Vehicle operation support device

Abstract

To provide a vehicle operation support device capable of achieving vehicle behavior that prevents interference between a bottom surface of a vehicle and a gradient of a road.SOLUTION: A travel ECU 14 recognizes a sloped road surface with a positive longitudinal gradient θ in a moving direction of an own vehicle O, relative to a road surface the own vehicle O is currently traveling on. The travel ECU 14 then determines whether a bottom surface of a front bumper 2a (vehicle body 2) interferes with the sloped road surface when the own vehicle enters the sloped road surface. When determining that the bottom surface of the front bumper 2a interferes with the sloped road surface, the travel ECU 14 causes a brake 6f of a front wheel 5f to apply and then release braking force caused to the brake 6f immediately before the own vehicle O enters the sloped road surface.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to a driving support device for a vehicle that performs driving support based on driving environment information outside the vehicle.

Background Art

[0002] In recent years, driving support devices have been installed in vehicles such as automobiles. The driving support device performs various driving supports for reducing the driver's driving load based on driving environment information outside the vehicle.

[0003] In such a driving support device, as part of driving support, various techniques for notifying the driver of driving environment information around the vehicle have been proposed. For example, Patent Document 1 discloses a technique of acquiring a gradient position and a gradient value on a road surface using a laser scanner or the like, and notifying the driver of the comparison result between the acquired gradient value and a reference gradient value that the vehicle can pass, in association with the gradient position. According to such a technique, by notifying the driver of the gradient information on the road surface, interference between the bottom surface of the vehicle body and the gradient on the road surface can be suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in order to more effectively suppress the interference between the bottom surface of the vehicle body and the gradient on the road surface, it is preferable to perform not only notification of gradient information to the driver but also additional vehicle behavior control with respect to the gradient.

[0006] An object of the present invention is to provide a driving support device for a vehicle that can realize a vehicle behavior for suppressing interference between the bottom surface of the vehicle body and a gradient on the road surface.

Means for Solving the Problem

[0007] A driving support device for a vehicle according to one aspect of the present invention includes a gradient road surface recognition means for recognizing a gradient road surface having a positive longitudinal gradient based on the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle, an interference determination means for determining whether or not the bottom surface of the vehicle body interferes with the gradient road surface when the host vehicle enters the gradient road surface, and a braking control means for generating a braking force on the front wheels of the host vehicle and releasing the braking force immediately before the host vehicle enters the gradient road surface when it is determined that the bottom surface of the vehicle body interferes with the gradient road surface.

[0008] Further, a driving support device for a vehicle according to another aspect of the present invention includes a gradient road surface recognition means for recognizing a gradient road surface having a positive longitudinal gradient based on the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle, an interference determination means for determining whether or not the bottom surface of the vehicle body interferes with the gradient road surface when the host vehicle enters the gradient road surface, and a steering angle control means for tilting the entry direction of the front wheels when the host vehicle enters the gradient road surface with respect to the maximum inclination direction of the gradient road surface when it is determined that the bottom surface of the vehicle body interferes with the gradient road surface.

[0009] Further, a driving support device for a vehicle according to another aspect of the present invention includes a processor. The processor recognizes a gradient road surface having a positive longitudinal gradient based on the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle, determines whether or not the bottom surface of the vehicle body interferes with the gradient road surface when the host vehicle enters the gradient road surface, and generates a braking force on the front wheels of the host vehicle and releases the braking force immediately before the host vehicle enters the gradient road surface when it is determined that the bottom surface of the vehicle body interferes with the gradient road surface.

[0010] In addition, a vehicle driving support device according to another aspect of the present invention includes a processor. The processor recognizes a gradient road surface having a positive longitudinal gradient with respect to the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle, determines whether the bottom surface of the vehicle body interferes with the gradient road surface when the host vehicle enters the gradient road surface, and when it is determined that the bottom surface of the vehicle body interferes with the gradient road surface, tilts the entry direction of the front wheels when the host vehicle enters the gradient road surface with respect to the maximum inclination direction of the gradient road surface.

Effect of the Invention

[0011] According to the vehicle driving support device of the present invention, it is possible to realize a vehicle behavior for suppressing interference between the bottom surface of the vehicle body and the gradient on the road surface.

Brief Description of the Drawings

[0012]

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Mode for Carrying Out the Invention

[0013] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, and FIG. 1 is a schematic configuration diagram showing a driving support device for a vehicle.

[0014] As shown in FIG. 1, the driving support device 1 is configured to include a camera unit 10. This camera unit 10 is fixed, for example, at the upper center of the front part inside the vehicle (own vehicle) O.

[0015] The camera unit 10 includes a stereo camera 11 as an imaging means, an image processing unit (IPU) 12, an image recognition unit (image recognition_ECU) 13, and a travel control unit (travel_ECU) 14.

[0016] The stereo camera 11 has the main camera 11a and the sub - camera 11b as sensors. The main camera 11a and the sub - camera 11b are configured with imaging elements such as CMOS. These main camera 11a and sub - camera 11b are arranged, for example, at symmetric positions with respect to the center in the vehicle width direction. Thereby, the main camera 11a and the sub - camera 11b perform stereo imaging of the driving environment in the forward area outside the vehicle from different viewpoints at a predetermined imaging cycle synchronized with each other.

[0017] The IPU 12 performs image processing on the driving environment image captured by the stereo camera 11 in a predetermined manner. Thereby, the IPU 12 detects edges of various objects such as three - dimensional objects represented on the image and lane lines on the road surface. Also, the IPU 12 obtains distance information from the amount of positional deviation of corresponding edges in the left and right images. Through these, the IPU 12 generates image information (distance image information) including distance information.

