JP2011057072A - Automatic braking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adequately carry out automatic braking control during abrupt braking of a preceding vehicle in a simple configuration relating to an automatic braking device. <P>SOLUTION: The automatic braking device includes an imaging means 5 for picking up the image of the lighting device of the preceding vehicle, an emergency braking determination means 3 for determining presence or absence of emergency braking operation in the preceding vehicle based on the image picked up by the imaging means 5, and an automatic braking means 4 for carrying out automatic braking of a self-vehicle when determined as the emergency braking operation in the emergency braking determination means 3. The emergency braking determination means 3 includes a blinking cycle detection means 1a for detecting the blinking cycle of the lighting device and a flushing determination means 1b for determining presence or absence of flushing in the lighting device based on the blinking cycle detected by the blinking cycle detection means 1a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an automatic braking device that automatically applies a braking force to a host vehicle.

  2. Description of the Related Art Conventionally, large vehicles such as large trucks are equipped with an automatic braking device for reducing damage at the time of contact with a preceding vehicle. In such an automatic braking device, when the braking operation of the preceding vehicle is recognized, control for applying a braking force to the host vehicle is performed according to the inter-vehicle distance and relative speed from the preceding vehicle. In general, as a sensor for grasping the behavior of a preceding vehicle, a camera device that captures the front of the host vehicle, a radar device that detects a relative speed and a relative distance from the preceding vehicle, and the like are used.

  For example, Patent Document 1 calculates a predicted time required to collide with an object based on a relative distance and a relative speed between the host vehicle and a front object, and determines the braking force according to the magnitude of the predicted time. A configuration for changing the application pattern is described. In this technique, an image of a preceding vehicle is taken to analyze a vehicle type, and lighting of a brake lamp or a hazard lamp is detected, and a braking force application pattern is selected according to an estimated time at that time. By such control, it is supposed that appropriate braking control can be performed at the time of sudden braking of the preceding vehicle.

JP 2007-196901 A

  In recent years, the number of vehicles equipped with emergency braking indicator lights is increasing due to the revision of the safety standards for road transport vehicles. The emergency brake indicator lamp flashes lighting devices such as brake lights, auxiliary brake lights, direction indicators, and auxiliary direction indicators during sudden deceleration to notify the driver of the following vehicle that the emergency braking operation has been performed. It is a device for doing. In a vehicle equipped with an emergency braking indicator lamp, the lighting state of the lighting device is controlled according to the emergency level of braking.

However, in the technique of Patent Document 1, since only the lighting of the brake lamp or the hazard lamp of the preceding vehicle is a detection target, it is not possible to deal with the blinking operation of the lighting device by the emergency braking indicator lamp as described above.
Also, the lighting operation of the lighting device does not depend on the amount of braking operation. For example, the braking amount of the preceding vehicle is not always large just because the brake lamp or the hazard lamp is lit, so that May be too strong. That is, in the conventional automatic braking control, there is a problem that it is difficult to automatically set an optimal braking amount for the braking operation of the preceding vehicle.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide an automatic braking device that is capable of appropriately performing automatic braking control at the time of sudden braking of a preceding vehicle with a simple configuration. And

  (1) In order to achieve the above object, the disclosed automatic braking device includes an imaging unit that captures an image of a lighting device of a preceding vehicle, and an emergency braking operation in the preceding vehicle based on the image captured by the imaging unit. An emergency braking determining means for determining the presence or absence of the vehicle and an automatic braking means for automatically braking the host vehicle when the emergency braking determining means determines that the emergency braking operation is performed. .

The emergency braking operation means a sudden braking operation. Specifically, it is a brake operation that causes a deceleration of a predetermined deceleration (for example, 5.0 [m / s ² ]) or more when traveling at a predetermined speed (for example, 50 [km / h]) or more.
(2) The imaging unit captures a plurality of images of the lighting device as a moving image, and the emergency braking determination unit determines the blinking cycle of the lighting device based on the moving image captured by the imaging unit. It is preferable to include a flashing cycle detection unit to detect, and a flushing determination unit that determines whether or not the lighting device has flashing based on the flashing cycle detected by the flashing cycle detection unit.

The flushing means that the lighting device is repeatedly turned on and off at a predetermined cycle (flashing display of the lighting device).
Note that the shooting speed of the moving image (the number of frames taken per unit time) is preferably at least twice the flashing frequency of the lighting device (the reciprocal of the flashing cycle). In addition, the flushing determination unit determines that the flushing is performed when the blinking period (or blinking frequency) is within a predetermined period range (for example, 4 ± 1 [Hz]). On the other hand, when the blinking cycle is out of the predetermined cycle range, it is determined that the flushing is not performed.

  (3) In addition, the blinking cycle detection means detects a first lighting time, a subsequent first turn-off time, and a subsequent second lighting time in the lighting device, and the first lighting time and the It is preferable to detect the blinking cycle based on the lighting time calculated as the difference between the first lighting times and the lighting time calculated as the difference between the first lighting times and the second lighting times.

