Vehicle control device

Abstract

To provide a vehicle control device which is improved to reduce a risk of a driver delaying recognition of an obstacle in front of an own vehicle when both the obstacle ahead and a following vehicle behind are detected.SOLUTION: A vehicle control device includes: obstacle detection devices 12 and 14 which detect an obstacle ahead of an own vehicle 102; a following vehicle detection device which detects a following vehicle behind the own vehicle; notification devices 52 and 56 which alert a driver to a risk of collision when the own vehicle is determined to be on a collision course with the obstacle; and notification devices 52, 54, and 56 which alert the driver when a following vehicle gets too close to the own vehicle. The notification devices advance timing of an alert to the driver about the risk of collision when a notification has been made about the following vehicle approaching the own vehicle, compared to when no such notification has been made.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle such as an automobile. [Background technology]

[0002] 2. Description of the Related Art A collision prevention device is known as a control device for vehicles such as automobiles. When an obstacle is detected in front of the vehicle, the collision prevention device determines whether the vehicle is at risk of colliding with the obstacle, and if there is a risk of collision, the collision is prevented by applying a braking force to the vehicle using automatic braking.

[0003] For example, the following Patent Document 1 describes a collision prevention device that predicts a risk of collision between the vehicle and an obstacle ahead, and when a following vehicle is detected, applies automatic braking earlier than when the following vehicle is not detected, and applies automatic braking to a degree that prevents the following vehicle from colliding with the vehicle from behind.

[0004] In addition, as a control device for a vehicle such as an automobile, a notification device is known that notifies the driver that a following vehicle is approaching the host vehicle when a following vehicle is detected behind the host vehicle and it is determined that the following vehicle is approaching the host vehicle. With this type of control device, when the following vehicle is approaching the host vehicle, the driver can recognize that the following vehicle is approaching the host vehicle earlier than when the following vehicle is not approaching the host vehicle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-52546 A Summary of the Invention

[0006] [Problem to be solved by the invention] In a situation where an obstacle is detected ahead of the vehicle, if a following vehicle is detected behind the vehicle and a notification device displays a message indicating that the following vehicle is approaching the vehicle, the driver will pay attention to the notification displayed on the notification device, which may cause a delay in the driver recognizing the obstacle ahead of the vehicle.

[0007] The main objective of the present invention is to provide an improved vehicle control device that can reduce the risk of a delay in the driver recognizing an obstacle in front of the vehicle when an obstacle is detected in front of the vehicle and a following vehicle is detected behind the vehicle.

[0008] [Means for solving the problems and effects of the invention] According to the present invention, there is provided a vehicle control device (100) including an obstacle detection device (camera sensor 12 and radar sensor 14) that detects an obstacle in front of the host vehicle (102), a following vehicle detection device (camera sensor 12 and radar sensor 14) that detects a following vehicle behind the host vehicle, a notification device (driving assistance ECU 10, meter ECU 50, display device 52, and warning device 56) that notifies the driver of the risk of collision when it is determined that the host vehicle is at risk of colliding with an obstacle detected by the obstacle detection device (S70), and a notification device (driving assistance ECU 10, meter ECU 50, display device 52, electronic inner mirror 54, and warning device 56) that notifies the driver that the following vehicle is approaching the host vehicle when it is determined that the following vehicle detected by the following vehicle detection device is approaching the host vehicle (S240).

[0009] The notification device is configured to notify the driver of the risk of collision earlier (S60) when the notification device notifies the driver that a following vehicle is approaching the vehicle (S40) than when the notification device does not notify the driver that a following vehicle is approaching the vehicle.

[0010] According to the above configuration, when the notification device notifies the driver that a following vehicle is approaching the vehicle, the timing of notifying the driver that there is a risk of collision is earlier than when the notification device does not notify the driver that a following vehicle is approaching the vehicle.

[0011] Therefore, when the notification device notifies the driver that a following vehicle is approaching the vehicle, the driver can recognize the risk of a collision earlier than when the notification device does not notify the driver that a following vehicle is approaching the vehicle. Therefore, when an obstacle is detected in front of the vehicle and a following vehicle is detected behind the vehicle, the risk of a delay in the driver recognizing that there is an obstacle in front of the vehicle can be reduced.

