Vehicle driving support device

Abstract

The present invention provides a vehicle driving support device that can avoid unnecessary deceleration of a vehicle and more reliably avoid secondary collisions. The vehicle driving support device (10) performs a secondary collision mitigation control for forcibly decelerating the vehicle when a light collision condition is satisfied, in which a collision index value representing the magnitude of a collision of the vehicle (100) is within a predetermined light collision range and a light collision has occurred in the vehicle, and the drowsiness level of the driver of the vehicle, i.e., the drowsiness level, is above a predetermined threshold level. When the light collision condition and the drowsiness condition are satisfied, the vehicle driving support device performs forced deceleration in such a way that the vehicle decelerates at a smaller deceleration when the drowsiness level at that time is low than when the drowsiness level is high.

Description

Technical Field

[0001] The present invention relates to a vehicle driving support device. Background Art

[0002] There is a case where another collision occurs to the vehicle after a collision of a degree that does not cause the airbag to deploy (a light collision). A vehicle driving support device for preventing another collision (a secondary collision) from occurring after such a light collision is known (for example, see Patent Document 1). This conventional vehicle driving support device prevents the occurrence of a secondary collision by implementing forced deceleration in which the vehicle is forced to decelerate and stop at a predetermined deceleration when a light collision occurs.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-2868 Summary of the invention

[0006] There are also cases where the driver is dozing off to the extent that he or she can wake up in the event of a minor collision and take personal action to avoid a secondary collision. In such a case, when forced deceleration is implemented to slow down the vehicle, there is a possibility that the deceleration of the vehicle becomes unnecessary for the driver. As a means to avoid this situation, it is possible to consider implementing forced deceleration only when the driver is dozing off to the extent that he or she will not wake up even in the event of a minor collision (that is, when it is determined that the driver is dozing off with a certain degree of certainty). Furthermore, as a method of determining that the driver is dozing off with a certain degree of certainty, it is possible to consider a method of determining that the driver is dozing off with a certain degree of certainty based on the fact that this state has continued for a certain period of time since the time when the driver was presumed to be dozing off.

[0007] However, as a result, forced deceleration is not performed even if a minor collision occurs until it is determined with a certain degree of certainty that the driver is dozing off, and as a result, a secondary collision may not be avoided.

[0008] In this way, if forced deceleration is implemented only when there is a high degree of certainty that the driver is dozing off, a secondary collision may be unavoidable. On the other hand, if forced deceleration is implemented even if there is a low degree of certainty that the driver is dozing off, the vehicle may be decelerated unnecessarily.

[0009] An object of the present invention is to provide a vehicle driving support device that can avoid unnecessary deceleration of a vehicle and more reliably avoid a secondary collision.

[0010] The vehicle driving support device of the present invention is a device that performs a secondary collision mitigation control for forcibly decelerating the vehicle when a light collision condition in which a collision index value indicating the magnitude of the collision of the vehicle is within a predetermined light collision range has occurred in the vehicle and a dozing condition in which the drowsiness level of the driver of the vehicle, i.e., the drowsiness level, is above a predetermined threshold level is satisfied. Furthermore, the vehicle driving support device of the present invention is configured to perform the forced deceleration in a manner that, when the light collision condition and the drowsiness condition are satisfied, the vehicle decelerates at a smaller deceleration when the drowsiness level at that time is low than when the drowsiness level is high.

[0011] In the case where a minor collision occurs to the vehicle while the driver is dozing off, it is possible that the vehicle will collide again (secondary collision) just after the collision occurs. As a means to avoid such a secondary collision, it is possible to implement a means of forced deceleration to force the vehicle to slow down and stop when a minor collision occurs to the vehicle while the driver is dozing off. However, there is also a situation where the driver only dozes off to the extent that he can wake up when a minor collision occurs and personally take actions to avoid a secondary collision. In such a case, when forced deceleration is implemented to decelerate the vehicle, it is possible that the deceleration of the vehicle becomes an unnecessary deceleration for the driver. As a means to avoid this situation, it is possible to implement a means of forced deceleration only when the driver is dozing off to the extent that he will not wake up even if a minor collision occurs (that is, when it is judged that the driver is dozing off with a certain degree of certainty). And, as a method for judging that the driver is dozing off with a certain degree of certainty, it is possible to consider a method of judging that the driver is dozing off with a certain degree of certainty based on the fact that the state has continued for a certain period of time since the time point when it is estimated that the driver is dozing off. However, as a result, forced deceleration is not performed even if a minor collision occurs until it is determined with a certain degree of certainty that the driver is dozing off, and as a result, a secondary collision may not be avoided.

[0012] In this way, if forced deceleration is implemented only when there is a high degree of certainty that the driver is dozing off, a secondary collision may be unavoidable. On the other hand, if forced deceleration is implemented even if there is a low degree of certainty that the driver is dozing off, a scene may occur where the vehicle is unnecessarily decelerated.

[0013] According to the present invention, forced deceleration is implemented when the driver's drowsiness level is low. When the driver's drowsiness level becomes higher, the deceleration of the host vehicle due to forced deceleration becomes larger. Therefore, unnecessary deceleration of the host vehicle can be avoided and the reliability of avoiding a secondary collision can be improved.

[0014] The vehicle driving support device according to the present invention may be configured to perform the forced deceleration by applying a braking force greater than a predetermined braking force to the host vehicle or by limiting the driving force applied to the host vehicle to a driving force less than a predetermined driving force.

[0015] Generally speaking, "the deceleration of the vehicle achieved by forced braking" and "the deceleration of the vehicle achieved by driving force limitation" are different from each other. According to the present invention, forced deceleration that can achieve appropriate deceleration of the vehicle to avoid a secondary collision can be appropriately selected from forced braking and driving force limitation. Therefore, the vehicle can be decelerated appropriately to avoid a secondary collision.

[0016] In addition, the vehicle driving support device according to the present invention may also be configured to determine whether to perform the forced deceleration by the forced braking or by the driving force limitation according to the drowsiness level when the light collision condition and the drowsiness condition are satisfied. In this case, the vehicle driving support device according to the present invention performs the forced deceleration by the forced braking when the drowsiness level is higher than the predetermined switching level higher than the predetermined threshold level, and performs the forced deceleration by the driving force limitation when the drowsiness level is lower than the predetermined switching level.

[0017] In order to avoid a secondary collision, it is preferred that when the dozing level is high, the vehicle is decelerated more than when the dozing level is low. In addition, generally speaking, forced braking can decelerate the vehicle more than driving force limitation. According to the present invention, when forced deceleration is implemented, when the dozing level is high, the vehicle is decelerated by forced braking, and when the vehicle speed is low, the vehicle is decelerated by driving force limitation. Therefore, a secondary collision can be avoided more reliably.

[0018] In addition, the vehicle driving support device according to the present invention may also be configured to determine whether to perform the forced deceleration by the forced braking or by the driving force limitation according to the speed of the host vehicle when the light collision condition and the dozing condition are satisfied. In this case, the vehicle driving support device according to the present invention performs the forced deceleration by the forced braking when the speed of the host vehicle is above the predetermined speed, and performs the forced deceleration by the driving force limitation when the speed of the host vehicle is less than the predetermined speed.

[0019] In order to avoid a secondary collision, it is preferred that when the vehicle speed is high, the vehicle is decelerated more than when the vehicle speed is low. In addition, generally speaking, compared with the driving force limitation, the forced braking can decelerate the vehicle more. According to the present invention, when the vehicle speed is high, the vehicle is decelerated by the forced braking, and when the vehicle speed is low, the vehicle is decelerated by the driving force limitation. Therefore, the secondary collision can be avoided more reliably.