(4) The apparatus further includes a lighting actual area calculation unit that calculates a lighting actual area of the lighting device in the preceding vehicle based on the image captured by the imaging unit, and the emergency braking determination unit includes the lighting actual determination unit. It is preferable to determine the presence or absence of the emergency braking operation based on the actual lighting area calculated by the area calculating means.
The emergency braking determination means preferably determines that the emergency braking operation is performed when the actual lighting area is equal to or larger than a predetermined area.

  (5) Further, a distance detection unit that detects a distance to the preceding vehicle is further provided, and the lighting actual area calculation unit calculates the lighting area of the lighting device in the image and the distance detected by the distance detection unit. It is preferable to have an area calculating means for calculating the actual lighting area based on the area.

  (6) The automatic braking means is based on the preceding vehicle detecting means for detecting the inter-vehicle distance and relative speed with the preceding vehicle, and the inter-vehicle distance and the relative speed detected by the preceding vehicle detecting means, A margin time calculating means for calculating a margin time (TTC) until contact with the preceding vehicle, and a braking force applied to the host vehicle when the margin time calculated by the margin time calculating means is less than a predetermined margin time. A determination condition for correcting the predetermined margin time related to the determination condition in the braking force applying means in an increasing direction when the emergency braking operation is determined by the braking force applying means to be applied and the emergency braking determination means It is preferable to have correction means.

  It is preferable that the correction amount in the increasing direction of the predetermined margin time is set according to the inter-vehicle distance and the relative speed at that time. In this case, it is preferable to increase the correction amount as the inter-vehicle distance is smaller or as the relative speed is larger (a negative value is larger).

(7) When the automatic braking means is determined to be the emergency braking operation by the emergency braking determining means, the magnitude of the braking force applied by the braking force applying means is corrected in an increasing direction. It is preferable to further have a braking force correcting means for performing the above.
The magnitude of the braking force is preferably set according to the distance between the vehicles and the relative speed at that time. In this case, it is preferable to increase the braking force as the inter-vehicle distance is smaller or as the relative speed is larger (a negative value is larger).

  According to the automatic braking device of the present invention, the emergency braking operation can be immediately grasped by the determination based on the image of the lighting device of the preceding vehicle, and the automatic braking control can be appropriately performed.

It is a top view which shows the front-end part of the vehicle to which the automatic braking device which concerns on one Embodiment of this invention was applied. It is a block block diagram which shows the structure of this automatic braking device. It is a flowchart which shows the control procedure of this automatic braking device. It is a graph for demonstrating determination of flushing in this automatic braking device. It is a block block diagram which shows the structure of the automatic braking device as a modification of this invention. It is a schematic diagram for demonstrating the determination conditions of the emergency braking operation of the preceding vehicle in the automatic braking device as a modification of this invention, (a) is the lighting state of the lighting apparatus corresponding to weak brake operation, (b) is The lighting state of the lighting device corresponding to a moderate brake operation, (c) shows the lighting state of the lighting device corresponding to a strong brake operation. It is a flowchart which shows the control procedure in the automatic braking device of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[1. overall structure]
FIG. 1 illustrates a vehicle 11 including an ECU 10 having a function as an automatic braking device of the present invention. A front camera 5 and a millimeter wave radar 6 are provided at the front end of the vehicle 11.
The front camera 5 (imaging means) is a video camera that captures an image in front of the vehicle 11 as a moving image. Here, the angle of view of the front camera 5 is set so that the lighting device 21 of the preceding vehicle 20 enters the photographed image. In FIG. 1, the shooting range of the front camera 5 in a top view of the vehicle 11 is indicated by a broken line. Note that the lighting device 21 of the preceding vehicle 20 includes at least one of a braking light, an auxiliary braking light, a direction indicator, an auxiliary direction indicator, and the like. A plurality of pieces of image information captured here are input to the ECU 10.

The millimeter wave radar 6 (preceding vehicle detection means) is a radar device that detects an object ahead of the vehicle 11, the preceding vehicle 20, and the like. The millimeter wave radar 6 emits a millimeter wave to a range indicated by a one-dot chain line in FIG. 1 and receives the reflected wave. The millimeter wave radar 6 has a built-in radar ECU, which detects the relative distance D _R (inter-vehicle distance) and the relative speed V _R to the preceding vehicle 20 by analyzing the received reflected wave. Here it was detected relative distance D _R and the relative speed V _R is inputted to the ECU 10.

The ECU 10 is an electronic control unit including a storage device (ROM, RAM, etc.) and a central processing unit (CPU) that are used for storing control programs, control maps, and the like. The block configuration shown in FIG. 2 is a visualization of the various functions of the program that is arithmetically processed in the ECU 10.
As shown in FIG. 2, a brake stroke sensor 7 is connected to the input side of the ECU 10 in addition to the front camera 5 and the millimeter wave radar 6 described above. The brake stroke sensor 7 is a sensor that detects depression of the brake pedal by the driver. Information regarding the presence or absence of the depression detected here is input to the ECU 10.

