Driving assistance method and driving assistance device

Abstract

To prevent, in a case where there is an other vehicle which is about to enter between an own vehicle and a preceding vehicle, the other vehicle from blocking a passage of another mobile body without excessively limiting traveling of the own vehicle.SOLUTION: An operation support method, for use in controlling a vehicular speed of an own vehicle Vh so as to establish a target inter-vehicular distance between a preceding vehicle Vf and the own vehicle Vh, includes: predicting whether an other vehicle Vo blocks a passage of other mobile bodies (m1, m2) if the other vehicle Vo, which is likely to enter between the own vehicle Vh and the preceding vehicle Vf, stops in the midst of entering the front side of the own vehicle Vh; determining whether the preceding vehicle Vf is moving; setting a target inter-vehicular distance at a first distance applicable to a case where the other vehicle Vo is not predicted to block the passage of the mobile bodies (m1, m2) or where it is not determined that the preceding vehicle Vf is moving; and setting the target inter-vehicular distance at a second distance being longer than the first distance applicable to a case where the other vehicle Vo is predicted to block the passage of the mobile bodies (m1, m2) and it is determined that the preceding vehicle is moving.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a driving assistance method and a driving assistance device. [Background technology]

[0002] Patent document 1 describes a driving control device that detects a target vehicle that is predicted to enter the vehicle's own lane between the vehicle and the vehicle ahead, and stops the vehicle at a position that allows the target vehicle to enter the vehicle's own lane if there is no stopping space between the vehicle ahead and the entry space required for the target vehicle to enter the vehicle's own lane. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-6818 Summary of the Invention [Problem to be solved by the invention]

[0004] If another vehicle that is trying to enter between the host vehicle and the preceding vehicle stops midway through entering in front of the host vehicle, the path of other moving bodies other than the host vehicle may be obstructed by the other vehicle, which may hinder smooth traffic. However, the cruise control device of Patent Document 1 yields the path to other vehicles when the host vehicle has priority over the other vehicles, regardless of whether the other vehicle obstructs the path of the other moving body, which may excessively restrict the travel of the host vehicle. To eliminate the obstruction of the path of another moving body by another vehicle without excessively restricting the travel of one's own vehicle when there is another vehicle attempting to enter between one's own vehicle and a preceding vehicle. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a driving assistance method for detecting a vehicle ahead of a host vehicle and controlling the vehicle speed of the host vehicle so that the inter-vehicle distance between the preceding vehicle and the host vehicle becomes a target inter-vehicle distance. In the driving assistance method, a controller executes the following processes: detecting another vehicle that may enter between the host vehicle and the preceding vehicle from a lane different from the lane in which the host vehicle is currently traveling; predicting whether the other vehicle will block the path of a moving body other than the other vehicle by stopping on the way to enter in front of the host vehicle; determining whether the preceding vehicle is moving; and setting the target inter-vehicle distance to a predetermined first distance when it is not predicted that the other vehicle will block the path of the moving body or when it is not determined that the preceding vehicle is moving, and setting the target inter-vehicle distance to a second distance longer than the first distance when it is predicted that the other vehicle will block the path of the moving body and it is determined that the preceding vehicle is moving. [Effects of the Invention]

[0006] According to the present invention, when there is another vehicle attempting to enter between the vehicle and the preceding vehicle, it is possible to eliminate the other vehicle's obstruction of the path of another moving body without excessively restricting the vehicle's travel. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of an example of a driving assistance device according to an embodiment; [Figure 2] 1(a) is a schematic diagram of a first example of a driving scene in which the host vehicle yields to another vehicle, and FIG. 1(b) is a schematic diagram of a first example of a driving scene in which the host vehicle does not yield to another vehicle. [Figure 3] FIG. 2 is a block diagram illustrating an example of a functional configuration of a controller. [Figure 4] 10A is a schematic diagram of a second example of a driving scene in which the host vehicle does not yield to another vehicle, and FIG. 10B is a schematic diagram of a second example of a driving scene in which the host vehicle yields to another vehicle. [Figure 5] 10A is a schematic diagram of a third example of a driving scene in which the host vehicle does not yield to other vehicles, and FIG. 10B is a schematic diagram of a third example of a driving scene in which the host vehicle yields to other vehicles. [Figure 6]10A is a schematic diagram of a fourth example of a driving scene in which the host vehicle does not yield to other vehicles, and FIG. 10B is a schematic diagram of a fourth example of a driving scene in which the host vehicle yields to other vehicles. [Figure 7] 1 is a flowchart illustrating an example of a driving assistance method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are schematic and may differ from the actual product. Furthermore, the embodiments of the present invention shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the structure, arrangement, etc. of component parts to those described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims.

