JP5131551B2 - Brake light control device for vehicle - Google Patents

Description

  The present invention relates to a brake light control device for a vehicle, and more particularly to a brake light control device for a vehicle that controls the timing of starting the lighting of a brake light when a braking means is operated.

  In recent years, various obstacle detection devices that detect obstacles ahead of the host vehicle have been proposed in order to improve vehicle running safety. Then, when a collision between the detected obstacle and the own vehicle is predicted, the braking means is automatically operated to decelerate or stop the own vehicle, thereby protecting the occupant from the impact caused by the collision. Has been done.

  In recent years, a travel control device having a follow-up travel control function that causes the host vehicle to follow the preceding vehicle while maintaining a set inter-vehicle distance has been put into practical use. The following Patent Document 1 discloses a technique for performing a rearward alarm by turning on a brake light when the target deceleration is equal to or greater than a predetermined deceleration in the following traveling control.

JP 2001-030791 A

By the way, from the viewpoint of preventing the rear-end collision of the following vehicle, it is desirable that the brake lamp starts to be turned on simultaneously with the start of the operation of the braking means.
However, if lighting of the brake lamp is started simultaneously with the start of the operation of the brake means, the brake light is released after the brake means has been operated for a short time, and when the brake means is operated and released repeatedly, Will flash frequently. Frequent flashing of the brake light not only disturbs the driver of the following vehicle, but also promotes battery consumption.

  Accordingly, an object of the present invention is to provide a control light control device for a vehicle that can appropriately issue a warning by a brake light to a following vehicle.

In order to achieve the above object, a braking light control device for a vehicle according to the present invention includes a target detection unit that detects a target ahead of the host vehicle, and a target detection unit that detects a target when the target detection unit detects the target. Under the conditions, the travel control means for operating the braking means of the own vehicle, the lighting control means for lighting the brake light in accordance with the operation of the braking means by the travel control means, and the vehicle speed detection for detecting the vehicle speed of the own vehicle And the lighting control means changes the lighting start time difference from the start of operation of the braking means to the start of lighting of the brake light according to the vehicle speed of the host vehicle at the start of operation of the braking means , The lighting control means is characterized in that the lighting start time difference is shortened continuously or stepwise as the vehicle speed of the host vehicle increases .

Thus, according to the present invention, the warning by the brake light is given to the following vehicle by changing the lighting start time difference from the start of the operation of the braking means to the start of lighting of the brake light according to the vehicle speed of the host vehicle. Can be performed appropriately.
Generally, when the braking means of the host vehicle is operated, the risk of rear-end collision increases as the vehicle speed of the following vehicle increases. Further, when the vehicle speed of the host vehicle is high, the vehicle speed of the following vehicle tends to be high. For this reason, when the vehicle speed of the host vehicle is high, it is desirable to notify the following vehicle earlier that the braking means is operated than when the vehicle speed of the host vehicle is low. Therefore, when the vehicle speed of the host vehicle is high, if the brake light is turned on earlier than when the vehicle speed of the host vehicle is low, a warning by the brake light can be more appropriately given to the following vehicle.

In order to achieve the above object, a braking light control device for a vehicle according to the present invention includes a target detection unit that detects a target ahead of the host vehicle, and a target detection unit that detects a target when the target detection unit detects the target. Under the conditions, the travel control means for operating the braking means of the own vehicle, the lighting control means for lighting the brake light in accordance with the operation of the braking means by the travel control means, and the vehicle speed detection for detecting the vehicle speed of the own vehicle And the lighting control means changes the lighting start time difference from the start of operation of the braking means to the start of lighting of the brake light according to the vehicle speed of the host vehicle at the start of operation of the braking means, The succeeding vehicle detecting means detects a relative speed of the succeeding vehicle with respect to the own vehicle, and the lighting control means indicates the difference in lighting start time when the succeeding vehicle is approaching the own vehicle, and the succeeding vehicle is the own vehicle. If you are not approaching Shorter than the lighting start time difference, is characterized in that.

When the following vehicle is approaching the own vehicle, the vehicle speed of the following vehicle is faster than the vehicle speed of the own vehicle. In this case, it is considered that the risk of rear-end collision is higher when the braking means of the host vehicle is activated. Therefore, as in the present invention, when the following vehicle is faster than the own vehicle, if the brake light is turned on earlier than when it is late, the warning by the brake light can be more appropriately given to the following vehicle.