  A brake ECU 8 is connected to the output side of the ECU 10. The brake ECU 8 is an electronic control unit that performs control to apply a braking force to the wheels 9 provided in the vehicle 11, and includes a storage device (ROM, RAM, etc.) and a central processing unit (CPU) as with the ECU 10. Configured. The wheel 9 here includes a drive wheel and a driven wheel. The brake ECU 8 performs brake system control such as damage reduction brake control, automatic braking control, ABS (anti-lock braking system) control, and VSC (vehicle stability control) control.

Damage reduction brake control is braking control for reducing damage caused by contact with the preceding vehicle 20. In the damage reduction brake control, a surplus time TTC (time to collision) until it is predicted to come into contact with the preceding vehicle 20 is calculated, and when this TTC becomes less than the first threshold, contact with an obstacle is performed. If it is determined that the possibility has increased, a weak braking force is applied. Further, when the margin time TTC is less than the smaller second threshold, it is determined that contact is inevitable, and a strong braking force is applied to reduce the speed at the time of contact. In the present embodiment, this second threshold value is referred to as a predetermined margin time TTC ₀ .

On the other hand, when the preceding vehicle performs an emergency braking operation, the ECU 10 changes the start condition of damage reduction brake control in the brake ECU 8 to advance the timing of braking, and is applied to the wheel 9 by the damage reduction brake control. Implement control to increase braking force and increase braking effectiveness.
As described above, the damage reduction brake control is executed at any time in the brake ECU 8, and the brake ECU 8 functions to adjust the content of the damage reduction brake control. The ECU 10 calculates the allowance time TTC separately from the damage reduction brake control in the brake ECU 8 (or diverts the control information) and issues a braking command for damage reduction brake control in the brake ECU 8. A specific configuration for carrying out this control will be described later.

[2. Configuration of ECU]
As shown in FIG. 2, the ECU 10 includes an emergency braking determination unit 3 and an automatic braking unit 4.
The emergency braking determination unit 3 (emergency braking determination means) determines whether or not an emergency braking operation has been performed by the driver of the preceding vehicle 20 based on an image taken by the front camera 5. That is, rather than calculating the traveling speed and acceleration of the preceding vehicle and determining the degree of braking, the presence / absence of an emergency braking operation is determined based on visual information on the image. Further, the emergency braking operation means an abrupt braking operation. Specifically, it is a brake operation that causes a deceleration of a predetermined deceleration (for example, 5.0 m / s ² ) or more when traveling at a predetermined speed (for example, 50 km / h) or more.

  The emergency braking determination unit 3 is provided with a flushing detection unit 1. The flushing detection unit 1 detects flushing of the lighting device 21 of the preceding vehicle 20. For example, in the safety standard for road transport vehicles, there is a provision that the blinking cycle of the lighting device 21 in the flushing brake of the vehicle is constant between 180 and 300 times per minute. Therefore, the flushing detection unit 1 determines whether or not the blinking cycle of the lighting device 21 of the vehicle ahead is consistent with such regulations.

The flushing detection unit 1 is provided with a blinking cycle detection unit 1a and a flushing determination unit 1b. The blinking cycle detection unit 1 a (flashing cycle detection means) detects the blinking cycle of the lighting device 21 from the moving image captured by the front camera 5. Here, based on the brightness of the lighting device 21 in the image, the first lighting time t ₀ when the lighting device 21 that was turned off is turned on, the first turning-off time t ₁ when the lighting device 21 is turned off, and then after that, lamp device 21 detects a second lighting time t ₂ lit.

Note that the moving image shooting speed (the number of shot frames per unit time) in the front camera 5 is preferably at least twice the blinking frequency of the lighting device 21 (the reciprocal of the blinking cycle). The faster the moving image shooting speed is, the faster the blinking state change in the lighting device 21 can be captured.
Also, flashing cycle detecting unit 1a calculates, based lighting time of the lighting device 21 T ₁ and the extinguishing time T ₂ in the following equation (1) and (2). The flushing period is the sum of these times (T ₁ + T ₂ ).
T ₁ = t ₁ -t ₀ ··· formula (1)
T ₂ = t ₂ −t ₁ Formula (2)

Flushing judgment unit 1b (flushing determination means) is to determine the presence or absence of flushing based on the lighting time calculated by the flashing cycle detecting unit 1a T ₁ and extinguishing time T _2. Here, as shown in the following formulas (3) and (4), it is determined that “the lighting device 21 has been flushed” when each of the lighting time T ₁ and the lighting time T ₂ is within a predetermined range. When at least one of them is out of this range, it is determined that “the lighting device 21 is not flushed”.
T _A ≦ T ₁ ≦ T _B Formula (3)
T _C ≦ T ₂ ≦ T _D Formula (4)

For example, when determining the blinking cycle of the lighting device 21 that meets the above-mentioned road vehicle safety standards, T _A = T _C = 1/2 (300/60) = 1/10 [s] and T _B = T _D = 1/2 (180/60) = 1/6 [s].