[0018] The image recognition _ ECU 13 recognizes lane - dividing lines that divide lanes on the road based on the distance image information received from the IPU 12 and the like. For example, the image recognition _ ECU 13 obtains the curvature [1 / m] of the left and right lane - dividing lines that divide each lane on the road and the width (lane width) between the left and right dividing lines. Further, the image recognition _ ECU 13 calculates the lane width from the difference in the curvature of the left and right dividing lines. Through these recognition processes of the lane - dividing lines, the image recognition _ ECU 13 recognizes each lane on the road including the lane (own - vehicle driving lane) in which the host vehicle O is traveling.

[0019] Also, the image recognition _ ECU 13 performs predetermined pattern matching and the like on the distance image information. Thereby, the image recognition _ ECU 13 recognizes three - dimensional objects such as guardrails extending along the road, curbstones, slopes beside the road, and surrounding vehicles traveling on the road. Here, in the recognition of three - dimensional objects by the image recognition _ ECU 13, for example, recognition of the type of three - dimensional object, the distance to the three - dimensional object, the speed of the three - dimensional object, and the relative speed between the three - dimensional object and the host vehicle O is performed.

[0020] In addition, the image recognition ECU 13 recognizes the road surface existing in front of the host vehicle O. For example, the image recognition ECU 13 refers to the distance image information and recognizes the road surface based on the distribution of edges between the left and right lane lines and the like. In this road surface recognition, the image recognition ECU 13 recognizes the road surface gradient (longitudinal gradient θ) in front of the host vehicle O as road surface information. Here, the longitudinal gradient θ recognized by the image recognition ECU 13 is the relative inclination with respect to the optical axis direction of the stereo camera 11. Therefore, in the image recognition ECU 13, the longitudinal gradient θ of the front road surface is recognized, for example, with reference to the road surface on which the host vehicle O is traveling (assuming that the road surface on which the host vehicle O is traveling is horizontal).

[0021] Various information recognized by the image recognition ECU 13 is output to the driving ECU 14 as driving environment information.

[0022] The driving ECU 14 is a control unit for overall control of the driving support device 1.

[0023] Connected to the driving ECU 14 are various sensors such as, for example, a distance measuring sensor 15 and a longitudinal and lateral acceleration sensor 16.

[0024] The distance measuring sensor 15 is constituted by an infrared sensor or the like. This distance measuring sensor 15 is provided, for example, at the lower part on the front end side of the front bumper 2a of the vehicle body 2 (see FIG. 2). Thereby, the distance measuring sensor 15 measures the distance from the road surface to the bottom surface on the front end side of the front bumper 2a as the height H0 of the front bumper 2a.

[0025] The longitudinal and lateral acceleration sensor 16 detects the acceleration (longitudinal and lateral acceleration) a acting in the longitudinal direction of the vehicle body 2. Note that using this longitudinal and lateral acceleration a, the driving ECU 14 can also estimate the gradient of the road surface on which the host vehicle O travels. In this case, the driving ECU 14 estimates the gradient of the road surface on which the host vehicle travels based on, for example, the difference between the longitudinal and lateral acceleration a detected by the longitudinal and lateral acceleration sensor 16 and the longitudinal and lateral acceleration obtained by differentiating the vehicle speed based on the wheel speed and the like.

[0026] In addition, as various control units, for example, a cockpit control unit (CP_ECU) 21, a brake control unit (BK_ECU) 22, and a power steering control unit (PS_ECU) 23 are connected to the traveling ECU 14 via an in-vehicle communication line such as a CAN (Controller Area Network).

[0027] Connected to the CP_ECU 21 are, for example, a display 31 and a speaker 32 as a human-machine interface (HMI) disposed around the driver's seat. These display 31 and speaker 32 transmit various information to the driver through screen display, voice output, etc.

[0028] Connected to the output side of the BK_ECU 22 is a brake actuator 33 for adjusting the brake hydraulic pressure for each brake 6 provided on each wheel 5. Also connected to the input side of the BK_ECU 22 are various sensors such as a wheel speed sensor 34 provided on each wheel 5 and a brake pedal switch 35.

[0029] Based on a control signal from the traveling ECU 14 or a detection signal from various sensors, the BK_ECU 22 controls the brake actuator 33, etc. Thereby, the BK_ECU 22 appropriately generates a braking force for performing forced braking control, yaw rate control, etc. on the host vehicle O for each wheel. For this purpose, the brake actuator 33 can supply an independent brake hydraulic pressure to each brake 6. Also, the BK_ECU 22 outputs signals such as the wheel speed detected by various sensors and the brake operation state to the traveling ECU 14.

[0030] In the following description, as appropriate, among the wheels 5, the front wheels are labeled with the symbol "5f" and the rear wheels are labeled with the symbol "5r". Also, as appropriate, among the brakes 6, the brake of the front wheel 5f is labeled with the symbol "6f" and the brake of the rear wheel 5r is labeled with the symbol "6r".

[0031] On the output side of the PS_ECU23, an electric power steering motor 36 that applies a steering torque due to the rotational force of the motor to the steering mechanism is connected. Also, on the input side of the PS_ECU23, various sensors such as a steering angle sensor 37 are connected.

