JP2023083646A - Device for reducing damage when subjected to rear-end collision - Google Patents

Abstract

To provide a device for reducing damage when subjected to a rear-end collision that has been improved so as not only to reduce the damage when subjected rear-end collision but also to prevent an automatic brake from being operated unnecessarily at car wash by a self-propelled car washing machine and at servicing etc. at a maintenance factory.SOLUTION: A device for reducing damage when subjected to a rea-end collision, includes: camera sensors and radar sensors serving as circumference information detection devices which detect information around an own vehicle; and vehicle controller or the like which operates automatic brake (S60) when determining, with the camera sensors and the like having detected another vehicle approaching from behind the own vehicle, that the another vehicle may collide against the stationary own vehicle (S40). Therein, when a shift position is at an N range and application of brake force by operation of a driver is not performed, the vehicle controller or the like prohibits the operation of the automatic brake (S50).SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear-end collision damage reduction device for reducing damage in the event of a rear-end collision of a vehicle such as an automobile.

BACKGROUND ART As one of driving support devices for vehicles such as automobiles, there is known a rear-end collision damage reduction device that reduces damage when one's own vehicle is rear-ended by another vehicle following it. For example, Patent Literature 1 below describes a rear-end collision configured so that, when the possibility of a rear-end collision is determined in a situation where the own vehicle is stopped, rear-end collision damage mitigation control that activates automatic braking is executed. A time damage mitigation device is described.

According to this type of rear-end collision damage mitigation device, when the possibility of a rear-end collision is determined in a situation where the own vehicle is stopped, the automatic brake is activated, so that the own vehicle is moved forward due to the rear-end collision. It is possible to reduce the risk of secondary collision of the own vehicle with an obstacle in front due to the above.

JP-A-2000-355273

[Problems to be solved by the invention]
However, in a vehicle equipped with a rear-end collision damage reduction device, unnecessary execution of rear-end collision damage reduction control may cause the automatic brake to be unnecessarily actuated. For example, when a vehicle is washed by a self-propelled car wash machine (a car wash machine in which the vehicle is automatically moved relative to a fixed car wash device) or when the vehicle is maintained at a maintenance shop, the vehicle may be moved by belt conveyors or rollers. In such a case, the shift position is set to the N range, and braking such as a foot brake is not applied.

In such a situation, if it is erroneously determined that an object in the vicinity of the own vehicle, such as a car wash machine or another vehicle, is approaching the own vehicle from behind, the automatic brakes are unnecessarily activated. As a result, the own vehicle may run off the belt conveyor or the like, or may collide with another vehicle conveyed from behind by the belt conveyor or the like.

In order to prevent unnecessary automatic braking operation as described above, it is possible to prohibit the automatic braking operation as long as the shift position is set to the N range, regardless of whether the brake is applied or not. Conceivable. However, in that case, if the shift position is set to the N range and the vehicle is stationary, and there is a possibility of a rear-end collision with another vehicle approaching from behind, the automatic brakes must be activated. can not reduce the damage in the event of a rear-end collision.

A major object of the present invention is to reduce damage in the event of a rear-end collision, and to prevent unnecessary operation of the automatic brake during car washing by a self-propelled car wash machine or maintenance at a maintenance shop. To provide an improved device for reducing damage in the event of a rear-end collision.

[Means for Solving the Problems and Effect of the Invention]
According to the present invention, an object approaching from behind the own vehicle is detected by the surrounding information detection device (camera sensor 12, radar sensor 14) for detecting information around the own vehicle (102) and the surrounding information detection device, When it is determined that there is a possibility of an object colliding with the stopped vehicle (S40), a control device (vehicle control ECU 10, etc.) that activates the automatic brake (S60), and a rear-end collision damage mitigation device ( 100) are provided.

The control device is configured to prohibit the operation of the automatic brake (S250, S50) when the shift position is in the N range (S210) and braking force is not being applied by the driver's operation (S220-S240). be done.

