Vehicle driving assistance device

Abstract

To provide a drive support device of a vehicle that can perform appropriate drive support control without giving a feeling of strangeness and a feeling of discomfort to a driver.SOLUTION: The drive support device of a vehicle comprises: surrounding situation information obtaining devices 21 and 23 that obtain surrounding situation information around the vehicle; a steering angle detection sensor 15 that detects a steering angle and a steering direction of the vehicle; and a travelling control part 24 that includes a steering support control part 11 that performs travelling control accompanying steering support control on the basis of respective output information pieces from the surrounding situation information obtaining devices and the steering angle detection sensor, and integrally performs controls of the whole of the vehicle. The steering support control part determines a tendency of deviation of the vehicle from a travelling lane on the basis of the output information pieces from the surrounding situation information obtaining devices and the steering angle detection sensor, and when determining that the vehicle has a lane departure tendency and also recognizing an opposing vehicle, sets a new lane-keeping target travelling route, at a position at which a lateral distance from the opposing vehicle is larger.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a driving assistance device for a vehicle that performs lane keeping control and lane departure prevention control to assist a driver in driving. [Background technology]

[0002] In recent years, development of automatic driving control technology for vehicles such as automobiles that allows the vehicle to travel automatically without the need for driver operation has been progressing. In addition, various driving assistance devices that utilize this type of automatic driving control technology to perform various controls to assist the driver in driving operations have been proposed and are becoming generally put into practical use.

[0003] Among conventional driving assistance devices, for example, there are some that are equipped with an Active Lane Keeping (ALK) driving control function that constantly recognizes the vehicle's surroundings using various sensor devices, etc., and keeps the vehicle traveling along the lane it is traveling in based on the various information data acquired.

[0004] In addition, some conventional driving assistance devices are equipped with a lane departure prevention (LDP) control function that, when it is determined that the vehicle is tending to deviate from the lane in which it is traveling, intervenes a predetermined steering assistance control as appropriate to prevent the vehicle from deviating from the lane in which it is traveling or to suppress lane departure.

[0005] Generally, on roads on which vehicles travel, such as general roads that do not have a central median or other three-dimensional structure in the middle of the road, there are various obstacles, such as curbs, guardrails, side walls (including snow walls on snowy roads), utility poles, and other three-dimensional structures located at the boundary between the roadway and the sidewalk, as well as other vehicles parked or stopped on the side of the road (shoulder), other vehicles stopped on the left or right of the vehicle's lane (own lane) just before an intersection and attempting to turn right or left, and road cones installed to restrict road construction or to separate the lane from other construction areas.

[0006] Here, these various obstacles are collectively referred to as "objects to be avoided." Such objects to be avoided may impede the travel of a vehicle, so the vehicle must avoid collisions with these obstacles. Therefore, on this type of general road, the area in which a vehicle can travel is determined by the presence of the various obstacles.

[0007] Therefore, in order for a vehicle equipped with a conventional driving assistance device to continue driving reliably and safely on the road while performing lane keeping control and lane departure prevention control, it is required to recognize the situation around the vehicle (such as the situation of obstacles on the road) and constantly recognize the area in which the vehicle can travel.

[0008] Furthermore, especially on public roads where there are no three-dimensional structures such as central medians, the vehicle's driving assistance device must also recognize the presence of other vehicles traveling in the oncoming lane and vehicles parked or stopped in the oncoming lane (hereinafter collectively referred to as vehicles in the oncoming lane) as surrounding conditions and take these into consideration when controlling the vehicle's driving.

[0009] To this end, in conventional driving assistance devices, various proposals have been made, for example in Patent Publication Nos. 2018-158709, 2020-149527, and 2018-106243, regarding technologies for recognizing the surrounding conditions of a vehicle while it is traveling on a road and appropriately controlling the vehicle's driving in accordance with the recognized surrounding conditions.

[0010] The driving assistance device disclosed in the above-mentioned Patent Publication No. 2018-158709, etc., takes into account the distance between the vehicle and surrounding obstacles or oncoming vehicles, recognizes the area in which the vehicle can travel between the vehicle and surrounding obstacles or oncoming vehicles, and if the area in which the vehicle can travel is confirmed, generates a driving route for the vehicle to travel and guides the driving operations of the driver of the vehicle.

[0011] The driving assistance device disclosed in the above-mentioned Patent Publication No. 2020-149527, etc., takes into account the distance between the vehicle and surrounding obstacles or oncoming vehicles, and provides driving assistance by notifying the driver to avoid contact with surrounding objects or oncoming vehicles.

[0012] The driving assistance device disclosed in the above-mentioned Patent Publication No. 2018-106243 and the like provides driving assistance by notifying the driver of the surrounding conditions when passing an oncoming vehicle, taking into account the distance between the vehicle and the oncoming vehicle. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japanese Patent Application Publication No. 2018-158709 [Patent Document 2] Japanese Patent Publication No. 2020-149527 [Patent Document 3] Japanese Patent Application Publication No. 2018-106243 Summary of the Invention [Problem to be solved by the invention]

[0014] Generally, when a vehicle is traveling on a general road or the like that does not have a three-dimensional structure such as a median strip, and there is a vehicle in the oncoming lane, the closer the lateral distance between the vehicle and the oncoming vehicle, the more likely the driver is to feel intimidated or oppressed by the oncoming vehicle. Therefore, in such a situation, the driver may steer the vehicle in a direction that moves it laterally away from the oncoming vehicle.

[0015] In this case, the direction away from the vehicle on the oncoming lane is the direction opposite the oncoming lane, i.e., the direction toward the shoulder. Specifically, the direction opposite the oncoming lane corresponds to the left side area of ​​the road, for example, in the case of a road with left-hand traffic regulations. An object to be avoided may exist in the direction of this area (the direction opposite the oncoming lane; the shoulder).

[0016] For this reason, in the above-mentioned situation, if the driver, while traveling, is aware of the presence of a vehicle in the oncoming lane and steers in a direction to avoid the vehicle in the oncoming lane, that is, toward the opposite side of the oncoming lane (shoulder), the vehicle will head in the direction opposite the oncoming lane (shoulder). At this time, the driving assistance device of the vehicle will respond to the object to be avoided that exists on the shoulder, and in some cases, may activate lane keeping control or lane departure prevention control.

[0017] However, in this situation, the steering performed by the driver is the result of a driving maneuver performed to avoid the oncoming vehicle due to a sense of intimidation or pressure from the oncoming vehicle, and therefore the driver recognizes the steering as a necessary driving maneuver.

[0018] However, the lane departure prevention control that may be activated in response to such steering is a control that intervenes to correct the steering in the direction of the oncoming lane, contrary to the driver's intended steering (steering toward the opposite side of the oncoming lane (toward the shoulder)). Therefore, such intervention of the lane departure prevention control is a behavior that is not intended by the driver, and there is a problem in that the driver feels strange or uncomfortable.

[0019] Conventional driving assistance devices disclosed in the above-mentioned Patent Publications No. 2018-158709, No. 2020-149527, No. 2018-106243, etc., only take into account the distance between the vehicle and surrounding obstacles or oncoming vehicles, and set the vehicle's driving route according to the surrounding conditions, or notify the driver of the surrounding conditions, but do not particularly consider driving control in the event that, for example, the driver steers in a direction that deviates from the set driving route.

