JP2002166824A - Vehicle rear end collision preventing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle rear end collision preventing device capable of applying brakes to the driver's own vehicle with a proper strength and at a proper timing upon acquiring the information on the foregoing vehicle including its braked condition. SOLUTION: The vehicle rear end collision preventing device is composed of a distance measuring device 1 to measure the inter-vehicle distance between driver's own vehicle A and the foregoing vehicle B, a communication device 2 to receive the running information including the start of braking operation and deceleration of the foregoing vehicle B sent therefrom, a warning device 3 to emit a warning of rear end collision upon acquiring the inter-vehicle distance and running information and judging the possibility of rear end collision to the foregoing vehicle B from the acquired information and the running speed of the driver's own vehicle A, and an automatic brake device 4 to apply brakes to the driver's own vehicle A so that its deceleration becomes greater than that of the foregoing vehicle B in case there is such possibility of rear end collision. Thereby the brakes are applied to the driver's own vehicle A with a proper strength and at a proper timing by getting the running information including the braked condition of the foregoing vehicle B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle rear-end collision prevention device for preventing a rear-end collision with a preceding vehicle while the vehicle is traveling. The present invention relates to a vehicle collision prevention device that applies a brake to a host vehicle.

[0002]

2. Description of the Related Art Conventionally, in order to prevent a collision with a preceding vehicle while the vehicle is running, it is known that the preceding vehicle has applied a brake by seeing the lighting of a brake lamp or the like, and thereafter, the following vehicle operates the brake. The vehicle decelerates, increasing the distance between vehicles or stopping the vehicle to prevent a rear-end collision. However, in this case, there is a time delay between the time when the preceding vehicle applies the brake and the time when the following vehicle operates the brake while watching the lighting of the brake lamp or the like of the preceding vehicle, and when the driver depresses the brake pedal and the brake pressure is reduced. There was a brake pressure delay until the pressure increased to a predetermined pressure, and it was not possible to effectively prevent a rear-end collision by performing a brake operation at an appropriate timing.

On the other hand, for example, Japanese Patent Application Laid-Open No.
As described in Japanese Patent Publication No. 64 and Japanese Utility Model Laid-Open No. 5-72629, the distance between the host vehicle and the preceding vehicle is measured, and when the distance between the vehicles becomes a dangerous distance, a rear-end collision warning is issued. A vehicle rear-end collision prevention device that automatically applies a brake to a host vehicle has been proposed.

[0004]

However, such a conventional vehicle rear-end collision prevention device simply measures the inter-vehicle distance between the host vehicle and the preceding vehicle, and when the inter-vehicle distance becomes a predetermined dangerous distance. Since only the brakes were automatically applied to the own vehicle, the information such as the start of the brake operation of the preceding vehicle and the deceleration thereof was not known, and the collision prevention operation of the own vehicle in accordance with the running state of the preceding vehicle could not be performed. There was something. For example, when the preceding vehicle is suddenly braked and suddenly decelerated, even if the inter-vehicle distance is equal to or longer than the dangerous distance, it quickly falls below the dangerous distance, and it may not be possible to effectively prevent a rear-end collision. Further, it is impossible to provide a warning to a vehicle in front that the vehicle is approaching from behind.

In view of the above, the present invention has been made to solve the above-mentioned problem, and provides a vehicle rear-end collision prevention device that obtains driving information including a brake operation of a preceding vehicle and applies a brake to an own vehicle at an appropriate timing and intensity. The purpose is to.

[0006]

In order to achieve the above object, a vehicle rear-end collision prevention apparatus according to the present invention comprises a distance measuring device for measuring an inter-vehicle distance between a host vehicle and a preceding vehicle, and A communication device that receives travel information including the start of braking operation of the vehicle and its deceleration, and determines the possibility of a rear-end collision with the preceding vehicle from the inter-vehicle distance to the preceding vehicle and the traveling information and the traveling speed of the own vehicle. An alarm device that issues a rear-end collision alarm, and an automatic brake device that applies a brake to the own vehicle so as to have a deceleration greater than the deceleration of the preceding vehicle when there is a possibility of a rear-end collision with the preceding vehicle Things.

