Vehicle driving assistance device

Abstract

To provide a drive support device of a vehicle that performs travelling control in accordance with steering that is intentionally performed by a driver and performs appropriate drive support control without giving a feeling of strangeness and a feeling of discomfort to the driver.SOLUTION: The drive support device of a vehicle comprises: surrounding situation information obtaining devices 21 and 23; a steering torque sensor 12; a steering angle detection sensor 15; and a travelling control part 24 including 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, the steering torque sensor and the steering angle detection sensor. The travelling control part, when steering torque is detected, generates a new lane-keeping target travelling route or a prescribed lane-departure suppression target travelling route, in accordance with an amount of steering torque, a steering angle and a steering direction, and when the steering torque is re-detected within a predetermined time, sets the new lane- keeping target travelling route or the prescribed lane-departure suppression target travelling route.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] 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, if there is an object to be avoided, such as a vehicle in the oncoming lane or a side wall, the closer the lateral distance between the vehicle and the object to be avoided, the stronger the sense of intimidation or oppression the driver feels from the object to be avoided. For this reason, the driver may be conscious of the object to be avoided and try to drive in a position that is further away from the object to be avoided in the lateral direction. In this case, the driver may steer the vehicle in a direction that is further away from the object to be avoided. Note that, when actually traveling on a road, some drivers tend to drive in a position that is closer to the shoulder than the center of the lane they are traveling in, regardless of whether or not there is a vehicle in the oncoming lane.

[0010] In conventional driving assistance devices for vehicles, during lane keeping control, the vehicle is typically controlled to travel along a driving path (lane keeping target driving path) set approximately in the center of the lane in which the vehicle is traveling. In this case, if the driver, aware of the presence of an object to be avoided, such as a vehicle in an oncoming lane or a side wall, intentionally steers the vehicle in a direction away from the object to be avoided, the vehicle will deviate from the set lane keeping target driving path. In this case, the driving assistance device may activate driving control, i.e., lane keeping control or lane departure prevention control, to return the vehicle that has deviated from the lane keeping target driving path back to the lane keeping target driving path.

[0011] However, at this time, as described above, the driver is intentionally steering the vehicle to change the driving route while being aware of the object to be avoided. Therefore, the vehicle behavior caused by the lane keeping control or lane departure prevention control that may be activated in response to the driver's intentional steering is unintended by the driver. This poses a problem in that the driver may feel uncomfortable or uneasy.

[0012] Therefore, in conventional driving assistance devices, various technologies have been proposed, such as in JP 2010-36852 A and JP 11-91606 A, which switch to driving control that takes into account the driver's intentions when an intentional steering input by the driver is detected while lane keeping driving control or lane departure prevention control is being executed.

[0013] The driving assistance device disclosed in the above-mentioned JP 2010-36852 A and the like, when a vehicle is traveling with lane keeping control and lane departure prevention control being executed, detects a steering input in a direction that strengthens the tendency for the vehicle to depart from the lane, for example, when the driver intentionally steers the vehicle to change lanes, and suppresses the lane departure prevention control, thereby performing control that prioritizes the intentional steering by the driver. This prevents unnecessary intervention of lane keeping control or lane departure prevention control when changing lanes.

[0014] The driving assistance device disclosed in the above-mentioned Japanese Patent Laid-Open Publication No. 11-91606 and the like generates a steering torque to return the vehicle to the center of the lane when, for example, a tendency for the vehicle to depart from the lane is detected while the vehicle is running with lane keeping control and lane departure prevention control being executed. If the tendency for the vehicle to depart from the lane is detected for a predetermined period of time, the driving assistance device determines that the driver is continuing to steer intentionally against the return steering torque and limits the steering torque to return the vehicle to the center of the lane. This suppresses the intervention of lane keeping control and lane departure prevention control against the driver's will, and enables driving based on intentional steering by the driver.