[0012] [Mode of the invention] In one aspect of the present invention, the notification device is configured to notify the driver by displaying on the display device (52) that a following vehicle is approaching the vehicle, and the alarm device is configured to display on the display device (S80) that there is a risk of collision when the display device displays that a following vehicle is approaching the vehicle (S40).

[0013] In another embodiment of the present invention, the display device is a rearview mirror device (electronic inner mirror 54) configured to be capable of notifying the driver of information.

[0014] In another aspect of the present invention, the host vehicle (102) is equipped with a collision prevention device (driving assistance ECU 10, automatic braking device 34) that performs collision prevention control (S110) to reduce the risk of collision with the obstacle by automatic braking when it is determined that the host vehicle is at risk of colliding with an obstacle detected by the obstacle detection device (S90), and the collision prevention device is configured to initiate automatic braking earlier (S60) when the notification device has not notified the host vehicle that a following vehicle is approaching the host vehicle (S40) than when the notification device has not notified the host vehicle that a following vehicle is approaching the host vehicle.

[0015] In another aspect of the present invention, the collision prevention device is configured to notify the driver that automatic braking may be initiated earlier when the notification device notifies the driver that a following vehicle is approaching the vehicle than when the notification device does not notify the driver that a following vehicle is approaching the vehicle.

[0016] Other objects, other features and attendant advantages of the present invention will become readily apparent from the following description of the embodiments of the present invention which is given with reference to the accompanying drawings. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic configuration diagram showing an embodiment of a vehicle control device according to the present invention; [Diagram 2] 4 is a flowchart showing a collision prevention control routine in the embodiment. [Diagram 3] 4 is a flowchart showing a rear approach control routine in the embodiment. [Figure 4] 4 is a flowchart showing a flag setting control routine in the embodiment. [Diagram 5] FIG. 13 is a diagram showing a case where there is a risk that the host vehicle will collide with an obstacle ahead and there is a following vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] As shown in Fig. 1, a control device 100 according to an embodiment of the present invention is applied to a vehicle 102 and includes a driving assistance ECU 10. The vehicle 102 may be an autonomous vehicle, and includes a drive ECU 20, a brake ECU 30, and a meter ECU 50. The ECU means an electronic control unit having a microcomputer as a main part. In the following description, the vehicle 102 will be referred to as the host vehicle 102 as necessary in order to distinguish it from other vehicles.

[0020] The microcomputer of each ECU includes a CPU, ROM, RAM, a readable / writable non-volatile memory (N / M), and an interface (I / F). The CPU realizes various functions by executing instructions (programs, routines) stored in the ROM. Furthermore, these ECUs are connected to each other via a Controller Area Network (CAN) 104 so that they can exchange data (communicate). Therefore, the detection values ​​of sensors (including switches) connected to a specific ECU are also sent to other ECUs.

[0021] The driving assistance ECU 10 is a central control device that performs driving assistance control such as collision prevention control and lane keeping control. A camera sensor 12 and a radar sensor 14 are connected to the driving assistance ECU 10. The camera sensor 12 includes, but is not limited to, four camera sensors that capture images of the front, rear, right side, and left side. The radar sensor 14 includes, but is not limited to five radar sensors that detect three-dimensional objects present in the front area, the right front area, the left front area, the right rear area, and the left rear area and acquire information about the objects.

[0022] The camera sensor 12 and the radar sensor 14 function as an obstacle detection device that detects an obstacle ahead of the vehicle (host vehicle) 102. In addition, the camera sensor 12 and the radar sensor 14 function as a following vehicle detection device that detects a following vehicle behind the vehicle 102.

[0023] Each camera sensor of the camera sensor 12 analyzes image data obtained by capturing images to obtain information on targets such as white lines on the road and other vehicles, and supplies the target information to the driving assistance ECU 10 at predetermined time intervals.