  In the present invention, it is preferable that the vehicle further includes a subsequent vehicle detection unit that detects a subsequent vehicle of the host vehicle, and the lighting control unit responds to a vehicle speed of the host vehicle when the subsequent vehicle detection unit detects the subsequent vehicle. To change the lighting start time difference.

  As described above, when the following vehicle is detected, the lighting of the brake light is controlled more effectively by selectively changing the lighting start time difference from the start of the operation of the braking means to the lighting start of the brake light. The

  Thus, according to the vehicle brake light control device of the present invention, it is possible to appropriately issue a warning by the brake light to the following vehicle.

Hereinafter, an embodiment of a brake light control device for a vehicle according to the present invention will be described with reference to the accompanying drawings.
First, with reference to the block diagram of FIG. 1, the configuration of the vehicle brake light control device of the embodiment will be described. As shown in FIG. 1, the brake light control device for a vehicle according to this embodiment includes a target detection unit 1 that detects a target ahead of the host vehicle and a target detection unit that detects a target when the target detection unit detects a target. Under the conditions, the travel control means 2 for operating the braking means 5 of the host vehicle, the lighting control means 3 for lighting the brake lamp 6 in accordance with the operation of the braking means 5 by the travel control means 2, and the vehicle speed of the host vehicle. Vehicle speed detecting means 4 for detecting and subsequent vehicle detecting means 7 for detecting a succeeding vehicle of the host vehicle are provided.

In the present embodiment, the target detection means 1 can detect an obstacle ahead of the host vehicle and can also detect a preceding vehicle traveling in front of the host vehicle. The target detection means 1 may be constituted by, for example, a millimeter wave radar device. The millimeter wave radar device emits radio waves toward the front of the host vehicle, and detects an obstacle or a preceding vehicle when the intensity of the reflected wave is equal to or greater than a predetermined threshold. Further, the distance from the vehicle to the target is obtained from the time difference between the transmitted wave and the received wave. Further, the relative speed between the host vehicle and the target is obtained from the wavelength shift of the received wave with respect to the transmitted wave.
The target detection means 1 is not limited to the millimeter wave radar device, and any suitable device such as a stereo camera device can be used. The obstacle may be stopped or moved.

  The traveling control means 2 performs follow-up traveling control and also performs collision prevention control when a collision with an obstacle ahead is predicted. The travel control unit 2 operates the braking unit (for example, a brake actuator) 5 when the distance between the host vehicle and the preceding vehicle is equal to or less than a predetermined distance as follow-up travel control. The automatic brake is activated without depending on it. As the predetermined inter-vehicle distance, for example, an arbitrary suitable value may be set according to the vehicle speed of the host vehicle.

  Further, the traveling control means 2 operates the braking means 5 even when a collision between the host vehicle and the obstacle is predicted in order to prevent a collision with an obstacle ahead. The prediction of a collision can be determined by any suitable method known in the art. For example, on the condition that the time until the host vehicle collides with the obstacle is within a predetermined reference time, which is obtained from the distance from the host vehicle to the obstacle and the relative speed difference between the host vehicle and the obstacle. It may be determined that there is a collision.

  Further, the lighting control means 3 changes the lighting start time difference from the start of operation of the braking means 5 to the start of lighting of the brake lamp 6 according to the vehicle speed of the host vehicle when the operation of the braking means 5 starts. The detailed contents of the control of the lighting start time difference will be described in an operation example of a control device such as vehicle braking described later.

Note that the processing functions of the travel control means 2 and the lighting control means are performed by executing a predetermined program in a computer such as an ECU (electric control unit) mounted on the host vehicle, or by using an IC This is realized by a chip or the like.
Further, any suitable vehicle speed sensor can be used as the vehicle speed detection means 4 for detecting the vehicle speed of the host vehicle.

The following vehicle detection means 7 detects the following vehicle behind the host vehicle. Similarly to the target detection means 1, the subsequent vehicle detection means 7 may be constituted by, for example, a millimeter wave radar device. The millimeter wave radar device emits radio waves toward the rear of the host vehicle, and detects the following vehicle when the intensity of the reflected wave is equal to or greater than a predetermined threshold. Further, the distance from the own vehicle to the following vehicle is obtained from the time difference between the transmitted wave and the received wave. Furthermore, the relative speed between the host vehicle and the following vehicle is obtained from the wavelength shift of the received wave with respect to the transmitted wave. Based on the relative speed, it can be determined whether or not the following vehicle is approaching the own vehicle, that is, whether or not the vehicle speed of the following vehicle is higher than the vehicle speed of the own vehicle.
The following vehicle detection means 7 is not limited to the millimeter wave radar device, and any suitable device such as a stereo camera device can be used.

