocity V ₁ is whether zero or more, i.e. whether the vehicle is moving away or approaching the preceding vehicle. If the relative speed V ₁ is less than zero i.e. the vehicle is determined to be approaching the preceding vehicle, the process proceeds to S4,
Vehicle distance L ₁ is equal to or threshold L ₂ smaller than or of alarm. In S4, when the headway distance L ₁ is determined to be the threshold value L ₂ is smaller than the alarm, the process proceeds to S5, whether the relative velocity V ₁ is greater than a predetermined value, i.e. rapidly on the vehicle is the preceding vehicle It is determined whether or not it is approaching.
If the relative velocity V ₁ is greater than the predetermined value, since already been determined to have entered a warning generation region in S4,
At S6, an alarm is issued by sounding the alarm buzzer 24 (see FIG. 1). Then, in S7, the inter-vehicle distance L
₁ determines whether the threshold L ₀ is smaller than or not starting the automatic braking. If the inter-vehicle distance L ₁ is determined to the threshold value L ₀ is smaller than the start automatic braking, because it is automatic braking initiation region, at S8, apply automatic braking.

[0016] On the other hand, in S5, when the relative velocity V ₁ is below the predetermined value, the process proceeds to S9, and determines the vehicle acceleration Vα whether greater than a predetermined value. If the acceleration Vα of the own vehicle is larger than the predetermined value, it is considered that the driver is consciously accelerating for overtaking and approaching the preceding vehicle.
For this reason, in such a case, since it is determined that the vehicle is in the warning generation area, only a warning is issued in S10, and the automatic braking is not applied. If it is determined in S9 that the acceleration Vα of the vehicle is equal to or less than the predetermined value, the process proceeds to S6.

Next, in S3, when it is determined that the own vehicle is moving away from the preceding vehicle, the process proceeds to S11, where the following distance L is set.
₁ determines whether the threshold L ₃ is smaller than or not automatic brake release. If not, the process proceeds to S12 and the braking is released. As described above, the relative velocity V ₁ at S5 is determined to be equal to or lower than a predetermined value, further, when the vehicle acceleration Vα is determined to be greater than the predetermined value at S9 is consciously for drivers of overtaking It is considered that the vehicle accelerated and was approaching the preceding vehicle. In such a situation,
According to this embodiment, only an alarm is issued and automatic braking is not applied. For this reason, when the vehicle speed is low and the flow of the vehicle is obstructed during overtaking, when overtaking the preceding vehicle, the brake is not inadvertently actuated and the vehicle may collide with the following vehicle. Absent.

[0018] In the above embodiment, the relative velocity V ₁ at S5 is determined to be equal to or lower than a predetermined value, further, when the vehicle acceleration Vα is determined to be greater than the predetermined value at S9, as the danger avoidance operation, It only issues an alarm,
The automatic braking is not applied. In the present invention, as a danger avoiding operation in such a situation, after an alarm is issued, the braking amount may be reduced and automatic braking may be applied. Also, when applying automatic braking may be set the threshold L ₀ of the automatic braking start to a smaller value.

[0019]

As described above, according to the present invention, in the case of overtaking during a following run with a small relative speed, safety can be ensured by properly performing the danger avoiding operation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a safety device of the present invention.

FIG. 2 is a threshold value calculation map used in the safety device of the present invention.

FIG. 3 is a flowchart showing control contents by the safety device of the present invention.

[Explanation of symbols]

 6 Distance / relative speed detecting means 11 Vehicle speed sensor 13 Acceleration sensor 21 Control unit 24 Alarm buzzer 31 Automatic brake device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G08G 1/09-1/16 B60T 7/12 B60R 21/00

Claims (1)

(57) [Claims] 1. A relative speed detecting means for detecting a relative speed between a host vehicle and a preceding vehicle, an acceleration detecting means for detecting acceleration of the host vehicle, a distance detecting means for detecting a distance between the host vehicle and the preceding vehicle. An automatic braking means for performing automatic braking when a distance between the own vehicle and the preceding vehicle is smaller than a first predetermined distance set in accordance with the relative speed; and a distance between the own vehicle and the preceding vehicle being greater than the first predetermined distance. Alarm means for issuing an alarm when the distance is smaller than a second predetermined distance set to a large value, wherein the automatic braking means is configured to determine that the relative speed is equal to or less than a predetermined value larger than zero and the acceleration of the own vehicle is equal to a predetermined acceleration. In the above, the vehicle safety device is configured not to perform the automatic braking regardless of the distance between the own vehicle and the preceding vehicle.