[0009] (composition) 1 is a schematic configuration diagram of an example of a driving assistance device according to an embodiment. A host vehicle Vh is equipped with a driving assistance device 10 that assists in driving the host vehicle Vh. The driving assistance control by the driving assistance device 10 is, for example, autonomous driving control that automatically drives the host vehicle Vh without driver involvement based on the driving environment around the host vehicle Vh. The driving assistance device 10 includes an object sensor 11, a vehicle sensor 12, a positioning device 13, a map database (map DB) 14, a communication device 15, a navigation device 16, an actuator 17, a display device 18, and a controller 19. The object sensor 11 includes a plurality of different types of object detection sensors mounted on the host vehicle Vh, such as a laser radar, a millimeter wave radar, a camera, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) that detect objects around the host vehicle Vh.

[0010] The vehicle sensor 12 is mounted on the host vehicle Vh and detects various information (vehicle signals) obtained from the host vehicle Vh. The vehicle sensor 12 includes, for example, a vehicle speed sensor that detects the vehicle speed of the host vehicle Vh, a wheel speed sensor that detects the rotational speed of the tires of the host vehicle Vh, a three-axis acceleration sensor that detects the acceleration and deceleration in three axial directions of the host vehicle Vh, a steering angle sensor that detects the steering angle of the steering wheel, a turning angle sensor that detects the turning angle of the steered wheels, a gyro sensor that detects the angular velocity of the host vehicle Vh, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the accelerator opening of the host vehicle Vh, and a brake sensor that detects the amount of brake operation by the driver.

[0011] The positioning device 13 includes a Global Navigation Satellite System (GNSS) receiver and receives radio waves from multiple navigation satellites to measure the current position of the vehicle Vh. The GNSS receiver may be, for example, a Global Positioning System (GPS) receiver. The positioning device 13 may also be, for example, an inertial navigation system. The map database 14 stores road map data. For example, the map database 14 may store high-precision map data (hereinafter simply referred to as "high-precision map") suitable as map information for autonomous driving. The map database 14 may also store map data for navigation (hereinafter simply referred to as "navigation map"). The communication device 15 performs wireless communication with a communication device outside the vehicle Vh. The communication method used by the communication device 15 may be, for example, wireless communication using a public mobile phone network, vehicle-to-vehicle communication, road-to-vehicle communication, or satellite communication.

[0012] The navigation device 16 recognizes the current position of the vehicle Vh using the positioning device 13 and obtains map information for the current position from the map database 14. The navigation device 16 sets a target driving route to a destination input by an occupant (e.g., a driver) and provides route guidance to the occupant along this target driving route. The navigation device 16 also outputs information about the set target driving route to the controller 19. The controller 19 automatically drives the vehicle Vh so that the vehicle travels along the target driving route set by the navigation device 16.

[0013] The actuator 17 generates vehicle behavior of the host vehicle Vh by operating the steering wheel, accelerator opening, and brake device of the host vehicle Vh in response to control signals from the controller 19. The actuator 17 includes a steering actuator, an accelerator opening actuator, and a brake control actuator. The steering actuator controls the steering direction and steering amount of the host vehicle Vh.

[0014] The accelerator opening actuator controls the accelerator opening of the host vehicle Vh, and the brake control actuator controls the braking operation of the brake device of the host vehicle Vh. The display device 18 is provided in a position visible to the occupants of the host vehicle Vh, and displays visual information (e.g., text messages, images, videos, figures, icons, etc.) provided to the occupants from the driving assistance device 10. The display device 18 may be a display screen of a navigation system or a display device provided near a meter in front of the driver's seat.