[0032] The PS_ECU23 performs drive control for the electric power steering motor 36 etc. based on a control signal from the traveling_ECU14 or a detection signal from various sensors. Thereby, the PS_ECU23 generates a steering torque for the steering mechanism. Also, the PS_ECU23 outputs signals such as the steering angle detected by various sensors to the traveling_ECU14.

[0033] As part of the driving support control, the traveling_ECU14 performs vehicle body control when, for example, the host vehicle O enters a sloped road surface. This vehicle body control is control to prevent the bottom surface of the front bumper 2a of the host vehicle O from interfering with the sloped road surface. Although detailed description is omitted, the traveling_ECU14 can perform following inter-vehicle distance control (ACC: Adaptive Cruise Control), lane center maintenance control (ALKC: Active Lane Keep Centering), emergency lane departure suppression control (ELKA: Emergency Lane Keep Assist), and auto lane change control (ALC: Auto Lane Changing) etc. as other driving support controls.

[0034] At the time of vehicle body control, the traveling_ECU14 calculates the target traveling path of the host vehicle O. For example, the traveling_ECU14 calculates the target traveling path based on the traveling route input from a navigation device (not shown). Or, the traveling_ECU14 calculates the target traveling path based on the steering angle etc. input from the steering angle sensor 37.

[0035] Then, the traveling ECU 14 reads the road surface information on the target driving route from the image recognition ECU. Thereby, the traveling ECU 14 acquires road surface information such as a gradient road surface existing in the traveling direction of the host vehicle O. In this case, when a slope or the like on the side of the road is included on the target driving route, the traveling ECU 14 also acquires information such as the slope as road surface information. When acquiring the road surface information, the traveling ECU 14 extracts a road surface having a positive longitudinal gradient θ with respect to the road surface on which the host vehicle O is currently traveling. Further, the traveling ECU 14 calculates the start position of the gradient road surface having the positive longitudinal gradient θ. For example, the traveling ECU 14 calculates the position where the road surface on which the host vehicle O is currently traveling intersects with the gradient road surface ahead as the start position of the gradient road surface.

[0036] In addition, when the host vehicle O enters the gradient road surface, the traveling ECU 14 determines whether or not the bottom surface of the vehicle body 2 interferes with the gradient road surface. More specifically, when the host vehicle O enters the gradient road surface, the traveling ECU 14 determines whether or not the bottom surface of the front bumper 2a interferes with the gradient road surface.

[0037] At the time of this determination, the traveling ECU 14 acquires the height H0 of the front bumper 2a of the host vehicle O and the approach angle θ0 of the host vehicle O (see, for example, FIG. 2). For example, the traveling ECU 14 acquires the height H0 measured by the distance measuring sensor 15 as the height of the front bumper 2a. In this case, it is preferable that the traveling ECU 14 acquires the height H0 measured when the absolute value |a| of the acceleration a is less than a preset threshold value ath. Here, the threshold value ath is, for example, the limit value of the acceleration (or deceleration) capable of suppressing the pitching of the vehicle body 2. Such a threshold value ath is set by experiments, simulations, or the like. Further, the traveling ECU 14 calculates the approach angle θ0 based on, for example, the length from the ground contact point of the front wheel 5f to the tip of the front bumper 2a and the height H0 of the front bumper 2a.

[0038] Further, the traveling ECU 14 sets a threshold value Hth based on the height H0 of the front bumper 2a and a threshold value θth1 (first threshold value θth1) based on the approach angle θ0 of the host vehicle O as threshold values for determining the interference between the front bumper 2a and the gradient road surface. In this case, it is preferable that the traveling ECU sets the threshold value Hth and the threshold value θth1 to values smaller than the height H0 and the approach angle θ0, respectively, in consideration of the minute vibration of the vehicle body 2 during the traveling of the host vehicle O.

[0039] And basically, the traveling ECU 14 determines whether the front bumper 2a interferes with the gradient road surface based on the comparison between the longitudinal gradient θ of the gradient road surface and the threshold value θth1.

[0040] For example, as shown in FIG. 3, when the longitudinal gradient θ of the gradient road surface is less than the threshold value θth1, the traveling ECU 14 determines that the front bumper 2a does not interfere with the gradient road surface.

[0041] On the other hand, for example, as shown in FIG. 4, when the longitudinal gradient θ of the gradient road surface is greater than or equal to the threshold value θth1, the traveling ECU 14 determines that the front bumper 2a interferes with the gradient road surface.

[0042] However, when the height H of the gradient road surface can be recognized, the traveling ECU 14 determines whether the front bumper 2a interferes with the gradient road surface based on a comprehensive judgment using the longitudinal gradient θ and the height H of the gradient road surface.

[0043] That is, for example, as shown in FIG. 5, even when the longitudinal gradient θ is greater than or equal to the threshold value θth1, when the height H of the road surface gradient is less than the threshold value Hth, the traveling ECU 14 determines that the front bumper 2a does not interfere with the gradient road surface.

[0044] On the other hand, for example, as shown in FIG. 6, when the longitudinal gradient θ is greater than or equal to the threshold value θth1 and the height H of the road surface gradient is greater than or equal to the threshold value Hth, the traveling ECU 14 determines that the front bumper 2a interferes with the road surface gradient.

[0045] Note that, as a gradient road surface where the height H can be recognized, for example, a slope for accessing a store or the like beside a road can be assumed.

[0046] Further, when it is determined that the front bumper 2a of the host vehicle O interferes with the gradient road surface, the traveling ECU 14 performs vehicle body control to avoid such interference.