[0015] As described above, the driving assistance devices disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2010-36852 and Japanese Patent Application Laid-Open No. 11-91606, etc., mainly disclose techniques for suppressing the intervention of lane departure control when changing lanes, or the intervention of lane keeping control when the driver intentionally changes the driving route. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-36852 [Patent Document 2] Japanese Patent Application Publication No. 11-91606 Summary of the Invention [Problem to be solved by the invention]

[0017] In general, for example, even if a driver, being aware of an object to be avoided that exists in the lane in which the vehicle is traveling, changes the driving route away from the center of the lane by steering in a direction away from the object to be avoided and continues driving by changing the driving route away from the center of the lane, if the object to be avoided that caused the change in driving route no longer exists, it is desirable to return the current driving route (driving route away from the center of the lane) to the original driving route (center of the lane).

[0018] However, in the conventional driving assistance devices disclosed in the above-mentioned JP 2010-36852 A, JP 11-91606 A, etc., no consideration was given to driving control when the driver intentionally steers the vehicle to change the driving route, suppressing the intervention of unnecessary lane keeping driving control or lane departure prevention control, and then returning the vehicle to the original driving route.

[0019] The present invention aims to provide a driving assistance device for a vehicle that can smoothly perform driving control in accordance with steering intended by the driver, and can perform more appropriate driving assistance control without causing the driver any sense of incongruity or discomfort. [Means for solving the problem]

[0020] In order to achieve the above object, a driving assistance device for a vehicle according to one aspect of the present invention is a driving assistance device for a vehicle that is capable of at least performing 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 that acquires surrounding situation information for the vehicle; a steering torque sensor that detects a steering torque applied using a steering mechanism of the vehicle; a steering angle detection sensor that detects a steering angle and a steering direction of the vehicle; and a driving control unit that includes a steering assist control unit that performs driving control with steering assist control based on output information from the surrounding situation information acquisition device, the steering torque sensor, and the steering angle detection sensor, and that performs overall control of the entire vehicle, and when an output from either the steering torque sensor or the steering angle detection sensor is detected, the driving control unit calculates a steering torque amount of the vehicle based on the steering torque amount of the vehicle. 、 Steering angle 、 A new lane keeping target driving path or a predetermined lane departure suppression target driving path for the vehicle is generated according to the steering direction, and when an output from either the steering torque sensor or the steering angle detection sensor is detected again within a predetermined time, the new lane keeping target driving path or the predetermined lane departure suppression target driving path is set, and driving control is performed along these driving paths. The predetermined lane departure prevention target driving path is set by delaying the start timing of lane departure prevention control that prevents the vehicle from departing from the driving lane. [Effects of the Invention]

[0021] The present invention can provide a vehicle driving assistance device that can smoothly perform driving control in accordance with the steering intended by the driver, and can perform more appropriate driving assistance control without causing the driver any sense of incongruity or discomfort. [Brief explanation of the drawings]

[0022] [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 showing the operation of a driving assistance device according to an embodiment of the present invention. [Figure 4] 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. [Figure 5] FIG. 1 is a conceptual diagram illustrating a situation in which lane keeping control is performed when steering left 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 keeping control is performed when steering to the right in a driving assistance device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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).

[0034] 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.

[0035] 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.

[0036] 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).

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Here, the EPS device 6 is a component unit for intervening predetermined steering assist control at predetermined timing as needed.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] Next, among the actions of the driving assistance device of this embodiment, actions when lane keeping control and lane departure prevention control are performed will be described below with reference to Figures 3 to 6. Figure 3 is a flowchart showing actions mainly when lane keeping control and lane departure prevention control are performed in the driving assistance device of one embodiment of the present invention.

[0066] Fig. 4 is a diagram conceptually showing a situation in which lane departure prevention control intervenes in a driving assistance device of one embodiment of the present invention. Figs. 5 and 6 are conceptual diagrams showing a situation in which lane keeping control is performed when steering to the left or right in a driving assistance device of one embodiment of the present invention. Of these, Fig. 5 is an example of a case in which steering is performed toward the road shoulder (left), and Fig. 6 is an example of a case in which steering is performed toward the road center line (right).

[0067] 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 4, 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 addition, in the following description of this embodiment, the terms "left" and "right" refer to the left and right when facing an object.

[0068] 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.