[0015] The controller 19 is an electronic control unit (ECU) that performs driving assistance control for the host vehicle Vh. The controller 19 includes a processor 19a and peripheral components such as a storage device 19b. The processor 19a may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage device 19b may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The storage device 19b may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main memory device, and a RAM (Random Access Memory).

[0016] The functions of the controller 19 described below are realized by, for example, the processor 19a executing a computer program stored in the storage device 19b. The controller 19 may be formed of dedicated hardware for executing each of the information processes described below. For example, the controller 19 may include a functional logic circuit configured in a general-purpose semiconductor integrated circuit. For example, the controller 19 may include a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

[0017] Next, an example of a driving assistance method by the controller 19 will be described. 2(a) shows an example of a driving scene to which the driving assistance method according to the present invention is applied. In this driving scene, the host vehicle Vh turns left at an intersection C, which is a crossroad, following a preceding vehicle Vf, and is in the process of moving from the host vehicle Vh's current lane Lh to the planned driving lane Le in which the host vehicle Vh is planned to travel. The controller 19 controls the vehicle speed of the host vehicle Vh so that the inter-vehicle distance between the preceding vehicle Vf and the host vehicle Vh becomes a target inter-vehicle distance Dt. Under normal conditions, the target inter-vehicle distance Dt is set to a first distance D1. Meanwhile, another vehicle Vo is entering intersection C through the oncoming lane Lo of the own lane Lh, and is about to turn right at intersection C and proceed onto the intended driving lane Le.

[0018] In such a driving scenario, if the subject vehicle Vh does not yield to the other vehicle Vo, the other vehicle Vo may stop midway while entering in front of the subject vehicle Vh, causing the other vehicle Vo to obstruct the paths of moving bodies m1 and m2 other than the subject vehicle Vo. For example, the other vehicle Vo may obstruct the path of an intersecting vehicle m1 traveling in an intersecting lane Lc that intersects the subject vehicle lane Lh and the oncoming lane Lo. In addition, the other vehicle Vo may obstruct the path of a straight-moving vehicle m2 traveling straight through the intersection C via the subject vehicle lane Lh. This may disrupt smooth traffic at the intersection C.

[0019] Therefore, when it is predicted that the other vehicle Vo will block the paths of the moving bodies m1 and m2 other than the other vehicle Vo by stopping midway while entering in front of the host vehicle Vh, the controller 19 allows the other vehicle Vo to enter in front of the host vehicle Vh, thereby eliminating the obstruction of the paths of the other moving bodies m1 and m2 by the other vehicle Vo. This achieves safety and efficient traffic flow at the intersection C.

[0020] For this reason, the controller 19 performs the following processes: detecting another vehicle Vo that may enter between the host vehicle Vh and the preceding vehicle Vf from a lane other than the host vehicle Lh; predicting whether the other vehicle Vo will obstruct the path of a moving body other than the host vehicle Vh by stopping midway while entering in front of the host vehicle Vh; determining whether the preceding vehicle Vf is moving; and setting the target inter-vehicle distance Dt to a second distance D2 that is longer than the normal first distance D1 when it is predicted that the other vehicle Vo will obstruct the path of a moving body and it is determined that the preceding vehicle Vf is moving. This allows the other vehicle Vo to easily move in front of the host vehicle Vh, eliminating the possibility of the other vehicle Vo stopping to obstruct the path of other moving bodies.

[0021] For example, the controller 19 may predict whether the other vehicle Vo will block the path of a moving body other than the other vehicle Vo by stopping on the way to enter ahead of the host vehicle Vh, based on the amount of protrusion d1 of the body of the other vehicle Vo protruding from the oncoming lane Lo toward the host vehicle Vh. For example, if the amount of protrusion d1 is equal to or greater than a threshold, the controller 19 predicts that the other vehicle Vo is likely to enter between the host vehicle Vh and the preceding vehicle Vf, and will block the path of an intersecting vehicle m1 or a straight-moving vehicle m2 by stopping on the way to enter ahead of the host vehicle Vh. In addition, when another vehicle Vo enters the intersection C and the lane markings of the oncoming lane Lo are interrupted within the intersection C, the amount of protrusion from the extension of the lane markings of the oncoming lane Vo on the side of the own lane Vh toward the own vehicle Vh is defined as protrusion amount d1.

