Vehicle control device

Abstract

A vehicle control device is configured so as to relax a contact risk determination condition when a first condition for determining that a road on which a host vehicle travels is a narrow road, a second condition for determining that the road on which the host vehicle travels is a narrow road, a third condition for determining that the road on which the host vehicle travels is a narrow road, and a predetermined fourth condition are satisfied. The second condition is a condition for determining that there are an opposing vehicle approaching the own vehicle and a moving body moving at a low speed between the opposing vehicle and the own vehicle within a predetermined range. The third condition is a condition for determining that the possibility that the opposite vehicle reaches the rear end of the moving body before the own vehicle reaches the front end of the moving body is high, and the predetermined fourth condition is a condition pertaining to the relative movement of the opposite vehicle and the moving body.

Description

Technical Field

[0001] The present invention relates to a vehicle control device which, when a predetermined condition is satisfied, starts risk reduction control for controlling the own vehicle in a manner that reduces the risk of contact (the probability of contact between the own vehicle and a target object or the damage caused when contact occurs between the two) between the own vehicle and the target object. Background Art

[0002] Sometimes, in a situation where the widths of the roads on which the own vehicle and an oncoming vehicle are traveling are relatively small, conditions for determining that the risk of contact between the own vehicle and the oncoming vehicle is high are satisfied. A vehicle control device has been proposed which, in this case, starts risk reduction control for controlling the own vehicle in a manner that reduces this risk of contact (for example, refer to International Publication No. 2014 / 027420 below). The vehicle control device of International Publication No. 2014 / 027420 (hereinafter referred to as the "conventional device") can execute notification control for issuing a predetermined alarm to the driver of the own vehicle, braking control for braking the own vehicle, and automatic steering control for steering the own vehicle away from the oncoming vehicle as risk reduction control. Summary of the Invention

[0003] It is assumed that, on a narrow road, there is a scenario in which an oncoming vehicle overtakes a moving body moving at a low speed in an interval in front of the oncoming vehicle (the area between the oncoming vehicle and the own vehicle). In this scenario, since the widths of the roads on which the own vehicle and the oncoming vehicle are traveling are relatively small, when the oncoming vehicle overtakes the moving body, there is a high possibility that the oncoming vehicle will significantly enter the front area of the own vehicle. In this case, there is a high possibility that it is difficult to steer the own vehicle to avoid the oncoming vehicle. Therefore, preferably, in the scenario where the oncoming vehicle overtakes the moving body on a narrow road, braking of the own vehicle is started as early as possible (for example, before the oncoming vehicle starts to overtake the moving body).

[0004] Here, in the conventional device, the start condition of the risk reduction control is configured to be satisfied when the time obtained by dividing the distance between the own vehicle and the oncoming vehicle by the relative speed is equal to or less than a threshold value. That is, the start condition of the risk reduction control is independent of the behavior of the oncoming vehicle and the moving body. That is, the conventional device cannot adjust the start timing of the risk reduction control according to the likelihood of the oncoming vehicle overtaking the moving body on a narrow road. Therefore, sometimes the start condition is satisfied after the oncoming vehicle starts to overtake the moving body. In this case, the effect (the effect of reducing the risk of contact between the own vehicle and the oncoming vehicle) obtained by executing the risk reduction control may be very small.

[0005] One object of the present invention is to provide a vehicle control device that can control its own vehicle in a manner that sufficiently reduces the contact risk with an oncoming vehicle when there is a high possibility that the oncoming vehicle can overtake a moving object in front of it on a narrow road.

[0006] To solve the above problems, when a contact risk determination condition is satisfied, the vehicle control device (1) of the present invention executes risk reduction control for controlling its own vehicle in a manner that reduces the contact risk, and the contact risk determination condition is a condition for determining that there is a high contact risk between a target object within a predetermined range in the traveling direction of its own vehicle and its own vehicle.

[0007] The vehicle control device is configured such that

[0008] when a first condition, a second condition, a third condition, and a predetermined fourth condition are satisfied, the contact risk determination condition is relaxed.

[0009] The first condition is a condition for determining that the road on which its own vehicle is traveling is a narrow road.

[0010] The second condition is a condition for determining that there is an oncoming vehicle approaching its own vehicle and a moving object moving at a low speed between the oncoming vehicle and its own vehicle within the predetermined range.

[0011] The third condition is a condition for determining that there is a high possibility that the oncoming vehicle reaches the rear end of the moving object before its own vehicle reaches the front end of the moving object.