Next, an operation example of the vehicle brake light control device of the present embodiment will be described with reference to the flowchart of FIG.
Here, the brake light control under adaptive cruise control (ACC) will be described. Under ACC (in the case of “Yes” in S1), when the preceding vehicle is not detected by the target detection means 1 (in the case of “No” in S2), the vehicle travels to maintain the set target speed. The constant speed running control is performed (S3). On the other hand, when a preceding vehicle is detected (in the case of “Yes” in S2), follow-up running control is performed in which the host vehicle follows the preceding vehicle while keeping the set inter-vehicle distance (S10).

  Then, the traveling control unit 2 operates the braking unit 5 of the host vehicle under a predetermined condition (“Yes” in S4). Specifically, the traveling control unit 2 activates the braking unit 5 when the inter-vehicle distance between the host vehicle and the preceding vehicle is equal to or less than a predetermined distance during the following traveling control. The traveling control means 2 also activates the braking device 5 when predicting a collision between the obstacle detected by the target detection means 1 and the host vehicle.

  In the present embodiment, when the brake light 6 is lit, the lighting control means 3 is provided with the braking means only when the following vehicle amount detecting means 7 detects the following vehicle (in the case of “Yes” in S5). The lighting start time difference (Δt) from the start of operation 5 to the start of lighting of the brake lamp 6 is changed.

  In the present embodiment, as shown in the graph of FIG. 3, the lighting start time difference (Δt) is changed so that the lighting start time difference (Δt) decreases stepwise as the vehicle speed (v) of the host vehicle increases. . When the following vehicle is approaching the host vehicle, that is, when the vehicle speed of the following vehicle is higher than the vehicle speed of the host vehicle, the lighting start time difference (Δt) is further reduced so that the lighting time difference (Δt) is further shortened. ) Is changed.

The horizontal axis of the graph in FIG. 3 indicates the vehicle speed (v) of the host vehicle when the braking means 5 starts to be braked, and the vertical axis indicates the lighting start time difference from the start of operation of the braking means 5 to the lighting start of the brake lamp 6 ( Δt). A solid line I in the graph indicates a lighting start time difference when a subsequent vehicle is not detected, and a broken line II in the graph indicates a lighting start time difference when a subsequent vehicle is detected.
Hereinafter, the lighting start time difference according to the presence or absence of the following vehicle and the vehicle speed of the host vehicle will be described.

  First, when the vehicle speed of the host vehicle is equal to or lower than a predetermined first speed (V1) (“Yes” in S6) and the following vehicle is approaching the host vehicle (“Yes” in S7), the light is on. The control means 3 sets the lighting start time difference (Δt) to (ΔT1−α) shorter by α than the predetermined first time difference (ΔT1). Such a case corresponds to the section “a” of the broken line II in the graph of FIG.

  Here, the predetermined first speed (V1) is, for example, 35 km / h. The predetermined first time difference (ΔT1) is, for example, 300 milliseconds. If the shortening time (α) is 50 milliseconds, the set lighting start time difference (ΔT1−α) is 250 milliseconds. In such a case, the lighting of the brake lamp 6 is started after (ΔT1-α) = 250 milliseconds from the start of the operation of the braking means 5 (S8).

  Next, when the vehicle speed of the host vehicle is equal to or lower than a predetermined first speed (V1) (“Yes” in S6) and the following vehicle is not approaching the host vehicle (“No” in S7), the light is on. The control means 3 sets the lighting start time difference (Δt) to a predetermined first time difference (ΔT1). Such a case corresponds to the section “b” of the solid line I in the graph of FIG.

  Here, the predetermined first speed (V1) is, for example, 35 km / h. The predetermined first time difference (ΔT1) is, for example, 300 milliseconds. In such a case, the lighting of the brake lamp 6 is started after (ΔT1) = 300 milliseconds from the start of the operation of the braking means 5 (S11).

  Next, the vehicle speed of the host vehicle is faster than the first speed (V1) (“No” in S6), is equal to or lower than a predetermined second speed (V2) (“Yes” in S12), and the following vehicle is When the vehicle is approaching (in the case of “Yes” in S13), the lighting control means 3 has the lighting start time difference (Δt) shorter by α than the predetermined second time difference (ΔT2) (ΔT2-α). Set to. Such a case corresponds to the section “c” of the broken line II in the graph of FIG.