The emergency braking determination unit 3 determines that the emergency braking operation has been performed on the preceding vehicle 20 when the flushing determination unit 1b detects the flashing of the lighting device 21. The determination result here is transmitted to the automatic braking unit 4.
The automatic braking unit 4 (automatic braking means) outputs a braking command to the brake ECU 8 and performs automatic braking of the vehicle 11. Here, the start condition of damage reduction brake control executed by the brake ECU 8 is always determined. On the other hand, when the emergency braking determination unit 3 determines the emergency braking operation of the preceding vehicle 20, the start condition and the control content of the damage reduction brake control are changed.

The automatic braking unit 4 includes a margin time calculating unit 4a, a braking force applying unit 4b, a determination condition correcting unit 4c, and a braking force correcting unit 4d.
Margin time calculating section 4a (margin time calculating means), those based on relative distance D _R and the relative speed V _R detected by the millimeter-wave radar 6, calculates the time to collision TTC to the contact with the preceding vehicle 20 is there. Here, the margin time TTC is calculated according to the following equation (5).
TTC = D _R / V _R (5)

The braking force applying unit 4b (braking force applying means) is configured to apply a strong braking force to the vehicle 11 when the margin time TTC calculated by the margin time calculating unit 4a is less than the predetermined margin time TTC ₀ (the above-described second threshold). Is output to the brake ECU 8. That is, the braking force application unit 4b has a function of causing the brake ECU 8 to start damage reduction brake control.

The determination condition correction unit 4c (determination condition correction means) changes the predetermined margin time TTC ₀ related to the start condition of the damage reduction brake control determined by the braking force application unit 4b. Here, when the emergency braking operation by the preceding vehicle 20 has been made, control for correcting the direction of increasing the predetermined margin time TTC ₀ is performed based on the relative distance D _R and the relative speed V _R.
For example, a correction is made to increase the initial value (default value) of the predetermined margin time TTC ₀ from 0.8 [s] to 1.6 [s]. That is, when the preceding vehicle 20 decelerates rapidly, the damage reduction brake control is started from a traveling state in which the margin time TTC of the vehicle 11 is larger, and the timing for applying the braking force is advanced.

Further, when the relative distance D _R is less than a predetermined distance, or even increase the TTC ₀ if the relative speed V _R is equal to or higher than a predetermined speed (e.g., a 2.0 [s]) correction is made. Alternatively, as the relative distance D _R is small, or, as the relative velocity V _R is greater (in this case, the traveling direction of the vehicle 11 means a relative speed V _R in the opposite direction, i.e. approaching the preceding vehicle 20 A correction may be made to increase TTC _{0 (} as the speed increases).

  The braking force correcting unit 4d (braking force correcting means) changes the magnitude of the braking force applied to the wheels 9 by the damage reduction brake control performed by the brake ECU 8. Here, when an emergency braking operation is performed on the preceding vehicle 20, control for correcting the magnitude of the braking force in the increasing direction is performed. That is, when the preceding vehicle 20 decelerates suddenly, the damage reduction brake control works strongly and a large deceleration occurs in the vehicle 11.

The magnitude of the braking force to be corrected in the increasing direction may be set in advance may be those set on the basis of the relative distance D _R and the relative speed V _R. For example, as the relative distance D _R is small, or, it is considered to increase the magnitude of the braking force larger the relative speed V _R.

[3. flowchart]
The ECU 10 performs control according to the flowchart shown in FIG. This flow is repeatedly executed at a predetermined cycle set in advance. The flags F ₁ and F ₂ described in the flow are control flags for detecting flashing of the lighting device 21 of the preceding vehicle 20. The flag F ₁ corresponds to the lighting or extinguishing state of the lighting device 21, and F ₁ = 0 corresponds to the extinguishing state and F ₁ = 1 corresponds to the lighting state. The flag F ₂ is a flag serving as an index of the number of blinks, and F ₂ = 0 corresponds to a state until the first lighting is completed, and F ₂ = 1 corresponds to a state after the first lighting is completed. . The initial values of these flags F ₁ and F ₂ are F ₁ = F ₂ = 0.

In step A1, the image taken by the front camera 5, the relative distance D _R and the relative speed V _R detected by the millimeter wave radar 6, and the brake pedal depression information detected by the brake stroke sensor 7 are read into the ECU 10. It is. In the subsequent step A2, the margin time TTC is calculated in accordance with the equation (5) in the margin time calculation unit 4a of the automatic braking unit 4.
Step A3 following is a step of determining conditions for starting the mitigation brake control, where the time to collision TTC calculated in step A2 whether the predetermined time to contact TTC ₀ or more is determined. Here, if TTC ≧ TTC ₀ , the damage reduction brake control start condition is not satisfied, and the process proceeds to step A4. On the other hand, in the case of TTC <TTC ₀ is, the conditions for starting the mitigation brake control is established, the process proceeds to step A6.