[0012] The predetermined fourth condition is a condition regarding the relative motion between the oncoming vehicle and the moving object.

[0013] In the vehicle control device according to one aspect of the present invention,

[0014] the fourth condition is satisfied in a situation where the speed difference between the oncoming vehicle and the moving object exceeds a predetermined first threshold and the acceleration of the oncoming vehicle exceeds a second threshold, or in a situation where the speed difference is equal to or less than the first threshold and the acceleration of the oncoming vehicle exceeds a predetermined third threshold.

[0015] In the vehicle control device described in another aspect of the present invention,

[0016] the contact risk determination condition is satisfied when the predicted time until contact between its own vehicle and the oncoming vehicle is equal to or less than a fourth threshold.

[0017] The value assigned to the fourth threshold is determined based on the relative speed between its own vehicle and the oncoming vehicle.

[0018] When at least one of the first condition to the fourth condition is not satisfied and the relative speed is the first speed, a first predetermined value is assigned to the fourth threshold value.

[0019] When the first condition to the fourth condition are satisfied and the relative speed is a second speed lower than the first speed, a second predetermined value greater than the first predetermined value is assigned to the fourth threshold value.

[0020] In a vehicle control device according to another aspect of the present invention,

[0021] The contact risk determination condition is satisfied when the predicted time until the own vehicle contacts the oncoming vehicle is equal to or less than the fourth threshold value.

[0022] The value assigned to the fourth threshold value is determined according to the degree of overlap, i.e., the overlap rate, between the area predicted for the own vehicle to pass through and the area predicted for the oncoming vehicle to pass through.

[0023] When at least one of the first condition to the fourth condition is not satisfied and the overlap rate is the first overlap rate, a first predetermined value is assigned to the fourth threshold value.

[0024] When the first condition to the fourth condition are satisfied and the overlap rate is a second overlap rate less than the first overlap rate, a second predetermined value greater than the first predetermined value is assigned to the fourth threshold value.

[0025] In a vehicle control device according to another aspect of the present invention,

[0026] When the distance between the moving body and the own vehicle is equal to or less than a predetermined fifth threshold value, the vehicle speed of the own vehicle is limited to be equal to or less than a predetermined upper limit value.

[0027] As described above, when the first condition to the fourth condition are satisfied, the vehicle control device according to the present invention determines that there is a high possibility that the oncoming vehicle overtakes the moving body on a narrow road, and relaxes the start condition (contact risk determination condition) of the risk reduction process. That is, in this scenario, the execution start timing of the risk reduction control is advanced. As a result, the contact risk between the own vehicle and the oncoming vehicle is sufficiently reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Hereinafter, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, in which like reference numerals denote like elements, and wherein:

[0029] Figure 1 is a block diagram of a vehicle control device according to an embodiment of the present invention;

[0030] Figure 2 is a plan view showing the overlapping rate;

[0031] Figure 3 is a plan view showing a scenario where there is a high possibility that an oncoming vehicle will overtake a moving body on a narrow road; and

[0032] Figure 4 is a flowchart of a program executed by the CPU to implement the functions of the vehicle control device. Detailed implementation mode

[0033] Overview

[0034] As Figure 1 shown, the vehicle control device 1 according to an embodiment of the present invention is applied to a vehicle V0 (hereinafter referred to as "own vehicle") having an autonomous driving function. The vehicle control device 1 has the following function (risk reduction function): in a state where the autonomous driving function is invalidated, it executes risk reduction control for controlling the own vehicle (notification device 30 and braking device 40) in a manner that reduces the contact risk with the oncoming vehicle V1.

[0035] Specific configuration

[0036] As Figure 1 shown, the vehicle control device 1 includes an ECU 10, an in-vehicle sensor 20, a notification device 30, and a braking device 40.

[0037] The ECU 10 includes a CPU 10a, a ROM 10b, a RAM 10c, a timer 10d, etc. The ECU 10 is connected to other ECUs via a CAN (communication line).

[0038] The in-vehicle sensor 20 includes a camera 21 and a millimeter-wave radar 22.