[0047] Such vehicle body control can be realized, for example, by braking control using the brake 6f of the front wheel 5f. Specifically, the traveling ECU 14 generates a braking force on the brake 6f of the front wheel 5f of the host vehicle O immediately before the host vehicle O enters the gradient road surface, and then releases the braking force. Thereby, the traveling ECU 14 controls the attitude of the vehicle body 2 by using the inertial force of the vehicle body 2 during traveling, the suspension of the front wheel 5f (front suspension 7f), and the suspension of the rear wheel 5r (rear suspension 7r).

[0048] That is, the traveling ECU 14 concentrates the inertial force of the vehicle body 2 on the front wheel 5f side by generating a braking force on the brake 6f of the front wheel 5f. Due to such concentration of the inertial force on the front wheel 5f side, the front suspension 7f compresses and the rear suspension 7r extends. As a result, pitching that sinks the front part of the vehicle body 2 downward occurs in the vehicle body 2 (see, for example, FIG. 7).

[0049] Further, the traveling ECU 14 releases the concentration of the inertial force on the front wheel 5f side by releasing the braking force on the brake 6f of the front wheel 5f at the timing when the front part of the vehicle body 2 sinks downward. As a result, rocking occurs in the vehicle body 2, the front suspension 7f extends, and the rear suspension 7r compresses. As a result, pitching that pushes up the front part of the vehicle body 2 upward occurs in the vehicle body 2. Then, since the front part of the vehicle body 2 is pushed up, interference between the front bumper 2a and the gradient road surface is avoided (see, for example, FIG. 8).

[0050] Here, when a predetermined braking force is generated on the host vehicle O before performing such vehicle body control, it is preferable that the traveling ECU 14 switches from braking using the brakes 6 of each wheel 5 to braking using the rear wheel brake 6r at a position set distance ahead of the host vehicle O entering the gradient road surface. Thereby, even during deceleration on a downhill gradient or the like, it becomes possible to realize vehicle body control using the front wheel brake 6f of the front wheels 5f (see, for example, FIGS. 9 and 10).

[0051] Also, vehicle body control for avoiding interference between the front bumper 2a and the gradient road surface can also be realized by steering control for the front wheels 5f. That is, the traveling ECU 14 performs steering control to tilt the entry direction Di of the front wheels 5f when the host vehicle O enters the gradient road surface with respect to the maximum gradient direction Dt of the gradient road surface (see, for example, FIG. 11). That is, the traveling ECU 14 refers to a preset map or the like and calculates the entry angle α of the front wheels 5f according to the longitudinal gradient θ. Then, the traveling ECU 14 performs steering control so that the actual steering angle of the front wheels 5f with respect to the maximum gradient direction Dt of the gradient road surface becomes α. Thereby, the effective inclination angle of the gradient road surface with respect to the front bumper 2a is alleviated, and interference between the front bumper 2a and the gradient road surface is avoided.

[0052] Here, prior to executing these vehicle body controls, it is preferable that the traveling ECU 14 determines whether it is possible to avoid interference between the front bumper 2a and the gradient road surface by vehicle body control. This determination is realized, for example, by comparing the longitudinal gradient θ with a threshold θth2 (second threshold θth2: θth2 > θth1). The threshold θth2 is set based on, for example, the displacement amount in the height direction of the front bumper 2a that can be displaced due to pitching of the vehicle body 2 or the like.

[0053] Thus, in the present embodiment, the traveling EUC 14 corresponds to a specific example of gradient road surface recognition means, interference determination means, braking control means, and steering angle control means.

[0054] Next, regarding the recognition of the vehicle state and the gradient road surface, an explanation will be given according to the flowchart showing the recognition routine of the vehicle state and the gradient road surface shown in FIG. 12. This routine is repeatedly executed at regular intervals in the traveling ECU 14.

[0055] When the routine starts, in step S101, the traveling ECU 14 calculates the target traveling path of the host vehicle O. That is, the traveling ECU 14 calculates the target traveling path of the host vehicle O based on the traveling route input from a navigation device (not shown) or the steering angle or the like input from the steering angle sensor 37.

[0056] In the subsequent step S102, the traveling ECU 14 checks whether or not the absolute value |a| of the acceleration detected by the longitudinal acceleration sensor 16 is less than a preset threshold value ath.

[0057] If it is determined in step S102 that the absolute value |a| of the acceleration is equal to or greater than the threshold value ath (step S102: NO), the traveling ECU 14 exits the routine as it is. That is, when the absolute value |a| of the acceleration is equal to or greater than the threshold value ath, the traveling ECU 14 determines that a predetermined pitching has occurred in the vehicle body 2 due to the acceleration or deceleration of the host vehicle O, and exits the routine as it is.

[0058] On the other hand, if it is determined in step S102 that the absolute value |a| of the acceleration is less than the threshold value ath (step S102: YES), the traveling ECU 14 proceeds to step S103.

[0059] In step S103, the traveling ECU 14 reads the height H0 of the front bumper 2a detected by the distance measuring sensor 15. That is, the traveling ECU 14 measures the reference value H0 of the height of the front bumper 2a that varies depending on the occupants and luggage or the like in a state where no pitching occurs in the vehicle body 2.

[0060] In the subsequent step S104, the traveling ECU 14 calculates an approach angle θ0 based on, for example, the length from the ground contact point of the front wheel 5f to the tip of the front bumper 2a and the height H0 of the front bumper 2a.

[0061] In the subsequent step S105, the traveling ECU 14 extracts a gradient road surface on the target traveling path within a preset distance in front of the host vehicle O (for example, about 5 to 10 [m] in front of the host vehicle O).