[0020] An object of the present invention is to provide a driving assistance device for a vehicle that can perform more appropriate driving assistance control without causing discomfort or annoyance to the driver. [Means for solving the problem]

[0021] In order to achieve the above object, a driving assistance device for a vehicle is capable of performing at least lane keeping driving control for driving a vehicle along a driving lane and lane departure prevention control for preventing the vehicle from deviating from the driving lane, and includes a surrounding situation information acquisition device for acquiring surrounding situation information of the vehicle, a steering angle detection sensor for detecting the steering angle and steering direction of the vehicle, and a driving control unit that performs driving control with steering assist control based on output information from the surrounding situation information acquisition device and the steering angle detection sensor, and that performs overall control of the vehicle as a whole, wherein the steering assist control unit determines a tendency of the vehicle to deviate from the driving lane towards the shoulder based on output information from the surrounding situation information acquisition device and the steering angle detection sensor, and when it is determined that the vehicle has a tendency to deviate from the lane, and a vehicle is recognized in an oncoming lane based on output information from the surrounding situation information acquisition device, A timing for starting lane departure prevention control that prevents the vehicle from departing from the driving lane is delayed to set a lane departure prevention target driving path for the vehicle, and when it is determined that the vehicle is not prone to deviating from its lane and a vehicle is recognized in an oncoming lane based on output information from the surrounding situation information acquisition device, A new lane-keeping target driving route for the vehicle is set at a position that is laterally farther away from the vehicle in the oncoming lane. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a driving assistance device for a vehicle that can perform more appropriate driving assistance control without causing discomfort or annoyance to the driver. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a vehicle equipped with a driving assistance device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram showing the schematic configuration of a camera unit and a cruise control unit (MCU) in a driving assistance device according to an embodiment of the present invention. [Figure 3] 1 is a flowchart (first half) showing the operation of a driving assistance device according to an embodiment of the present invention. [Figure 4] 1 is a flowchart (second half) showing the operation of a driving assistance device according to an embodiment of the present invention. [Figure 5]FIG. 1 is a conceptual diagram illustrating a situation in which lane keeping control is performed in a driving assistance device according to an embodiment of the present invention. [Figure 6] FIG. 1 is a conceptual diagram illustrating a situation in which lane departure prevention control intervenes in a driving assistance device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be described below with reference to the illustrated embodiments. The drawings used in the following description are schematic, and the dimensional relationships and scales of the components may be different for each component in order to show each component at a size that allows it to be recognized on the drawing. Therefore, the present invention is not limited to the illustrated embodiments in terms of the number of components shown in the drawings, the shapes of the components, the size ratios of the components, the relative positional relationships of the components, and so on.

[0025] A driving assistance device according to one embodiment of the present invention is a device that is mounted on a vehicle such as an automobile and that executes driving assistance control to assist the driver of the vehicle in driving operations. The driving assistance device according to this embodiment acquires information about the surrounding conditions of the vehicle using various sensor devices, such as an image sensor of a camera unit or a radar sensor of a radar device. These various sensor devices are autonomous sensor devices that operate autonomously.

[0026] Here, information about the surrounding conditions of the vehicle refers to information about various objects to be avoided that exist around the vehicle while it is moving, such as a preceding vehicle, a following vehicle, an oncoming vehicle, a vehicle traveling alongside the vehicle, other vehicles including motorcycles, pedestrians, bicycles, and other moving objects, as well as various three-dimensional structures such as curbs, guardrails, side walls, and utility poles, and stationary objects such as other vehicles parked or stopped on the side of the road (shoulder). Hereinafter, information about the surrounding conditions of the vehicle will be referred to as surrounding condition information, etc. As described above, this surrounding condition information is acquired using various sensor devices.

[0027] The driving assistance device of this embodiment appropriately uses surrounding situation information, etc. acquired using various sensor devices, etc. as information when executing driving assistance control to assist the driving operation of the driver of the vehicle.

[0028] Examples of driving assistance control executed by the driving assistance device of this embodiment include active lane keeping (ALK) driving control and lane departure prevention (LDP) control.

[0029] The schematic configuration of a driving assistance device according to one embodiment of the present invention will be described below with reference to Figures 1 and 2. Figure 1 is a block diagram showing the schematic configuration of a vehicle equipped with a driving assistance device according to one embodiment of the present invention. Figure 2 is a block diagram showing the schematic configuration of a camera unit and a cruise control unit (MCU) in the driving assistance device according to one embodiment of the present invention.

[0030] As described above, the driving assistance device 1 of this embodiment is a device mounted on a vehicle M such as an automobile. The driving assistance device 1 basically has substantially the same configuration as conventional driving assistance devices of the same type. Therefore, in FIGS. 1 and 2, only the components of the driving assistance device 1 of this embodiment that are directly related to the present invention are shown, and components that are not directly related to the present invention are not shown. In the following description, detailed description of components other than those directly related to the present invention will be omitted, assuming that they are substantially the same as those of conventional driving assistance devices, and only the components directly related to the present invention will be described in detail below.

[0031] As shown in FIG. 1, the driving assistance device 1 of this embodiment is configured to include a camera unit 21 and a radar device 23, which are surrounding situation information acquisition devices, a driving control unit 24, which is a driving control unit including a steering assistance control unit 11, an electric power steering (EPS) device 6 (hereinafter abbreviated as the EPS device 6), and the like.

[0032] As shown in Figures 1 and 2, the camera unit 21 is composed of a stereo camera consisting of a main camera 22a and a sub-camera 22b, and is composed of an on-board camera 22 which is an ambient condition acquisition sensor and an autonomous sensor device, an image processing unit (IPU) 21c (not shown in Figure 1; hereinafter abbreviated as IPU21c) connected to the on-board camera 22 (22a, 22b), and an image recognition processing unit 21d (not shown in Figure 1) to which the IPU21c is connected.

[0033] The vehicle-mounted camera 22 is installed, for example, in a position above and in front of the rearview mirror at the front of the vehicle interior of the vehicle M, close to the inner surface of the windshield of the vehicle M. In this case, the two cameras (22a, 22b) of the vehicle-mounted camera 22 are arranged horizontally at approximately equal intervals on the left and right sides of the center position in the vehicle width direction of the vehicle M.

[0034] The on-board camera 22 is, for example, an autonomous sensor device that senses the real space ahead of the vehicle M and acquires image information of the surrounding conditions mainly ahead of the vehicle M. As described above, the main camera 22a and the sub-camera 22b of the on-board camera 22 are arranged at symmetrical positions on either side of the center in the vehicle width direction. As a result, the on-board camera 22 acquires two sets of image data obtained by capturing an area of ​​a predetermined range ahead of the vehicle M from different viewpoints using the two cameras (22a, 22b).

[0035] The IPU 21c is a circuit unit that performs predetermined image processing based on two sets of image data acquired by the on-board cameras 22 (22a, 22b). That is, the IPU 21c generates stereo image information (three-dimensional image information) based on the two sets of image data acquired by the on-board cameras 22 (22a, 22b), and generates image information (hereinafter referred to as distance image information) containing distance information calculated from the amount of positional deviation between the two images of the same object captured in each of the two sets of image data. The distance image information generated in this manner is sent to the image recognition processing unit 21d.

[0036] The image recognition processing unit 21d receives distance image information and the like transmitted from the IPU 21c, and functions as a surrounding situation recognition processing unit that recognizes the surrounding situation of the vehicle M based on the distance image information and the like.

[0037] The image recognition processing unit 21d, for example, recognizes the lane dividing lines that separate the left and right lane of the road on which the vehicle M is traveling, and obtains various information such as the road curvature [1 / m] of each of the left and right lane dividing lines and the width between the left and right lane dividing lines (lane width).