[0069] Here, for example, assume the situations shown in Figures 4, 5, and 6. Details will be described later, but the outline of the example situation shown in Figure 4 assumes the following situation. That is, for example, when the driver of the host vehicle M executing lane keeping control is aware of an oncoming vehicle M1 or the like or a vehicle parked or stopped in the oncoming lane (not shown; in the following description, an oncoming vehicle in motion and a vehicle parked or stopped in the oncoming lane will be abbreviated as "vehicles on the oncoming lane") regardless of whether or not the vehicle is present, and steers the vehicle in a direction away from the vehicle on the oncoming lane (see, for example, symbol M1), i.e., to the left (towards the shoulder), this is an example of when the lane departure suppression control intervenes when it is determined that the host vehicle M has a tendency to depart from the lane. Furthermore, in the following description, the term "oncoming vehicle" refers to, for example, not only oncoming vehicles in motion indicated by the symbols M1 and M2 in the drawings, but also vehicles (not shown) parked on the oncoming lane. 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 on the oncoming lane" or "vehicles on the oncoming lane," etc., and can be considered the same.

[0070] In addition, the outline of the example situation shown in Figures 5 and 6 is an example of when, for example, the driver of the vehicle M performing lane keeping driving control is aware of the oncoming vehicle M1 regardless of whether it is present or not and steers in a direction away from the oncoming vehicle M1, i.e., to the left (towards the shoulder) (see Figure 5), or when the driver of the vehicle M is aware of a side wall etc. 204 on the left side (the shoulder side of the vehicle's lane) and steers to the right (towards the center line of the road) (see Figure 6), and it is determined that the vehicle M is not prone to deviating from its lane and lane keeping driving control is performed.

[0071] First, in Figures 4, 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, a sidewall 204 or the like is provided along the host lane 201 at the left edge of the host lane 201 (hereinafter referred to as the shoulder side). Similarly, a sidewall 204 or the like is provided in the oncoming lane 202 on the shoulder side of the oncoming vehicle M1 traveling in the oncoming lane 202.

[0072] 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.

[0073] 4, 5, and 6, the oncoming vehicle traveling in the oncoming lane 202 is indicated by the symbol M1. In this case, the oncoming vehicle M1, indicated by the dashed line in FIGS. 4, 5, and 6, is traveling on the oncoming lane 202 along the lane keeping target traveling path 205x set at approximately the center position of the oncoming lane 202.

[0074] Under such circumstances, 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 in which the host vehicle M is currently traveling (host vehicle lane 201) in step S11 of Fig. 3. Here, the determination of whether or not the host vehicle M is tending to deviate from the lane is performed by checking whether or not the host vehicle M is traveling at a position that deviates from the currently set lane keeping target driving path 205, based on signals from the surrounding situation information acquisition device (camera unit 21 and radar device 23), the steering torque sensor 12, the steering angle detection sensor 15, etc.

[0075] 3, if it is determined that the host vehicle M is in a situation where it is likely to deviate from the host lane 201 (has a tendency to deviate from the lane), the process proceeds to the next step S12. On the other hand, if it is determined in this step S11 that the host vehicle M is not in a situation where it is likely to deviate from the host lane 201, the lane keeping driving control currently being executed is continued.

[0076] Next, in step S12, the cruise control unit 24 checks whether or not steering torque has been generated in the host vehicle M based on signals from the steering torque sensor 12, the steering angle detection sensor 15, etc. If steering torque is detected, the process proceeds to step S13. If steering torque is not detected, the process proceeds to step S21.

[0077] Then, in step S21, the cruise control unit 24 intervenes and executes normal lane departure suppression control. Thereafter, the process returns to step S11 and the lane keeping cruise control is continued. As a result, the host vehicle M is prevented from departing from the host lane 201, and returns to the lane keeping target cruise path 205 set in the center of the lane during normal control, and cruise control is performed to follow the cruise path 205.

[0078] The normal lane departure prevention control performed here is, for example, a series of processes that generate the lane departure prevention target driving path 207b shown in Figure 4, and then control the host vehicle M to travel along this lane departure prevention target driving path 207b, thereby preventing the host vehicle M from departing from its own lane 201.

[0079] The lane departure prevention target driving route 207b shown in FIG. 4 is a driving route generated by the lane departure prevention control that is started at the timing when the process proceeds to step S21.