[0022] For example, the controller 19 may predict whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping midway while entering in front of the host vehicle Vh, based on the angle θ between the fore-and-aft direction of the body of the other vehicle Vo and the direction of the oncoming lane Lo. For example, if the angle θ is greater than or equal to a threshold value, it is highly likely that another vehicle Vo will enter between the host vehicle Vh and the preceding vehicle Vf, and it is predicted that the other vehicle Vo will stop midway as it enters ahead of the host vehicle Vh, thereby obstructing the path of the intersecting vehicle m1 or the straight-moving vehicle m2.

[0023] For example, when the preceding vehicle Vf starts from a stopped state, the controller 19 may predict, based on the behavior of the other vehicle Vo in accordance with the start of the preceding vehicle Vf, whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping while entering in front of the host vehicle Vh. For example, the behavior of the other vehicle Vo in accordance with the start of the preceding vehicle Vf may be the behavior of the other vehicle Vo, which is stopped, starting at the same time as the preceding vehicle Vf starts from a stopped state, or the behavior of the other vehicle Vo, which is moving, accelerating at the same time as the preceding vehicle Vf starts from a stopped state.

[0024] If the other vehicle Vo behaves in accordance with the departure of the preceding vehicle Vf, it is highly likely that the other vehicle Vo will enter between the subject vehicle Vh and the preceding vehicle Vf, and it is predicted that the other vehicle Vo will stop midway while entering in front of the subject vehicle Vh, thereby obstructing the path of the intersecting vehicle m1 and the straight-moving vehicle m2. For example, in the example of Figure 2(a), when a preceding vehicle Vf stops and waits for a pedestrian m3 to finish crossing the crosswalk and starts moving, if another vehicle Vo starts moving in conjunction with the preceding vehicle Vf, it is predicted that the other vehicle Vo will stop on its way in front of the host vehicle Vh, obstructing the path of the intersecting vehicle m1 and the straight-moving vehicle m2.

[0025] 2(b), when the controller 19 does not predict that another vehicle Vo will obstruct the path of the moving object or when it does not determine that the preceding vehicle Vf is moving, it sets the target inter-vehicle distance Dt to the normal first distance D1, which is shorter than the second distance D2. For example, if the amount of protrusion d1 of the body of the other vehicle Vo or the angle θ between the body of the other vehicle Vo and the oncoming lane Lo is smaller than a threshold value, or if the other vehicle Vo does not behave in a manner that matches the departure of the preceding vehicle Vf, the target inter-vehicle distance Dt is set to a relatively short first distance D1 so as not to predict that the other vehicle Vo will obstruct the path of the moving body.

[0026] As a result, the host vehicle Vh travels following the preceding vehicle Vf without allowing the other vehicle Vo to enter between the host vehicle Vh and the preceding vehicle Vf. In this way, the controller 19 gives way to the other vehicle Vo only when the other vehicle Vo stops on the way in front of the host vehicle Vh and obstructs the path of another moving body, thereby avoiding excessive restrictions on the travel of the host vehicle Vh.

[0027] The controller 19 will be described in detail with reference to Fig. 3. The controller 19 includes an object detection unit 30, a host vehicle position estimation unit 31, a map acquisition unit 32, a detection integration unit 33, an object tracking unit 34, an in-map position calculation unit 35, and a vehicle control unit 36. The object detection unit 30 detects the positions, postures, sizes, speeds, etc. of objects around the host vehicle Vh, such as vehicles, motorcycles, pedestrians, obstacles, etc., based on the detection signals of the object sensor 11. The object detection unit 30 may acquire information about objects around the host vehicle Vh from other vehicles or infrastructure via vehicle-to-vehicle communication or road-to-vehicle communication using the communication device 15.