[0062] In the subsequent step S106, the traveling ECU 14 checks whether there is a gradient road surface with a positive longitudinal gradient θ in front of the host vehicle O. That is, the traveling ECU 14 checks whether there is a gradient road surface where the longitudinal gradient changes in a V shape with respect to the road surface on which the host vehicle O is traveling.

[0063] And in step S106, if it is determined that there is no gradient road surface with a positive longitudinal gradient θ (step S106: NO), the traveling ECU 14 exits the routine as it is.

[0064] On the other hand, in step S106, if it is determined that there is a gradient road surface with a positive longitudinal gradient θ (step S106: YES), the traveling ECU 14 proceeds to step S107.

[0065] In step S107, after the traveling ECU 14 calculates the start position of the gradient road surface with a positive longitudinal gradient θ, it exits the routine. That is, the traveling ECU 14 calculates, for example, the position where the road surface on which the host vehicle O is traveling and the gradient road surface in front of the host vehicle O intersect as the start position of the gradient road surface.

[0066] Next, the entry control of the host vehicle O with respect to the gradient road surface will be described according to the flowchart of the gradient road surface entry control routine shown in FIGS. 13 to 16. This routine is repeatedly executed by the traveling ECU 14 at each set time.

[0067] When the routine starts, the driving ECU 14 checks, in step S201, whether the gradient road surface entry flag F is set to "1". Here, the gradient road surface entry flag F is a flag that is set to "1" when it is determined, for example, that entry control (vehicle body control) for a gradient road surface is to be executed.

[0068] And, in step S201, when it is determined that the gradient road surface entry flag F is set to "1" (step S201: YES), the driving ECU 14 proceeds to step S211.

[0069] On the other hand, in step S201, when it is determined that the gradient road surface entry flag F is cleared to "0" (step S201: NO), the driving ECU 14 proceeds to step S202.

[0070] In step S202, the driving ECU 14 checks whether there is a gradient road surface with a positive longitudinal gradient θ within a set distance in front of the host vehicle O.

[0071] And, in step S202, when it is determined that there is no gradient road surface (step S202: NO), the driving ECU 14 exits the routine as it is.

[0072] On the other hand, in step S202, when it is determined that there is a gradient road surface (step S202: YES), the driving ECU 14 proceeds to step S203.

[0073] In step S203, the driving ECU 14 sets a first threshold value θth1 for the longitudinal gradient θ. That is, the driving ECU 14 sets the first threshold value θth1 based on the approach angle θ0 etc. of the host vehicle O.

[0074] In the subsequent step S204, the driving ECU 14 checks whether the longitudinal gradient θ of the road surface is greater than or equal to the first threshold value θth1.

[0075] And, in step S204, when it is determined that the longitudinal gradient θ of the road surface is less than the first threshold value θth1 (step S204: NO), the traveling ECU 14 exits the routine as it is. That is, when the longitudinal gradient θ of the road surface is less than the first threshold value θth1, the traveling ECU 14 determines that the front bumper 2a is less likely to interfere with the gradient road surface and that there is no need to perform vehicle body control with respect to the gradient road surface.

[0076] On the other hand, in step S204, when it is determined that the longitudinal gradient θ is greater than or equal to the first threshold value θth1 (step S204: YES), the traveling ECU 14 proceeds to step S205.

[0077] In step S205, the traveling ECU 14 sets a threshold value Hht for the height H0 of the gradient road surface. That is, the traveling ECU 14 sets the threshold value Hth based on the height H0 of the front bumper 2a and the like.

[0078] In the subsequent step S206, the traveling ECU 14 checks whether the height H of the gradient road surface is greater than or equal to the threshold value Hth.

[0079] And, in step S206, when it is determined that the height H of the gradient road surface is less than the threshold value Hth (step S206: NO), the traveling ECU 14 exits the routine as it is. That is, when the height H of the gradient road surface is less than the threshold value Hth, the traveling ECU 14 determines that the front bumper 2a is less likely to interfere with the gradient road surface and that there is no need to perform vehicle body control with respect to the gradient road surface.

[0080] On the other hand, in step S206, when it is determined that the height H of the gradient road surface is greater than or equal to the threshold value Hth, (step S206: YES), the traveling ECU 14 proceeds to step S207. Note that in the present embodiment, the determination that the height H of the gradient road surface is greater than or equal to the threshold value Hth includes cases where it is difficult to recognize the height H of the gradient road surface due to reasons such as the gradient road surface continuing to a distance.

[0081] In step S207, the driving ECU 14 sets a second threshold value θth2 for the longitudinal gradient θ. That is, the driving ECU 14 sets the second threshold value θth2 based on the approach angle θ0 of the host vehicle O and the displacement amount of the height of the front bumper 2a that is displaced due to pitching of the vehicle body 2 or the like.

[0082] In the subsequent step S208, the driving ECU 14 checks whether the longitudinal gradient θ of the road surface is equal to or greater than the second threshold value θth2.

[0083] And, in step S208, when it is determined that the longitudinal gradient θ of the road surface is less than the second threshold value θth2 (step S208: YES), the driving ECU 14 proceeds to step S211.

[0084] On the other hand, in step S208, when it is determined that the longitudinal gradient θ is equal to or greater than the second threshold value θth2 (step S208: NO), the driving ECU 14 proceeds to step S209. That is, when it is determined that the longitudinal gradient θ is equal to or greater than the second threshold value θth2, the driving ECU 14 determines that it is difficult to avoid interference between the front bumper 2a and the gradient road surface even if vehicle body control is performed.