[0038] Furthermore, the image recognition processing unit 21d performs predetermined pattern matching and the like based on the distance image information to recognize various three-dimensional objects (objects to be avoided), such as curbs, guardrails, side walls, utility poles, etc. that exist along the road, as well as other vehicles, including pedestrians, bicycles, and motorcycles, that exist on the road on which the vehicle M is traveling. Here, the recognition of objects performed by the image recognition processing unit 21d includes the acquisition of various information, such as the type of object, the distance to the object, the moving speed of the object, and the relative speed between the object and the vehicle M.

[0039] In this way, in the driving assistance device 1 of this embodiment, the camera unit 21 functions as a surrounding situation information acquisition device that recognizes the surrounding situation of the vehicle M based on image data of the surrounding situation acquired by the on-board camera 22, which is an autonomous sensor device serving as a surrounding situation acquisition sensor, and acquires it as surrounding situation information.

[0040] The cruise control unit 24 is configured by a processor including hardware configured by a well-known microcontroller unit (MCU) and its peripheral devices, which includes, for example, a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), non-volatile memory, non-volatile storage, and non-transitory computer readable medium. The ROM, non-volatile memory, non-volatile storage, etc. store software programs executed by the MCU and fixed data such as data tables. The MCU reads the software programs stored in the ROM, etc., expands them into the RAM, and executes them. The software programs appropriately refer to various data, etc., to realize the predetermined functions of the constituent units, etc., of the driving assistance device 1 of this embodiment.

[0041] The processor may be configured with a semiconductor chip such as an FPGA (Field Programmable Gate Array).The software program may be in a form in which the whole or part of the software program is recorded as a computer program product on a portable storage medium such as a flexible disk, CD-ROM, or DVD-ROM, or on a non-transitory computer readable medium such as a card-type memory, HDD (Hard Disk Drive), or SSD (Solid State Drive).

[0042] Various component units including various sensor devices such as the camera unit 21 described above and the radar device 23 described later are connected to the cruise control unit (MCU) 24. As a result, the cruise control unit 24 controls the operating conditions of the various connected component units, receives detection results (surrounding situation information) from the various sensor devices, performs predetermined cruise control as appropriate, and comprehensively controls the entire driving assistance device 1 of this embodiment.

[0043] In addition, various sensor devices for recognizing the surrounding conditions of vehicle M include, for example, the on-board camera 22 included in the camera unit 21 described above and the radar sensors (23fl, 23fr, 23rl, 23rr) included in the radar device 23 described later, as well as, for example, a vehicle speed sensor 13 that detects the current vehicle speed of vehicle M by detecting the rotational speed of each of the front, rear, left and right wheels of vehicle M, a lateral acceleration sensor or yaw rate sensor 14 that detects the yaw rate and lateral acceleration of vehicle M, a steering angle detection sensor 15 that detects the steering angle of vehicle M, a gyro sensor (not shown) that detects the angular velocity or angular acceleration of vehicle M, and a GNSS (Global Navigation Satellite System) receiver (not shown) that receives positioning signals transmitted from multiple positioning satellites.

[0044] The driving assistance device 1 of this embodiment is provided with a radar device 23 as a surrounding situation information acquisition device, as shown in Fig. 2. The radar device 23 is connected to a cruise control unit 24, acquires data on the surrounding situation, performs predetermined processing, and outputs the data to the cruise control unit 24 as recognition data in a predetermined format including the surrounding situation information.

[0045] The radar device 23 is configured with a plurality of radar sensors. The radar device 23 illustrated in this embodiment is an example configuration in which the vehicle M is equipped with four radar sensors. Here, the plurality (four) radar sensors include, for example, a left front-side radar sensor 23fl, a right front-side radar sensor 23fr, a left rear-side radar sensor 23rl, and a right rear-side radar sensor 23rr.

[0046] Of the four radar sensors (23fl, 23fr, 23rl, 23rr) in the radar device 23, the left front-side radar sensor 23fl and the right front-side radar sensor 23fr are provided, for example, on the left and right sides, respectively, of the front bumper of the vehicle M. These left front-side radar sensor 23fl and right front-side radar sensor 23fr recognize objects in areas diagonally forward and to the left and right of the vehicle M that cannot be recognized by the two image data acquired by the on-board cameras 22 (22a, 22b). Note that a portion of each of the areas recognized by the left front-side radar sensor 23fl and the right front-side radar sensor 23fr is set to overlap a portion of each of the areas recognized by the on-board cameras 22 (22a, 22b). As a result, the on-board camera 22 (22a, 22b), the left front side radar sensor 23fl, and the right front side radar sensor 23fr can recognize almost the entire area from the left and right sides near the front of the vehicle M to the front.

[0047] Of the four radar sensors (23fl, 23fr, 23rl, 23rr) in the radar device 23, the left rear-side radar sensor 23rl and the right rear-side radar sensor 23rr are provided, for example, on the left and right sides of the rear bumper of the vehicle M. These left rear-side radar sensor 23rl and right rear-side radar sensor 23rr recognize objects in an area extending from the left and right sides toward the rear of the vehicle M, which cannot be recognized by the above-mentioned left front-side radar sensor 23fl and right front-side radar sensor 23fr. Note that the areas recognized by the left rear-side radar sensor 23rl and the right rear-side radar sensor 23rr are set to partially overlap each other. As a result, the left rear-side radar sensor 23rl and the right rear-side radar sensor 23rr can recognize almost the entire area extending from the left and right sides toward the rear of the vehicle M.

[0048] In this case, the radar device 23 recognizes the position and relative speed of three-dimensional objects (objects to be avoided) in front of, behind, and on the left and right sides of the vehicle M, as well as the size of the three-dimensional objects, and functions as a surrounding situation information acquisition device that acquires information about the surrounding situation of the vehicle M.

[0049] Information about three-dimensional objects recognized by the radar device 23 is input to the cruise control unit 24. In response to this, the cruise control unit 24 recognizes as three-dimensional objects other vehicles around the vehicle M, such as other preceding vehicles in front, other vehicles running parallel to the left and right sides, other following vehicles behind, and other intersecting vehicles approaching the vehicle M from a direction intersecting the path of travel of the vehicle M at an intersection, as well as various moving bodies around the vehicle M, such as pedestrians and bicycles.

[0050] As the radar device 23, for example, a millimeter wave radar device, a laser radar device, a LiDAR (Light Detection and Ranging) device, or the like is applied.

[0051] On the other hand, the cruise control unit 24 is configured to include a steering assist control unit 11. Here, the steering assist control unit 11 is configured by, for example, an electronic circuit formed in the cruise control unit 24.

[0052] In addition, instead of being provided within the driving control unit 24 as described above, the steering assist control unit 11 may also be configured by a processor including hardware that is separate and independent from the driving control unit 24.

[0053] The steering assist control unit 11 in the driving assist device 1 of this embodiment performs driving control involving steering assist control, such as lane keeping driving control and lane departure prevention control, among various controls that can be executed by the driving assist device 1 of this embodiment. To this end, the steering assist control unit 11 has, for example, a lane keeping driving control unit (hereinafter referred to as ALK_ECU) 11a and a lane departure prevention control unit (hereinafter referred to as LDP_ECU) 11b.