In step A6, a braking instruction is output from the braking force applying unit 4b. In response to this braking instruction, the brake ECU 8 performs damage reduction brake control, and a braking force is applied to the wheels 9. Thereby, the speed of the vehicle 11 at the time of contact with the preceding vehicle 20 is reduced.
If the damage reduction brake control start condition is not satisfied in step A3, it is determined in step A4 whether or not the brake pedal is depressed based on the detection information of the brake stroke sensor 7 in the braking force application unit 4b. The

If the brake pedal is depressed, the process proceeds to step A5, where various time measurement values to be described later are reset to _0, and the predetermined margin time TTC ₀ and the braking force are reset to default values. finish. On the other hand, if the brake pedal is not depressed, the process proceeds to step A7.
The flow after step A7 is a flow for detecting the emergency braking operation of the preceding vehicle 20. First, in step A7, it is determined whether or not the determination of flushing is incomplete. Here, for example, if a turn-off time T ₂ described later is calculated, it is determined that the flushing determination has been completed, and the flow ends. This determination of flushing is continued until a braking operation is performed. On the other hand, if the turn-off time T ₂ has not been calculated (ie, T ₂ = 0), it is determined that the flushing has not yet been determined, and the process proceeds to step A10.

In the flow after step A10, the presence or absence of the emergency braking operation is determined by detecting the flushing of the lighting device 21 of the preceding vehicle 20. First, in step A10, it is determined whether or not the flag F ₂ is F ₂ = 0. If F ₂ = 0, the process proceeds to step A11. If F ₂ ≠ 0 (that is, F ₂ = 1), the process proceeds to step A18. In Step A11, it is determined whether or not the flag F ₁ is F ₁ = 0. If F ₁ = 0, the process proceeds to step A12. If F ₁ ≠ 0 (that is, F ₁ = 1), the process proceeds to step A15. These steps A10 and A11 are determination steps for dividing the lighting / light-off state of the lighting device 21 of the preceding vehicle 20 in the blinking cycle detection unit 1a.

In step A12, based on the image photographed by the front camera 5, it is determined whether or not the lighting device 21 of the preceding vehicle 20 is lit. Since this step is a step executed when the flag F ₁ is F ₁ = 0, when the lighting device 21 that has been turned off is turned on for the first time, lighting is detected in this step A12.
Therefore, if the condition of step A12 is satisfied, followed by the flag F ₁ in step A13 is set to F ₁ = 1, the further subsequent step A14, the flashing cycle detecting unit 1a, the first lighting time t ₀ is stored Is done. Here, this flow is finished, and is repeated from step A1. If the condition of step A12 is not satisfied, this flow is finished as it is.

On the other hand, if the flag F ₁ is set to F ₁ = 1 in step A13, the control proceeds from step A11 to step A15 when the flow is executed next time.
In step A15, it is determined based on the image photographed by the front camera 5 whether or not the lighting device 21 of the preceding vehicle 20 is turned off. Since this step is a step executed when the flag F ₁ is F ₁ = 1, when the lighting device 21 that has been turned on is turned off for the first time, the turning-off is detected at this step A15.

Therefore, when the condition of step A15 is satisfied, the flags F ₁ and F ₂ are set to F ₁ = 0 and F ₂ = 1 in the subsequent step A16, respectively, and in the subsequent step A17, the blinking cycle detector 1a. The first turn-off time t ₁ is stored. Further, the lighting time T ₁ of the lighting device 21 is calculated according to the equation (1). Here, this flow is finished, and is repeated from step A1. If the condition of step A15 is not satisfied, this flow is finished as it is.

Further, when the flag F ₂ is set to F ₂ = 1 in step A16, the control proceeds from step A10 to step A18 at the next flow execution.
In step A18, similarly to step A12, it is determined whether or not the lighting device 21 of the preceding vehicle 20 is lit based on the image taken by the front camera 5 again. Since this step is a step executed when the flag F ₂ is F ₂ = 1, the lighting of the lighting device 21 detected here is the second lighting.

Therefore, if the condition of step A18 is satisfied, followed by a flag F ₂ in step A19 is set to F ₂ = 0, the further subsequent step A20, the flashing cycle detecting unit 1a, the second lighting time t ₂ is stored Is done. Further, the extinguishing time T ₂ of the lighting device 21 is calculated according to the equation (2). Further, in the subsequent step A21, the presence / absence of flushing is determined by the flushing determination unit 1b, that is, it is determined whether or not both the expressions (3) and (4) are established.