[0080] On the other hand, in step S13, the cruise control unit 24 checks whether or not at least one of the steering torque amount and steering angle of the steering torque detected in the processing of step S12 described above exceeds a predetermined threshold value.

[0081] Here, for example, if at least one of the output result (steering torque amount) of the steering torque sensor 12 and 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 a predicted traveling route in either the left or right direction indicated by reference numeral 207aa (two-dot chain line) in Figures 5 and 6. Here, the predicted traveling route 207aa indicates that it will intersect with departure determination lateral position virtual lines 208 (dotted lines) on the left and right sides that are set in advance within the host vehicle lane 201 after a relatively long predetermined time.

[0082] The departure determination lateral position virtual line 208 is a virtual line that is set along the side edge (side wall 204, road center line 203, etc.) of the own vehicle lane 201 at a position a predetermined distance away from the left or right side edge (e.g., side wall 204 or road center line 203, etc.) of the own vehicle lane 201 toward the own vehicle lane 201. When the traveling path of the own vehicle M is expected to deviate to the left or right side of the departure determination lateral position virtual line 208, the own vehicle M is determined to have a tendency to deviate from the lane.

[0083] At this time, if the host vehicle M continues traveling while maintaining the current steering torque amount or steering angle (which does not exceed the predetermined value), it can be estimated that it will take a relatively long predetermined time until the host vehicle M deviates from the host lane 201 (the traveling path of the host vehicle M intersects with the departure determination lateral position virtual line 208). In other words, at this time, even if the host vehicle M is in a situation where it is likely to deviate from the lane eventually, as determined in the above-mentioned step S11, it can be determined that it is in a situation where it is unlikely to deviate from the lane within a predetermined short time. Therefore, when the host vehicle M is in such a situation (when the steering torque amount or steering angle does not exceed the predetermined threshold), the driving assistance device 1 proceeds to the processing of step S15.

[0084] Then, in step S15, the driving control unit 24 performs lane keeping driving control to generate a new lane keeping target driving path 205a. Here, the new lane keeping target driving path 205a is a driving path that is shifted a predetermined distance in either the left or right direction from the currently set lane keeping target driving path 205 in accordance with the input steering torque amount or steering angle, as shown in Figures 5 and 6. Then, the process proceeds to step S16.

[0085] On the other hand, for example, when at least one of the output result (steering torque amount) of the steering torque sensor 12 and the output result (steering angle) of the steering angle detection sensor 15 exceeds a predetermined value, it can be inferred that the host vehicle M is traveling along a predicted traveling route to the left (toward the shoulder) indicated by reference numeral 207ab (two-dot chain line) in Fig. 4. Here, the predicted traveling route 207ab indicates that the host vehicle M will intersect with a departure determination lateral position virtual line 208 (dotted line) on the left side (toward the shoulder) that is set in advance within the host vehicle lane 201 after a relatively short predetermined time.

[0086] At this time, if the host vehicle M continues traveling while maintaining the current steering torque amount or 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. Therefore, when the host vehicle M is in such a situation (when the steering torque amount or steering angle exceeds the predetermined threshold), the driving assistance device 1 proceeds to the processing of step S14.

[0087] Then, in step S14, the driving control unit 24 performs processing to intervene in lane departure prevention control and generate a predetermined lane departure prevention target driving path 207c that is different from the lane departure prevention target driving path 207b during normal control (see Figure 4).

[0088] Here, the predetermined lane departure prevention target driving path 207c shown in FIG. 4 is a driving path that is generated by delaying the start timing by a predetermined time from the start timing during normal control, for example.

[0089] For example, in Fig. 4, the driving path indicated by reference symbol 207b indicates the lane departure prevention target driving path during normal control. The control start timing at this time is the time indicated by reference symbol T1 in Fig. 4 (the time when the process proceeds to step S21 as described above). Also, in Fig. 4, the driving path indicated by reference symbol 207c indicates the lane departure prevention target driving path when a steering input is detected. The control start timing at this time is the time indicated by reference symbol T2 in Fig. 4. And, reference symbol TM in Fig. 4 indicates the time difference between the respective control start timings.