[0020] In addition, the vehicle driving assistance device involved in the present invention can also be configured such that, when the forced deceleration is performed by applying a braking force greater than a predetermined braking force to the vehicle when the light collision condition and the dozing condition are met, the predetermined braking force is set to a larger braking force when the dozing level is high than when the dozing level is low; and when the forced deceleration is performed by limiting the driving force applied to the vehicle to a driving force less than a predetermined driving force when the light collision condition and the dozing condition are met, the predetermined driving force is set to a smaller driving force when the dozing level is high than when the dozing level is low.

[0021] In order to avoid a secondary collision, it is preferred that when the drowsiness level is high, the vehicle is decelerated more than when the drowsiness level is low. According to the present invention, when the forced deceleration is implemented, when the drowsiness level is high, the vehicle is decelerated more than when the drowsiness level is low. Therefore, a secondary collision can be avoided more reliably.

[0022] In addition, the vehicle driving assistance device involved in the present invention may also be configured such that, when the forced deceleration is performed by applying a braking force greater than a predetermined braking force to the vehicle when the light collision condition and the dozing off condition are satisfied, the predetermined braking force is set to a larger braking force when the vehicle speed is high than when the vehicle speed is low; and when the forced deceleration is performed by limiting the driving force applied to the vehicle to a driving force less than a predetermined driving force when the light collision condition and the dozing off condition are satisfied, the predetermined driving force is set to a smaller driving force when the vehicle speed is high than when the vehicle speed is low.

[0023] In order to avoid a secondary collision, it is preferred that when the vehicle speed is high, the vehicle is decelerated more than when the vehicle speed is low. According to the present invention, when the vehicle speed is high, the vehicle is decelerated more than when the vehicle speed is low by forced deceleration. Therefore, a secondary collision can be avoided more reliably.

[0024] In addition, the vehicle driving support device according to the present invention may also be configured to determine the drowsiness level based on the duration of time that the eyelids of the driver of the vehicle are judged to be closed. In this case, the vehicle driving support device according to the present invention determines that the drowsiness level is higher when the duration is long than when the duration is short.

[0025] The longer the driver closes his eyelids, the higher the driver's dozing level is likely to be. According to the present invention, when the driver closes his eyelids for a long time, the driver's dozing level is judged to be higher than when the driver closes his eyelids for a short time. Therefore, the driver's dozing level can be judged more accurately.

[0026] Furthermore, in the vehicle driving support device according to the present invention, the predetermined light collision range is set to, for example, a range smaller than a range of the collision index value for deploying the airbag of the host vehicle.

[0027] In the case of a collision that causes the airbag to deploy, the necessity for implementing forced deceleration is low. According to the present invention, forced deceleration is implemented in the case of a collision that does not cause the airbag to deploy (so-called light collision). Therefore, it is possible to prevent forced deceleration from being implemented when the necessity for implementing forced deceleration is low.

[0028] In addition, the vehicle driving support device according to the present invention may also be configured to terminate the secondary collision mitigation control when a control termination condition is satisfied after the light collision condition and the dozing condition are satisfied. In this case, the control termination condition is satisfied, for example, when the dozing level becomes lower than the predetermined threshold level, or when the driver's operation for accelerating or decelerating or steering the host vehicle continues for more than a predetermined operation time, or when the host vehicle stops.

[0029] In the case where the drowsiness level becomes low, or the driver personally performs an operation for accelerating or decelerating the vehicle or steering, the necessity of further continuing the forced deceleration is low. In addition, in the case where the vehicle is stopped, there is no need to further continue the forced deceleration. According to the present invention, in such a case, the forced deceleration is terminated. Therefore, it is possible to prevent the forced deceleration from being performed more than necessary.

[0030] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, other features, and additional advantages of the present invention will be easily understood from the description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1It is a diagram showing a vehicle driving support device according to an embodiment of the present invention and a vehicle (host vehicle) equipped with the vehicle driving support device.

[0032] Figure 2 This is a time chart showing changes in the drowsiness level and the like when a notification is issued to call the attention of the driver of the host vehicle.

[0033] Figure 3 This is a diagram showing the driving force and braking force set according to the doze level and the vehicle speed in the secondary collision reduction control.

[0034] Figure 4 It is a time chart showing an example of changes in driving force, braking force, etc. when the secondary collision reduction control is executed.

[0035] Figure 5 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0036] Figure 6 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0037] Figure 7 This is a flowchart showing a routine executed by the vehicle driving support device according to the embodiment of the present invention.

[0038] Description of Reference Numerals

[0039] 10…Vehicle driving support device, 20…Vehicle running device, 21…Drive device, 22…Braking device, 23…Steering device, 30…Notification device, 40…Air bag device, 74…Front and rear acceleration sensors, 75…Vehicle speed detection device, 76…Driver information acquisition device, 90…ECU, 100…Own vehicle DETAILED DESCRIPTION

[0040] Hereinafter, a vehicle driving support device according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, a vehicle driving support device 10 according to an embodiment of the present invention is mounted on a host vehicle 100 .

[0041] <ecu>

[0042] The vehicle driving support device 10 includes an ECU 90. ECU is an abbreviation for an electronic control unit. The ECU 90 includes a microcomputer as a main part. The microcomputer includes a CPU, a ROM, a RAM, a nonvolatile memory, an interface, etc. The CPU implements various functions by executing instructions, programs, or routines stored in the ROM.

[0043] <Vehicle running equipment, etc.>

[0044] The vehicle 100 is equipped with a vehicle driving device 20, a notification device 30, and an airbag device 40. The vehicle driving device 20 is a device for driving, braking, and steering the vehicle 100, and in this example, it includes a driving device 21, a braking device 22, and a steering device 23. In addition, the notification device 30 is a device for notifying the driver of the vehicle 100, and in this example, it includes a display 31 and a buzzer 32. The airbag device 40 is a device that prevents the driver of the vehicle 100 from hitting the steering wheel 54 by deploying the airbag when the vehicle 100 collides, and in this example, it includes an inflator 41 and an airbag 42.

[0045] <Drive device>

[0046] The drive device 21 is a device that outputs a driving force applied to the vehicle 100 to drive the vehicle 100, and is, for example, an internal combustion engine or a motor. The drive device 21 is electrically connected to the ECU 90. The ECU 90 can control the driving force output from the drive device 21 by controlling the operation of the drive device 21.

[0047] <Braking device>

[0048] The brake device 22 is a device that outputs a braking force applied to the vehicle 100 in order to brake the vehicle 100, and is, for example, a brake device. The brake device 22 is electrically connected to the ECU 90. The ECU 90 can control the braking force output from the brake device 22 by controlling the operation of the brake device 22.

[0049] <Steering gear>

[0050] The steering device 23 is a device that outputs a steering force applied to the vehicle 100 for steering the vehicle 100, and is, for example, a power steering device. The steering device 23 is electrically connected to the ECU 90. The ECU 90 can control the steering force output from the steering device 23 by controlling the operation of the steering device 23.

[0051] In this way, the vehicle driving support device 10 (the ECU 90 thereof) can control the driving, braking, and steering of the host vehicle 100 by controlling the operation of the vehicle travel device 20 .

[0052] <Display>

[0053] The display 31 is a device for displaying various images. The display 31 is electrically connected to the ECU 90 . The ECU 90 can display various images on the display 31 .

[0054] <Buzzer>

[0055] The buzzer 32 is a device that outputs various alarm sounds. The buzzer 32 is electrically connected to the ECU 90. The ECU 90 can output various alarm sounds from the buzzer 32.