[0039] The camera 21 includes a photographing device and an image analysis device. The photographing device has a built-in CCD, for example. The photographing device is provided at the front of the own vehicle and faces the front of the own vehicle. The photographing device photographs the foreground (front scene) of the own vehicle at a predetermined frame rate and obtains a foreground image (image data). The image analysis device analyzes the foreground image and identifies (distinguishes) the objects existing within the viewing angle of the photographing device. The image analysis device identifies vehicles such as ordinary cars and trucks, for example. In addition, the image analysis device identifies moving bodies such as pedestrians and bicycles. That is, the image recognition device can distinguish between vehicles and moving bodies. In addition, the image analysis device identifies lane markings (road markings, guardrails, etc. of the road R) in the foreground image and obtains lane marking information including the coordinates, extending direction, etc. of the lane markings in the image. The image analysis device provides these calculation results to the ECU 10.

[0040] The millimeter-wave radar 22 has a transceiver unit and a signal processing unit. The transceiver unit emits millimeter-wave band radio waves (hereinafter referred to as "millimeter waves") toward the front of its own vehicle, and receives the millimeter waves (reflected waves) reflected by a three-dimensional object located in this area. The signal processing unit obtains various information related to each reflection point of the millimeter wave based on the physical quantities related to the transmitted wave and the reflected wave. For example, the signal processing unit calculates the position of each reflection point relative to its own vehicle (relative position (distance and direction)). In addition, the signal processing unit calculates the speed of each reflection point relative to its own vehicle (the change per unit time of the distance between its own vehicle and the reflection point (relative speed)). And the calculation result (distribution data of the reflection points (data including relative position and relative speed)) is provided to the ECU 10.

[0041] The shootable range of the above-described camera 21 overlaps with the area where the millimeter waves of the millimeter-wave radar 22 are emitted. In the following description, the overlapping area of the two is referred to as the field of view FOV of the object detection sensor DS. In a plan view, the field of view FOV is fan-shaped. The ECU 10 can obtain information based on the fusion information obtained by integrating the information obtained from the camera 21 and the information obtained from the millimeter-wave radar 22. The information includes information related to each object existing in the field of view FOV (type of object (vehicle, moving body, etc.), relative position of the object relative to its own vehicle, relative speed of the object relative to its own vehicle (relative speed (vector))).

[0042] The vehicle-mounted sensor 20 further includes a vehicle speed sensor 23. The vehicle speed sensor 23 obtains the speed sp0 of its own vehicle (speed (scalar) relative to the road R) based on the number of rotations of the wheels per unit time. And the vehicle speed sensor 23 provides the speed sp0 to the ECU 10.

[0043] The notification device 30 includes an image display device and an audio device. The image display device displays an image according to the image display instruction obtained from the ECU 10. The audio device reproduces a sound according to the sound reproduction instruction obtained from the ECU 10.

[0044] The braking device 40 applies a braking force to the wheels. The braking device 40 includes a brake caliper, a brake ECU, etc. The brake ECU controls the brake caliper based on an instruction (target value of the braking force (deceleration)) obtained from another ECU. Thereby, the own vehicle is braked.

[0045] Risk reduction function

[0046] When the ignition switch of its own vehicle is in the ON state, the ECU 10 sequentially acquires various information from the in-vehicle sensors 20 and performs various operations based on this information. Specifically, the ECU 10 detects the target object OB located within the field of view FOV based on the fusion information. And the ECU 10 predicts the time to collision TTC until its own vehicle contacts the target object OB. Specifically, the ECU 10 acquires the distance ΔD between its own vehicle and the target object OB and the relative velocity rv which is the velocity of the target object OB relative to its own vehicle. The ECU 10 acquires the value obtained by dividing the distance ΔD by the relative velocity rv as the predicted time TTC. When the following condition X holds, the ECU 10 determines that the contact risk between its own vehicle and the target object OB is high and executes risk reduction control to control its own vehicle in a manner that reduces this contact risk. In addition, condition X is also referred to as the "contact risk determination condition", the "start condition of risk reduction control", etc.

[0047] [Condition X]... The predicted time TTC is less than or equal to the threshold value TTCth (TTC ≤ TTCth). The ECU 10 can execute notification control and automatic braking control as risk reduction control.

[0048] Notification control

[0049] The ECU 10 displays an icon indicating a high contact risk with the target object OB to the driver and sends an instruction to reproduce an alarm sound (emit an alarm sound) to the notification device 30.

[0050] Automatic braking control

[0051] The ECU 10 sends an instruction (target value of deceleration) to decelerate its own vehicle to the braking device 40.

[0052] Here, the threshold value TTCth is not a fixed value. As described below, a value corresponding to the situation is assigned to the threshold value TTCth. The ECU 10 performs the following operations to determine the value assigned to the threshold value TTCth.