  Here, the predetermined second speed (V2) is, for example, 60 km / h. The predetermined second time difference (ΔT2) is shorter than the first time difference (ΔT1), and is, for example, 200 milliseconds. If the shortening time (α) is 50 milliseconds, the set lighting start time difference (ΔT2−α) is 150 milliseconds. In such a case, the lighting of the brake lamp 6 is started after (ΔT2−α) = 150 milliseconds from the start of the operation of the braking means 5 (S14).

  Next, the vehicle speed of the host vehicle is faster than the first speed (V1) (“No” in S6), is equal to or lower than a predetermined second speed (V2) (“Yes” in S12), and the following vehicle is When the vehicle is not approaching (“No” in S13), the lighting control unit 3 sets the lighting start time difference (Δt) to a predetermined second time difference (ΔT2). Such a case corresponds to the section “d” of the solid line I in the graph of FIG.

  Here, the predetermined second speed (V2) is, for example, 60 km / h. The predetermined second time difference (ΔT2) is, for example, 200 milliseconds. In such a case, the lighting of the brake lamp 6 is started after (ΔT2) = 200 milliseconds from the start of the operation of the braking means 5 (S15).

  Next, the vehicle speed of the host vehicle is faster than a predetermined first speed (V1) (“No” in S6), and further faster than a predetermined second speed (V2) (“No” in S12), and When the succeeding vehicle is approaching the own vehicle (in the case of “Yes” in S16), the lighting control means 3 has the lighting start time difference (Δt) shorter by α than the predetermined third time difference (ΔT3) (ΔT3). -Α). Such a case corresponds to the section “e” of the broken line II in the graph of FIG.

  Here, the predetermined first speed (V1) is, for example, 35 km / h. The predetermined second speed (V2) is, for example, 60 km / h. Further, the predetermined third time difference (ΔT3) is shorter than the second time difference (ΔT2), for example, 100 milliseconds. If the shortening time (α) is 50 milliseconds, the set lighting start time difference (ΔT3−α) is 50 milliseconds. In such a case, the lighting of the brake lamp 6 is started after (ΔT3-α) = 50 milliseconds from the start of the operation of the braking means 5 (S17).

  Next, the vehicle speed of the host vehicle is faster than a predetermined first speed (V1) (“No” in S6), and further faster than a predetermined second speed (V2) (“No” in S12), and When the following vehicle is not approaching the host vehicle (“No” in S16), the lighting control unit 3 sets the lighting start time difference (Δt) to a predetermined third time difference (ΔT3). Such a case corresponds to the section “f” of the straight line I in the graph of FIG.

  Here, the predetermined first speed (V1) is, for example, 35 km / h. The predetermined second speed (V2) is, for example, 60 km / h. The predetermined third time difference (ΔT3) is, for example, 100 milliseconds. In such a case, lighting of the brake lamp 6 is started after (ΔT3) = 100 milliseconds from the start of the operation of the braking means 5 (S18).

  Further, when the following vehicle is not detected (in the case of “No” in S5), in the present embodiment, a predetermined first time difference from the start of the operation of the braking means 5 (regardless of the vehicle speed of the own vehicle and the vehicle speed of the following vehicle) ΔT1), for example, after 300 milliseconds, the lighting of the brake lamp 6 is started (S19). In either case, the above process continues until the operation of the braking means S9 ends (S9).

  Thus, the lighting start time difference (Δt) from the start of the operation of the braking means 5 to the start of lighting of the brake light 6 is changed according to the vehicle speed of the host vehicle and the relative speed of the following vehicle. Thus, a warning with a brake light can be appropriately given to the following vehicle.

Next, a modification will be described with reference to the graph of FIG.
In the embodiment described above, the example in which the vehicle speed of the host vehicle is divided into three stages and the lighting start time difference (Δt) is changed has been described. However, in the modified example, as shown in the graph of FIG. ) Is faster, the lighting start time difference (ΔT) is continuously shorter.

  The horizontal axis of the graph in FIG. 4 indicates the vehicle speed (v) of the host vehicle, and the vertical axis indicates the lighting start time difference (Δt) from the start of operation of the braking means 5 to the start of lighting of the brake lamp 6. A solid line III in the graph indicates a lighting start time difference when the following vehicle is not approaching. A broken line IV in the graph indicates a lighting start time difference when the following vehicle is not approaching.