[0090] At this time, for example, if the driver intentionally steers the vehicle M and the vehicle M is in a situation where it is likely to deviate from the vehicle's lane 201 (the situation in FIG. 4), the start timing of the lane departure prevention control is delayed by a predetermined time indicated by the symbol TM in FIG. 4. This prevents the lane departure prevention control from immediately intervening. By taking such a measure, the driver does not feel any discomfort or annoyance. At the same time, the lane departure prevention target driving path 207c set at this time is set according to the steering amount, steering angle, and steering direction by the driver. Therefore, when the lane departure prevention control is performed according to the lane departure prevention target driving path 207c set in this manner, the vehicle M behaves in accordance with the driver's steering intention, and appropriate steering intervention is performed, making it possible to prevent the vehicle M from deviating from its lane without causing the driver any discomfort. Then, the process proceeds to step S16.

[0091] In step S16, the cruise control unit 24 checks whether or not a steering torque in the same direction has been detected again within a predetermined time (for example, about one minute) after the steering torque was detected in the processing of step S12. In other words, it checks whether or not multiple steering torques, including the steering torque detected in the processing of step S12, have been detected within a predetermined time from the time the steering torque was detected in the processing of step S12.

[0092] Here, when a steering torque is detected again, it can be assumed that the driver is continuing to intentionally steer in the same direction, for example. In this case (when a steering torque is detected again), the process proceeds to the next step S17. On the other hand, when a steering torque is not detected again, it is assumed that the driver's intentional steering has been released, and the process proceeds to step S19.

[0093] Next, in step S17, the driving control unit 24 executes driving control along the new driving route generated in steps S14 and S15 described above.

[0094] In step S17, for example, if a predetermined lane departure prevention target driving path 207c (see FIG. 4) has been generated in the processing of step S14, driving control is performed along this predetermined lane departure prevention target driving path 207c to prevent lane departure. After that, driving control is performed for a while to drive along departure determination lateral position virtual line 208. Here, symbol Ma in FIG. 4 indicates the position of the host vehicle at this time point.

[0095] That is, in this case, after the vehicle is controlled to travel along the predetermined lane departure prevention target travel path 207c to prevent the vehicle from leaving the lane, the vehicle is not immediately controlled to travel along the lane, but is controlled to travel in a position close to the shoulder. Then, the process proceeds to step S18.

[0096] Furthermore, in step S17, for example, if a new lane keeping target driving path 205a (see FIGS. 5 and 6) has been generated in the processing of step S15, driving control is performed to follow this new lane keeping target driving path 205a. This is control to drive the vehicle for a while along the new lane keeping target driving path 205a that is shifted a predetermined distance laterally from the lane keeping target driving path 205 during normal control. Here, symbol Ma in FIGS. 5 and 6 indicates the position of the host vehicle at this point in time. Note that FIG. 5 illustrates an example in which the steering direction is to the left (towards the shoulder), and FIG. 6 illustrates an example in which the steering direction is to the right (towards the center of the road). Thereafter, the process proceeds to step S18.

[0097] In step S18, the cruise control unit 24 checks information from the surrounding situation information acquisition devices (camera unit 21 and radar device 23) and the like to check whether the object to be avoided that is presumed to have caused the driver to steer no longer exists. Here, the processing of steps S17 and S18 is repeated while maintaining the current driving route until the object to be avoided no longer exists. Then, if the object to be avoided no longer exists, the process proceeds to the next step S19.

[0098] In step S19, the cruise control unit 24 returns the host vehicle M to the lane keeping target driving path 205 during normal control that is set in the center of the lane, and continues cruise control along the lane keeping target driving path 205. Then, the process returns to step S11 (return).

[0099] 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 make the host vehicle M travel along the travel lane (host lane 201) and lane departure prevention control to prevent the host vehicle M from deviating from the travel lane (host lane 201) is traveling on a public road that does not have a three-dimensional structure such as a central median while performing lane keeping driving control, if it is determined that the host vehicle M has a tendency to deviate from the host lane 201 and steering torque is detected, a check is made to see if the detected steering torque amount or steering direction exceeds a predetermined threshold value.