[0053] As Figure 2 shown, the ECU 10 calculates the predicted trajectory TR0 of the area predicted to be passed by its own vehicle and the predicted trajectory TRob of the area predicted to be passed by the target object OB (in the Figure 2 example, the oncoming vehicle V1).

[0054] Specifically, the ECU 10 obtains the orientation dir0 of its own vehicle relative to the road R based on lane marking information. In addition, the ECU 10 obtains the speed sp0 from the vehicle speed sensor 23. The ECU 10 obtains the speed sp0 and the orientation dir0 as the speed v0 (vector) of its own vehicle relative to the road R. The ECU 10 obtains the trajectory of its own vehicle in the most recent predetermined period based on the change in the speed v0 (the time series data of the speed v0 obtained in the most recent predetermined period), and obtains a strip-shaped area obtained by extending the trajectory forward as the predicted trajectory TR0. In addition, the ECU 10 may obtain the predicted trajectory TR0 based on information obtained from a steering angle sensor, a yaw rate sensor, etc. (not shown) in addition to the lane marking information.

[0055] In addition, the ECU 10 obtains the speed vob of the target object OB (the speed (speed, orientation) of the target object OB relative to the road R) by performing a vector operation of subtracting the speed v0 of its own vehicle from the relative speed rv between its own vehicle and the target object OB. The ECU 10 obtains the predicted trajectory TRob based on the change in the speed vob. In addition, the bandwidth of the predicted trajectory TR0 is equal to the vehicle width of its own vehicle, and the bandwidth of the predicted trajectory TRob is equal to the width of the target object OB.

[0056] The ECU 10 obtains the value obtained by dividing the width Δw of the overlapping part of the predicted trajectory TR0 and the predicted trajectory TRob by the vehicle width of its own vehicle as the overlapping rate wr. In addition, when the width Δw of the overlapping part of the predicted trajectory TR0 and the predicted trajectory TRob is not constant (when the two trajectories are not parallel), the value obtained by dividing the maximum value of the width Δw by the vehicle width of its own vehicle is obtained as the overlapping rate wr.

[0057] The ECU 10 determines the value assigned to the threshold TTCth according to the relative speed rv and the overlapping rate wr. The greater the relative speed rv, the greater the value the ECU 10 assigns to the threshold TTCth. That is, the start timing of the risk reduction control is advanced. In addition, the greater the overlapping rate wr, the greater the value the ECU 10 assigns to the threshold TTCth. That is, the greater the overlapping rate wr, the earlier the start timing of the risk reduction control. For example, the ECU 10 assigns the value obtained according to the following arithmetic expression (1) specified by the use coefficient k1, the relative speed rv, and the overlapping rate wr to the threshold TTCth.

[0058] TTCth = rv × wr × k1…(1)

[0059] In addition, the ECU 10 may also refer to a map (not shown) that specifies the relationship between "relative speed rv and overlapping rate wr" and "the value assigned to the threshold TTCth", and obtain the value corresponding to the relative speed rv and the overlapping rate wr at the current time point.

[0060] Imagine as follows Figure 3 As shown, a scenario where an oncoming vehicle V1 overtakes a moving body M moving at a low speed on a narrow road. On a narrow road, there is a high possibility that it is difficult to steer one's own vehicle to avoid the oncoming vehicle V1. Therefore, in this scenario (especially when one's own vehicle and the oncoming vehicle V1 are in a relatively close state, but the oncoming vehicle V1 still overtakes the moving body M), it is preferable to brake one's own vehicle as early as possible.

[0061] Therefore, when there is a high possibility that the oncoming vehicle V1 overtakes the moving body M on a narrow road, the ECU 10 reduces the contact risk between the oncoming vehicle V1 and one's own vehicle as described below.

[0062] Specifically, the ECU 10 successively executes a process (scenario determination process) for determining "whether one's own vehicle, the oncoming vehicle V1, and the moving body M (hereinafter referred to as 'one's own vehicle, etc.') are traveling on a narrow road, and in front of one's own vehicle, there is a high possibility that the oncoming vehicle V1 overtakes the moving body M". The scenario determination process includes the following first process to fourth process.

[0063] First process

[0064] The first process is a process (narrow road determination process) for determining whether the road R on which one's own vehicle, etc. are traveling is a narrow road. The ECU 10 obtains the width W of the road R based on the lane marking information (the interval between a pair of left and right lane markings in the foreground image). The ECU 10 determines that the road R is a narrow road when the following condition A is satisfied.