In general, when the vehicle is temporarily stopped while waiting for a signal, etc., braking force is applied by operating the brake pedal while the shift position is set to the D range, the shift position is switched to the P range, and braking force is applied by the parking brake. is given. Therefore, when the own vehicle stops temporarily, the operation of the automatic brake is not prohibited. Therefore, when it is determined that another vehicle approaching from the rear of the stopped vehicle is detected and it is determined that there is a possibility that the other vehicle will collide with the stopped vehicle, the automatic brake is activated. It is possible to reduce the risk of secondary collision of the own vehicle with an obstacle ahead due to the forward movement of the vehicle due to the rear-end collision.

In addition, when the vehicle is moved by a belt conveyor or rollers during washing by a self-propelled car wash machine or maintenance at a maintenance shop, the shift position is set to the N range, and braking force is applied by the driver's operation. is not performed. Therefore, since the operation of the automatic brake is prohibited, even if it is erroneously determined that an object in the vicinity of the own vehicle or another vehicle is approaching the own vehicle from behind, the automatic brake does not operate. Therefore, it is possible to prevent the own vehicle from derailing from the belt conveyor or colliding with another vehicle conveyed from behind by the belt conveyor or the like due to the unnecessary operation of the automatic brake.

It should be noted that the phrase "braking force is not applied by the driver's operation" means that, in the case of a vehicle in which brake hold control is not performed, the braking force is applied by operating the brake pedal and the parking brake is applied. It means that no power is applied. In addition, ``the braking force is not applied by the driver's operation'' means that, in the case of a vehicle in which brake hold control is performed, the braking force is applied by operating the brake pedal, and the braking force is applied by operating the parking brake. This means that neither the application of the brake force nor the application of the braking force by the operation of the brake hold is performed. Furthermore, in the case of a vehicle whose transmission is not an automatic transmission but a manual transmission, the condition "the shift position is in the N range" may be ignored.

In the above description, in order to facilitate understanding of the present invention, names and/or symbols used in the embodiments are added in parentheses to configurations of the invention corresponding to the embodiments to be described later. However, each component of the present invention is not limited to the component of the embodiment corresponding to the parenthesized names and/or symbols. Other objects, features and attendant advantages of the present invention will be readily understood from the description of embodiments of the present invention described with reference to the following drawings.

1 is a schematic configuration diagram showing an embodiment of a rear-end collision damage mitigation control device according to the present invention; FIG. 4 is a flowchart showing a rear-end collision damage mitigation control routine in the embodiment. 4 is a flow chart showing an automatic braking enable/disable determination control routine in the embodiment. It shows a situation in which another vehicle is approaching from behind the own vehicle while the own vehicle and the preceding vehicle are stopped. This shows a situation in which another vehicle approaching from behind the own vehicle has stopped while the own vehicle and the preceding vehicle are stopped.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

<Configuration>
As shown in FIG. 1, a rear-end collision damage reduction device 100 according to an embodiment of the present invention is applied to a vehicle 102 and includes a vehicle control ECU 10. As shown in FIG. The vehicle 102 includes a brake ECU 20 , an SBW (Shift-by-Wire) ECU 30 and a meter ECU 40 . ECU means an electronic control unit having a microcomputer as its main part. In the following description, the vehicle 102 will be referred to as own vehicle 102 as necessary to distinguish it from other vehicles.

A microcomputer of each ECU includes a CPU, a ROM, a RAM, a readable and writable nonvolatile memory (N/M), an interface (I/F), and the like. The CPU implements various functions by executing instructions (programs, routines) stored in the ROM. Further, these ECUs are connected to each other via a CAN (Controller Area Network) 50 so as to be able to exchange data (communicate). Therefore, detected values of sensors (including switches) connected to a specific ECU are transmitted to other ECUs as well.

The vehicle control ECU 10 is connected with a plurality of camera sensors 12F, 12B, 12R and 12L and a plurality of radar sensors 14F, 14B, 14R and 14L. The plurality of camera sensors 12F, 12B, 12R and 12L are referred to as "camera sensors 12" when there is no need to distinguish between them. Similarly, multiple radar sensors 14F, 14B, 14R and 14L are referred to as "radar sensors 14" when there is no need to distinguish between them. The camera sensor 12 and the radar sensor 14 function as a peripheral information acquisition device that acquires information around the vehicle 102 .