[0100] If the detected steering torque or steering direction exceeds a predetermined threshold, a predetermined lane departure suppression target driving path is generated according to the detected steering torque or steering direction, and if the detected steering torque or steering direction does not exceed the predetermined threshold, a new diagonal line maintenance target driving path is generated according to the detected steering torque or steering direction.

[0101] If the steering torque is detected multiple times, including the first time, within a predetermined time period from the time of the occurrence of the detected steering torque, the system performs driving control along the generated predetermined lane departure prevention target driving path or the new diagonal line maintenance target driving path. The system continues this driving control until the object to be avoided that caused the driver to steer no longer exists. After that, if the object to be avoided no longer exists, the system performs driving control to return the vehicle to the lane maintenance target driving path at the center of the lane.

[0102] As described above, in the driving assistance device 1 of this embodiment, for example, when the driver, aware of an object to be avoided such as an oncoming vehicle or a side wall, attempts to change the driving path by steering in a direction away from the object to be avoided, the steering torque at that time is detected, and a new lane keeping target driving path or lane departure prevention target driving path is generated according to the detected steering torque. If the system continues to detect intentional steering by the driver, driving control is performed to steer the vehicle along the newly generated lane keeping target driving path or lane departure prevention target driving path. Furthermore, if it is estimated that the object to be avoided that caused the driver to steer has disappeared, driving control is performed to return the vehicle to the lane keeping target driving path in the center of the lane, as in normal control.

[0103] This makes it possible to prevent lane keeping driving control or lane departure prevention control from immediately intervening against the driver's intention. At the same time, if the driver continues to steer intentionally, driving control is appropriately performed along a new lane keeping target driving path or lane departure prevention target driving path that conforms to the driver's intention, allowing lane keeping control or lane departure prevention control that reflects the driver's steering intention, so the driver does not feel uncomfortable or uneasy. Furthermore, since the system is configured to return to normal lane keeping driving control as appropriate depending on the surrounding conditions, more appropriate driving assistance control can be performed, allowing for smooth driving control.

[0104] 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]

[0105] 1...Driving assistance device 2...Steering mechanism 3...Tie rod 4...Handle 5...Steering axis 6...Electric power steering (EPS) device 7...EPS motor 8…EPS control unit (EPS_ECU) 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...Side wall etc. 205, 205x...Lane keeping target driving route 205a...New lane keeping target driving route 207aa...Predicted driving route 207ab... Expected route 207b...Lane departure prevention target driving path 207c...Lane departure prevention target driving route 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...Oncoming vehicles T1: Lane Departure Prevention Driving Control Start Timing (Normal) T2: Timing when lane departure prevention driving control starts TM: Control delay time

Claims

1. A driving assistance device for a vehicle that can perform at least a lane keeping control that causes a vehicle to travel along a driving lane and a lane departure suppression control that suppresses the vehicle from deviating from the driving lane, a surrounding situation information acquisition device for acquiring surrounding situation information of the vehicle; a steering torque sensor for detecting a steering torque applied by a steering mechanism 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 performs overall control of the vehicle, the driving control unit including a steering assist control unit that performs driving control including steering assist control based on output information from the surrounding situation information acquisition device, the steering torque sensor, and the steering angle detection sensor; Equipped with when an output from either the steering torque sensor or the steering angle detection sensor is detected, the driving control unit generates a new lane keeping target driving route or a predetermined lane departure suppression target driving route for the vehicle in accordance with the steering torque amount, steering angle, and steering direction of the vehicle, and when an output from either the steering torque sensor or the steering angle detection sensor is detected again within a predetermined time, the driving control unit sets the new lane keeping target driving route or the predetermined lane departure suppression target driving route and executes driving control along these driving routes; the predetermined lane departure prevention target driving path is set by delaying a start timing of lane departure prevention control that prevents the vehicle from departing from the driving lane. A vehicle driving assistance device characterized by:

2. 2. The vehicle driving assistance device according to claim 1, wherein the driving control unit continues to execute driving control for causing the vehicle to travel along the new lane keeping target driving path or the predetermined lane departure prevention target driving path for a predetermined period of time.

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