[0065] [Condition A]... The width W is equal to or less than the threshold value Wth.

[0066] In addition, the threshold value Wth is, for example, about "2.5 times" the vehicle width of one's own vehicle. In addition, the ECU 10 may also obtain the width W based on the map information of the navigation system (not shown). In addition, the ECU 10 may also determine that the road R is a narrow road when there is no center line.

[0067] Second process

[0068] When condition A is satisfied, the ECU 10 executes the second process. The second process includes an oncoming vehicle detection process and a moving body detection process.

[0069] Oncoming vehicle detection process

[0070] The oncoming vehicle detection process is a process for determining whether there is an oncoming vehicle V1. The ECU10 sometimes detects a situation where there is a vehicle in front of its own vehicle based on the fusion information. In this case, the ECU10 obtains the speed v1 (speed sp1 and direction dir1) of the vehicle based on the relative speed vr01 of the vehicle with respect to its own vehicle and the speed v0 of its own vehicle. When the following condition B1 is satisfied, the ECU10 determines that there is an oncoming vehicle V1.

[0071] [Condition B1]... The speed sp1 exceeds the threshold sp1th, and the direction dir1 is within a predetermined angular range θ1 on the side of its own vehicle (sp1 > sp1th, dir1 ∈ θ1).

[0072] Moving object detection process

[0073] The moving object detection process is a process for determining whether there is a moving object M (low-speed moving object). The ECU10 sometimes detects a situation where there is a moving object (pedestrian, bicycle, etc.) between its own vehicle and the oncoming vehicle V1 in the section in front of the oncoming vehicle V1 based on the fusion information. In this case, the ECU10 obtains the speed vm (speed spm, direction dirm) of the moving object based on the relative speed vrm of the moving object with respect to its own vehicle and the speed v0 of its own vehicle. When the following condition B is satisfied, the ECU10 determines that there is a moving object M.

[0074] [Condition B2]... The speed spm is greater than "0" and less than or equal to the threshold spmth, and the direction dirm is within a predetermined angular range θm opposite to the direction dir0 of its own vehicle. (0 < spm ≤ spmth, dirm ∈ θm)

[0075] When conditions B1 and B2 are satisfied, the ECU10 determines that condition B is satisfied.

[0076] Third process

[0077] When condition B is satisfied, the ECU10 executes the third process. The third process is a process for determining whether a condition C related to the positional relationship with its own vehicle, etc., is satisfied. The third process includes the following first approach determination process, arrival first determination process, and second approach determination process.

[0078] First approach determination process

[0079] The first approach determination process is a process for determining whether its own vehicle and the oncoming vehicle V1 are in an approaching state. The ECU10 obtains the distance ΔD01 between its own vehicle and the oncoming vehicle V1 based on the fusion information. When the following condition C1 is satisfied, the ECU10 determines that its own vehicle and the oncoming vehicle V1 are in an approaching state.

[0080] [Condition C1]…The distance ΔD01 is less than or equal to the threshold value ΔD01th (ΔD01 ≤ ΔD01th).

[0081] First arrival determination process

[0082] The first arrival determination process is a process for determining whether there is a high possibility that the oncoming vehicle V1 reaches the rear end of the moving body M before the host vehicle reaches the front end of the moving body M. The ECU10 obtains the time Δt0m until the host vehicle reaches the front end of the moving body M based on the distance ΔD0m between the host vehicle and the moving body M and the relative speed rv0m between the host vehicle and the moving body M. In addition, the ECU10 obtains the time Δt1m until the oncoming vehicle V1 reaches the rear end of the moving body M based on the distance ΔD1m between the oncoming vehicle V1 and the moving body M and the relative speed rv1m between the oncoming vehicle V1 and the moving body M. The ECU10 determines that there is a high possibility that the oncoming vehicle V1 reaches the rear end of the moving body M before the host vehicle reaches the front end of the moving body M when the following condition C2 is satisfied.

[0083] [Condition C2]…The time Δt1m is less than or equal to the value obtained by adding a predetermined margin Δt to the time Δt0m (Δt1m ≤ Δt0m + Δt).