[0085] And, when proceeding from step S208 to step S209, the driving ECU 14 outputs an alarm using, for example, the display 31 and the speaker 32. By outputting this alarm, the driving ECU 14 notifies the driver that there is a high possibility that the front bumper 2a will interfere with the gradient road surface.

[0086] In the subsequent step S210, after performing stop control on the host vehicle O, the driving ECU 14 exits the routine.

[0087] Also, when proceeding from step S201 or step S208 to step S211, the driving ECU 14 checks whether the gradient road surface entry flag F is set to "1".

[0088] And, in step S211, when it is determined that the gradient road surface entry flag F is set to "1" (step S211: YES), the traveling ECU 14 proceeds to step S217.

[0089] On the other hand, in step S211, when it is determined that the gradient road surface entry flag F is cleared to "0" (step S211: NO), the traveling ECU 14 proceeds to step S212.

[0090] In step S212, the traveling ECU 14 sets the gradient road surface entry flag F to "1".

[0091] In the subsequent step S213, the traveling ECU 14 checks whether the host vehicle O is in the process of braking.

[0092] And, in step S213, when it is determined that the host vehicle O is not in the process of braking (step S213: NO), the traveling ECU 14 proceeds to step S215.

[0093] On the other hand, in step S213, when it is determined that the host vehicle O is in the process of braking (step S213: YES), the traveling ECU 14 proceeds to step S214.

[0094] In step S214, the traveling ECU 14 switches the braking that was being performed using the brake 6f of the front wheel 5f and the brake 6r of the rear wheel 5r to braking using only the brake 6r of the rear wheel 5r. That is, the traveling ECU 14 releases the braking force generated by the brake 6f of the front wheel 5f. At the same time, the traveling ECU 14 causes the braking force of the released brake 6f of the front wheel 5f to be generated by the brake 6r of the rear wheel 5r. Thereby, the traveling ECU 14 maintains the braking of the host vehicle O using only the brake 6r of the rear wheel 5r.

[0095] When proceeding from step S213 or step S214 to step S215, the traveling ECU 14 calculates the entry angle α of the front wheel 5f when the host vehicle O enters the gradient road surface. That is, the traveling ECU 14 refers to a preset map or the like and calculates the entry angle α of the front wheel 5f with respect to the gradient road surface.

[0096] In the subsequent step S216, the traveling ECU 14 calculates the brake start position for vehicle body control with respect to the gradient road surface. That is, the traveling ECU 14 calculates the brake start position for generating a braking force on the brake 6f of the front wheel 5f based on the start position of the gradient road surface, the vehicle speed V of the host vehicle O, and the like.

[0097] When proceeding from step S211 or step S217 to step S218, the traveling ECU 14 checks whether the current position of the host vehicle O is the brake start position (brake start timing t1: refer to FIG. 17) with respect to the gradient road surface.

[0098] And in step S217, when it is determined that the current position of the host vehicle O is not the brake start position (step S217: NO), the traveling ECU 14 proceeds to step S219.

[0099] On the other hand, in step S217, when it is determined that the current position of the host vehicle O is the brake start position (step S217: YES), the traveling ECU 14 proceeds to step S218.

[0100] In step S218, after operating the brake 6f of the front wheel 5f with a predetermined brake hydraulic pressure, the traveling ECU 14 proceeds to step S219. That is, the traveling ECU 14 operates the brake 6f of the front wheel 5f to sink the front bumper 2a of the vehicle body 2 downward.

[0101] When proceeding from step S217 or step S218 to step S219, the traveling ECU 14 checks whether the brake 6f of the front wheel 5f is in operation.

[0102] And, in step S219, when it is determined that the brake 6f of the front wheel 5f is not in operation (step S219: NO), the traveling_ECU 14 proceeds to step S222.

[0103] On the other hand, in step S219, when it is determined that the brake 6f of the front wheel 5f is in operation (step S219: YES), the traveling_ECU 14 proceeds to step S220.

[0104] In step S220, the traveling_ECU 14 checks whether it is the release timing t2 of the brake 6f of the front wheel 5f (see FIG. 17). That is, the traveling_ECU 14 checks whether it is the timing at which the front bumper 2a has sufficiently sunk downward due to the operation of the brake 6. Note that the determination of whether it is the release timing of the brake 6f can be made, for example, by whether a set time has elapsed since the brake 6f was operated. Regarding this set time, it is possible to use a fixed value, but it is also possible to use a variable value according to the vehicle speed V of the host vehicle O, the value of the braking force by the brake 6f, and the like.

[0105] And, in step S220, when it is determined that it is not the release timing of the brake 6f (step S220: NO), the traveling_ECU 14 proceeds to step S222.

[0106] On the other hand, in step S220, when it is determined that it is the release timing of the brake 6f (step S220: YES), the traveling_ECU 14 proceeds to step S221.

[0107] In step S221, after the traveling_ECU 14 releases the braking force of the brake 6f of the front wheel 5f, it proceeds to step S222. That is, the traveling_ECU 14 releases the braking force of the brake 6f to push up the front bumper 2a upward by utilizing the swaying of the vehicle body 2. Thereby, the traveling_ECU 14 controls the behavior of the vehicle body so that the height of the front bumper 2a becomes maximum at the timing t3 (see FIG. 17) when the host vehicle O reaches the gradient road surface.