The solid line III in the graph represents the vehicle speed (v) in kilometers per hour (km / h) and the lighting start time difference (Δt) in milliseconds (ms). It is done.
Δt = (− 10/3) v + 400 (1)
Therefore, for example, when the host vehicle is traveling at a speed (v) = 45 km / h and the following vehicle is not approaching the host vehicle, the lighting start time difference (Δt) = 250 ms.

  In this way, by continuously changing the lighting time difference according to the vehicle speed of the host vehicle, it is possible to appropriately warn the following vehicle with a brake light.

Similarly, the broken line IV in the graph is given by the following equation (2), for example.
Δt = (− 10/3) v + 350 (2)
Therefore, for example, when the host vehicle is traveling at an hourly speed (v) = 45 km / h and the following vehicle is approaching the host vehicle, the lighting start time difference (Δt) = 200 ms.

In this way, when the succeeding vehicle is approaching, it is considered that there is a higher risk of collision than when the succeeding vehicle is not approaching. The warning by can be performed more appropriately.
In the graph of FIG. 3, the solid line III and the broken line IV are represented by straight lines, but may be represented by curves.

  In each embodiment mentioned above, although the example which constituted the present invention on specific conditions was explained, the present invention can perform various change and combination, and is not limited to this. For example, in the above-described embodiment, the example in which the difference in lighting start time from the start of operation of the braking means to the start of lighting of the brake light is changed only when the following vehicle is detected. Regardless of the presence or absence of detection, for example, even when a subsequent vehicle is detected, the lighting start time difference of the brake light may be changed.

  In the above-described embodiment, the target detection unit detects a front obstacle, detects a preceding vehicle, and the traveling control unit performs a collision prevention control when a collision with the obstacle is predicted, Although the example of performing the follow-up traveling control for the preceding vehicle has been described, in the present invention, the target detection means and the traveling control means may perform only one of these controls.

  In addition, the present invention is not limited to the following traveling control, and the braking means is operated regardless of the driver's operation, for example, when the vehicle speed of the host vehicle exceeds the set speed during the constant speed traveling control and automatically decelerates. It is suitable for application in all cases.

It is a block diagram explaining the structure of the brake light control apparatus of the vehicle of embodiment of this invention. It is a flowchart explaining the operation example of the brake light control apparatus of the vehicle of embodiment of this invention. It is a graph which shows the relationship between the vehicle speed of the own vehicle, and the lighting start time difference from the operation start of a braking means to the lighting start of a brake light in embodiment of this invention. It is a graph which shows the relationship between the vehicle speed of the own vehicle, and the lighting start time difference from the operation start of a braking means to the lighting start of a brake light in the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Target detection means 2 Travel control means 3 Lighting control means 4 Vehicle speed detection means 5 Braking means 6 Brake light 7 Subsequent vehicle detection means

Claims (3)

Target detection means for detecting a target in front of the host vehicle;
When the target detection means detects a target, a traveling control means for operating the braking means of the host vehicle under a predetermined condition;
With the operation of the braking means by the travel control means, a lighting control means for lighting a brake light,
Vehicle speed detecting means for detecting the vehicle speed of the host vehicle,
The lighting control means changes a lighting start time difference from the start of operation of the braking means to the start of lighting of the brake light according to the vehicle speed of the host vehicle at the start of operation of the braking means ,
The lighting control means shortens the lighting start time difference continuously or stepwise as the vehicle speed of the host vehicle increases.
A brake light control device for a vehicle characterized by the above. Target detection means for detecting a target in front of the host vehicle;
When the target detection means detects a target, a traveling control means for operating the braking means of the host vehicle under a predetermined condition;
With the operation of the braking means by the travel control means, a lighting control means for lighting a brake light,
Vehicle speed detecting means for detecting the vehicle speed of the host vehicle,
The lighting control means changes the lighting start time difference from the start of operation of the braking means to the start of lighting of the brake light according to the vehicle speed of the host vehicle at the start of operation of the braking means,
The vehicle further comprises a subsequent vehicle detection means for detecting a subsequent vehicle of the host vehicle,
The following vehicle detection means detects a relative speed of the following vehicle with respect to the own vehicle,
The lighting control means makes the lighting start time difference when the subsequent vehicle is approaching the own vehicle shorter than the lighting start time difference when the subsequent vehicle is not approaching the own vehicle.
A brake light control device for a vehicle characterized by the above. The vehicle further comprises a subsequent vehicle detection means for detecting a subsequent vehicle of the host vehicle,
The lighting control means changes the lighting start time difference according to the vehicle speed of the host vehicle when the subsequent vehicle detecting means detects the subsequent vehicle.
The brake light control device according to claim 2.

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