The camera sensor 12, although not shown in the figure, comprises a camera unit and a recognition unit that analyzes image data obtained by photographing by the camera unit and recognizes targets such as road white lines and other vehicles. I have. The recognition unit of the camera sensor 12 supplies information about the recognized target to the vehicle control ECU 10 every time a predetermined time elapses. LiDAR (Light Detection And Ranging) may be used instead of the camera sensor 12 .

The camera sensor 12F is a front camera sensor that captures an image of the front of the vehicle 102, and the camera sensor 12B is a back camera that captures an image of the rear of the vehicle 102. The camera sensor 12R is a right side camera that captures an image of the right side of the vehicle 102, and the camera sensor 12L is a left side camera that captures an image of the left side of the vehicle 102.

The radar sensor 14 includes a radar transmitter/receiver and a signal processor (not shown). It receives millimeter waves (that is, reflected waves) reflected by three-dimensional objects (eg, other vehicles, bicycles, guardrails, etc.) existing in the vehicle. Based on the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation level of the reflected wave, and the time from when the millimeter wave is transmitted to when the reflected wave is received, the signal processing unit determines whether the vehicle and the three-dimensional object , the relative speed between the vehicle and the three-dimensional object, and the relative position (direction) of the three-dimensional object with respect to the own vehicle (hereinafter referred to as peripheral information). supply to

The radar sensor 14F is provided at the front end of the vehicle 102 and acquires surrounding information in front of the vehicle. The radar sensor 14B is provided at the rear end portion of the vehicle 102 and acquires surrounding information behind the vehicle. The radar sensor 14R is provided on the right side of the vehicle 102 and acquires surrounding information on the right side of the vehicle. The radar sensor 14L is provided on the left side of the vehicle 102 and acquires surrounding information on the left side of the vehicle.

Furthermore, a vehicle speed sensor 16 is connected to the vehicle control ECU 10 . The vehicle speed sensor 16 detects the vehicle speed V by detecting the wheel speed of each wheel, and supplies a signal indicating the vehicle speed V to the vehicle control ECU 10 .

A braking device 22, a parking brake device 24, a pressure sensor 26 for detecting the master cylinder pressure Pm, and a brake hold switch 28 are connected to the brake ECU 20. FIG. In FIG. 1, the parking brake device is written as a PB device, and the brake hold switch is written as a BH switch. Although not shown in detail in FIG. 1, the braking device 22 includes a brake actuator and a braking force generating mechanism.

The brake ECU 20 normally controls the braking force generating mechanism via the brake actuator based on the master cylinder pressure Pm, and thus based on the operation of the brake pedal (not shown) by the driver. A braking force is generated according to the amount of braking operation. Further, the brake ECU 20 can perform automatic braking that generates a braking force without requiring a driver's braking operation by controlling the braking force generating mechanism according to an instruction from the vehicle control CU 10 .

The parking brake device 24 may be a mechanical parking brake device operated by operating a foot pedal or a parking lever, or may be an electric parking brake device operated by operating a parking brake switch. The parking brake device 24, when activated, maintains the vehicle 102 stationary by applying a braking force to the wheels. It should be noted that while the parking brake device 24 is operating, a display to that effect is displayed on a display device 42, which will be described later.

Furthermore, when the brake hold switch 28 is on and the vehicle 102 is stopped by braking, the brake ECU 20 controls the braking force generation mechanism to maintain the braking force even if the driver releases the braking operation. Execute hold control. Further, the brake ECU 20 releases the brake hold control when the driver performs a predetermined releasing operation such as a drive operation while the brake hold control is being executed. During execution of the brake hold control, a display to that effect is displayed on a display device 42, which will be described later.

As can be seen from the above description, when the driver operates the brake pedal, foot pedal, parking lever, etc., a braking force is applied, and when the vehicle 102 is stopped, the vehicle is stopped so as not to move. is maintained. Conversely, when the driver does not operate the brake pedal, foot pedal, parking lever, etc., no braking force is applied.

A shift position sensor 32 and an automatic transmission 34 are connected to the SBW-ECU 30, and the shift position sensor is indicated as an SP sensor in FIG. A shift position sensor 32 detects the position (shift position) of a shift lever not shown in FIG. The positions of the shift lever include N range (neutral position), P range (parking position), D range (forward position) and R range (reverse position). The SBW-ECU 30 receives information on the position of the shift lever from the shift position sensor 32, and controls the gear ratio and shift range of the automatic transmission 34 based on the position (that is, performs shift control). . Note that the automatic transmission 34 may be either a gear-type automatic transmission or a continuously variable transmission.