[0007] With this configuration, the inter-vehicle distance between the host vehicle and the preceding vehicle is measured, and travel information sent from the preceding vehicle including the start of braking operation of the preceding vehicle and the deceleration thereof is received. The collision distance between the vehicle and the traveling information of the vehicle and the traveling speed of the own vehicle are determined to determine the possibility of a rear-end collision with the front vehicle, and a rear-end collision warning is issued. If there is a possibility of the rear-end collision with the front vehicle, the deceleration of the front vehicle is determined The operation is performed so as to apply a brake to the own vehicle so that the deceleration becomes larger. Thereby, the traveling information including the braking operation of the preceding vehicle is obtained, and the own vehicle is braked at an appropriate timing and intensity.

Further, the communication device transmits a warning of approaching a vehicle from behind to the preceding vehicle. This warns that the vehicle is approaching the preceding vehicle from behind.

Further, the communication device performs bidirectional communication with a vehicle ahead only when necessary for a rear-end collision warning. Accordingly, communication is performed only when the inter-vehicle distance to the preceding vehicle is short and it is necessary to issue a rear-end collision warning, thereby reducing costs.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a vehicle rear-end collision prevention device according to the present invention.
FIG. 2 is a schematic diagram showing a state in which the vehicle rear-end collision prevention device is applied to an actual vehicle. This vehicle rear-end collision prevention device prevents a rear-end collision with a preceding vehicle while the vehicle is running, and includes a distance measurement device 1, a communication device 2, an alarm device 3, an automatic brake device 4, a speedometer 5, a control device 6.

The distance measuring device 1 measures an inter-vehicle distance between a host vehicle A and a preceding vehicle B shown in FIG. 2 and emits light, infrared rays, ultrasonic waves, radio waves, and the like from the front end of the host vehicle A. A distance sensor for measuring the distance from the reflected signal to the rear end of the preceding vehicle B is provided at the front end of the host vehicle A.

The communication device 2 receives traveling information including the time of the start of braking operation of the preceding vehicle B and the deceleration of the traveling of the vehicle sent from the preceding vehicle B, and is mounted at an appropriate position in the own vehicle A. Reference numeral 7 indicates the antenna. The communication device 2 transmits a warning of approaching the vehicle B from behind to the vehicle B in front. In addition, the communication device 2 is configured to perform bidirectional communication with the preceding vehicle B only when necessary for a rear-end collision warning described later.

The warning device 3 issues a rear-end collision warning by judging the possibility of a rear-end collision with the front vehicle B based on the inter-vehicle distance to the front vehicle B, its traveling information, and the traveling speed of the host vehicle A. A signal of an inter-vehicle distance to the preceding vehicle B is input from the measuring device 1, and a signal of driving information including a start time of a brake operation of the preceding vehicle B and a deceleration of vehicle driving is input from the communication device 2, and a speedometer 5 is input. A signal of the traveling speed of the host vehicle A is input, and the possibility of a rear-end collision with the preceding vehicle B is determined. An alarm buzzer that generates an alarm sound, an alarm lamp that generates a flashing light, or an audio device that transmits an alarm message by voice is provided near the driver's seat.

The automatic brake device 4 applies a brake to the own vehicle A so that the deceleration is greater than the deceleration of the preceding vehicle B when there is a possibility of a collision with the preceding vehicle B. As shown in FIG. 3, the horizontal axis represents time and the vertical axis represents deceleration, the map curve of the preceding vehicle B is indicated by a solid line, and the map curve of the host vehicle A is operated according to a braking map indicated by a broken line. I have.

For example, the preceding vehicle B starts the brake operation at time "0", the brake pressure increases, the brake is applied, the deceleration increases along the curve b1, and the maximum deceleration increases along the curve b2. Suppose the deceleration falls. in this case,
The own vehicle A starts the brake operation with a delay of time t1, applies the brake by rapidly increasing the brake pressure by the function of the automatic brake device 4 (the rising speed of the brake pressure is faster than the manual operation), and applies the curve b1. The deceleration rises rapidly along a curve a1 that rises faster than the vehicle, and reaches a deceleration greater than the maximum deceleration of the preceding vehicle B. The curve b2 is delayed from the maximum deceleration of the preceding vehicle B by a time t2. The deceleration is set to decrease along a curve a2 that falls more slowly. Thereby, the own vehicle A is braked at a deceleration greater than the deceleration of the preceding vehicle B, and the inter-vehicle distance with the preceding vehicle B is increased or the vehicle is stopped.