[0084] When condition C2 is not satisfied, since there is a high possibility that the host vehicle passes through the side of the moving body M before the oncoming vehicle V1, the ECU10 determines that there is a low possibility that the oncoming vehicle V1 overtakes the moving body M in front of the host vehicle. In addition, the ECU10 can also simply determine that condition C2 is satisfied when the distance ΔD1m is less than the distance ΔD0m.

[0085] Second approach determination process

[0086] The second approach determination process is a process for determining whether the oncoming vehicle V1 and the moving body M are in an approaching state. The ECU10 obtains the distance ΔD1m between the oncoming vehicle V1 and the moving body M based on the fusion information. The ECU10 determines that the host vehicle and the oncoming vehicle V1 are in an approaching state when the following condition C3 is satisfied.

[0087] [Condition C3]…The distance ΔD1m is less than or equal to the threshold value ΔD1mth (ΔD1m ≤ ΔD1mth).

[0088] The ECU10 determines that condition C is satisfied when conditions C1 to C3 are satisfied.

[0089] Fourth process

[0090] When condition C is satisfied, ECU10 performs the fourth process. The fourth process is to determine whether condition D related to the speed relationship (motion) between oncoming vehicle V1 and moving body M holds. The third process includes the following speed difference determination process, deceleration determination process, and acceleration determination process.

[0091] Speed difference determination process

[0092] The speed difference determination process is to determine whether the speed difference Δsp between oncoming vehicle V1 and moving body M (the speed difference Δsp between oncoming vehicle V1 and moving body M = sp1 - spm) is large enough (large enough to be regarded as the intention of the driver of oncoming vehicle V1 to overtake moving body M). When the following condition D1 holds, ECU10 determines that the speed difference Δsp is large enough.

[0093] [Condition D1]... The speed difference Δsp exceeds the threshold value Δspth (sp1 - spm > Δspth).

[0094] Here, even if the speed difference Δsp is large enough, when oncoming vehicle V1 is decelerating, the possibility of oncoming vehicle V1 overtaking moving body M is low. On the other hand, even if the speed difference Δsp is not that large, when oncoming vehicle V1 is accelerating, there is a possibility of oncoming vehicle V1 overtaking moving body M. Therefore, based on whether condition D1 holds, ECU10 performs the following deceleration determination process or acceleration determination process.

[0095] Deceleration determination process

[0096] The deceleration determination process is to determine whether oncoming vehicle V1 is decelerating. When condition D1 holds, ECU10 performs the deceleration determination process. ECU10 obtains the acceleration a1 of oncoming vehicle V1 (acceleration relative to road R) based on the change in the speed sp1 of oncoming vehicle V1 (time series data of the speed sp1 in the recent predetermined time). When the following condition D2 holds, ECU10 determines that oncoming vehicle V1 is decelerating.

[0097] [Condition D2]... The acceleration a1 is less than or equal to the negative threshold value na1th (a1 ≤ na1th).

[0098] Acceleration determination process

[0099] The deceleration determination process is to determine whether oncoming vehicle V1 is accelerating. When condition D1 does not hold, ECU10 performs the acceleration determination process. When the following condition D3 holds, ECU10 determines that oncoming vehicle V1 is accelerating.

[0100] [Condition D3]…The acceleration a1 exceeds the positive threshold value pa1th (a1 > pa1th).

[0101] When condition D1 is satisfied and condition D2 is not satisfied (when the speed difference Δsp is large enough and the oncoming vehicle V1 is not decelerating), the ECU10 determines that condition D is satisfied. In addition, when condition D1 is not satisfied and condition D3 is satisfied (when the speed difference Δsp is not that large but the oncoming vehicle V1 is accelerating), the ECU10 determines that condition D is satisfied.

[0102] When conditions A to D are satisfied, the ECU10 determines that "the host vehicle, the oncoming vehicle V1, and the moving body M are traveling on a narrow road, and in front of the host vehicle, the possibility that the oncoming vehicle V1 overtakes the moving body M is high". In this case, as Figure 3 shown, in order to determine the level of the contact risk between the host vehicle and the oncoming vehicle V1 in a predetermined area RLX near the oncoming vehicle V1, instead of the arithmetic expression (1), the ECU10 determines the threshold value TTCth based on the following arithmetic expression (2). That is, the relative speed rv01 between the host vehicle and the oncoming vehicle V1 and the overlapping rate wr01 between the host vehicle and the oncoming vehicle V1 are substituted into the relative speed vr and the overlapping rate wr in the arithmetic expression (2).