[0024] Each radar sensor of the radar sensor 14 acquires information indicating the distance between the vehicle and a three-dimensional object, the relative speed between the vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the vehicle, etc. at predetermined time intervals, and supplies the information to the driving assistance ECU 10. Note that instead of or in addition to the radar sensor 14, a LiDAR (Light Detection And Ranging) may be used.

[0025] Furthermore, a setting operator 16 is connected to the driving assistance ECU 10, and the setting operator 16 is provided at a position where it can be operated by the driver. Although not shown in Fig. 1, the setting operator 18 includes a collision prevention control switch, and the driving assistance ECU 10 executes collision prevention control when the collision prevention control switch is on. The setting operator 18 includes a rear approach control switch, and the driving assistance ECU 10 executes rear approach control when the rear approach control switch is on. The collision prevention control and rear approach control will be described in detail later.

[0026] A drive device 22 that accelerates the vehicle 102 by applying a drive force to drive wheels not shown in Fig. 1 is connected to the drive ECU 20. The drive ECU 20 normally controls the drive device so that the drive force generated by the drive device 22 changes according to the driving operation by the driver, and when a command signal is received from the driving assistance ECU 10, the drive ECU 20 controls the drive device 22 based on the command signal.

[0027] The drive device 22 is not limited to a combination of an internal combustion engine and an automatic transmission. That is, the drive device 22 may be any drive device known in the art, such as a combination of an internal combustion engine and a continuously variable transmission, a so-called hybrid system which is a combination of an internal combustion engine and a motor, a so-called plug-in hybrid system, a combination of a fuel cell and a motor, or a motor.

[0028] A braking device 32 that applies a braking force to wheels (not shown in Fig. 1) to decelerate the vehicle 102 is connected to the braking ECU 30. The braking ECU 30 normally controls the braking device 32 so that the braking force generated by the braking device 32 varies according to the braking operation by the driver, and when a command signal is received from the driving assistance ECU 10, the braking ECU 30 performs automatic braking by controlling the braking device 32 based on the command signal. Thus, the braking ECU 30 and the braking device 32 function as an automatic braking device. When a braking force is applied to the wheels, a brake lamp (not shown in Fig. 1) is turned on.

[0029] A display 52 is connected to the meter ECU 50, which displays the status of control by the driving assistance ECU 10, and a visual warning indicating that the vehicle is at risk of colliding with another vehicle. The display 52 may be, for example, a head-up display or a multi-information display that displays meters and various information, or may be a display of a navigation device.

[0030] Furthermore, an electronic inner mirror 54, an alarm device 56, and a hazard lamp 58 are connected to the meter ECU 50. The electronic inner mirror 54 is a rearview mirror device configured to display an image captured by a camera that captures the rear of the vehicle and to display information to be communicated to the driver as necessary. The alarm device 56 issues an alarm. The alarm device 56 may be any of an alarm device that issues a visual alarm such as a display or an alarm lamp, an alarm device that issues an auditory alarm such as an alarm buzzer, and an alarm device that issues a bodily alarm such as seat vibration, or any combination thereof.

[0031] The driving operation sensor 60 and the vehicle condition sensor 62 are connected to the CAN 104. Information detected by the driving operation sensor 60 and the vehicle condition sensor 62 (called sensor information) is transmitted to the CAN 104. The sensor information transmitted to the CAN 104 can be used appropriately in each ECU. Note that the sensor information may be information of a sensor connected to a specific ECU and transmitted to the CAN 104 from the specific ECU.

[0032] The driving operation sensor 60 includes a driving operation amount sensor that detects the amount of operation of the accelerator pedal, a braking operation amount sensor that detects the master cylinder pressure or the depression force on the brake pedal, and a brake switch that detects whether the brake pedal is operated. Furthermore, the driving operation sensor 60 includes a steering angle sensor that detects the steering angle, a steering torque sensor that detects the steering torque, etc.

[0033] The vehicle condition sensor 62 includes a vehicle speed sensor that detects the speed of the vehicle 102, a longitudinal acceleration sensor that detects the longitudinal acceleration of the vehicle, a lateral acceleration sensor that detects the lateral acceleration of the vehicle, and a yaw rate sensor that detects the yaw rate of the vehicle.