The control section 6 controls the operation of each of the above-mentioned components, and comprises, for example, a CPU (Central Processing Unit), and all of the above-mentioned components are connected.

As shown in FIG. 2, each component of the vehicle rear-end collision prevention device shown in FIG.
It is desirable to be equipped as well. In this case, the front vehicle B needs to be provided with the communication device 2 that transmits at least the traveling information including the start of the brake operation of the front vehicle B and the deceleration thereof, and receives the vehicle approach warning from the own vehicle A. There is. As a result, it is possible to determine the possibility of a rear-end collision with the front vehicle B between the host vehicle A and the front vehicle B to prevent the rear-end collision. Further, between the host vehicle A and a subsequent vehicle not shown, the possibility of a rear-end collision is similarly determined to prevent a rear-end collision.

Next, the operation of the thus configured vehicle rear-end collision prevention device will be described with reference to FIG. Here, as shown in FIG. 2, it is assumed that the host vehicle A is traveling behind the front vehicle B, and a case where a rear-end collision is prevented between the two will be described. First, the communication device 2 of the own vehicle A shown in FIG. 2 is turned on, and the travel information including the brake operation start and the deceleration thereof transmitted from the communication device 2 of the preceding vehicle B is received (step S1).

In this state, it is determined whether or not the preceding vehicle B has started the brake operation (step S2). If the preceding vehicle B has not started the brake operation, step S
2 proceeds to the “NO” side to continue monitoring the start of the brake operation, and proceeds to the “YES” side when a signal for starting the brake operation such as a sudden brake is received.

Next, the distance between the host vehicle A and the preceding vehicle B is measured by the distance measuring device 1 shown in FIG. 2 (step S).
3). The measured inter-vehicle distance signal is sent to the control unit 6 shown in FIG. 1, and the control unit 6 receives the information on the deceleration of the forward vehicle B received in step S1 and the traveling speed of the own vehicle A from the speedometer 5. The control unit 6 determines whether there is a possibility of a rear-end collision with the preceding vehicle B based on the information (step S4).

Now, the inter-vehicle distance with the preceding vehicle B is sufficient, or the deceleration of the preceding vehicle B is small, or the own vehicle A
If it is determined that the traveling speed of the vehicle is slow and there is no possibility that the vehicle will collide with the vehicle B ahead, step S4 proceeds to the “NO” side. In this case, the automatic brake device 4 shown in FIG.

On the other hand, the distance between the vehicle and the preceding vehicle B is small,
Or the deceleration due to the brake operation of the preceding vehicle B is large,
Alternatively, if the traveling speed of the host vehicle A is high and these three conditions are overlapped, and it is determined that there is a possibility of a rear-end collision with the preceding vehicle B, step S4 proceeds to the “YES” side. Then, a rear-end collision alarm is issued by the alarm device 3 to the own vehicle A, and an approach warning of the vehicle from behind is transmitted to the preceding vehicle B via the communication device 2 of the own vehicle A and the preceding vehicle B (step S5). ). In this case, the preceding vehicle B receives the approach warning in its own communication device 2, and the driver recognizes that the vehicle is approaching from behind.

Next, the deceleration required for the vehicle A in the above state is calculated (step S6). That is, the control unit 6 illustrated in FIG. 1 uses the information on the brake operation start time and the deceleration of the preceding vehicle B input via the communication device 2 and calculates the information according to the braking map illustrated in FIG.
In FIG. 3, a deceleration curve a1 of the host vehicle A is added to add a time delay t1 until the host vehicle A starts the braking operation, and the deceleration curve a1 of the host vehicle A is twice as fast as the deceleration curve b1 of the front vehicle B, for example. The deceleration from the maximum deceleration of the preceding vehicle B reaches a deceleration greater than the maximum deceleration of the preceding vehicle B with a delay of time t2 from the maximum deceleration of the preceding vehicle B.
The deceleration is set so as to decrease along a curve a2 that falls more slowly. As a result, the host vehicle A is braked at a deceleration greater than the deceleration of the preceding vehicle B.