[0108] When proceeding from step S219, step S220, or step S221 to step S222, the traveling ECU 14 checks whether it is the steering timing for the front wheels 5f. That is, the traveling ECU 14 checks, for example, whether it is the timing immediately before the front wheels 5f enter the gradient road surface.

[0109] And in step S222, when it is determined that it is not the steering timing for the front wheels 5f (step S222: NO), the traveling ECU 14 proceeds to step S224.

[0110] On the other hand, in step S222, when it is determined that it is the steering timing for the front wheels 5f (step S222: YES), the traveling ECU 14 proceeds to step S223.

[0111] In step S223, after the traveling ECU 14 controls the actual steering angle of the front wheels 5f based on the entry angle α, it proceeds to step S224. That is, the traveling ECU 14 performs control to set the actual steering angle of the front wheels 5f to the entry angle α independently of the steering angle detected by the steering angle sensor 37.

[0112] When proceeding from step S222 or step S223 to step S224, the traveling ECU 14 checks whether the left and right front wheels 5f have entered the gradient road surface.

[0113] And in step S224, when it is determined that the left and right front wheels 5f have not entered the gradient road surface (step S224: NO), the traveling ECU 14 exits the routine as it is.

[0114] On the other hand, in step S224, when it is determined that the left and right front wheels 5f have entered the gradient road surface (step S224: YES), the traveling ECU 14 proceeds to step S225.

[0115] In step S225, after the traveling ECU 14 returns the actual steering angle control for the front wheels 5f from the actual steering angle control based on the entry angle α to the actual steering angle control according to the steering angle detected by the steering angle sensor 37, it proceeds to step S226.

[0116] In step S226, the traveling ECU 14 checks whether or not braking is being performed using the brake 6r of the rear wheels 5r.

[0117] And, in step S226, if it is determined that braking is not being performed using the brake 6r (step S226: NO), the traveling ECU 14 proceeds to step S228.

[0118] On the other hand, in step S226, if it is determined that braking is being performed using the brake 6r (step S226: YES), the traveling ECU 14 proceeds to step S227.

[0119] In step S227, the traveling ECU 14 switches the braking being performed using the brake 6r of the rear wheels 5r to braking using the brake 6f of the front wheels 5f and the brake 6r of the rear wheels 5r. That is, the traveling ECU 14 releases a part of the braking force generated by the brake 6r of the rear wheels 5r. At the same time, the traveling ECU 14 causes the braking force of the released brake 6r of the rear wheels 5r to be generated by the brake 6f of the front wheels 5f. Thereby, the traveling ECU 14 maintains the braking of the host vehicle O using the brake 6f of the front wheels 5f and the brake 6r of the rear wheels 5r.

[0120] When proceeding from step S226 or step S227 to step S228, the traveling ECU 14 clears the gradient road surface entry flag F to "0" and then exits the routine.

[0121] According to such an embodiment, the traveling_ECU 14 recognizes a gradient road surface having a positive longitudinal gradient θ with respect to the road surface on which the host vehicle O is currently traveling in the traveling direction of the host vehicle O, and determines whether or not the bottom surface of the front bumper 2a (vehicle body 2) interferes with the gradient road surface when the host vehicle O enters the gradient road surface. When it is determined that the bottom surface of the front bumper 2a interferes with the gradient road surface, the traveling_ECU 14 generates a braking force with respect to the brake 6f of the front wheel 5f immediately before the host vehicle O enters the gradient road surface, and releases the braking force generated in the brake 6f. Thereby, interference between the bottom surface of the vehicle body 2 and the gradient on the road surface can be suppressed.

[0122] That is, the traveling_ECU 14 concentrates the inertial force of the vehicle body 2 during the traveling of the host vehicle O on the front wheel 5f side by generating a braking force in the brake 6f of the front wheel 5f. Thereby, the traveling_ECU 14 generates pitching that causes the front part of the vehicle body 2 to sink downward. Further, the traveling_ECU 14 releases the braking force generated in the brake 6f in a state where the front part of the vehicle body 2 has sunk sufficiently, thereby generating a rocking-back of the vehicle body 2. Thereby, the traveling_ECU 14 generates pitching that pushes up the front part of the vehicle body 2 upward at the timing when the vehicle body 2 enters the gradient road surface. Thereby, the front bumper 2a of the vehicle body 2 enters the gradient road surface at an angle larger than the approach angle θ0. Therefore, interference between the bottom surface of the vehicle body 2 and the gradient on the road surface can be suppressed.

[0123] Also, when it is determined that the bottom surface of the front bumper 2a interferes with the gradient road surface, the traveling_ECU 14 performs actual steering angle control so as to incline the entry direction Di of the front wheel 5f when the host vehicle O enters the gradient road surface with respect to the maximum inclination direction Dt of the gradient road surface. Thereby, interference between the bottom surface of the vehicle body 2 and the gradient on the road surface can be suppressed.

[0124] That is, the traveling ECU 14 performs steering control so that the actual steering angle of the front wheel 5f with respect to the maximum inclination direction Dt of the gradient road surface becomes α. Thereby, the traveling ECU 14 can relax the effective inclination angle of the gradient road surface with respect to the front bumper 2a and suppress the interference between the front bumper 2a and the gradient road surface.

[0125] Here, in the above-described embodiment, as vehicle body control for suppressing the interference between the front bumper 2a and the gradient road surface, an example of using both braking control for generating temporary braking force for the brake 6f of the front wheel 5f and steering angle control for the front wheel 5f using the approach angle α has been described. On the other hand, it is also possible to realize vehicle body control for suppressing the interference between the front bumper 2a and the gradient road surface by using only either one of the braking control or the steering angle control.