[0054] The ALK_ECU 11a is a control unit that contributes to steering assist control (lane keeping control) for stably driving the vehicle M within the driving lane. Here, the lane keeping driving control is driving control that recognizes the left and right dividing lines of the driving lane in which the vehicle M is traveling, as well as three-dimensional structures and the like (objects to be avoided such as curbs, guardrails, side walls, utility poles, etc.) that exist in the surroundings based on the surrounding conditions mainly in front and to the sides of the vehicle M recognized by surrounding condition acquisition sensors such as the on-board camera 22 of the camera unit 21 and the radar sensors (23fl, 23fr, 23rl, 23rr) of the radar device 23, and includes steering control for driving the vehicle M along the center of the left and right dividing lines.

[0055] The LDP_ECU 11b is also a control unit that contributes to steering assist control (lane departure prevention control) that assists the driver in steering when avoiding a dangerous situation that the vehicle M may encounter while traveling, such as a collision or contact between the vehicle M and an obstacle on the road while traveling. Here, the lane departure prevention control recognizes the surrounding conditions of the vehicle M, mainly in front and to the sides, of the lane in which the vehicle M is traveling, as well as the left and right dividing lines of the lane in which the vehicle M is traveling, as well as surrounding three-dimensional structures and the like (objects to be avoided, such as curbs, guardrails, side walls, and utility poles), based on the surrounding conditions mainly in front and to the sides of the vehicle M recognized by surrounding condition acquisition sensors such as the on-board camera 22 of the camera unit 21 and the radar sensors (23fl, 23fr, 23rl, 23rr) of the radar device 23, and when it is determined that the traveling direction of the vehicle M tends to deviate from the lane, it controls the steering torque and intervenes a predetermined steering control to make the vehicle M parallel to the left and right dividing lines, thereby preventing the vehicle M from deviating from the lane or suppressing the lane departure.

[0056] The configurations of the ALK_ECU 11a and the LDP_ECU 11b applied to the driving assistance device 1 of this embodiment are substantially the same as those applied to conventional driving assistance devices of the same type, etc. Therefore, further detailed description of the configurations of these control units will be omitted.

[0057] Here, the EPS device 6 is a component unit for intervening predetermined steering assist control at predetermined timing as needed.

[0058] As shown in FIG. 1, vehicle M has left and right front wheels FL, FR and left and right rear wheels RL, RR, and the left and right front wheels FL, FR are connected to a steering mechanism 2 consisting of a rack and pinion mechanism or the like via tie rods 3. Also, a steering shaft 5 having a handlebar 4 fixed to its tip is connected to the steering mechanism 2. With this configuration, when the driver operates the handlebar 4, the left and right front wheels FL, FR are steered via the steering shaft 5 and steering mechanism 2. In this way, the steering mechanism of vehicle M is made up of the steering mechanism 2, tie rods 3, handlebar 4, steering shaft 5, etc. Note that a steering mechanism of this type has a configuration substantially similar to that of steering mechanisms generally provided in conventional vehicles such as automobiles.

[0059] The EPS device 6 acts on the steering shaft 5 in such a steering mechanism. The EPS device 6 is configured to include an EPS motor 7, an EPS control unit (EPS_ECU) 8, a steering torque sensor 12, and the like.

[0060] In addition to the EPS_ECU 8, the driving control unit 24, the camera unit 21, etc., the vehicle M also includes various control units (not shown) that control the driving state of the vehicle, such as a drive source control unit that controls a drive source such as an engine or an electric motor, a transmission control unit, a brake control unit, etc. These various control units are connected to each other via an in-vehicle network using a CAN (Controller Area Network) communication 10 or the like, for free two-way communication.

[0061] The EPS motor 7 of the EPS device 6 is connected to the steering shaft 5 via a transmission mechanism (not shown). The EPS_ECU 8 controls the steering torque applied to the steering shaft 5 by the EPS motor 7.

[0062] The steering torque sensor 12 is a sensor device that detects the steering torque applied to the steering wheel 4 as the amount of driving operation by the driver. For this purpose, the steering torque sensor 12 is attached to the steering shaft 5. The steering torque sensor 12 is connected to the EPS_ECU 8. As a result, the detection result of the steering torque sensor 12 is output to the EPS_ECU 8.

[0063] The EPS_ECU 8 sets a torque (assist torque) that assists the steering torque applied by the driver to the steering wheel 4, according to various data such as the steering torque detected by the steering torque sensor 12 and the speed of the vehicle M detected by a vehicle speed sensor 13 (described later). By applying the assist torque to the steering shaft 5, the burden on the driver in operating the steering wheel is reduced, and steering assistance is provided to the driver.

[0064] In addition, the driving control unit 24 is connected to sensor devices that detect the behavior of the vehicle M, such as a vehicle speed sensor 13 that detects the vehicle speed, a yaw rate sensor 14 that detects the yaw rate and lateral acceleration generated in the vehicle body, and a steering angle detection sensor 15 that detects the steering angle and steering direction from the rotation angle of the steering shaft 5.

[0065] The ALK_ECU 11a and LDP_ECU 11b in the cruise control unit 24 receive outputs from the various sensor devices described above and execute cruise control including predetermined steering control as appropriate. The schematic configuration of the driving assistance device 1 of this embodiment has been described above.

[0066] Next, the actions of the driving assistance device of this embodiment when lane keeping control and lane departure prevention control are performed will be described below with reference to Figures 3 to 6. Figures 3 and 4 are flowcharts showing the actions of the driving assistance device of one embodiment of the present invention when mainly lane keeping control and lane departure prevention control are performed. Note that Figure 3 shows the first half of the flowchart, and Figure 4 shows the second half of the flowchart.

[0067] Fig. 5 is a diagram conceptually showing a situation when lane keeping control is performed in a driving assistance device according to an embodiment of the present invention. Fig. 6 is a diagram conceptually showing a situation when lane departure prevention control intervenes in a driving assistance device according to an embodiment of the present invention.

[0068] In the following description of this embodiment, a road system based on left-hand traffic where vehicles are allowed to drive on the left side is exemplified as shown in Figures 5 and 6. Therefore, the configuration of the present invention can be easily applied to a road system based on right-hand traffic by simply switching the left and right. In the following description of this embodiment, the terms "left" and "right" refer to the left and right when facing an object.

[0069] First, consider a situation in which a vehicle M (hereinafter referred to as the host vehicle M) equipped with a driving assistance device 1 according to one embodiment of the present invention is traveling on an ordinary road without a three-dimensional structure such as a median strip while executing lane keeping driving control. At this time, the host vehicle M is in a state in which it can further execute lane departure prevention control at any time (i.e., a standby state for lane departure prevention control). In this case, the driving control unit 24 in the driving assistance device 1 of the host vehicle M while traveling continuously receives a signal from the steering torque sensor 12. Therefore, for example, when the steering torque sensor 12 detects a steering torque generated by a steering operation (steering) by the driver of the host vehicle M, the driving control unit 24 appropriately executes a predetermined driving control based on the received detection result of the steering torque.

[0070] Here, for example, assume the situations shown in Figures 5 and 6. Details will be described later, but the outline of the example situation shown in Figure 5 assumes the following situation. That is, for example, this is an example of lane keeping control that is performed when the driver of the host vehicle M, who is executing lane keeping control, is aware of an oncoming vehicle (M1 or M2) or a vehicle parked or stopped in the oncoming lane (not shown; in the following description, oncoming vehicles that are traveling and vehicles parked or stopped in the oncoming lane will be abbreviated as "vehicles on the oncoming lane") and steers the vehicle in a direction to avoid the vehicle on the oncoming lane (for example, see symbol M1 or M2), i.e., to the left (towards the shoulder), and it is determined that the host vehicle M is not prone to deviating from its lane.