The deceleration curve a1 of the host vehicle A is not limited to twice the deceleration curve b1 of the preceding vehicle B, but increases as the deceleration curve b1 of the preceding vehicle B increases.
Eventually it may rise to the maximum.

Next, the control section 6 sends the signal of the calculated deceleration of the vehicle A to the automatic brake device 4 to operate the automatic brake device 4 (step S7). As a result, the automatic brake device 4 automatically operates according to the braking map shown in FIG. 3, and applies a brake to the host vehicle A at a deceleration greater than the deceleration of the preceding vehicle B.
Therefore, the inter-vehicle distance with the preceding vehicle B increases or the vehicle stops.

In this state, a signal from the distance measuring device 1 is input, and it is determined whether or not the inter-vehicle distance is greater than the safe distance (step S8). If still less than the safe distance,
The step S8 proceeds to the "NO" side and the automatic braking device 4
Continue operation, and if the safety distance is exceeded,
Go to “YES” side. And, the automatic braking device 4
Is stopped (step S9). As a result, the host vehicle A can safely travel while avoiding a rear-end collision with the preceding vehicle B.

The above operation is also performed in the case of preventing rear-end collision between the host vehicle A and a subsequent vehicle (not shown) in FIG. That is, if each vehicle is equipped with the vehicle rear-end collision prevention device shown in FIG. 1, the above rear-end collision can be prevented between all vehicles.

[0028]

The present invention has been configured as described above.
According to the first aspect of the invention, it is possible to obtain the travel information including the brake operation of the preceding vehicle and apply the brake to the own vehicle at an appropriate timing and intensity. Therefore, the rear-end collision prevention operation of the own vehicle according to the traveling state of the preceding vehicle can be performed.
For example, even when the preceding vehicle is suddenly braked and suddenly decelerated, an appropriate brake can be applied to the own vehicle in accordance with the inter-vehicle distance at that time and the deceleration of the preceding vehicle, and a rear-end collision can be effectively prevented.

According to the second aspect of the present invention, the communication device transmits a vehicle approach warning to the preceding vehicle from behind, so that the vehicle approaches the preceding vehicle from behind. Can be warned.
Therefore, the preceding vehicle receives the approach warning by its own communication device, and the driver can recognize that the vehicle is approaching from behind and take a corresponding action.

Further, according to the third aspect of the present invention, the communication device communicates with the vehicle in front of the vehicle only when necessary for a rear-end collision warning. The communication can be performed only when it is necessary to issue a rear-end collision warning by approaching the vehicle to reduce the cost.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a vehicle rear-end collision prevention device according to the present invention.

FIG. 2 is a schematic diagram showing a state in which the vehicle rear-end collision prevention device is applied to an actual vehicle.

FIG. 3 is a graph showing a braking map for controlling an operation of an automatic brake device of the vehicle rear-end collision prevention device.

FIG. 4 is a flowchart illustrating an operation of the vehicle rear-end collision prevention device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Distance measuring device 2 ... Communication device 3 ... Alarm device 4 ... Automatic brake device 5 ... Speedometer 6 ... Control part A ... Own vehicle B ... Forward vehicle

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Claims (3)

[Claims] A distance measuring device for measuring an inter-vehicle distance between a host vehicle and a preceding vehicle; a communication device for receiving travel information sent from the preceding vehicle including the start of braking operation of the preceding vehicle and the deceleration thereof; An alarm device that determines the possibility of a rear-end collision from the preceding vehicle based on the inter-vehicle distance to the preceding vehicle and its traveling information and the traveling speed of the own vehicle and issues a rear-end collision warning, and An automatic brake device for applying a brake to the own vehicle so as to have a deceleration greater than the deceleration of the preceding vehicle. 2. The vehicle rear-end collision prevention device according to claim 1, wherein said communication device transmits a vehicle approach warning from behind to said front vehicle. 3. The vehicle rear collision prevention device according to claim 1, wherein the communication device performs bidirectional communication with a vehicle ahead only when necessary for a rear collision warning.