A display 42 and a brake lamp 44 are connected to the meter ECU 40 . The meter ECU 40 displays, on the display 42, various vehicle control information including rear-end collision damage mitigation control in accordance with a display command from the vehicle control ECU 10. FIG. The display 42 is, for example, a head-up display or a multi-information display that displays meters and various information. Further, the meter ECU 40 illuminates the brake lamp 44 when a brake switch provided on the brake pedal (not shown in FIG. 1) is turned on, that is, when the driver is performing a braking operation.

In the embodiment, the ROM of the vehicle control ECU 10 stores a rear-end collision damage reduction control program corresponding to the flowchart shown in FIG. 2, and the CPU executes the rear-end collision damage reduction control according to the program. do. In addition, the ROM of the vehicle control ECU 10 stores a program for judging whether automatic braking is possible or not, corresponding to the flowchart shown in FIG. Note that the vehicle control ECU 10 may perform various driving support controls known in the art, such as lane departure prevention control and constant speed running control, while the vehicle 102 is running.

<Rear-end collision damage reduction control routine>
Next, a rear-end collision damage mitigation control routine according to the embodiment will be described with reference to the flowchart shown in FIG. In the rear-end collision damage mitigation control according to the flowchart shown in FIG. 2, the vehicle control ECU 10 is started by the CPU and repeatedly executed at a predetermined control cycle. In the following description, the rear-end collision damage mitigation control is simply referred to as "control." Note that flags Fa and Fb, which will be described later, are reset to 0 at the start of control.

First, in step S10, the CPU determines whether or not another vehicle exists behind the own vehicle 102 and the other vehicle is approaching the own vehicle. When the CPU makes a negative determination, it advances the control to step S80, and when it makes an affirmative judgment, it advances the control to step S20.

In step S<b>20 , the CPU calculates a collision prediction time TTC, which is the prediction time until the other vehicle collides with the own vehicle 102 . The estimated collision time TTC is calculated according to the following formula (1) based on the distance Dr between the own vehicle and the other vehicle and the relative speed Vr of the other vehicle with respect to the own vehicle (=vehicle speed of the other vehicle). . The collision prediction time TTC is an index that indicates the degree of possibility that another vehicle will collide with the host vehicle 102 from behind.
TTC=Dr/Vr (1)

In step S30, the CPU determines whether or not the flag Fa is 1, that is, determines whether or not automatic braking has already started by executing step S60, which will be described later. When the CPU makes an affirmative determination, the control proceeds to step S90, and when it makes a negative determination, the control proceeds to step S40.

In step S40, the CPU determines whether or not the collision prediction time TTC is equal to or less than the automatic braking start threshold TTCs (positive constant), i. judgment is made. When the CPU makes a negative determination, it once ends the control, and when it makes an affirmative determination, it advances the control to step S50.

In step S50, the CPU determines whether or not the flag Fb is 0, that is, determines whether or not automatic braking for reducing damage caused by a rear-end collision is permitted. When the CPU makes a negative determination, it once ends the control, and when it makes an affirmative determination, it advances the control to step S60. It should be noted that the flag Fb is set to 0 or 1 by the automatic braking enable/disable determination control executed according to the flowchart shown in FIG.

In step S60, the CPU outputs an automatic braking start command to the brake ECU 20 to start automatic braking that generates a braking force without requiring a braking operation by the driver. Set to 1. When the automatic braking is started and executed, the indicator 42 displays to that effect.

In step S80, the CPU determines whether or not the flag Fa is 1, that is, determines whether or not automatic braking has already started, as in step S30. When the CPU makes an affirmative determination, it advances the control to step S100, and when it makes a negative determination, it once ends the control.