[0071] Furthermore, the outline of the example situation shown in Figure 6 is an example of when, for example, the driver of vehicle M, while performing lane keeping driving control, becomes aware of a vehicle (M1 or M2, etc.) in the oncoming lane and steers in a direction to avoid the vehicle in the oncoming lane, i.e., to the left (towards the shoulder), and it is determined that vehicle M is prone to deviating from its lane, and lane departure prevention control intervenes.

[0072] 5 and 6, the lane in which the host vehicle M is traveling is indicated by reference numeral 201 (hereinafter referred to as the host lane 201). Reference numeral 202 indicates an oncoming lane that is provided adjacent to and parallel to the host lane 201. Reference numeral 203 indicates a road centerline that is a dividing line that separates the host lane 201 from the oncoming lane 202. In this case, the road centerline 203 is indicated by a white dashed line. Also, it is assumed that a curb 204 or the like is provided along the host lane 201 on the left side edge (hereinafter referred to as the shoulder side) of the host lane 201. Similarly, in the oncoming lane 202, a curb 204 or the like is provided on the shoulder side of oncoming vehicles (M1, M2; described in detail later) traveling in the oncoming lane 202.

[0073] The host vehicle M traveling on such a road travels within the host lane 201 by lane keeping driving control as described above. At this time, the driving assistance device 1 of the host vehicle M sets a lane keeping target driving path (a virtual line indicated by reference numeral 205; a two-dot chain line) at a predetermined position on the host lane 201, and executes driving control to make the host vehicle M travel along the lane keeping target driving path 205. This lane keeping target driving path 205 is a virtual line that is set in consideration of the surrounding conditions of the host vehicle M. Normally, the lane keeping target driving path 205 is set at approximately the center position of the host lane 201.

[0074] 5 and 6, oncoming vehicles traveling in the oncoming lane 202 are indicated by the symbols M1 and M2. In the following description, the term "oncoming vehicle" refers to, for example, not only oncoming vehicles traveling indicated by the symbols M1 and M2 in the figures, but also vehicles parked and stopped on the oncoming lane (not shown). Therefore, in the following description, the terms "oncoming vehicle," "oncoming vehicle M1," "oncoming vehicle M2," "oncoming vehicles (M1, M2)," etc., can be replaced with "vehicles parked and stopped on the oncoming lane" or "vehicles on the oncoming lane," etc., and can be considered the same. In this case, the oncoming vehicle M1 indicated by the dashed line in FIGS. 5 and 6 is traveling on the oncoming lane 202 along the lane keeping target traveling path 205x set at approximately the center of the oncoming lane 202.

[0075] At this time, the distance between the host vehicle M and the oncoming vehicle M1 (the distance in the lateral direction relative to the traveling direction of each vehicle M, M1, i.e., the distance in the vehicle width direction) is indicated by the lateral distance G1 between, for example, an extension line 206a (shown by a dashed line in FIGS. 5 and 6) in the traveling direction along the right side of the host vehicle M and an extension line 206b (shown by a dashed line in FIGS. 5 and 6) in the traveling direction along the right side of the oncoming vehicle M1. The range in which the host vehicle M can travel (drivable range) at this time is indicated by symbol R1a. Furthermore, symbol R1b indicates half of the drivable range (drivable range / 2). Note that the drivable range is indicated here by the distance in the lateral direction relative to the traveling direction of the host vehicle M, i.e., the distance in the vehicle width direction. In other words, the drivable range here refers to the distance in the width direction in which the host vehicle M can travel.

[0076] On the other hand, the oncoming vehicle M2 shown by the dashed line in Figures 5 and 6 is traveling in a position close to the road center line 203 on the oncoming lane 202. Note that the example shown in Figures 5 and 6 shows a case in which the oncoming vehicle M2 crosses the road center line 203 and travels with part of its body protruding into the traveling lane of the host vehicle M (host lane 201).

[0077] At this time, the distance between the host vehicle M and the oncoming vehicle M2 (the distance laterally with respect to the traveling direction of each vehicle, i.e., the distance in the vehicle width direction) is indicated by the lateral distance G2 between, for example, a line 206a (shown by a dashed line in FIGS. 5 and 6) along the right side of the host vehicle M and an extension line 206c (shown by a dashed line in FIGS. 5 and 6) in the traveling direction along the right side of the oncoming vehicle M2. The range in which the host vehicle M can travel (drivable range) at this time is indicated by the symbol R2a. The symbol R2b indicates half of the drivable range (drivable range / 2). Note that the drivable range in this case is also indicated by the distance laterally with respect to the traveling direction of the host vehicle M, i.e., the distance in the vehicle width direction. In other words, the drivable range here refers to the distance in the width direction in which the host vehicle M can travel.

[0078] 5 and 6 do not indicate that the oncoming vehicles M1 and M2 are simultaneously present at the positions shown in the drawings on the road, but are depicted on the same drawing to indicate the difference in the lateral (vehicle width) positional relationship between the vehicle M and each of the oncoming vehicles M1 and M2. In this case, the longitudinal (vehicle travel direction) positional relationship between the vehicle M and each of the oncoming vehicles M1 and M2 is depicted shifted in the front-to-rear direction to avoid cluttering the drawing and avoiding overlapping on the drawing. Therefore, the longitudinal (vehicle travel direction) positional relationship between the vehicle M and each of the oncoming vehicles M1 and M2 is not limited to the depicted illustration.

[0079] In such a situation, the cruise control unit 24 in the driving assistance device 1 of the host vehicle M checks whether or not the host vehicle M is tending to deviate from the driving lane (host lane 201) in which the host vehicle M is currently traveling in step S11 in Fig. 3. Here, the determination of whether or not the host vehicle M is tending to deviate from the lane is made based on the output result of the steering angle detection sensor 15.

[0080] For example, if the output result (steering angle) of the steering angle detection sensor 15 does not exceed a predetermined value, it can be assumed that the host vehicle M is traveling along the predicted traveling route indicated by reference numeral 207aa (two-dot chain line) in Fig. 5. Here, the predicted traveling route 207aa indicates that it will intersect with a departure determination lateral position imaginary line 208 (dotted line) set in advance within the host vehicle lane 201 after a relatively long predetermined time (the situation in Fig. 5).

[0081] This means that it can be estimated that even if the host vehicle M continues traveling while maintaining the current steering angle (which does not exceed the predetermined value), it will take a relatively long predetermined time before it deviates from the host vehicle lane 201. In other words, it can be determined that the host vehicle M is not in a situation where it is likely to deviate within the predetermined time. Therefore, in this case, the driving assistance device 1 determines that the host vehicle M is not prone to deviating from the lane (the situation in FIG. 5).

[0082] On the other hand, for example, when the output result (steering angle) of the steering angle detection sensor 15 exceeds a predetermined value, it can be assumed that the host vehicle M is traveling along the predicted traveling route indicated by the reference symbol 207ab (two-dot chain line) shown in Fig. 6. Here, the predicted traveling route 207ab indicates that the host vehicle M will intersect with a departure determination lateral position imaginary line 208 (dotted line) set in advance within the host vehicle lane 201 within a relatively short predetermined time (the situation in Fig. 6).

[0083] This means that if the host vehicle M continues traveling while maintaining the current steering angle (exceeding the predetermined value), it can be estimated that the host vehicle M will deviate from the host vehicle lane 201 within a relatively short predetermined time. In other words, it can be determined that the host vehicle M is in a situation where it is likely to deviate within the predetermined time. Therefore, in this case, the driving assistance device 1 determines that the host vehicle M has a tendency to deviate from the lane (the situation in FIG. 6).