[0056] In this way, the vehicle driving support device 10 (the ECU 90 thereof) can perform various notifications to the driver of the host vehicle 100 by operating the notification device 30 .

[0057] <Airbag>

[0058] The inflator 41 is a device for generating gas for deploying the airbag 42. The inflator 41 is electrically connected to the ECU 90. When a collision index value C having a correlation with a longitudinal deceleration Gd detected by a longitudinal acceleration sensor 74 described later becomes equal to or greater than a predetermined value Cth, the ECU 90 operates the inflator 41 to generate gas. The gas is sent to the airbag 42, so that the airbag 42 is deployed.

[0059] <Sensors, etc.>

[0060] In addition, the vehicle 100 is equipped with an accelerator pedal 51, a brake pedal 52, a steering shaft 53, a steering wheel 54, an accelerator pedal operation amount sensor 71, a brake pedal operation amount sensor 72, a steering angle sensor 73, a front and rear acceleration sensor 74, a vehicle speed detection device 75 and a driver information acquisition device 76.

[0061] <Accelerator pedal operation amount sensor>

[0062] The accelerator pedal operation amount sensor 71 is a sensor that detects the operation amount of the accelerator pedal 51. The accelerator pedal operation amount sensor 71 is electrically connected to the ECU 90. The accelerator pedal operation amount sensor 71 transmits information on the detected operation amount of the accelerator pedal 51 to the ECU 90. Based on this information, the ECU 90 acquires the operation amount of the accelerator pedal 51 as the accelerator pedal operation amount AP.

[0063] The ECU 90 obtains the required driving force DRreq (required driving torque) by calculation based on the accelerator pedal operation amount AP and the vehicle speed V of the host vehicle 100 . The required driving force DRreq is the driving force that the driver of the host vehicle 100 requires the drive device 21 to output.

[0064] <Brake pedal operation amount sensor>

[0065] The brake pedal operation amount sensor 72 is a sensor that detects the operation amount of the brake pedal 52. The brake pedal operation amount sensor 72 is electrically connected to the ECU 90. The brake pedal operation amount sensor 72 sends information on the detected operation amount of the brake pedal 52 to the ECU 90. Based on this information, the ECU 90 obtains the operation amount of the brake pedal 52 as the brake pedal operation amount BP.

[0066] The ECU 90 obtains the required braking force BKreq (required braking torque) according to the brake pedal operation amount BP through calculation. The required braking force BKreq is the braking force that the driver of the host vehicle 100 requires the brake device 22 to output.

[0067] <Steering angle sensor>

[0068] The steering angle sensor 73 is a sensor that detects the rotation angle of the steering shaft 53 relative to the neutral position. The driver of the vehicle 100 can rotate the steering shaft 53 by rotating the steering wheel 54 connected to the steering shaft 53. The steering angle sensor 73 is electrically connected to the ECU 90. The steering angle sensor 73 sends information on the detected rotation angle of the steering shaft 53 to the ECU 90. The ECU 90 obtains the rotation angle of the steering shaft 53 as the steering angle θ based on the information.

[0069] The ECU 90 obtains the required steering force (required steering torque) according to the steering angle θ through calculation. The required steering force is the steering force required to be output by the steering device 23. The ECU 90 controls the operation of the steering device 23 so that the steering device 23 outputs the required steering force.

[0070] <Front and rear acceleration sensors>

[0071] The front-rear acceleration sensor 74 is a device for detecting the acceleration in the front-rear direction of the host vehicle 100. The front-rear acceleration sensor 74 is electrically connected to the ECU 90. The front-rear acceleration sensor 74 sends information on the detected acceleration in the front-rear direction of the host vehicle 100 to the ECU 90. The ECU 90 obtains the acceleration in the front-rear direction of the host vehicle 100 based on the information. In addition, when the obtained acceleration is a negative value, the acceleration is the deceleration in the front-rear direction of the host vehicle 100 (longitudinal deceleration Gd).

[0072] <Vehicle speed detection device>

[0073] The vehicle speed detection device 75 is a device for detecting the vehicle speed of the host vehicle 100, for example, a wheel speed sensor. The vehicle speed detection device 75 is electrically connected to the ECU 90. The vehicle speed detection device 75 sends information on the detected vehicle speed of the host vehicle 100 to the ECU 90. The ECU 90 obtains the vehicle speed V of the host vehicle 100 based on the information. In addition, when the vehicle speed V is zero, the ECU 90 determines that the host vehicle 100 is stopped.

[0074] <Driver Information Acquisition Device>

[0075] The driver information acquisition device 76 is a device that acquires information related to the driver of the host vehicle 100, for example, a so-called driver monitor. The driver information acquisition device 76 is electrically connected to the ECU 90. The driver information acquisition device 76 sends the acquired information (driver information I_D) to the ECU 90. The ECU 90 can determine whether the eyelids of the driver of the host vehicle 100 are closed based on the driver information I_D.

[0076] <Overview of Operation of Vehicle Driving Assistance Device>

[0077] Next, an overview of the operation of the vehicle driving support device 10 is described. When the vehicle driving support device 10 determines that the driver of the host vehicle 100 is dozing off, the vehicle driving support device 10 notifies the driver of the host vehicle 100. Furthermore, when a minor collision of the host vehicle 100 occurs while the vehicle driving support device 10 determines that the driver of the host vehicle 100 is dozing off, the vehicle driving support device 10 performs a secondary collision mitigation control that automatically decelerates the host vehicle 100.

[0078] These notifications and the secondary collision mitigation control will be described below.

[0079] The vehicle driving support device 10 obtains a drowsiness level LV indicating the drowsiness level of the driver of the vehicle 100. In the present example, the drowsiness level LV is obtained based on the duration (duration T) of the state in which the eyelids of the driver of the vehicle 100 are judged to be closed. In addition, in the present example, whether the eyelids of the driver of the vehicle 100 are closed is judged based on the driver information I_D. In addition, in the present example, the vehicle driving support device 10 judges that the eyelids of the driver of the vehicle 100 are closed when the eyelids are completely closed, but it may be configured to judge that the eyelids of the driver are closed when the opening condition of the eyelids is less than a predetermined condition, such as when the state in which the driver's eyelids are fully opened is set to 100%, and the opening condition of the eyelids is judged to be 10% or less.

[0080] The vehicle driving support device 10 is as follows Figure 2 As shown, when it is determined that the eyelids of the driver of the host vehicle 100 are in a closed state (time t20), the time (continuation time T) that has elapsed from this time starts to be measured.

[0081] Furthermore, the vehicle driving support device 10 determines that the dozing condition is satisfied when the duration T reaches the predetermined time (first time T_1) (time t21) and the dozing condition is satisfied when the dozing level LV is above the predetermined threshold level LVth. More specifically, the vehicle driving support device 10 determines that the dozing level LV is the first level LV_1 when the duration T reaches the first time T_1 (time t21). Thereafter, the vehicle driving support device 10 determines that the dozing level LV is the second level LV_2 when the duration T reaches the second time T_2 (time t22), and thereafter, when the duration T reaches the third time T_3 (time t23), the vehicle driving support device 10 determines that the dozing level LV is the third level LV_3.

[0082] In this example, the first time T_1 is set to a time longer than zero, but may be set to zero.

[0083] <Notice>

[0084] The vehicle driving support device 10 is in a period in which the dozing level LV is the first level LV_1 (from Figure 2 During the period from time t21 to time t22, an image (first image) urging the driver of the host vehicle 100 to pay attention is displayed on the display 31 and an alarm sound of a predetermined volume is continuously output from the buzzer 32 (first notification).