Here, when the flashing of the lighting device 21 is not detected, the process proceeds to Step A24, and the stored first lighting time t ₀ , first lighting time t ₁ , second lighting time t _2, lighting time T ₁ , lighting time is turned off. information of T ₂ is reset, the flow ends. That is, it is determined that the emergency braking operation of the preceding vehicle 20 is not performed in the emergency braking determination unit 3. On the other hand, when the flashing of the lighting device 21 is detected, it is determined that the emergency braking operation of the preceding vehicle 20 is performed in the emergency braking determination unit 3, and the process proceeds to Step A22.

In step A22, the determination condition correction unit 4c, a predetermined margin time TTC ₀ according to the determination condition at step A5 of the flow is increased corrected according to the relative distance D _R and the relative speed V _R at that time. Thereby, the timing for applying the braking force by the damage reduction brake control is advanced. Moreover, In step A23, the braking force correction section 4d, the magnitude of the braking force of the damage reduction brake control is corrected to increase direction according to the relative distance D _R and the relative speed V _R at that time. As a result, the braking force applied to the wheel 9 is strengthened when the start condition of the damage reduction brake control is satisfied at the next and subsequent flows.

[4. effect]
FIG. 4 illustrates temporal changes in the lighting state and the extinguishing state in the lighting device 21 of the preceding vehicle 20 taken by the front camera 5 of the vehicle 11. In the preceding vehicle 20, the emergency braking operation is performed at time t _0, lighting apparatus 21 starts flashing. In response to this, the ECU10 vehicle 11, the time of detecting the lighting of the lighting device 21 in the flashing cycle detecting portion 1a is stored as the first lighting time t _0.

Also then, the time at which lighting apparatus 21 of the leading vehicle 20 is turned off is stored as the first off time t _1, the lighting time T ₁ is calculated. Thereafter, the time that lamp device 21 is lit again is stored as the second lighting time t _2, the off time T ₂ is calculated.
Here, if the flashing of the lighting device 21 is flushing, the total time of the lighting time T ₁ and the lighting time T ₂ calculated here coincides with the flushing cycle, that is, the lighting time T ₁ and the lighting time. each T ₂ should become half the time flushing cycle. On the contrary, if the flashing of the lighting device 21 is caused by a normal brake operation, at least one of these times is different from the half of the flushing cycle.

Therefore, the flushing of the lighting device 21 can be accurately detected by the condition determination of the above formulas (3) and (4), and thus the emergency braking operation in the preceding vehicle 20 can be detected.
Further, as shown in FIG. 4, since the determination is made at the time (T ₁ + T ₂ ) corresponding to one cycle of the flushing from the flushing start time (the time when the emergency braking operation is performed on the preceding vehicle 20). The emergency braking operation of the vehicle 20 can be immediately grasped. In the case of flushing with a frequency of 5 [Hz], an emergency braking operation can be detected at approximately 0.2 [s] from the start of flushing.

Further, when the flashing of the lighting device 21 is detected, the predetermined margin time TTC ₀ related to the damage reduction brake control start condition is corrected in the increasing direction, so that the start timing of the damage reduction brake control in the brake ECU 8 can be advanced, The deceleration effect due to automatic braking can be fully exhibited. Further, since the predetermined margin time TTC ₀ being increased correction is set based on the relative distance D _R and the relative speed V _R, it is possible to control in accordance with the urgency of the brake, further enhancing the reduction effect by the automatic braking be able to.

Furthermore, when the flashing of the lighting device 21 is detected, the braking force in the damage reduction brake control is also corrected in the increasing direction, so that the deceleration generated by the damage reduction brake control can be increased, and the deceleration effect by automatic braking can be further increased. Can be improved. In addition, since the magnitude of the braking force to be corrected for correction is set based on the relative distance D _R and the relative speed V _R , control according to the emergency level of the brake is possible, and the deceleration effect by automatic braking is further enhanced. be able to.

[5. Modified example]
[5-1. Configuration of Modification]
FIG. 5 illustrates an ECU 10A that functions as an automatic braking device as a modification of the present invention. In addition, the same code | symbol is attached | subjected about the component same as the above-mentioned embodiment, and description is abbreviate | omitted.

  The emergency braking determination unit 3 of the ECU 10A is provided with a lighting actual area calculation unit 2 in addition to the flushing detection unit 1. The lighting actual area calculation unit 2 (lighting actual area calculation means) calculates the lighting actual area S of the lighting device 21 of the preceding vehicle 20. For example, as shown in FIGS. 6A to 6C, there is a lighting device 21 of a type that changes the lighting area in accordance with the emergency degree of brake operation, the operation amount, and the like. Therefore, the lighting actual area calculation unit 2 calculates the value of the lighting actual area S, and the emergency braking determination unit 3 determines the presence or absence of an emergency braking operation in the preceding vehicle 20 according to the lighting actual area S. The lighting actual area calculation unit 2 is provided with an area calculation unit 2a.