[0084] The deviation determination lateral position virtual line 208 is a virtual line that is set along the shoulder side (for example, the curb 204) of the own vehicle lane 201 at a position a predetermined distance away from the shoulder side (for example, the curb 204) toward the own vehicle lane 201. When the travel path of the own vehicle M is expected to deviate further toward the shoulder side than the deviation determination lateral position virtual line 208, it is determined that the own vehicle M is prone to deviating from the lane.

[0085] 3, if it is determined in the processing of step S11 that the host vehicle M is in a situation where it is likely to deviate from the host vehicle lane 201, the process proceeds to the next step S12. In this case, in the processing steps after step S12, lane departure suppression control intervenes, and a predetermined driving route is set appropriately in accordance with the surrounding conditions (the situation in FIG. 6).

[0086] On the other hand, if it is determined in the processing of step S11 that the vehicle M is not in a situation where it is likely to deviate from the lane 201, the process proceeds to the processing of step S21 in Fig. 4 (see circle 4 in Fig. 3 and Fig. 4). In this case, in the processing steps after step S21 in Fig. 4, a predetermined driving route is set appropriately according to the surrounding conditions by lane keeping driving control (the situation in Fig. 5).

[0087] First, if it is determined in the processing of step S11 that the host vehicle M is in a situation where it is likely to deviate from the host vehicle lane 201 (the situation in FIG. 6), the process proceeds to the processing of step S12. In this step S12, the cruise control unit 24 checks whether or not an oncoming vehicle (M1 or M2) has been recognized based on the output information of the surrounding situation information acquisition device (22, 23, etc.). If an oncoming vehicle (M1 or M2) has been recognized, the process proceeds to the next step S13. If an oncoming vehicle (M1 or M2) has not been recognized, the process proceeds to the processing of step S16.

[0088] In this situation, the oncoming vehicles recognized by the driving assistance device 1 of the host vehicle M are shown as symbols M1 and M2 in Fig. 6. In the situation assumed in this case, the oncoming vehicle recognized by the host vehicle M is assumed to be either symbol M1 or M2. In addition, a situation in which an oncoming vehicle is not recognized is not shown, but a situation in which the oncoming vehicle (M1 or M2) in Fig. 6 does not exist is assumed.

[0089] Next, in step S13, the cruise control unit 24 checks the estimated time to collision (TTC) for the recognized oncoming vehicle based on the output information of the surrounding situation information acquisition device (22, 23, etc.), and determines whether the estimated time to collision (TTC) is within 3 seconds (TTC≦3 seconds). In this case, the estimated time to collision (TTC) is a value (sec.) obtained by dividing the distance (m) between the host vehicle M and the recognized oncoming vehicle (M1 or M2) in the longitudinal direction (the direction of vehicle travel) by the relative speed (m / sec.) between the host vehicle M and the recognized oncoming vehicle (M1 or M2).

[0090] In this step S13, when it is confirmed that TTC ≤ 3 seconds, it can be estimated that the longitudinal (travel direction) distance between the host vehicle M and the oncoming vehicle (M1 or M2) is relatively close. Therefore, in this case (TTC ≤ 3 seconds), the process proceeds to the next step S14. Also, when it is confirmed that TTC > 3 seconds, it can be estimated that the longitudinal (travel direction) distance between the host vehicle M and the oncoming vehicle (M1 or M2) is relatively far apart. Therefore, in this case (TTC > 3 seconds), the process proceeds to the step S16.

[0091] In step S14, the travel control unit 24 checks whether the lateral distance (G1 or G2) between the host vehicle M and the oncoming vehicle (M1 or M2) is narrower than half (R1b or R2b) of the travelable range (R1a or R2a). Here, when the lateral distance (G1 or G2) between the host vehicle M and the oncoming vehicle (M1 or M2) is narrower than half (R1b or R2b) of the travelable range (R1a or R2a), the process proceeds to the next step S15. Also, when the lateral distance between the host vehicle M and the oncoming vehicle is wider than half of the travelable range, the process proceeds to the step S16.

[0092] In this case, for example, when the host vehicle M shown in FIG. 6 recognizes the oncoming vehicle M1, the lateral distance between the host vehicle M and the oncoming vehicle M1 is the symbol G1. The travelable range (lateral distance) at this time is the symbol R1a. And half of the travelable range is the symbol R1b. Therefore, in this case, the determination in the process of step S14 refers to G1 < R1b.

[0093] Also, for example, when the host vehicle M shown in FIG. 6 recognizes the oncoming vehicle M2, the lateral distance between the host vehicle M and the oncoming vehicle M2 is the symbol G2. The travelable range (lateral distance) at this time is the symbol R2a. And half of the travelable range is the symbol R2b. Therefore, in this case, the determination in the process of step S14 refers to G2 < R2b.

[0094] In the above example, the criterion for the determination made in the processing of step S14 (determination of switching between normal control and oncoming vehicle control) is whether the lateral distance (G1 or G2) between the host vehicle M and the oncoming vehicle (M1 or M2) is smaller than half the driving range. However, the determination criterion used in the processing of step S14 is not limited to the exemplified means.

[0095] For example, in addition to or instead of the above-mentioned criteria, the means may acquire lateral distance information from the vehicle to the curb, etc. 204 based on information acquired by a surrounding situation information acquisition device, and use as the criterion whether the acquired lateral distance information is equal to or less than a predetermined threshold value.

[0096] In this case, if the lateral distance (G1 or G2) between the host vehicle M and the oncoming vehicle (M1 or M2) is less than a predetermined threshold, lane departure prevention control is performed to a position away from the oncoming vehicle (step S15), and if the lateral distance exceeds the predetermined threshold, normal lane departure prevention control is performed (step S16).

[0097] 3, in the next step S15, the cruise control unit 24 performs control to generate a new lane departure prevention target driving path at a position where the host vehicle M is away from the oncoming vehicle M2. To achieve this, for example, the cruise control unit 24 executes processing to delay the start timing of the lane departure prevention control. Thereafter, the process returns to step S11, and the lane keeping driving control is continued.

[0098] For example, in Fig. 6, the driving route indicated by reference symbol 207b represents the lane departure prevention target driving route during normal control. The control start timing in this case is the time indicated by reference symbol T1. Also, in Fig. 6, the driving route indicated by reference symbol 207c represents the lane departure prevention target driving route during oncoming vehicle response control. The control start timing in this case is the time indicated by reference symbol T2. And, reference symbol TM in Fig. 6 represents the difference in the start timing of both controls.

[0099] In this way, when the driver intentionally steers the vehicle M and the vehicle is in a situation where it is likely to deviate from its own lane 201, the timing to start lane departure prevention control is delayed by a predetermined time indicated by the symbol TM in Figure 6.

[0100] As a result, the lane departure prevention control does not immediately intervene, so the driver does not feel any discomfort or annoyance, and at the same time, the lane departure prevention target driving path 207c set at this time is set at a position laterally distant from the oncoming vehicle M2. In other words, the lateral distance between the host vehicle M and the oncoming vehicle M2 is set to be greater than the distance between the host vehicle M and a three-dimensional structure such as a curb 204 (a surrounding obstacle on the shoulder side of the road).