[0085] In addition, the vehicle driving support device 10 is in a period in which the dozing level LV is the second level LV_2 (from Figure 2 In the example, the second image is the same as the first image, but may be different from the first image.

[0086] In addition, the vehicle driving support device 10 is in a period in which the dozing level LV is the third level LV_3 (in Figure 2 After time t23 (after time t23), an image (third image) urging the driver of the vehicle 100 to pay attention is displayed on the display 31 and an alarm sound of a predetermined volume is intermittently output at a predetermined period (third notification). However, the vehicle driving support device 10 may also be configured to stop the display on the display 31 and the output of the alarm sound from the buzzer 32 when the drowsiness level LV reaches the third level LV_3.

[0087] In addition, the vehicle driving support device 10 ends the ongoing notification when the notification end condition is satisfied while the first notification, the second notification, or the third notification is being performed. In this example, the notification end condition is satisfied when the doze level LV becomes lower than the predetermined threshold level LVth, that is, when the time for which the eyelids of the driver of the vehicle 100 are continuously judged to be not closed (that is, open) reaches a predetermined time. In addition, the notification end condition is satisfied when the operation of the accelerator pedal 51 by the driver for accelerating the vehicle 100 continues for more than a predetermined operation time. In addition, the notification end condition is satisfied when the operation of the brake pedal 52 by the driver for decelerating the vehicle 100 continues for more than a predetermined operation time. In addition, the notification end condition is satisfied when the operation of the steering wheel 54 by the driver for steering the vehicle 100 continues for more than a predetermined operation time. In addition, the notification end condition is satisfied when the vehicle 100 stops.

[0088] <Secondary Collision Mitigation Control>

[0089] In addition, the vehicle driving support device 10 determines whether the light collision condition is satisfied. In this example, the light collision condition is satisfied when the longitudinal deceleration Gd of the host vehicle 100 is within the predetermined longitudinal deceleration range Rgd and the cumulative value ΣGd of the longitudinal deceleration Gd when the longitudinal deceleration Gd is a value within the predetermined longitudinal deceleration range Rgd becomes greater than the predetermined cumulative value ΣGd_th. In other words, the light collision condition is satisfied when the collision index value C indicating the magnitude of the collision of the host vehicle 100 is within the predetermined light collision range Rc. In this example, the predetermined light collision range Rc is set to a range smaller than the range of the collision index value C for deploying the airbag 42. Therefore, in this example, it can be said that the vehicle driving support device 10 uses the longitudinal deceleration Gd of the host vehicle 100 and its cumulative value ΣGd as the collision index value C indicating the magnitude of the collision of the host vehicle 100.

[0090] When the minor collision condition is satisfied, the vehicle driving support device 10 determines whether the dozing condition is satisfied, that is, the dozing level LV is equal to or higher than a predetermined threshold level LVth. More specifically, the vehicle driving support device 10 determines whether the dozing level LV is the first level LV_1, the second level LV_2, or the third level LV_3.

[0091] The vehicle driving support device 10 performs secondary collision mitigation control when the dozing level LV is greater than a predetermined threshold level LVth. In this example, the secondary collision mitigation control is a control for forcibly decelerating the vehicle 100 by limiting the driving force DR applied to the vehicle 100 to a driving force less than a predetermined driving force DRth and applying a braking force BK greater than a predetermined braking force BKth to the vehicle 100 as a forced deceleration control.

[0092] The vehicle driving support device 10 may also be configured to set a target deceleration as the deceleration of the host vehicle 100 based on the drowsiness level LV and the vehicle speed V when the light collision condition and the drowsiness condition are satisfied, and to set the predetermined driving force DRth and the predetermined braking force BKth in such a manner as to achieve the target deceleration. However, in this example, Figure 3 As shown in FIG. 1 , the predetermined driving force DRth and the predetermined braking force BKth are set in advance according to the doze level LV and the vehicle speed V. Therefore, the secondary collision reduction control is performed as follows.

[0093] <Secondary collision mitigation control at level 1>

[0094] <Level 1 and low speed>

[0095] The vehicle driving support device 10 determines whether the requested driving force DRreq is greater than the predetermined driving force DRth and whether the requested braking force BKreq is greater than the first braking force BK_1 when the light collision condition is satisfied and the doze level LV is the first level LV_1 and the vehicle speed V is within the first vehicle speed range R_1.

[0096] The first vehicle speed range R_1 is a range greater than the first vehicle speed V_1 (zero in this example) and less than the second vehicle speed V_2. The second vehicle speed V_2 is set to a value greater than the first vehicle speed V_1. The predetermined driving force DRth is set to a value greater than zero. In addition, in this example, although the first braking force BK_1 is set to zero, it can also be set to a value slightly greater than zero.

[0097] The vehicle driving support device 10 sets the predetermined driving force DRth as the target driving force DRtgt when the required driving force DRreq is greater than the predetermined driving force DRth. On the other hand, the vehicle driving support device 10 sets the required driving force DRreq as the target driving force DRtgt when the required driving force DRreq is less than the predetermined driving force DRth. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target driving force DRtgt is output from the drive device 21.

[0098] On the other hand, when the required braking force BKreq is greater than the first braking force BK_1 (i.e., zero), the vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt, and controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the braking device 22. On the other hand, when the required braking force BKreq is less than the first braking force BK_1 (i.e., when the required braking force BKreq is zero), the vehicle driving support device 10 sets the target braking force BKtgt to zero, and controls the operation of the vehicle travel device 20 so that the braking force BK is not output from the braking device 22.

[0099] In this way, when the minor collision condition is satisfied and the doze level LV at this time is the first level LV_1 and the vehicle speed V is within the first vehicle speed range R_1, the vehicle driving support device 10 performs forced deceleration by limiting the driving force DR applied to the host vehicle 100 to a driving force limit that is less than the predetermined driving force DRth. In addition, when the minor collision condition is satisfied and the doze level LV at this time is the first level LV_1 and the vehicle speed V is within the first vehicle speed range R_1, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than the predetermined braking force BKth (zero) to the host vehicle 100.

[0100] <Level 1 and medium speed>

[0101] In addition, when the light collision condition is met and the drowsiness level LV at this time is the first level LV_1 and the vehicle speed V is within the second vehicle speed range R_2, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the drive device 21.

[0102] In other words, when the light collision condition is met and the dozing level LV at this time is the first level LV_1 and the vehicle speed V is within the second vehicle speed range R_2, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0103] The second vehicle speed range R_2 is a range that is greater than the second vehicle speed V_2 and equal to or less than the third vehicle speed V_3. The third vehicle speed V_3 is set to a value greater than the second vehicle speed V_2.

[0104] Furthermore, when the minor collision condition is satisfied and the doze level LV at that time is the first level LV_1 and the vehicle speed V is within the second vehicle speed range R_2, the vehicle driving support device 10 determines whether the required braking force BKreq is equal to or greater than the second braking force BK_2.

[0105] The second braking force BK_2 is set to a value greater than the first braking force BK_1 (zero in this example). In this example, the second braking force BK_2 is set to a constant value regardless of the vehicle speed V, but may be set to a larger value as the vehicle speed V increases.

[0106] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the second braking force BK_2. On the other hand, when the required braking force BKreq is less than the second braking force BK_2, the vehicle driving support device 10 sets the second braking force BK_2 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the brake device 22.

[0107] In this way, when the light collision condition is met and the doze level LV at this time is the first level LV_1 and the vehicle speed V is within the second vehicle speed range R_2, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than a predetermined driving force DRth (second braking force BK_2) to the vehicle 100.