[0034] In this embodiment, the ROM of the driving assistance ECU 10 stores a program for collision prevention control corresponding to the flowchart shown in Fig. 2, and the CPU executes collision prevention control according to the program when the collision prevention control switch is on. In the following description, the collision prevention control is referred to as PCS control.

[0035] As will be described in detail later, the driving assistance ECU 10, the meter ECU 50, the display 52 and the warning device 56 function as an alarm device that alerts the driver of the risk of collision when it is determined that the vehicle 102 is at risk of colliding with an obstacle detected by the obstacle detection device.

[0036] In addition, the ROM of the driving support ECU 10 stores a program for rear approach control corresponding to the flowchart shown in FIG. 3, and the CPU executes rear approach control according to the program when the rear approach control switch is on. The rear approach control is a control for notifying the driver that a following vehicle is approaching the host vehicle to arouse attention when the following vehicle is approaching the host vehicle.

[0037] As will be described in detail later, when it is determined that the following vehicle detected by the following vehicle detection device is approaching the host vehicle 102, the driving support ECU 10, the meter ECU 50, the display 52, the electronic inner mirror 54, and the warning device 56 function as a notification device for notifying the driver that the following vehicle is approaching the host vehicle.

[0038] Furthermore, the ROM of the driving support ECU 10 stores a program for flag setting control corresponding to the flowchart shown in FIG. 4, and the CPU executes flag setting control according to the program when the rear approach control switch is on. The flag setting control is a control for setting a flag Frp indicating whether the reference value for determining the magnitude of the collision prediction time TTCf should be increased.

[0039] <PCS control routine> (FIG. 2) First, in step S10, the CPU determines whether there is an obstacle in front of the vehicle 102, that is, whether the obstacle detection device has detected an obstacle in front of the vehicle 102. When the CPU makes a negative determination, the PCS control is terminated once, and when the CPU makes an affirmative determination, the PCS control proceeds to step S20.

[0040] In step S20, a collision prediction time TTCf, which is a predicted time until the vehicle 102 collides with an obstacle, is calculated. The collision prediction time TTCf is calculated according to the following formula (1) based on the distance Drf between the obstacle and the host vehicle based on the detection result by the obstacle detection device, and the relative speed Vrf of the host vehicle with respect to the obstacle. The collision prediction time TTCf is an index that indicates the likelihood that the host vehicle will collide with an obstacle, and the smaller the value, the higher the likelihood (risk) that the host vehicle will collide with the obstacle. TTCf = Drf / Vrf (1)

[0041] In step S30, the CPU determines whether or not the flag Fpcs is 1, that is, whether or not automatic braking by PCS control is being performed. If the CPU makes a positive determination, it advances the PCS control to step S120, and if the CPU makes a negative determination, it advances the PCS control to step S40. The flag Fpcs is initialized to 0 at the start of PCS control prior to step S10.

[0042] In step S40, the CPU determines whether a flag Frp, which is set according to the flowchart shown in Fig. 4 described later, is 1, that is, whether the reference value for determining whether the collision prediction time TTCf is large or small should be increased. If the CPU makes a negative determination, it sets the reference values ​​TTCfw, TTCfb, and TTCfe to standard values ​​TTCfwn, TTCfbn, and TTCfen (positive constants), respectively, in step S50. In contrast, if the CPU makes a positive determination, it sets the reference values ​​TTCfw, TTCb, and TTCfe to values ​​TTCfwh, TTCfbh, and TTCfeh (positive constants) larger than the standard values ​​TTCfwn, TTCfbn, and TTCfen, respectively, in step S60.

[0043] In step S70, the CPU determines whether the collision prediction time TTCf is equal to or less than the warning reference value TTCfw, that is, whether it is necessary to issue a warning that the host vehicle may collide with an obstacle. If the CPU determines that the collision prediction time TTCf is equal to or less than the warning reference value TTCfw, the CPU temporarily ends the PCS control. If the CPU determines that the collision prediction time TTCf is equal to or less than the warning reference value TTCfw, the CPU causes the PCS control to proceed to step S80.