[0101] Therefore, the host vehicle M behaves in accordance with the driver's steering intention, while appropriate steering intervention is performed through lane departure prevention control. Then, the driving assistance device 1 of the host vehicle M performs driving control along the newly set lane departure prevention target driving path 207c to avoid or suppress lane departure. Therefore, the host vehicle M performs lane departure prevention control while traveling at a position laterally separated from the oncoming vehicle M2 in accordance with the driver's steering. In this way, lane departure of the host vehicle M is avoided, and the host vehicle M travels at the position indicated by symbol Ma in FIG. 6. Thereafter, although not shown in the drawing, when the oncoming vehicle M2 is no longer recognized, driving control is performed to return the host vehicle M to the original lane keeping target driving path 205.

[0102] The above example shows an example in which the control start timing is delayed to generate a new lane departure prevention target driving path 207c that passes closer to the shoulder than usual, but the present invention is not limited to this example.

[0103] For example, a new target driving route that passes through a position closer to the shoulder than the target driving route 207b during normal control may be generated using a well-known means that performs predetermined calculations using various situational data of the vehicle M, such as the vehicle's driving speed and lateral acceleration.

[0104] On the other hand, if the process proceeds from each of steps S12, S13, and S14 to step S16, the cruise control unit 24 executes normal lane departure suppression control in step S16. Also, in this case, if an oncoming vehicle has been recognized, and the oncoming vehicle is no longer recognized, cruise control is executed to return the host vehicle M to the original lane keeping target travel path 205. Thereafter, the process returns to step S11, and lane keeping travel control is continued.

[0105] The normal lane departure suppression travel control executed here is executed, for example, at the start timing indicated by reference symbol T1 in Fig. 6. In this case, as described above, It is determined that the vehicle is likely to depart from the lane (Y in step S11), and If an oncoming vehicle is not recognized (N in step S12), Or, even if an oncoming vehicle is recognized (Y in step S12), if TTC > 3 seconds (N in step S13), Or, even if TTC≦3 seconds (Y in step S13), if the driving range / 2≦lateral distance to the oncoming vehicle (N in step S14), This is either of the following cases.

[0106] In other words, the driver's steering is causing the vehicle M to deviate from its lane, and the detected steering is If the driver did not act as a result of recognizing an oncoming vehicle (possibly unconsciously or distracted), Or, when the oncoming vehicle recognized by the driver is located at a sufficient distance in the longitudinal direction (direction of travel), Or, if the oncoming vehicle recognized by the driver is located at a sufficient distance in the lateral direction (vehicle width direction), It can be assumed that the situation is as follows.

[0107] Therefore, in such a case, even if the lane departure prevention control is intervened in accordance with the driver's steering timing, it is possible to reduce the sense of incongruity or discomfort felt by the driver. Furthermore, since the lane departure prevention control in this case is initiated relatively early after the steering, a gradual lane departure prevention target driving path 207b can be set. Therefore, the host vehicle M can suppress or avoid lane departure without any sudden behavior (see symbol Ma in FIG. 6).

[0108] On the other hand, if it is determined in the processing of step S11 in Figure 3 described above that the vehicle M is unlikely to deviate from the vehicle's lane 201, the process proceeds to step S21 in Figure 4, and as described above, in the processing steps after step S21, a predetermined driving route is set appropriately according to the surrounding conditions by lane keeping driving control.

[0109] In step S21 of Fig. 4, the cruise control unit 24 performs the same process as step S12 described above. That is, the cruise control unit 24 checks whether an oncoming vehicle (M1 or M2) has been recognized. If an oncoming vehicle (M1 or M2) has been recognized, the process proceeds to the next step S22. If an oncoming vehicle (M1 or M2) has not been recognized, the process proceeds to step S25.

[0110] In this situation, symbols M1 and M2 in FIG. 5 are shown as examples of oncoming vehicles recognized by the driving assistance device 1 of the host vehicle M, as in the situation in FIG. 6 described above (step S12 in FIG. 3). That is, the oncoming vehicle recognized by the host vehicle M in the situation assumed in this case is assumed to be either symbol M1 or M2. In addition, a situation in which an oncoming vehicle is not recognized is not shown, but a situation in which the oncoming vehicle (M1 or M2) in FIG. 5 does not exist is assumed.

[0111] Subsequently, in step S22 of FIG. 4, the travel control unit 24 performs the same process as step S13 described above. That is, it checks the time to collision (TTC) for the recognized oncoming vehicle, and determines whether the time to collision (TTC) is within 3 seconds (TTC≤3 seconds).

[0112] In this step S22, if it is confirmed that TTC≤3 seconds, it can be estimated that the longitudinal (travel direction) distance between the host vehicle M and the oncoming vehicle (M1 or M2) is relatively approaching. Therefore, in this case (TTC≤3 seconds), the process proceeds to the next step S23. Also, if it is confirmed that TTC>3 seconds, it can be estimated that the longitudinal (travel direction) distance between the host vehicle M and the oncoming vehicle (M1 or M2) is relatively far apart. Therefore, in this case (TTC>3 seconds), the process proceeds to step S25.

[0113] In step S23, the travel control unit 24 performs the same process as step S14 described above. That is, in step S23, the travel control unit 24 checks whether the lateral distance (G1 or G2) between the host vehicle M and the oncoming vehicle (M1 or M2) is narrower than half (R1b or R2b) of the travelable range (R1a or R2a). Here, if the lateral distance (G1 or G2) between the host vehicle M and the oncoming vehicle (M1 or M2) is narrower than half (R1b or R2b) of the travelable range (R1a or R2a), the process proceeds to the next step S24. Also, if the lateral distance between the host vehicle M and the oncoming vehicle is wider than half of the travelable range, the process proceeds to step S25.

[0114] In this case, for example, when the host vehicle M shown in FIG. 5 recognizes the oncoming vehicle M1, the lateral distance between the host vehicle M and the oncoming vehicle M1 is the symbol G1. The travelable range (lateral distance) at this time is the symbol R1a. And half of the travelable range is the symbol R1b. Therefore, in this case, the determination in the process of step S23 refers to G1<R1b.

[0115] Also, for example, when the host vehicle M shown in FIG. 5 recognizes the oncoming vehicle M2, the lateral distance between the host vehicle M and the oncoming vehicle M2 is the sign G2. The drivable range (lateral distance) at this time is the sign R2a. And one half of the drivable range is the sign R2b. Therefore, in this case, the determination in the process of step S23 refers to G2 < R2b.

[0116] Returning to FIG. 4, in the next step S24, the travel control unit 24 performs control to generate a new lane-keeping target travel route at a position where the host vehicle M is away from the oncoming vehicle M2. For this purpose, for example, in FIG. 5, the travel control unit 24 sets a new lane-keeping target travel route 205a at a predetermined position closer to the road shoulder side than the lane-keeping target travel route 205 that has been set at a substantially central position within the host lane 201.

[0117] Here, the lateral distance between the host vehicle M and the oncoming vehicle (M1 or M2) is set to be larger than the distance between the host vehicle M and a three-dimensional structure such as a curb 204 (a surrounding obstacle on the road shoulder side). Then, the travel control unit 24 executes control to make the host vehicle M travel along this new lane-keeping target travel route 205a (see the sign Ma in FIG. 5). After that, although not shown in the figure, when the oncoming vehicle is no longer recognized, travel control is performed to return the host vehicle M to the original lane-keeping target travel route 205. Then, the process returns to the process of step S11 in FIG. 3, and the lane-keeping travel control is continued.

[0118] On the other hand, when proceeding from the processes of steps S21, S22, and S23 described above to the process of step S25, in step S25, the travel control unit 24 executes normal lane-keeping travel control. Also, here too, when an oncoming vehicle has been recognized and then the oncoming vehicle is no longer recognized, travel control is performed to return the host vehicle M to the original lane-keeping target travel route 205. Then, the process returns to the process of step S11 in FIG. 3, and the lane-keeping travel control is continued.