[0108] <Level 1 and high speed>

[0109] In addition, when the light collision condition is met and the drowsiness level LV at this time is the first level LV_1 and the vehicle speed V is within the third vehicle speed range R_3, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the drive device 21.

[0110] In other words, when the light collision condition is met and the dozing level LV at this time is the first level LV_1 and the vehicle speed V is within the third vehicle speed range R_3, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0111] The third vehicle speed range R_3 is a range greater than the third vehicle speed V_3.

[0112] Furthermore, when the minor collision condition is satisfied and the doze level LV at that time is the first level LV_1 and the vehicle speed V is within the third vehicle speed range R_3 , the vehicle driving support device 10 determines whether the required braking force BKreq is equal to or greater than the third braking force BK_3 .

[0113] The third braking force BK_3 is set to a value greater than the second braking force BK_2. In this example, the third braking force BK_3 is set to a constant value regardless of the vehicle speed V, but may be set to a larger value as the vehicle speed V increases.

[0114] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the third braking force BK_3. On the other hand, when the required braking force BKreq is less than the third braking force BK_3, the vehicle driving support device 10 sets the third braking force BK_3 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the brake device 22.

[0115] In this way, when the light collision condition is met and the doze level LV at this time is the first level LV_1 and the vehicle speed V is within the third vehicle speed range R_3, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than a predetermined driving force DRth (third braking force BK_3) to the vehicle 100.

[0116] <Secondary collision mitigation control at level 2>

[0117] <Level 2 and low speed>

[0118] In addition, when the light collision condition is met and the drowsiness level LV at this time is the second level LV_2, or when the duration T reaches the second time T_2 and it is judged that the drowsiness level LV is the second level LV_2 and the vehicle speed V is within the fourth vehicle speed range R_4, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the drive device 21.

[0119] In other words, when the light collision condition is met and the dozing level LV at this time is the second level LV_2 and the vehicle speed V is within the fourth vehicle speed range R_4, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0120] The fourth vehicle speed range R_4 is a range greater than the fourth vehicle speed V_4 (zero in this example) and less than the fifth vehicle speed V_5. The fifth vehicle speed V_5 is set to a value greater than the fourth vehicle speed V_4. In this example, the fourth vehicle speed V_4 is set to the same value as the first vehicle speed V_1, but it may be set to a value different from the first vehicle speed V_1. In addition, the fifth vehicle speed V_5 is set to the same value as the second vehicle speed V_2, but it may be set to a value different from the second vehicle speed V_2.

[0121] Furthermore, when the minor collision condition is satisfied and the doze level LV at that time is the second level LV_2 and the vehicle speed V is within the fourth vehicle speed range R_4, the vehicle driving support device 10 determines whether the required braking force BKreq is equal to or greater than the fourth braking force BK_4.

[0122] The fourth braking force BK_4 is set to a value greater than zero. In this example, the fourth braking force BK_4 is set to the same value as the second braking force BK_2, but it may be set to a value different from the second braking force BK_2. In addition, in this example, the fourth braking force BK_4 is set to a constant value regardless of the vehicle speed V, but it may be set to a larger value as the vehicle speed V increases.

[0123] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the fourth braking force BK_4. On the other hand, when the required braking force BKreq is less than the fourth braking force BK_4, the vehicle driving support device 10 sets the fourth braking force BK_4 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 in such a manner that the set target braking force BKtgt is output from the brake device 22.

[0124] In this way, when the light collision condition is met and the doze level LV at this time is the second level LV_2 and the vehicle speed V is within the fourth vehicle speed range R_4, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than a predetermined driving force DRth (fourth braking force BK_4) to the vehicle 100.

[0125] <Level 2 and medium speed>

[0126] In addition, when the light collision condition is met and the dozing level LV is the second level LV_2 and the vehicle speed V is within the fifth vehicle speed range R_5, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the drive device 21.

[0127] In other words, when the light collision condition is met and the dozing level LV at this time is the second level LV_2 and the vehicle speed V is within the fifth vehicle speed range R_5, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0128] The fifth vehicle speed range R_5 is a range that is greater than the fifth vehicle speed V_5 and equal to or less than the sixth vehicle speed V_6. The sixth vehicle speed V_6 is set to a value greater than the fifth vehicle speed V_5.

[0129] Furthermore, when the minor collision condition is satisfied and the doze level LV at that time is the second level LV_2 and the vehicle speed V is within the fifth vehicle speed range R_5, the vehicle driving support device 10 determines whether the required braking force BKreq is equal to or greater than the fifth braking force BK_5.

[0130] The fifth braking force BK_5 is set to a value greater than the fourth braking force BK_4. In this example, the fifth braking force BK_5 is set to a constant value regardless of the vehicle speed V, but may be set to a larger value as the vehicle speed V increases.

[0131] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the fifth braking force BK_5. On the other hand, when the required braking force BKreq is less than the fifth braking force BK_5, the vehicle driving support device 10 sets the fifth braking force BK_5 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the brake device 22.

[0132] In this way, when the light collision condition is met and the doze level LV at this time is the second level LV_2 and the vehicle speed V is within the fifth vehicle speed range R_5, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than a predetermined driving force DRth (fifth braking force BK_5) to the vehicle 100.

[0133] <Level 2 and high speed>

[0134] In addition, when the light collision condition is met and the drowsiness level LV is the second level LV_2 and the vehicle speed V is within the sixth vehicle speed range R_6, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the drive device 21.

[0135] In other words, when the light collision condition is met and the dozing level LV at this time is the second level LV_2 and the vehicle speed V is within the sixth vehicle speed range R_6, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0136] The sixth vehicle speed range R_6 is a range greater than the sixth vehicle speed V_6.

[0137] Furthermore, when the minor collision condition is satisfied and the doze level LV at that time is the second level LV_2 and the vehicle speed V is within the sixth vehicle speed range R_6, the vehicle driving support device 10 determines whether the required braking force BKreq is equal to or greater than the sixth braking force BK_6.

[0138] The sixth braking force BK_6 is set to a value greater than the fifth braking force BK_5. In this example, the sixth braking force BK_6 is set to a constant value regardless of the vehicle speed V, but may be set to a larger value as the vehicle speed V increases.

[0139] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the sixth braking force BK_6. On the other hand, when the required braking force BKreq is less than the sixth braking force BK_6, the vehicle driving support device 10 sets the sixth braking force BK_6 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the brake device 22.

[0140] In this way, when the light collision condition is met and the doze level LV at this time is the second level LV_2 and the vehicle speed V is within the sixth vehicle speed range R_6, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than a predetermined driving force DRth (sixth braking force BK_6) to the vehicle 100.

[0141] <Secondary collision mitigation control at level 3>

[0142] <Level 3 and low speed>

[0143] In addition, when the light collision condition is met and the drowsiness level LV at this time is the third level LV_3, or when the duration T reaches the third time T_3 and it is judged that the drowsiness level LV is the third level LV_3 and the vehicle speed V is within the seventh vehicle speed range R_7, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the driving device 21.

[0144] In other words, when the light collision condition is met and the dozing level LV at this time is the third level LV_3 and the vehicle speed V is within the seventh vehicle speed range R_7, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0145] The 7th vehicle speed range R_7 is a range greater than the 7th vehicle speed V_7 (zero in this example) and less than the 8th vehicle speed V_8. The 8th vehicle speed V_8 is set to a value greater than the 7th vehicle speed V_7. In this example, the 7th vehicle speed V_7 is set to the same value as the 1st vehicle speed V_1 and the 4th vehicle speed V_4, but it can also be set to a value different from the 1st vehicle speed V_1 and the 4th vehicle speed V_4. In addition, the 8th vehicle speed V_8 is set to the same value as the 2nd vehicle speed V_2 and the 5th vehicle speed V_5, but it can also be set to a value different from the 2nd vehicle speed V_2 and the 5th vehicle speed V_5.