[0044] In step S80, the CPU activates the warning device 58 to issue a warning that the host vehicle may collide with an obstacle, and displays a warning that the host vehicle may collide with an obstacle on the electronic inner mirror 54. In particular, when the CPU makes a positive determination in step S40, it activates the warning device 56 to notify the driver that there is a possibility that automatic braking will be initiated.

[0045] In step S90, the CPU determines whether the collision prediction time TTCf is equal to or less than the braking reference value TTCfb, that is, whether automatic braking is necessary. If the CPU determines that the collision prediction time TTCf is equal to or less than the braking reference value TTCfb, the CPU temporarily ends the PCS control. If the CPU determines that the collision prediction time TTCf is equal to or less than the braking reference value TTCfb, the CPU sets the flag Fpcs to 1 in step S100.

[0046] In step S110, the CPU calculates the PCS required deceleration Gpcs as a target deceleration for preventing a collision, and outputs a PCS brake command to the brake ECU 30 to set the deceleration of the vehicle 102 to the PCS required deceleration Gpcs. Thus, the brake ECU 30 controls the braking device 32 so that the deceleration of the vehicle 102 becomes the PCS required deceleration Gpcs, and automatic braking is performed. The CPU also cancels the notification that automatic braking may start, and displays on the display 52 that automatic braking is being performed.

[0047] The PCS required deceleration Gpcs is calculated as follows: If the deceleration of the host vehicle is Gb (<0) and the time until the host vehicle stops is t, the travel distance X until the host vehicle stops can be expressed by the following equation (2). X = Vrf t - (1 / 2) Gb t2 (2)

[0048] Moreover, the time t until the host vehicle stops can be expressed by the following equation (3). t = -Vrf / Gb (3)

[0049] Therefore, by substituting the time t calculated by equation (3) into the time t in equation (2), the travel distance X until the host vehicle stops can be expressed by the following equation (4). X=-V 2 / (2Gb) ···(4)

[0050] In order to stop the vehicle at a distance β before the obstacle, the deceleration Gb is calculated by setting the travel distance X to the distance Drf detected by the obstacle detection device minus the distance β (>0), that is, (Drf-β). The PCS required deceleration Gpcs is set to the sign-inverted value of the deceleration Gb calculated in this way.

[0051] In step S120, the CPU determines whether the collision prediction time TTCf is greater than the termination reference value TTCfe. If the CPU determines that the collision prediction time TTCf is greater than the termination reference value TTCfe, the CPU advances the PCS control to step S110. If the CPU determines that the collision prediction time TTCf is greater than the termination reference value TTCfe, the CPU advances the PCS control to step S130.

[0052] In step S130, the CPU resets the flag Fpcs to 0, cancels the automatic braking and the issuance of a warning, and causes the display 52 to display the fact that the automatic braking has been canceled.

[0053] <Rear approach control routine> (Fig. 3) First, in step S210, the CPU determines whether or not there is a following vehicle behind the host vehicle 102, i.e., whether or not a following vehicle has been detected by the following vehicle detection device. If the CPU makes a negative determination, it advances the rear approach control to step S280, and if the CPU makes a positive determination, it advances the rear approach control to step S220.

[0054] In step S220, a collision prediction time TTCr, which is a predicted time until the following vehicle collides with the host vehicle 102, is calculated based on the distance Drr between the host vehicle 102 and the following vehicle and the relative speed Vrr of the following vehicle with respect to the host vehicle, which are based on the detection result by the following vehicle detection device. The collision prediction time TTCr is calculated according to the following formula (5) based on the distance Drr and the relative speed Vrr of the following vehicle with respect to the host vehicle. The collision prediction time TTCf is an index that indicates the likelihood that the following vehicle will collide with the host vehicle, and the smaller its value, the higher the likelihood (risk) of the following vehicle colliding with the host vehicle. TTCr=Drr / Vrr (56)

[0055] In step S230, the CPU determines whether or not the flag Fra is 1, that is, whether or not an alarm has been issued to the effect that the following vehicle may collide with the host vehicle. If the CPU makes a positive determination, the CPU advances the rear approach control to step S250, and if the CPU makes a negative determination, the CPU advances the rear approach control to step S240. The flag Fra is initialized to 0 at the start of the rear approach control prior to step S210.