[0126] Further, in the above-described embodiment, an example of recognizing a gradient road surface based on the distance image information acquired using the stereo camera 11 has been described. On the other hand, for example, it is also possible to recognize a gradient road surface based on the distance information at a plurality of locations on the road acquired by the distance measuring sensor 15. In this case, for example, as shown in FIG. 18, the distance measuring sensor 15 detects the distance information not only below the vehicle body 2 but also in a plurality of diagonal front directions of the vehicle body 2.

[0127] Here, in the above-described embodiments, all or part of the image recognition ECU 13, the driving ECU 14, the CP ECU 21, the BK ECU 22, the PS ECU 23, etc. are constituted by a processor including hardware. Here, the processor is constituted by, for example, a well-known configuration including a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), a non-volatile memory, a non-volatile storage device, etc., and peripheral devices thereof. Fixed data such as software programs and data tables executed by the CPU and the like are stored in advance in the ROM, the non-volatile memory, the non-volatile storage device, etc. Then, the CPU reads out the software program stored in the ROM or the like, expands it in the RAM, and executes it. Also, by appropriately referring to various data and the like by the software program, the functions of the above-described respective components and constituent units are realized.

[0128] Further, the processor may be constituted by a semiconductor chip such as a field programmable gate array (FPGA). Also, the above-described respective components and constituent units may be constituted by an electronic circuit.

[0129] Furthermore, the software program may be in a form in which all or part of it is recorded on a portable plate medium such as a flexible disk, a CD-ROM, a DVD-ROM, or a non-transitory computer readable medium such as a card type memory, a hard disk drive (HDD) device, or a solid state drive (SSD) device as a computer program product.

[0130] The invention described in the above embodiments is not limited to those embodiments, and various modifications can be made without departing from the gist thereof at the implementation stage. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

[0131] For example, even if some constituent elements are deleted from all the constituent elements shown in the above embodiments, if the described problems can be solved and the described effects can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention.

Explanation of Reference Numerals

[0132] 1... Driving assistance device 2... Vehicle body 2a... Front bumper 5... Wheels (5f... Front wheels, 5r... Rear wheels) 6... Brakes (6f... Front wheel brakes, 6r... Rear wheel brakes) 7f... Front suspension 7r... Rear suspension 10... Camera unit 11... Stereo camera 11a... Main camera 11b... Sub camera 13... Image recognition ECU 14... Driving ECU 15... Distance measuring sensor 16... Longitudinal and lateral acceleration sensors 21... CP ECU 22... BK ECU 23... PS ECU 31... Display 32... Speaker 33... Brake actuator 34... Wheel speed sensor 35... Brake pedal switch 36... Electric power steering motor 37... Steering angle sensor O... vehicle (own vehicle)

Claims

1. Gradient road surface recognition means for recognizing a gradient road surface having a positive longitudinal gradient with respect to the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle; Interference determination means for determining whether or not the bottom surface of the vehicle body interferes with the gradient road surface when the host vehicle enters the gradient road surface; When it is determined that the bottom surface of the vehicle body interferes with the gradient road surface, braking control means for generating a braking force with respect to the brakes of the front wheels of the host vehicle and releasing the braking force immediately before the host vehicle enters the gradient road surface; A vehicle driving support device, characterized by comprising the above.

2. The vehicle driving support device according to claim 1, further comprising steering angle control means for tilting the entry direction of the front wheels when the host vehicle enters the gradient road surface with respect to the maximum inclination direction of the gradient road surface when it is determined that the bottom surface of the vehicle body interferes with the gradient road surface.

3. The vehicle driving support device according to claim 1, wherein when a braking force is being generated in the host vehicle, the braking control means maintains the braking force using the brakes of the rear wheels at a set distance before the host vehicle enters the gradient road surface.

4. Gradient road surface recognition means for recognizing a gradient road surface having a positive longitudinal gradient with respect to the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle; Interference determination means for determining whether or not the bottom surface of the vehicle body interferes with the gradient road surface when the host vehicle enters the gradient road surface; Steering angle control means for tilting the entry direction of the front wheels when the host vehicle enters the gradient road surface with respect to the maximum inclination direction of the gradient road surface when it is determined that the bottom surface of the vehicle body interferes with the gradient road surface; A vehicle driving support device, characterized by comprising the above.

5. Comprising a processor, The processor is, Recognize a gradient road surface having a positive longitudinal gradient with respect to the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle, When the host vehicle enters the gradient road surface, determine whether the bottom surface of the vehicle body interferes with the gradient road surface, When it is determined that the bottom surface of the vehicle body interferes with the gradient road surface, generate a braking force on the brakes of the front wheels of the host vehicle and release the braking force immediately before the host vehicle enters the gradient road surface, A vehicle driving support device characterized by the above.

6. Equipped with a processor, The processor is, Recognize a gradient road surface having a positive longitudinal gradient with respect to the road surface on which the host vehicle is currently traveling in the traveling direction of the host vehicle, When the host vehicle enters the gradient road surface, determine whether the bottom surface of the vehicle body interferes with the gradient road surface, When it is determined that the bottom surface of the vehicle body interferes with the gradient road surface, tilt the entry direction of the front wheels when the host vehicle enters the gradient road surface with respect to the maximum inclination direction of the gradient road surface, A vehicle driving support device characterized by the above.

Images