[0146] Furthermore, when the light collision condition is satisfied and the doze level LV at that time is the third level LV_3 and the vehicle speed V is within the seventh vehicle speed range R_7, the vehicle driving support device 10 determines whether the required braking force BKreq is equal to or greater than the seventh braking force BK_7.

[0147] The seventh braking force BK_7 is set to a value greater than zero. In this example, the seventh braking force BK_7 is set to the same value as the fifth braking force BK_5, but it may be set to a value different from the fifth braking force BK_5. In addition, in this example, the seventh braking force BK_7 is set to a constant value regardless of the vehicle speed V, but it may be set to a larger value as the vehicle speed V increases.

[0148] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the seventh braking force BK_7. On the other hand, when the required braking force BKreq is less than the seventh braking force BK_7, the vehicle driving support device 10 sets the seventh braking force BK_7 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the brake device 22.

[0149] In this way, when the light collision condition is met and the doze level LV at this time is the third level LV_3 and the vehicle speed V is within the seventh vehicle speed range R_7, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than a predetermined driving force DRth (seventh braking force BK_7) to the vehicle 100.

[0150] <Level 3 and medium speed>

[0151] In addition, when the light collision condition is met and the drowsiness level LV is the third level LV_3 and the vehicle speed V is within the eighth vehicle speed range R_8, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the drive device 21.

[0152] In other words, when the light collision condition is met and the dozing level LV at this time is the third level LV_3 and the vehicle speed V is within the eighth vehicle speed range R_8, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0153] The eighth vehicle speed range R_8 is a range that is greater than the eighth vehicle speed V_8 and equal to or less than the ninth vehicle speed V_9. The ninth vehicle speed V_9 is set to a value greater than the eighth vehicle speed V_8.

[0154] Furthermore, when the light collision condition is satisfied and the doze level LV is the third level LV_3 and the vehicle speed V is within the eighth vehicle speed range R_8, the vehicle driving support device 10 determines whether the required braking force BKreq obtained based on the brake pedal operation amount BP is equal to or greater than the eighth braking force BK_8.

[0155] The eighth braking force BK_8 is set to a value greater than the seventh braking force BK_7. In this example, the eighth braking force BK_8 is set to a constant value regardless of the vehicle speed V, but may be set to a larger value as the vehicle speed V increases.

[0156] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the eighth braking force BK_8. On the other hand, when the required braking force BKreq is less than the eighth braking force BK_8, the vehicle driving support device 10 sets the eighth braking force BK_8 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the brake device 22.

[0157] In this way, when the light collision condition is met and the doze level LV at this time is the third level LV_3 and the vehicle speed V is within the eighth vehicle speed range R_8, the vehicle driving support device 10 performs forced deceleration by applying a braking force BK greater than a predetermined driving force DRth (eighth braking force BK_8) to the vehicle 100.

[0158] <Level 3 and high speed>

[0159] In addition, when the light collision condition is met and the drowsiness level LV is the third level LV_3 and the vehicle speed V is within the ninth vehicle speed range R_9, the vehicle driving assistance device 10 sets the target driving force DRtgt to zero regardless of the accelerator pedal operation amount AP, and controls the operation of the vehicle driving device 20 so that the driving force DR is not output from the drive device 21.

[0160] In other words, when the light collision condition is met and the dozing level LV at this time is the third level LV_3 and the vehicle speed V is within the ninth vehicle speed range R_9, the vehicle driving assistance device 10 performs forced deceleration by limiting the driving force DR applied to the vehicle 100 to a driving force below the predetermined driving force DRth (zero).

[0161] The ninth vehicle speed range R_9 is a range greater than the ninth vehicle speed V_9.

[0162] Furthermore, when the minor collision condition is satisfied and the doze level LV at that time is the third level LV_3 and the vehicle speed V is within the ninth vehicle speed range R_9, the vehicle driving support device 10 determines whether the required braking force BKreq is equal to or greater than the ninth braking force BK_9.

[0163] In this example, the 9th braking force BK_9 is set to the same value as the 8th braking force BK_8, but may be set to a value greater than the 8th braking force BK_8. In addition, in this example, the 9th braking force BK_9 is set to a constant value regardless of the vehicle speed V, but may be set to a larger value as the vehicle speed V increases.

[0164] The vehicle driving support device 10 sets the required braking force BKreq as the target braking force BKtgt when the required braking force BKreq is greater than the ninth braking force BK_9. On the other hand, when the required braking force BKreq is less than the ninth braking force BK_9, the vehicle driving support device 10 sets the ninth braking force BK_9 as the target braking force BKtgt. Furthermore, the vehicle driving support device 10 controls the operation of the vehicle travel device 20 so that the set target braking force BKtgt is output from the brake device 22.

[0165] In this way, when the light collision condition is met and the doze level LV at this time is the third level LV_3 and the vehicle speed V is within the 9th vehicle speed range R_9, the vehicle driving assistance device 10 performs forced deceleration by applying forced braking with a braking force BK greater than a predetermined driving force DRth (9th braking force BK_9) to the vehicle 100.

[0166] As described above, the vehicle driving support device 10 is configured to forcibly decelerate the host vehicle 100 at the longitudinal deceleration Gd corresponding to the doze level LV when the minor collision condition is satisfied and the doze condition is satisfied.

[0167] In addition, the vehicle driving support device 10 terminates the secondary collision mitigation control when the control termination condition is satisfied during the execution of the secondary collision mitigation control. The control termination condition is satisfied when the drowsiness level LV is lower than the predetermined threshold level LVth, that is, when the time for which the eyelids of the driver of the vehicle 100 are continuously judged to be not closed (that is, open) reaches a predetermined time. In addition, the control termination condition is satisfied when the operation of the accelerator pedal 51 by the driver for accelerating the vehicle 100 continues for more than a predetermined operation time. In addition, the control termination condition is satisfied when the operation of the brake pedal 52 by the driver for decelerating the vehicle 100 continues for more than a predetermined operation time. In addition, the control termination condition is satisfied when the operation of the steering wheel 54 by the driver for steering the vehicle 100 continues for more than a predetermined operation time. In addition, the control termination condition is satisfied when the vehicle 100 stops.

[0168] In addition, when the vehicle driving assistance device 10 determines that the control termination condition is met and the secondary collision mitigation control is terminated due to the stop of the vehicle 100, the vehicle driving assistance device 10 maintains the braking force BK applied to the vehicle 100 until the predetermined condition allowing the vehicle 100 to travel is met, or maintains the vehicle 100 in a stopped state using a parking brake (not shown) or the like.

[0169] When the secondary collision mitigation control is executed by the vehicle driving support device 10, the driving force DR and the braking force BK applied to the host vehicle 100 are, for example, Figure 4 is controlled as shown.

[0170] exist Figure 4 In the example shown, at time t40, it is determined that the eyelids of the driver of the vehicle 100 are closed, at time t41, the duration T reaches the first time T_1 and is determined to be the first level LV_1 for the drowsiness level LV, at time t42, it is determined that the light collision condition is met, at time t43, the duration T reaches the second time T_2 and is determined to be the second level LV_2 for the drowsiness level LV, and at time t44, the duration T reaches the third time T_3 and is determined to be the third level LV_3 for the drowsiness level LV.