[0056] In step S240, the CPU determines whether or not a condition for starting the issuance of a warning that a following vehicle may collide with the host vehicle is satisfied. If the CPU determines that the condition is not satisfied, the CPU advances the rear approach control to step S280, and if the CPU determines that the condition is satisfied, the CPU advances the rear approach control to step S260.

[0057] In this step S240, a positive determination may be made when the following condition 1 or 2 is satisfied. Condition 1: The collision prediction time TTCr is equal to or less than the warning start reference time TTCrs (a positive constant). Condition 2: The distance Drr between the vehicle behind and the own vehicle is equal to or less than the reference distance Drrs (a positive constant) for starting a warning.

[0058] In step S250, the CPU determines whether or not a termination condition for issuing a warning that a following vehicle may collide with the host vehicle is satisfied. If the CPU determines yes, the CPU advances the rear approach control to step S280, and if the CPU determines no, the CPU advances the rear approach control to step S260.

[0059] In this step S250, a positive determination may be made when the following condition 3 or 4 is satisfied. Condition 3: The collision prediction time TTCr is equal to or greater than the reference time TTCre (a positive constant greater than TTCrs) for ending the warning. Condition 4: The distance Drr between the host vehicle and the rear vehicle is equal to or greater than the reference distance Drrs for terminating the warning (a positive constant greater than Drrs).

[0060] In step S260, the CPU determines whether or not a prohibition condition for issuing a warning that a following vehicle may collide with the host vehicle is satisfied. If the CPU determines yes, the CPU advances the rear approach control to step S280, and if the CPU determines no, the CPU advances the rear approach control to step S270.

[0061] In this step S260, a positive determination may be made when the following condition 5 or 6 is satisfied. Condition 5: The driver is performing braking operations. Condition 6: The turn signal switch is on.

[0062] In step S270, when the flag Fra is 0, the CPU sets the flag Fra to 1. In addition, the CPU issues a warning that the following vehicle may collide with the host vehicle by displaying an indication on the electronic inner mirror 54 and activating the warning device 56, and also flashes the hazard lamps 58 at short flashing intervals to alert the driver of the following vehicle.

[0063] In step S280, the CPU resets the flag Fra to 0. If a warning is being issued, the CPU stops the operation of the electronic inner mirror 54 and the warning device 56, and stops the flashing of the hazard lamps 58.

[0064] <Flag setting control routine> (Fig. 4) First, in step S310, similarly to step S210, the CPU determines whether or not there is a following vehicle behind the host vehicle 102. When the CPU makes a negative determination, it repeatedly executes step S310, and when the CPU makes a positive determination, it advances the flag setting control to step S320.

[0065] In step S320, similarly to step S230, the CPU determines whether or not the flag Fra is 1, that is, whether or not an alarm has been issued to the effect that the following vehicle may collide with the host vehicle. If the CPU makes a negative determination, it advances the flag setting control to step S350, and if the CPU makes a positive determination, it sets the flag Frp to 1 in step S330.

[0066] In step S340, the CPU determines whether or not the flag Fra has become 0, that is, whether or not the issuance of the warning that the following vehicle may collide with the host vehicle has ended. If the CPU determines in the negative, it repeatedly executes step S340, and if the CPU determines in the positive, it advances the flag setting control to step S380.

[0067] In step S350, the CPU determines whether or not there is a high risk of the following vehicle colliding with the host vehicle from behind. If the CPU determines negative, it temporarily ends the flag setting control. If the CPU determines positive, it sets the flag Frp to 1 in step S360.

[0068] In this step S350, a positive determination may be made when the following condition 7 or 8 is satisfied. Condition 7: The collision prediction time TTCr is greater than the reference time TTCrs for starting an alarm, but the rate of decrease in the distance Drr is equal to or greater than a reference rate of decrease dDrr (a positive constant). Condition 8: The distance Drr between the vehicle behind and the own vehicle is greater than the reference distance Drrs for starting an alarm, but the reduction rate of the collision prediction time TTCr is equal to or greater than a reference reduction rate dTTCr (a positive constant).