Area calculation unit 2a (area calculating means) is configured to calculate the lighting area of the lighting device 21 on the image captured by the front camera 5, the relative distance D _R to the preceding vehicle 20 which is detected by the millimeter wave radar 6 It is used to calculate the actual lighting area S in the lighting device 21. Since the area of the subject on the captured image is inversely proportional to the square of the distance to the subject, when the lighting area on the image is S _R , the actual lighting area S is described as the following equation (6). . Note that k in equation (6) is a coefficient.
S = k · S _R · D _R ² ··· Equation (6)

Thus, by receiving the lights actual area S calculated at the lighting actual area calculating unit 2, the emergency braking determination unit 3, when the lighting actual area S is equal to or larger than a predetermined area threshold value S _A, with the preceding vehicle 20 It is determined that an emergency braking operation has been performed.

[5-2. Action and effect of modification]
FIG. 7 shows a flowchart of control executed by the ECU 10A. This flow is repeatedly executed at a predetermined cycle set in advance. The ECU 10A executes the control shown in FIG. 7 in parallel with the control shown in FIG.

In step B1, the image taken by the front camera 5, the relative distance D _R and the relative speed V _R detected by the millimeter wave radar 6, and the brake pedal depression information detected by the brake stroke sensor 7 are read into the ECU 10. It is. In the subsequent step B2, the margin time TTC is calculated according to the equation (5) in the margin time calculation unit 4a of the automatic braking unit 4.
In the subsequent step B3, the area calculation unit 2a calculates the lighting area S _R of the lighting device on the image. In the subsequent step B4, the emergency braking determination unit 3 calculates the actual lighting area S according to the equation (6).

Step B5 following is a step of determining conditions for starting the mitigation brake control, where the time to collision TTC calculated in step B2 is whether the predetermined time to contact TTC ₀ or more is determined. Here, in the case of TTC ≧ TTC ₀ is, the conditions for starting the mitigation brake control is not satisfied, the process proceeds to step B6. On the other hand, if TTC <TTC ₀ , the damage reduction brake control start condition is satisfied, and the process proceeds to step B8.

In step B8, a braking instruction is output from the braking force applying unit 4b. In response to this braking instruction, the brake ECU 8 performs damage reduction brake control, and a braking force is applied to the wheels 9. Thereby, the speed of the vehicle 11 at the time of contact with the preceding vehicle 20 is reduced.
If the start condition of damage reduction brake control is not satisfied in step B5, step B
6, the braking force application unit 4 b determines whether or not the brake pedal is depressed based on the detection information of the brake stroke sensor 7.

Here the process proceeds to step B7 in the case where the brake pedal is depressed, the calculated value of the lighting area S _R and the lighting actual area S is reset to 0, respectively, also predetermined margin time TTC ₀ and the braking force is the default value After resetting, this flow ends. On the other hand, if the brake pedal is not depressed, the process proceeds to step B9.
The flow after step B9 is a flow for detecting the emergency braking operation of the preceding vehicle 20. First, in step B9, it is determined whether or not the actual lighting area has been determined. Here, for example, it is determined whether or not the predetermined margin time TTC ₀ is a default value. When this condition is satisfied, the process proceeds to Step B10. On the other hand, when the predetermined margin time TTC ₀ is not the default value (when the predetermined margin time TTC ₀ has already been corrected in the increasing direction), the flow is finished as it is.

In step B10, in an emergency braking determination unit 3, the lighting actual area S is equal to or more than a predetermined area threshold value S _A is determined. Here, if S <S _A , the process proceeds to step B13, where the information on the lighting area S _R and the actual lighting area S is reset, and this flow ends. That is, it is determined that the emergency braking operation of the preceding vehicle 20 is not performed in the emergency braking determination unit 3. On the other hand, in the case of S ≧ S _A is determined that the emergency braking operation of the leading vehicle 20 has been made, the flow proceeds to step B11.

In step B11, the determination condition correction unit 4c, a predetermined margin time TTC ₀ is increased corrected according to the relative distance D _R and the relative speed V _R at that time. Thereby, the timing for applying the braking force by the damage reduction brake control is advanced. Moreover, In step B12, the braking force correction section 4d, the magnitude of the braking force of the damage reduction brake control is corrected to increase direction according to the relative distance D _R and the relative speed V _R at that time. As a result, the braking force applied to the wheel 9 is strengthened when the start condition of the damage reduction brake control is satisfied at the next and subsequent flows.

Thus, by calculating the lighting actual area S of the lighting device 21, an emergency braking operation in the preceding vehicle 20 including the lighting device 21 of the type shown in FIG. 6 can be detected. Moreover, in this modification, since the lighting area S of the actual lighting device 21 is calculated based on the lighting area S _R on the screen and the relative distance D _R to the preceding vehicle 20, the calculation result is accurate. In addition, the determination accuracy of the emergency braking operation can be improved.