[0171] exist Figure 4 In the example shown, at time t42, the light collision condition is satisfied and the dozing condition is satisfied, so the secondary collision mitigation control is started. At this time, the vehicle speed V is within the second vehicle speed range R_2, so the driving force DR applied to the host vehicle 100 is set to zero by the driving force limitation, and the braking force BK applied to the host vehicle 100 is set to the second braking force BK_2 by the forced braking. As a result, the vehicle speed V decreases.

[0172] Furthermore, when it is determined at time t43 that the doze level LV is the second level LV_2, the vehicle speed V is within the fifth vehicle speed range R_5, so the driving force DR applied to the host vehicle 100 is set to zero by the driving force limitation, and the braking force BK applied to the host vehicle 100 is set to the fifth braking force BK_5 which is greater than the second braking force BK_2 by the forced braking. As a result, the vehicle speed V is further reduced.

[0173] Furthermore, when it is determined at time t44 that the doze level LV is the third level LV_3, the vehicle speed V is within the eighth vehicle speed range R_8, so the driving force DR applied to the host vehicle 100 is set to zero by the driving force limitation, and the braking force BK applied to the host vehicle 100 is set to the eighth braking force BK_8 greater than the fifth braking force BK_5 by the forced braking. As a result, the vehicle speed V is further reduced.

[0174] Then, since the vehicle speed V becomes zero at time t45, the secondary collision reduction control is terminated.

[0175] <Effect>

[0176] If a minor collision occurs while the driver is dozing off, there is a possibility that the vehicle will be involved in a further collision (secondary collision) immediately after the minor collision occurs. As a means of avoiding such a secondary collision, a means of forcibly decelerating the vehicle and stopping it may be considered. However, there are also cases where the driver is dozing off to such an extent that he or she can wake up when a minor collision occurs and take actions to avoid a secondary collision. In such a case, when forced deceleration is implemented to decelerate the vehicle, there is a possibility that the deceleration of the vehicle becomes unnecessary for the driver.

[0177] As a means to avoid this situation, it is possible to implement forced deceleration only when the driver is dozing off to such an extent that he will not wake up even if a minor collision occurs (i.e., when it is determined that the driver is dozing off with a certain degree of certainty). Furthermore, as a method of determining that the driver is dozing off with a certain degree of certainty, it is possible to determine that the driver is dozing off with a certain degree of certainty based on the fact that the state has continued for a certain period of time since the time when the driver was estimated to be dozing off.

[0178] However, as a result, forced deceleration is not performed even if a minor collision occurs until it is determined with a certain degree of certainty that the driver is dozing off, and as a result, a secondary collision may not be avoided.

[0179] In this way, if forced deceleration is implemented only when there is a high degree of certainty that the driver is dozing off, a secondary collision may be unavoidable. On the other hand, if forced deceleration is implemented even if there is a low degree of certainty that the driver is dozing off, the vehicle may be decelerated unnecessarily.

[0180] According to the vehicle driving support device 10, forced deceleration is implemented when the driver's drowsiness level LV is low. When the driver's drowsiness level LV becomes higher, the deceleration of the vehicle 100 based on forced deceleration becomes larger, thereby avoiding unnecessary deceleration of the vehicle 100 and improving the certainty of avoiding secondary collision.

[0181] As described above, the vehicle driving assistance device 10 determines whether to perform forced deceleration by driving force limitation or forced deceleration by forced braking according to the vehicle speed V when the doze level LV is the first level LV_1. However, for example, it can also be configured such that when the doze level LV is the first level LV_1, driving force limitation is performed regardless of the vehicle speed V, when the doze level LV is the second level LV_2 and when the doze level LV is the third level LV_3, forced braking is performed regardless of the vehicle speed V, when the doze level LV is lower than the predetermined switching level LV_sw, forced deceleration is performed by driving force limitation regardless of the vehicle speed V, and when the doze level LV is above the predetermined switching level LV_sw, forced deceleration is performed by forced braking regardless of the vehicle speed V.

[0182] In addition, the vehicle driving assistance device 10 determines whether to perform forced deceleration by driving force limitation or by forced braking according to the drowsiness level LV when the vehicle speed V is relatively low (i.e., when the vehicle speed V is within the first vehicle speed range R_1, the fourth vehicle speed range R_4, and the seventh vehicle speed range R_7). However, it may also be configured such that, when the vehicle speed V is relatively low, forced deceleration is performed by driving force limitation regardless of the drowsiness level LV, and when the vehicle speed V is relatively high, forced deceleration is performed by forced braking regardless of the drowsiness level LV.

[0183] In addition, the vehicle driving assistance device 10 determines the predetermined driving force DRth in the driving force limitation and the predetermined braking force BKth in the forced braking according to the vehicle speed V when the drowsiness level LV is the same level. However, for example, it can also be configured so that the predetermined driving force DRth is set to a smaller value and the predetermined braking force BKth is set to a larger value when the drowsiness level LV is high than when the drowsiness level LV is low. In this case, when the drowsiness level LV is the same level, the predetermined driving force DRth is set to a constant value and the predetermined braking force BKth is set to a constant value regardless of the vehicle speed V.

[0184] The vehicle driving support device 10 divides the drowsiness level LV into three stages: LV_1, LV_2, and LV_3. However, the drowsiness level LV may be divided into two or four or more stages, or divided into at least two stages.

[0185] In addition, the vehicle driving assistance device 10 is configured to perform forced deceleration in a manner such that the longitudinal deceleration Gd of the vehicle 100 becomes larger when the drowsiness level LV is the second level LV_2 as compared to when the drowsiness level LV is the first level LV_1, and to perform forced deceleration in a manner such that the longitudinal deceleration Gd of the vehicle 100 becomes larger when the drowsiness level LV is the third level LV_3 as compared to when the drowsiness level LV is the second level LV_2. At least, it is configured to perform forced deceleration in a manner such that the longitudinal deceleration Gd of the vehicle 100 becomes larger when the drowsiness level LV is high as compared to when the drowsiness level LV is low.

[0186] <Specific Operation of Vehicle Driving Support Device>

[0187] Next, the specific operation of the vehicle driving support device 10 will be described. The CPU of the ECU 90 of the vehicle driving support device 10 executes the following operation every time a predetermined operation time has elapsed. Figure 5 Therefore, when the predetermined timing is reached, the CPU starts Figure 5 The process starts at step 500 and proceeds to step 510 to determine whether a light collision condition is satisfied.

[0188] When the CPU makes a “YES” determination at step 510, the CPU advances the process to step 520 and sets the value of the light collision flag X to “1.” Next, the CPU advances the process to step 595 and temporarily terminates this routine.

[0189] On the other hand, if the CPU determines "No" in step 510, the CPU proceeds to step 530 to set the required driving force DRreq obtained based on the accelerator pedal operation amount AP as the target driving force DRtgt, or sets the required braking force BKreq obtained based on the brake pedal operation amount BP as the target braking force BKtgt. Next, the CPU proceeds to step 540 to control the operation of the drive device 21 so that the target driving force DRtgt set in step 530 is output from the drive device 21, or controls the operation of the brake device 22 so that the target braking force BKtgt set in step 530 is output from the brake device 22. Next, the CPU proceeds to step 595 to temporarily terminate this routine.

[0190] Furthermore, the CPU executes the Figure 6 Therefore, when the predetermined timing is reached, the CPU starts Figure 6 The process starts at step 600, and the process proceeds to step 605 to determine whether the value of the light collision flag X is "1".