[0069] In step S370, the CPU determines whether the risk of the following vehicle colliding with the host vehicle has been eliminated. If the CPU determines that the risk is not present, the CPU repeats step S370. If the CPU determines that the risk is not present, the CPU resets the flag Frp to 0 in step S380.

[0070] <Operation of the embodiment> Next, the operation of the embodiment will be described for the case where the host vehicle 102 is at risk of colliding with an obstacle 106 ahead, such as a stopped vehicle, and there is a following vehicle 108, as shown in FIG.

[0071] C1: When the following vehicle is not approaching the vehicle 3, a negative determination is made, and therefore, in step S280, the flag Fra is reset to 0. Therefore, in steps S320 and S350 in FIG.

[0072] 2, the reference values ​​TTCfw, TTCfb, and TTCfe are set to the standard values ​​TTCfwn, TTCfbn, and TTCfen, respectively, in step S50, and steps S70 and after are executed. Note that, since a following vehicle is not approaching the host vehicle, no warning is issued (S80) and no automatic braking is performed (S110).

[0073] C2: When a following vehicle is approaching your vehicle First, in steps S230, S240, and S260 in Fig. 3, a negative determination, a positive determination, and a negative determination are respectively made, and therefore, in step S270, the flag Fra is set to 1. Thereafter, in steps S230 and S250, a positive determination and a negative determination are respectively made until a termination condition (S250) for issuing a warning that the following vehicle may collide with the vehicle is satisfied. Therefore, by executing step S270, the flag Fra is maintained at 1. In addition, a warning that the following vehicle may collide with the vehicle is issued, and the hazard lamps 58 are made to flash at short flashing intervals to alert the driver of the following vehicle.

[0074] Since an affirmative decision is made in step S320 of FIG. 4, the flag Frp is set to 1 in step S330 and is maintained at 1 until the flag Fra becomes 0, that is, until an affirmative decision is made in step S340.

[0075] In step S30 of FIG. 2, a negative judgment is made, but in step S40, a positive judgment is made, so in step S60, the reference values ​​TTCfw, TTCfb, and TTCfe are set to values ​​TTCfwh, TTCfbh, and TTCfeh that are greater than the standard values ​​TTCfwn, TTCfbn, and TTCfen, respectively, and steps S70 to S130 are executed.

[0076] Therefore, the determination in step S70 becomes positive earlier than when the reference value TTCfw is the standard value TTCfwn. Therefore, when the notification device notifies the driver that a following vehicle is approaching the vehicle, the timing to notify the driver that there is a risk of collision becomes earlier than when the notification device does not notify the driver that a following vehicle is approaching the vehicle.

[0077] Therefore, when the notification device notifies the driver that a following vehicle is approaching the vehicle, the driver can recognize the risk of a collision earlier than when the notification device does not notify the driver that a following vehicle is approaching the vehicle. Therefore, when an obstacle is detected in front of the vehicle and a following vehicle is detected behind the vehicle, the risk of a delay in the driver recognizing that there is an obstacle in front of the vehicle can be reduced.

[0078] In addition, in a situation where there is an obstacle ahead of the vehicle and a following vehicle is approaching the vehicle, if a display device shows that the following vehicle is approaching the vehicle and the driver pays attention to the display, there is a high likelihood that there will be a delay in the driver realizing that there is an obstacle ahead of the vehicle.

[0079] According to the embodiment, the driver is notified by displaying the fact that a following vehicle is approaching the vehicle on the electronic inner mirror 54 as a display device. Furthermore, when the electronic inner mirror displays that a following vehicle is approaching the vehicle (S40), the electronic inner mirror displays that there is a risk of collision (S80). Therefore, even when the driver is checking the following vehicle through the electronic inner mirror, the driver can easily recognize that there is an obstacle ahead of the vehicle, thereby reducing the risk of a delay in recognizing the presence of an obstacle.