In step S90, the CPU determines whether or not conditions for terminating automatic braking are satisfied. When the CPU makes a negative determination, it once ends the control, and when it makes an affirmative determination, it advances the control to step S100. In this case, it is determined that the conditions for terminating the automatic braking are satisfied when any one of the following E1 to E4 is satisfied.
E1: Flag Fb is 1 (automatic braking is prohibited).
E2: The collision prediction time TTC is equal to or greater than the automatic braking end threshold TTCe (positive constant greater than the start threshold TTCs).
E3: The shift position was switched to D range.
E4: Vehicle speed V is greater than or equal to reference value Ve (positive constant).

In step S100, the CPU terminates the automatic braking by outputting an automatic braking termination command to the brake ECU 20, and resets the flag Fa to 0 in step S110. Therefore, the display on the indicator 42 indicating that automatic braking is being executed is deleted.

<Routine for determining whether automatic braking is possible>
Next, an automatic braking enable/disable determination control routine in the embodiment will be described with reference to the flowchart shown in FIG. In the automatic braking determination control according to the flowchart shown in FIG. 3, the vehicle control ECU 10 is started by the CPU and repeatedly executed at a predetermined control cycle. In the following description, the automatic brake feasibility determination control is simply referred to as "feasibility determination control".

First, in step S210, the CPU determines whether or not the position of the shift lever detected by the shift position sensor 32 is in the N range. When the CPU makes a negative determination, it advances the acceptability determination control to step S260, and when it makes an affirmative determination, it advances the acceptability determination control to step S220.

In step S220, the CPU determines whether or not the brake lamp 44 is on. When the CPU makes an affirmative determination, it advances the propriety judgment control to step S260, and when it makes a negative judgment, it advances the propriety judgment control to step S230.

In step S230, the CPU determines whether or not the parking brake device 24 is operating. When the CPU makes an affirmative determination, it advances the propriety judgment control to step S260, and when it makes a negative judgment, it advances the propriety judgment control to step S240.

In step S240, the CPU determines whether brake hold control is being executed. When the CPU makes an affirmative determination, it advances the propriety judgment control to step S260, and when it makes a negative judgment, it advances the propriety judgment control to step S250.

In step S250, the CPU sets the flag Fb to 1 so that the automatic brake control for reducing the damage caused by the collision is prohibited, and in step S260, sets the flag Fb to 0 so that the automatic brake is permitted. set to

<Example of operation of the embodiment>
Next, with reference to FIGS. 4 and 5, the operation of the embodiment will be described for the case where the host vehicle 102 and the preceding vehicle 104 are stopped and another vehicle 106 is approaching from behind the host vehicle.

FIG. 4 shows that another vehicle 106 is approaching from behind the vehicle 102 at a relative speed Vr (=vehicle speed of the other vehicle), and the collision prediction time TTC calculated according to the above equation (1) is equal to the automatic braking start threshold value TTCs. It shows the situation as follows. The position of the shift lever is in the N range, and the application of the braking force by the operation of the driver, that is, the application of the braking force by operating the brake pedal, the application of the braking force by the operation of the parking brake device, and the braking force by the brake hold control. is performed.

In this situation, an affirmative determination is made in step S210 and an affirmative determination is made in any of steps S220 to S240, so flag Fb is set to 0 in step S260. It should be noted that the position of the shift lever is in a range other than the N range, and braking force is applied by operating the brake pedal, applying braking force by operating the parking brake device, and applying braking force by brake hold control. If not, the flag Fb is also set to 0.

Therefore, an affirmative determination is made in step S10, a negative determination is made in step S30, an affirmative determination is made in steps S40 and S50, and automatic braking is performed by starting automatic braking in step S60. Therefore, even if the following other vehicle 106 collides with the own vehicle 102 and the own vehicle moves forward, it is possible to reduce the risk of the own vehicle secondary collision with the preceding vehicle 104 ahead. .

FIG. 5 shows a case where another vehicle 106 behind the vehicle 106 stops behind the vehicle 102 without rear-colliding with the vehicle 102 . In this case, the vehicle speed of the other vehicle 106 decreases and the relative speed Vr becomes very small, so that the collision prediction time TTC becomes equal to or greater than the automatic braking termination threshold value TTCe. Therefore, affirmative determinations are made in steps S10, S30 and S90, and automatic braking is terminated in step S100. Therefore, if the preceding vehicle 104 starts moving, the own vehicle 102 can also start without any trouble.