[0191] When the CPU makes a “YES” determination at step 605, the CPU advances the process to step 610 to determine whether the doze level LV is the first level LV_1.

[0192] When the CPU determines "yes" in step 610, the process proceeds to step 615, and sets the target driving force DRtgt or the target braking force BKtgt according to the vehicle speed V as described above. Next, the CPU proceeds to step 640, and controls the operation of the vehicle travel device 20 so that the target driving force DRtgt set in step 615 is output from the drive device 21 or the target braking force BKtgt is output from the brake device 22. Next, the CPU proceeds to step 645.

[0193] On the other hand, when the CPU makes a “NO” determination at step 610, the CPU advances the process to step 620 to determine whether the doze level LV is the second level LV_2.

[0194] When the CPU determines "yes" in step 620, the process proceeds to step 625, and sets the target driving force DRtgt and the target braking force BKtgt according to the vehicle speed V as described above. In addition, at this time, the target driving force DRtgt is set to zero. Next, the CPU proceeds to step 640, and controls the operation of the vehicle travel device 20 so that the driving force DR is not output from the drive device 21 and the target braking force BKtgt is output from the brake device 22. Next, the CPU proceeds to step 645.

[0195] On the other hand, when the CPU determines "yes" in step 630, the process proceeds to step 635, and sets the target driving force DRtgt and the target braking force BKtgt according to the vehicle speed V as described above. In addition, at this time, the target driving force DRtgt is set to zero. Then, the CPU proceeds to step 640, and controls the operation of the vehicle travel device 20 so that the driving force DR is not output from the drive device 21 and the target braking force BKtgt is output from the brake device 22. Then, the CPU proceeds to step 645.

[0196] On the other hand, when the CPU makes a "No" determination in step 630, the CPU directly proceeds to step 695 and temporarily terminates this routine.

[0197] When the CPU advances the processing to step 645 , it determines whether the control end condition is satisfied.

[0198] When the CPU makes a “Yes” determination at step 645, the CPU sets the value of the light collision flag X to “0.” Next, the CPU advances the processing to step 695 and temporarily terminates this routine.

[0199] On the other hand, when the CPU makes a "No" determination in step 645, the CPU directly proceeds to step 695 and temporarily terminates this routine.

[0200] Furthermore, the CPU executes the Figure 7 Therefore, when the predetermined timing is reached, the CPU starts Figure 7 The process starts at step 700 and proceeds to step 710 to determine whether the doze level LV is the first level LV_1.

[0201] When the CPU makes a “yes” determination at step 710, the CPU advances the process to step 720 to execute the first notification described above. Next, the CPU advances the process to step 770.

[0202] On the other hand, when the CPU makes a “NO” determination at step 710, the CPU advances the process to step 730 to determine whether the doze level LV is the second level LV_2.

[0203] When the CPU makes a “yes” determination at step 730, the CPU advances the process to step 740 to execute the second notification described above. Next, the CPU advances the process to step 770.

[0204] On the other hand, when the CPU makes a “NO” determination at step 730, the CPU advances the process to step 750 to determine whether the doze level LV is the third level LV_3.

[0205] When the CPU makes a “Yes” determination at step 750, the CPU advances the process to step 760 to execute the third notification described above. Next, the CPU advances the process to step 770.

[0206] On the other hand, when the CPU makes a “No” determination in step 750, it directly proceeds to step 770.

[0207] When the CPU advances the processing to step 770 , it determines whether the notification end condition is satisfied.

[0208] When the CPU determines "yes" in step 770, the CPU advances the process to step 780 to terminate the notification. Next, the CPU advances the process to step 795 to temporarily terminate this routine.

[0209] On the other hand, when the CPU makes a "No" determination in step 770, the CPU directly proceeds to step 795 and temporarily terminates this routine.

[0210] The above is the specific operation of the vehicle driving support device 10 .

[0211] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.< / ecu>

Claims

1. A vehicle driving support device, the device being a device for executing a secondary collision mitigation control forcibly decelerating the host vehicle when a light collision in which a collision index value indicating the magnitude of a collision of the host vehicle is within a predetermined light collision range has occurred in the host vehicle and when the light collision condition is satisfied and the drowsiness level of the driver of the host vehicle, i.e., the drowsiness level, is above a predetermined threshold level, the device comprising: The vehicle driving support device is configured to perform the forced deceleration when the minor collision condition and the dozing condition are satisfied so that the host vehicle decelerates at a smaller deceleration when the dozing level is low than when the dozing level is high. The vehicle driving support device is configured as follows: The dozing level is determined based on a duration of time that the eyelids of the driver of the host vehicle are determined to be closed, that is, a duration of time, The dozing level is determined to be higher when the duration is long than when the duration is short, The vehicle driving support device is configured to perform the forced deceleration by applying a braking force greater than a predetermined braking force to the host vehicle or by limiting the driving force applied to the host vehicle to a driving force less than a predetermined driving force, The vehicle driving support device is configured as follows: whether to perform the forced deceleration by the forced braking or by the driving force limitation is determined according to the doze level when the light collision condition and the doze condition are satisfied; When the doze level is equal to or higher than a predetermined switching level higher than the predetermined threshold level, the forced deceleration is performed by the forced braking, When the doze level is lower than the predetermined switching level, the forced deceleration is performed by the driving force limitation.

2. The vehicle driving support device according to claim 1, wherein: The vehicle driving support device is configured as follows: whether to perform the forced deceleration by the forced braking or by the driving force limitation is determined according to the vehicle speed of the host vehicle when the minor collision condition and the dozing condition are satisfied, When the vehicle speed of the host vehicle is equal to or higher than a predetermined vehicle speed, the forced deceleration is performed by the forced braking, When the vehicle speed of the host vehicle is lower than the predetermined vehicle speed, the forced deceleration is performed by the driving force limitation.

3. The vehicle driving support device according to claim 1, wherein: The vehicle driving support device is configured as follows: When the minor collision condition and the dozing condition are satisfied, when the forced deceleration is performed by applying a braking force greater than a predetermined braking force to the host vehicle, the predetermined braking force is set to a larger braking force when the dozing level is high than when the dozing level is low. When the forced deceleration is performed by limiting the driving force applied to the host vehicle to a predetermined driving force or less when the light collision condition and the dozing condition are satisfied, the predetermined driving force is set to a smaller driving force when the dozing level is high than when the dozing level is low.

4. The vehicle driving support device according to claim 1, wherein: The vehicle driving support device is configured as follows: When the minor collision condition and the dozing condition are satisfied, in the case where the forced deceleration is performed by applying a braking force greater than a predetermined braking force to the host vehicle, the predetermined braking force is set to a larger braking force when the vehicle speed of the host vehicle is high than when the vehicle speed of the host vehicle is low. When the forced deceleration is performed by limiting the driving force applied to the vehicle to a driving force below a predetermined driving force when the light collision condition and the dozing condition are met, the predetermined driving force is set to a smaller driving force when the vehicle speed is high than when the vehicle speed is low.

5. The vehicle driving support device according to any one of claims 1 to 4, wherein: The predetermined light collision range is set to a range smaller than a range of the collision index value that causes the air bag of the host vehicle to deploy.

6. The vehicle driving support device according to any one of claims 1 to 4, wherein: The vehicle driving support device is configured to terminate the secondary collision mitigation control when a control termination condition is satisfied after the minor collision condition and the dozing condition are satisfied, The control end condition is satisfied when the doze level becomes lower than the predetermined threshold level, when the driver's operation for accelerating, decelerating, or steering the host vehicle continues for a predetermined operation time or longer, or when the host vehicle stops.

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