[0080] Also, the determination in step S90 becomes positive earlier than when the reference value TTCfb is the standard value TTCfbn. Therefore, when the vehicle is notified that the following vehicle is approaching the vehicle (S40), the automatic braking is started earlier (S110) than when the vehicle is not notified that the following vehicle is approaching the vehicle. Therefore, even if the driver is late in recognizing that there is an obstacle ahead of the vehicle, the possibility of preventing the vehicle from colliding with the obstacle can be increased.

[0081] Furthermore, the determination in step 70 becomes positive earlier than when the reference value TTCfw is the standard value TTCfwn. Therefore, when the vehicle is notified that the following vehicle is approaching (S40), the advance notice of the start of automatic braking is given earlier (S80) than when the vehicle is not notified that the following vehicle is approaching (S40). Therefore, the driver can recognize the start of automatic braking earlier.

[0082] Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various other embodiments are possible within the scope of the present invention.

[0083] For example, in the above embodiment, the common display device that displays that a following vehicle is approaching the vehicle and that the vehicle is at risk of colliding with an obstacle ahead is the electronic inner mirror 54. However, the common display device may be the indicator 52, or may be a reflective inner mirror provided with an indicator.

[0084] In the above embodiment, when the vehicle is notified that the following vehicle is approaching the host vehicle, the initiation of automatic braking and the advance notice thereof are made earlier than when the vehicle is not notified that the following vehicle is approaching the host vehicle. However, at least one of the advancement of the initiation of automatic braking and the advance notice thereof may be omitted.

[0085] Furthermore, in the above-described embodiment, the flag setting control is executed according to the flowchart shown in Fig. 4. However, the flag setting control may be omitted, and step S350 may be executed when a negative determination is made in step S240, and the rear approach control may proceed to step S260 when a positive determination is made, and the rear approach control may proceed to step S280 when a negative determination is made. [Explanation of symbols]

[0086] 10...driving assistance ECU, 12...camera sensor, 14...radar sensor, 20...driving ECU, 30...braking ECU, 50...meter ECU, 52...display, 54...electronic inner mirror, 56...alarm device, 58...hazard lamp, 60...driving operation sensor, 62...vehicle state sensor, 100...control device, 102...own vehicle

Claims

1. A vehicle control device including an obstacle detection device that detects an obstacle ahead of the vehicle, a following vehicle detection device that detects a following vehicle behind the vehicle, a notification device that notifies a driver of the risk of collision when it is determined that the vehicle is at risk of colliding with an obstacle detected by the obstacle detection device, and a notification device that notifies a driver of the risk of the following vehicle approaching the vehicle when it is determined that the following vehicle detected by the following vehicle detection device is approaching the vehicle, The vehicle control device is configured to notify the driver of the risk of collision earlier when the notification device notifies the driver that a following vehicle is approaching the vehicle than when the notification device does not notify the driver that a following vehicle is approaching the vehicle.

2. 2. A vehicle control device as described in claim 1, wherein the notification device is configured to notify the driver by displaying on a display device that a following vehicle is approaching the vehicle, and the alarm device is configured to display on the display device that there is a risk of collision when the display device displays that a following vehicle is approaching the vehicle.

3. 3. The vehicle control device according to claim 2, wherein the display device is a rearview mirror device configured to be capable of notifying a driver of information.

4. In the vehicle control device described in claim 1, the host vehicle is equipped with a collision prevention device that performs collision prevention control to reduce the risk of collision with the obstacle by automatic braking when it is determined that the host vehicle is at risk of colliding with an obstacle detected by the obstacle detection device, and the collision prevention device is configured to initiate the automatic braking earlier when the notification device has not notified the host vehicle that a following vehicle is approaching the host vehicle than when the notification device has not notified the host vehicle that a following vehicle is approaching the host vehicle.

5. 5. The vehicle control device according to claim 4, wherein the collision prevention device is configured to notify the driver of the possibility of automatic braking being initiated earlier when the notification device notifies the driver that a following vehicle is approaching the vehicle than when the notification device does not notify the driver that a following vehicle is approaching the vehicle.

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