[0103] TTCth = rv × wr × k2…(2)

[0104] Here, the coefficient k2 of the arithmetic expression (2) is greater than the coefficient k1 of the arithmetic expression (1). Thus, compared with the case of using the arithmetic expression (1), the threshold value TTCth in the case of using the arithmetic expression (2) becomes larger. That is, in the area RLX, the start condition of the risk reduction control (the condition for determining that the contact risk is high) is relaxed. In addition, the area RLX is a rectangle extending along the long side direction of the road R in a plan view. The width of the area RLX is equal to the width W of the road R. One end and the other end in the long side direction of the area RLX are respectively located near the windshield of the oncoming vehicle V1 and near the front end of the moving body M. In addition, the ECU10 may also determine TTCth with reference to a map (not shown).

[0105] Speed limit control

[0106] In addition, when Conditions A to D are satisfied, execution of the following speed limit control is permitted. Specifically, the ECU 10 controls the braking device 40 so that the speed sp0 of the host vehicle becomes equal to or less than the upper limit value sp0th within the area SPL near the moving body M. Here, the area SPL is a rectangle extending along the long side direction of the road R in a plan view, and a part of the area SPL overlaps with the area RLX. The width of the area SPL is equal to the width of the road R. One end and the other end in the long side direction of the area SPL are respectively located near the front end of the oncoming vehicle V1 and in front of the moving body M in the traveling direction. The distance Δd between the other end and the front end of the moving body M is set to a predetermined value Δdth. That is, when the distance ΔD0m between the host vehicle and the moving body M is equal to or less than the predetermined value Δdth, the ECU 10 executes the speed limit control. In addition, the deceleration of the host vehicle by the speed limit control is slower than the deceleration of the host vehicle by the automatic braking control. When Condition X is not satisfied in the area S where the area RLX and the area SPL overlap, the speed limit control is executed and the notification control and the automatic braking control are not executed. On the other hand, when Condition X is satisfied in the area S, the notification control and the automatic braking control are executed and the speed limit control (slow deceleration) is not executed.

[0107] Next, with reference to Figure 4 , a program PR1 executed by the CPU 10a (hereinafter simply referred to as "CPU") of the ECU 10 to achieve the above functions of the vehicle control device 1 will be described.

[0108] Program PR1

[0109] The CPU starts execution of the program PR1 at a predetermined cycle. The CPU starts execution of the program PR1 from step 100 and advances the process to step 101.

[0110] The CPU determines whether Condition A is satisfied in step 101. When the CPU determines that Condition A is satisfied (101: Yes), the process advances to step 102. On the other hand, when the CPU does not determine that Condition A is satisfied (101: No), the process advances to step 111 described later.

[0111] The CPU determines whether Condition B is satisfied in step 102. When the CPU determines that Condition B is satisfied (102: Yes), the process advances to step 103. On the other hand, when the CPU does not determine that Condition B is satisfied (102: No), the process advances to step 111 described later.

[0112] The CPU determines whether condition C holds in step 103. When the CPU determines that condition C holds (103: Yes), the process proceeds to step 104. On the other hand, when the CPU does not determine that condition C holds (103: No), the process proceeds to step 111 described below.

[0113] The CPU determines whether condition D1 holds in step 104. When the CPU determines that condition D1 holds (104: Yes), the process proceeds to step 105. On the other hand, when the CPU does not determine that condition D1 holds (104: No), the process proceeds to step 106 described below.

[0114] The CPU determines whether condition D2 holds in step 105. When the CPU determines that condition D2 holds (105: Yes), the process proceeds to step 112 described below. On the other hand, when the CPU does not determine that condition D2 holds (105: No), the process proceeds to step 107 described below.

[0115] The CPU determines whether condition D3 holds in step 106. When the CPU determines that condition D3 holds (106: Yes), the process proceeds to step 107. On the other hand, when the CPU does not determine that condition D3 holds (106: No), the process proceeds to step 107 described below.

[0116] The CPU determines whether the host vehicle is located within area SPL in step 107. When the CPU determines that the host vehicle is located within area SPL (107: Yes), the process proceeds to step 108. On the other hand, when the CPU does not determine that the host vehicle is located within area SPL (107: No), the process proceeds to step 111.

[0117] The CPU executes speed limit control in step 108. That is, the CPU sends a deceleration command to the braking device 40 so that the speed sp0 of the host vehicle becomes equal to or less than the upper limit value sp0th. Then, the CPU causes the process to proceed to step 109.