Next, although not shown in the drawings, the operation of the embodiment will be described for the case where the own vehicle 102 is moved by a belt conveyor or rollers during car washing by a self-propelled car wash, maintenance at a maintenance shop, or the like. .

In the case of car washing by a self-propelled car wash machine, maintenance at a maintenance shop, etc., the shift position is set to the N range, and the braking force is applied by the operation of the driver, that is, the braking force is applied by operating the brake pedal, and the parking brake device. Neither the application of the braking force by the operation of the brake hold control nor the application of the braking force by the brake hold control is performed.

Therefore, affirmative determination is made in step S210, but negative determinations are made in all of steps S220 to S240. Therefore, in step S250, the flag Fb is set to 1 and the operation of the automatic brake is prohibited. Therefore, in step S10, it is erroneously determined that an object in the vicinity of own vehicle 102 or another vehicle is approaching the own vehicle from behind, and even if an affirmative determination is made in step S40, a negative determination is made in step S50. Since step S60 is not executed, the automatic brake does not operate. Therefore, it is possible to prevent the own vehicle 102 from running off the belt conveyor or the like or colliding with another vehicle conveyed from behind by the belt conveyor or the like due to unnecessary automatic braking. .

Although the present invention has been described in detail with respect to particular embodiments, it should be understood that the present invention is not limited to the embodiments described above and that various other embodiments are possible within the scope of the present invention. will be clear to those skilled in the art.

For example, in the above-described embodiment, the vehicle 102 has the brake hold switch 28, and when the vehicle 102 stops due to braking, brake hold control is executed to maintain the braking force even if the driver releases the braking operation. . However, the rear-end collision damage reduction device 100 of the present invention may be applied to a vehicle in which the brake hold control is not executed. In that case, step S240 in the flow chart shown in FIG. 3 is omitted. Therefore, the requirement for prohibiting the operation of the automatic brake, ``no braking force is applied by the driver's operation'', applies only to the application of braking force by operating the brake pedal and the application of braking force by operating the parking brake. Granting is not performed.

Further, in the above-described embodiment, when it is determined in step S40 of the flowchart shown in FIG. judged to be likely to However, an alarm may be issued by activating an alarm device (not shown) when TTCw (positive constant), which is larger than the start threshold value TTCs of the automatic braking, becomes equal to or less.

In the above-described embodiment, the camera sensor 12 and the radar sensor 14 are used as the surrounding information detection device for detecting the surrounding information of the vehicle 102. However, one of the camera sensor 12 and the radar sensor 14 may be omitted. good.

Further, in the above-described embodiment, the automatic braking enable/disable determination control according to the flowchart shown in FIG. 3 is executed as a separate control from the rear-end collision damage mitigation control according to the flowchart shown in FIG. However, the automatic braking feasibility determination control may be modified so as to be executed as part of the rear-end collision damage mitigation control, for example, at a stage prior to step S50.

Furthermore, in the embodiment described above, the vehicle 102 includes the SBW ECU 30 and the shift position sensor 32 and automatic transmission 34 connected thereto. However, the rear-end collision damage reduction device 100 of the present invention may be applied to a vehicle having a manual transmission. In that case, step S210 in the flow chart shown in FIG. 3 is omitted. Therefore, the requirement "the shift position is in the N range and", which is a requirement for prohibiting the operation of the automatic brake, is omitted.

Reference Signs List 10 Vehicle control ECU 12 Camera sensor 14 Radar sensor 16 Vehicle speed sensor 20 Brake ECU 22 Braking device 24 Parking brake device 26 Pressure sensor 28 Brake hold switch 30 SBW ECU 32 Shift position sensor 34 Automatic transmission 40 Meter ECU 42 Indicator 44 Brake lamp 100 Rear-end collision damage reduction device 102 Vehicle 104 Preceding vehicle 106 …other vehicles following

Claims (1)

An ambient information detection device for detecting information about the surroundings of the vehicle, and an object approaching the vehicle from behind is detected by the ambient information detection device, and the object may collide with the stopped vehicle. In a rear-end collision damage mitigation device that includes a control device that activates automatic braking when it is determined,
The control device is configured to prohibit the operation of the automatic brake when the shift position is in the N range and the braking force is not applied by the driver's operation.

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