[0028] The vehicle position estimation unit 31 measures the absolute position of the vehicle Vh, i.e., the position, attitude, and speed of the vehicle Vh relative to a predetermined reference point, based on odometry using measurement results from the positioning device 13 and detection results from the vehicle sensor 12. The map acquisition unit 32 acquires map information indicating the structure of the road on which the host vehicle Vh is traveling from the map database 14. The map acquisition unit 32 may acquire the map information from an external map data server via the communication device 15.

[0029] The detection integration unit 33 integrates the multiple detection results obtained by the object detection unit 30 from each of the multiple object detection sensors, and outputs one detection result for each object. Specifically, the most rational object behavior that minimizes error is calculated from the object behavior obtained from each object detection sensor, taking into account the error characteristics of each object detection sensor. For example, sensor fusion technology can be used to comprehensively evaluate the detection results of multiple types of sensors to obtain more accurate detection results.

[0030] The object tracking unit 34 tracks the objects detected by the object detection unit 30. Specifically, based on the detection results integrated by the detection integration unit 33, the object tracking unit 34 verifies (associates) the identity of the objects between different times from the behavior of the objects output at different times, and predicts the behavior of the objects, such as their speed, based on the association. The intra-map position calculation unit 35 estimates the position and attitude of the host vehicle Vh on the map from the absolute position of the host vehicle Vh obtained by the host vehicle position estimation unit 31 and the map information acquired by the map acquisition unit 32. The intra-map position calculation unit 35 also identifies the road on which the host vehicle Vh is traveling. Furthermore, it identifies the lane on which the host vehicle Vh is traveling.

[0031] The vehicle control unit 36 executes autonomous driving control to automatically drive the host vehicle Vh along a target driving route to a destination set by the navigation device 16, based on the surrounding environment of the host vehicle Vh. In autonomous driving control, the vehicle control unit 36 generates a target driving trajectory along which the host vehicle Vh will travel. The target driving trajectory may be information including, for example, a sequence of points on the target trajectory along which the host vehicle Vh will travel, and a target value of the vehicle speed of the host vehicle Vh at each point on the sequence of points. In the following description, the target value of the vehicle speed of the host vehicle Vh on the target driving trajectory (i.e., the vehicle speed plan) will be referred to as a "target vehicle speed profile." The vehicle control unit 36 drives the actuator 17 so that the host vehicle Vh travels along the target travel path at a speed that conforms to the target vehicle speed profile, thereby automatically causing the host vehicle Vh to travel.

[0032] The vehicle control unit 36 includes a surrounding vehicle detection unit 40 , a path obstruction prediction unit 41 , a target inter-vehicle distance setting unit 42 , a target driving trajectory generation unit 43 , a vehicle speed control unit 44 , and a steering angle control unit 45 . The surrounding vehicle detection unit 40 detects a preceding vehicle Vf located immediately in front of the host vehicle Vh based on the detection results of the objects around the host vehicle Vh by the object detection unit 30, the detection integration unit 33, and the object tracking unit . The surrounding vehicle detection unit 40 also detects another vehicle Vo that may enter between the host vehicle Vh and the preceding vehicle Vf from a lane different from the host vehicle Vh currently traveling in the lane Lh.

[0033] The surrounding vehicle detection unit 40 may detect a vehicle turning right from the oncoming lane Lo at the intersection C as another vehicle Vo, for example, when the host vehicle Vh turns left at the intersection C following the preceding vehicle Vf, or when the host vehicle Vh goes straight at the intersection C following the preceding vehicle Vf, as shown in Figures 2(a), 2(b), 4(a) and 4(b). For example, as shown in Figures 5(a) and 5(b), when the host vehicle Vh follows the preceding vehicle Vf and goes straight through an intersection C, the surrounding vehicle detection unit 40 may detect a vehicle that turns left or right from the intersecting lane Lc at the intersection C and enters the host vehicle lane Lh as another vehicle Vo. For example, as shown in Figures 6(a) and 6(b), when the host vehicle Vh is traveling in the host lane Lh following the preceding vehicle Vf, the surrounding vehicle detection unit 40 may detect a vehicle entering the host lane Lh from the adjacent lane La (i.e., changing lanes) as another vehicle Vo.