[0119] The normal lane keeping driving control executed here is, for example, driving control along the lane keeping target driving path 205 shown in Fig. 5. The situation at this time is when it is determined that the vehicle is unlikely to deviate from the lane, as described above (N in step S11 in Fig. 3). Therefore, at this time, the host vehicle M may be traveling at a position slightly deviated toward the shoulder from the lane keeping target driving path 205 that the host vehicle M is currently traveling on, in response to steering to the left. Therefore, here, steering intervention is performed to correct the deviation from the lane keeping target driving path 205, and driving control is performed to return the host vehicle to the lane keeping target driving path 205. In this way, lane keeping driving control is continuously performed.

[0120] As described above, according to the above embodiment, when a host vehicle M equipped with a vehicle driving assistance device 1 capable of performing at least lane keeping driving control to cause the host vehicle M to drive along the driving lane (host lane 201) and lane departure prevention control to prevent the host vehicle M from deviating from the driving lane (host lane 201) is driving on a public road that does not have a three-dimensional structure such as a central median while performing lane keeping driving control, if the driver steers to the left (towards the shoulder) while being aware of an oncoming vehicle (M1 or M2), and it is determined that the host vehicle M is unlikely to deviate from the host lane 201, a new lane keeping target driving path 205a can be set as the lane keeping target driving path for the lane keeping driving control to a position laterally away to the left (towards the shoulder) from the lane keeping target driving path 205, which is approximately in the center of the host lane 201. Here, the lateral distance between the host vehicle M and the oncoming vehicle (M1 or M2) is set to be greater than the distance between the host vehicle M and a three-dimensional structure such as a curb 204 (a surrounding obstacle on the shoulder side of the road).

[0121] On the other hand, under similar circumstances, if it is determined that the host vehicle M is in a situation where it is likely to deviate from the host vehicle lane 201, control is performed to delay the start timing of the lane departure prevention control. As a result, a new lane departure prevention target driving path 207c can be set at a position further to the left (toward the shoulder) in the lateral direction than the lane departure prevention target driving path 207b set by the normal lane departure prevention control. Here, the lateral distance between the host vehicle M and the oncoming vehicle (M1 or M2) is set to be greater than the distance between the host vehicle M and a three-dimensional structure (surrounding obstacle on the shoulder side) such as a curb 204.

[0122] In this way, with the driving assistance device 1 of this embodiment, even if the driver is aware of the presence of an oncoming vehicle and steers in a direction (towards the shoulder) to avoid the oncoming vehicle, it is possible to prevent the lane departure prevention control from immediately intervening against the driver's intention. At the same time, by appropriately performing lane keeping control or lane departure prevention control according to the driver's intention, it is possible to perform more appropriate driving assistance control without causing the driver any sense of incongruity or discomfort.

[0123] The present invention is not limited to the above-described embodiments, and various modifications and applications can be made without departing from the spirit and scope of the invention. Furthermore, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the disclosed multiple constituent elements. For example, if the problem to be solved by the invention can be solved and the effects of the invention can be obtained even if some constituent elements are deleted from all the constituent elements shown in one embodiment, the configuration from which these constituent elements are deleted can be extracted as the invention. Furthermore, constituent elements from different embodiments may be appropriately combined. The present invention is not limited by specific embodiments other than as limited by the appended claims. [Explanation of symbols]

[0124] 1...Driving assistance device 2...Steering mechanism 3...Tie rod 4...Handle 5...Steering axis 6...Electric power steering (EPS) device 7...EPS motor 10...CAN communication 11...Steering assist control unit 11a...Lane keeping control unit (ALK_ECU) 11b...Lane Departure Prevention Control Unit (LDP_ECU) 12...Steering torque sensor 13...Vehicle speed sensor 14...Yaw rate sensor 15...Steering angle detection sensor 21...Camera unit 21c...Image Processing Unit (IPU) 21d...Image recognition processing section 22...In-car camera 22a...Main camera 22b...Sub camera 23...Radar equipment 23fl...Left front side radar sensor 23fr...Right front side radar sensor 23rl...Left rear side radar sensor 23rr...Right rear side radar sensor 24...Drive control unit 201…own lane 202...Oncoming traffic 203...Road center line 204...Curb 205, 205x...Lane keeping target driving route 205a...New lane keeping target driving path (when controlling for oncoming vehicles) 206a...extension of the right side of the vehicle 206b...extension of the right side of the oncoming vehicle M1 206c...extension of the right side of the oncoming vehicle M2 207aa...Predicted driving route (small steering angle) 207ab…Predicted driving route (large steering angle) 207b...Lane departure prevention target driving route (normal) 207c...Lane departure prevention target driving path (when controlling for oncoming vehicles) 208...Departure judgment horizontal position virtual line FL, FR…Left and right front wheels RL, RR…Left and right rear wheels G1: Lateral distance between your vehicle and oncoming vehicle M1 G2: Lateral distance between your vehicle and oncoming vehicle M2 M, Ma...own vehicle M1, M2...Oncoming vehicles R1a: Driving range for oncoming vehicle M1 R1b: Half the driving range for oncoming vehicle M1 R2a: Driving range for oncoming vehicle M2 R2b: Half the driving range for oncoming vehicle M2 T1: Lane Departure Prevention Driving Control Start Timing (Normal) T2: Lane departure prevention driving control start timing (when controlling for oncoming vehicles) TM: Control delay time

Claims

1. A driving assistance device for a vehicle that can perform at least lane keeping control to keep the vehicle in a driving lane and lane departure prevention control to prevent the vehicle from deviating from the driving lane, a surrounding situation information acquisition device for acquiring surrounding situation information of the vehicle; a steering angle detection sensor for detecting a steering angle and a steering direction of the vehicle; a driving control unit that includes a steering assist control unit that performs driving control including steering assist control based on output information from the surrounding situation information acquisition device and the steering angle detection sensor, and that performs overall control of the vehicle; Equipped with The steering assist control unit determines a tendency of the vehicle to deviate from the driving lane toward the shoulder based on output information from the surrounding situation information acquisition device and the steering angle detection sensor, and when it is determined that the vehicle is prone to deviating from the lane and a vehicle is recognized in the oncoming lane based on the output information from the surrounding situation information acquisition device, delaying a start timing of lane departure prevention control that prevents the vehicle from departing from the driving lane, and setting a lane departure prevention target driving route for the vehicle; When it is determined that the vehicle is not prone to deviating from its lane and a vehicle is recognized on the opposite lane based on the output information of the surrounding situation information acquisition device, A vehicle driving assistance device, characterized in that a new lane keeping target driving path of the vehicle is set at a position that increases the lateral distance from the vehicle in the oncoming lane.

2. The steering assist control unit further detects a lateral distance between the vehicle and a vehicle on the oncoming lane and a lateral driving range of the vehicle based on output information from the surrounding situation information acquisition device, When setting the lane keeping target driving path or the lane departure prevention target driving path of the vehicle, if the lateral distance between the vehicle and a vehicle on the oncoming lane is narrower than half of the lateral travelable range of the vehicle, 2. The vehicle driving assistance device according to claim 1, wherein the lateral distance between the vehicle and a vehicle on the oncoming lane is set to be greater than the distance between the vehicle and an object to be avoided on the opposite side of the oncoming lane in the lateral direction.

Images