[0118] The CPU determines whether the host vehicle is located within area RLX in step 109. When the CPU determines that the host vehicle is located within area RLX (109: Yes), the process proceeds to step 110. On the other hand, when the CPU does not determine that the host vehicle is located within area RLX (109: No), the process proceeds to step 111.

[0119] In step 110, the CPU assigns the value obtained according to arithmetic expression (2) to the threshold value TTCth. Then, the CPU causes the process to proceed to step 113.

[0120] In step 111, the CPU assigns the value obtained according to arithmetic expression (1) to the threshold value TTCth. Then, the CPU advances the process to step 113. Additionally, in step 112, the CPU performs the same process as in step 111.

[0121] In step 113, the CPU determines whether condition X holds. When the CPU determines that condition X holds (113: Yes), it advances the process to step 114. On the other hand, when the CPU does not determine that condition X holds (113: No), it advances the process to step 115.

[0122] In step 114, the CPU executes risk reduction control. Then, ECU 10 advances the process to step 115, where the execution of program PR1 ends.

[0123] Effect

[0124] When conditions A to D hold, the vehicle control device 1 determines that there is a high possibility that the oncoming vehicle V1 overtakes the moving body M on a narrow road, and relaxes condition X, which is the start condition of the risk reduction control. That is, in this scenario, the start timing of the execution of the risk reduction control is advanced. As a result, the contact risk between the host vehicle and the oncoming vehicle is sufficiently reduced.

[0125] Modification example

[0126] The function of performing the above speed limit control in the function of the vehicle control device 1 may also be omitted.

Claims

1. A vehicle control device, when the contact risk determination condition is satisfied, performs risk reduction control to control its own vehicle in a manner that reduces the contact risk, where the contact risk determination condition is a condition for determining that there is a high contact risk between a target object within a predetermined range in the traveling direction of its own vehicle and its own vehicle, the vehicle control device is configured to relax the contact risk determination condition when a first condition, a second condition, a third condition, and a predetermined fourth condition are satisfied, the first condition is a condition for determining that the road on which its own vehicle is traveling is a narrow road, the second condition is a condition for determining that there is an oncoming vehicle approaching its own vehicle and a moving body moving at a low speed between the oncoming vehicle and its own vehicle within the predetermined range, the third condition is a condition for determining that there is a high possibility that the oncoming vehicle will reach the rear end of the moving body before its own vehicle reaches the front end of the moving body, the predetermined fourth condition is a condition regarding the relative motion between the oncoming vehicle and the moving body.

2. The vehicle control device according to claim 1, the vehicle control device is configured to, when the speed difference between the oncoming vehicle and the moving body exceeds a predetermined first threshold and the acceleration of the oncoming vehicle exceeds a second threshold, or when the speed difference is equal to or less than the first threshold and the acceleration of the oncoming vehicle exceeds a predetermined third threshold, the fourth condition is satisfied.

3. The vehicle control device according to claim 1, the vehicle control device is configured to, the contact risk determination condition is satisfied when the predicted time until contact between its own vehicle and the oncoming vehicle is equal to or less than a fourth threshold, determine the value assigned to the fourth threshold according to the relative speed between its own vehicle and the oncoming vehicle, when at least one of the first condition to the fourth condition is not satisfied and the relative speed is a first speed, assign a first predetermined value to the fourth threshold, when the first condition to the fourth condition are satisfied and the relative speed is a second speed lower than the first speed, assign a second predetermined value greater than the first predetermined value to the fourth threshold.

4. The vehicle control device according to claim 1, the vehicle control device is configured to, the contact risk determination condition is satisfied when the predicted time until contact between its own vehicle and the oncoming vehicle is equal to or less than a fourth threshold, determine the value assigned to the fourth threshold according to the degree of overlap, i.e., the overlap rate, between the area predicted to be passed by its own vehicle and the area predicted to be passed by the oncoming vehicle, when at least one of the first condition to the fourth condition is not satisfied and the overlap rate is a first overlap rate, assign a first predetermined value to the fourth threshold, when the first condition to the fourth condition are satisfied and the overlap rate is a second overlap rate less than the first overlap rate, assign a second predetermined value greater than the first predetermined value to the fourth threshold.

5. The vehicle control device according to claim 1, the vehicle control device is configured to, When the distance between the moving object and the host vehicle is equal to or less than a predetermined fifth threshold value, limit the vehicle speed of the host vehicle to be equal to or less than a predetermined upper limit value.

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