[6. Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the conditions of Expressions (3) and (4) are determined when a time corresponding to one period of flushing has elapsed from the start time of flushing. It is good also as a structure which implements determination. In this case, for example, the condition of Expression (3) is determined at time t ₁ in FIG. 4, and the condition of Expression (4) is determined at time t ₂ . With such a configuration, it is possible to improve the determination speed when it is not flushing.

Or it is good also as what judges the conditions of Formula (3) and (4) when the judgment time is delayed and the time corresponding to two cycles of flushing passes. In this case, it is possible to improve the determination accuracy of flushing.
In the above-described embodiment, the configuration in which the start condition and the control content of the damage reduction brake control are changed when the flashing of the lighting device 21 of the preceding vehicle 20 is detected is exemplified. However, the present invention is applied to other automatic braking controls. May be.

  In the above-described embodiment, the front camera 5, the millimeter wave radar 6 and the brake stroke sensor 7 are connected to the input side of the ECU 10, but specific types of sensors should be changed as appropriate. Can do. The front camera 5 only needs to capture at least an image of the lighting device 21 of the preceding vehicle 20, and any optical video camera or infrared camera can be used.

  In the modification of the above-described embodiment, the emergency braking determination unit 3 includes the flushing determination unit 1 and the lighting actual area detection unit 2. However, instead of such a configuration, the lighting actual area detection is performed. Only the unit 2 may be provided. In the control based on the actual lighting area S of the lighting device 21, at least the actual lighting area detection unit 2 is sufficient.

DESCRIPTION OF SYMBOLS 1 Flushing detection part 1a Flashing period detection part (flashing period detection means)
1b Flushing determination unit (flushing determination means)
2 lighting actual area calculation part (lighting actual area calculation means)
2a Area calculation part (area calculation means)
3 Emergency braking determination unit (emergency braking determination means)
4 Automatic braking part (automatic braking means)
4a Margin time calculation unit (margin time calculation means)
4b Braking force applying part (braking force applying means)
4c Determination condition correction unit (determination condition correction means)
4d Braking force correction unit (braking force correction means)
5 Front camera (imaging means)
6 Millimeter wave radar (preceding vehicle detection means)
7 Brake stroke sensor 8 Brake ECU
9 wheels 10, 10A ECU
11 vehicle 20 preceding vehicle 21 lighting device t ₀ first lighting time t ₁ first lighting time t ₂ second lighting time T ₁ lighting time T ₂ lighting time

Claims (7)

Imaging means for capturing an image of the lighting device of the preceding vehicle;
Emergency braking determination means for determining the presence or absence of an emergency braking operation in the preceding vehicle based on the image photographed by the imaging means;
An automatic braking device, comprising: an automatic braking unit that performs automatic braking of the host vehicle when the emergency braking determination unit determines that the emergency braking operation is performed. The imaging means captures a plurality of images of the lighting device as moving images,
The emergency braking determination means is
A blinking period detecting means for detecting a blinking period of the lighting device based on the moving image photographed by the imaging means;
2. The automatic braking device according to claim 1, further comprising: a flushing determination unit that determines presence / absence of flushing in the lighting device based on the blinking cycle detected by the blinking cycle detection unit. The blinking cycle detecting means detects a first lighting time, a first lighting time after that, and a second lighting time after that, and between the first lighting time and the first lighting time. The blinking period is detected based on a lighting time calculated as a difference between the first lighting time and a lighting time calculated as a difference between the first lighting time and the second lighting time. Automatic braking device. Based on the image taken by the imaging means, further comprising a lighting actual area calculating means for calculating a lighting actual area of the lighting device in the preceding vehicle,
The emergency braking determination means determines whether or not there is an emergency braking operation based on the actual lighting area calculated by the actual lighting area calculation means. The automatic braking device described. Further comprising distance detection means for detecting the distance to the preceding vehicle;
The lighting actual area calculating means includes area calculating means for calculating the lighting actual area based on the lighting area of the lighting device in the image and the distance detected by the distance detecting means. Item 5. The automatic braking device according to item 4. The automatic braking means,
Preceding vehicle detection means for detecting the inter-vehicle distance and relative speed with the preceding vehicle;
Margin time calculation means for calculating a margin time until contact with the preceding vehicle based on the inter-vehicle distance and the relative speed detected by the preceding vehicle detection means;
Braking force applying means for applying a braking force to the host vehicle when the margin time calculated by the margin time calculating means is less than a predetermined margin time;
And determining condition correcting means for correcting the predetermined margin time related to the determination condition in the braking force applying means in an increasing direction when the emergency braking determining means determines that the emergency braking operation is being performed. The automatic braking device according to any one of claims 1 to 5. The automatic braking means,
And a braking force correcting unit that corrects the magnitude of the braking force applied by the braking force applying unit in an increasing direction when the emergency braking determining unit determines that the emergency braking operation is performed. The automatic braking device according to claim 6.

Images