[0034] Referring to Fig. 3, the path obstruction prediction unit 41 predicts whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping midway while entering in front of the host vehicle Vh. For example, as described above with reference to Figure 2(a), the path obstruction prediction unit 41 may predict whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping while entering ahead of the host vehicle Vh, based on at least one of the amount d1 that the body of the other vehicle Vo protrudes from the oncoming lane Lo toward the host vehicle Vh, the angle θ between the fore-and-aft direction of the body of the other vehicle Vo and the direction of the oncoming lane Lo, and the behavior of the other vehicle Vo as it adjusts to the preceding vehicle Vf starting from a stopped state.

[0035] The path obstruction prediction unit 41 may predict, based on changes in the signals displayed by the traffic lights at intersection C, whether another vehicle Vo will obstruct the path of a moving body other than the vehicle Vo by stopping midway while entering in front of the vehicle Vh. Please refer to Figure 4(b). The driving scene in Figure 4(b) is similar to the driving scene in Figure 2(a) except that traffic signals S1 to S4 are taken into consideration. Traffic signals S1 to S3 are traffic signals for vehicles in the current lane Lh, the oncoming lane Lo, and the intersecting lane Lc, respectively, and traffic signal S4 is a traffic signal for pedestrians crossing the intersecting lane Lc.

[0036] When the traffic light S2 for the oncoming lane Lo changes from a go signal to a stop signal, causing the other vehicle Vo to stop while moving in front of the host vehicle Vh, and the traffic light S3 for the intersecting lane Lc changes from a stop signal to a go signal, the oncoming lane Lo will obstruct the path of the intersecting vehicle m1. Therefore, when the traffic lights S1 and S2 change from a go signal to a stop signal, the path obstruction prediction unit 41 may determine that the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping while entering in front of the host vehicle Vh.

[0037] The path obstruction prediction unit 41 may determine that when the pedestrian traffic light S4 changes from a go signal to a stop signal, the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping while entering in front of the host vehicle Vh.

[0038] 4(a), when the traffic signals S1, S2, and S4 are in the proceeding signal state, the path obstruction prediction unit 41 does not determine that the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping midway while entering ahead of the host vehicle Vh. The path obstruction prediction unit 41 may receive signal information of the traffic signals S1, S2, and S4 from the infrastructure, for example, via road-to-vehicle communication using the communication device 15, and detect that the traffic signals S1, S2, and S4 will change from a go signal to a stop signal. Also, for example, the path obstruction prediction unit 41 may detect that the traffic signals S1, S2, and S4 will change from a go signal to a stop signal by performing image recognition on images of the traffic signals S1, S2, and S4 captured by the camera of the object sensor 11.

[0039] See FIG. 5(b). In the driving scene in FIG. 5(b), the host vehicle Vh follows the preceding vehicle Vf through a three-way intersection C. Therefore, the planned driving lane in which the host vehicle Vh is scheduled to travel is the host vehicle lane Lh in which the host vehicle Vh is currently traveling. The other vehicle Vo is about to turn left at the intersection C from an intersecting lane Lc that intersects with the host vehicle lane Lh and proceed onto the host vehicle lane Lh. Note that while FIG. 5(b) shows an example in which the other vehicle Vo turns left at the intersection C, the same applies when the other vehicle Vo turns right from an intersecting lane and proceeds onto the host vehicle lane Lh.

[0040] In such a driving scenario, another vehicle Vo may stop midway while entering in front of the subject vehicle Vh, thereby blocking the path of moving bodies m2 and m3 other than the subject vehicle Vo. For example, the subject vehicle Vo may block the path of vehicle m2 traveling straight through the subject vehicle lane Lh and going straight through intersection C. The subject vehicle Vo may also block the path of pedestrian m3 walking on a crosswalk across the intersecting lane Lc.

[0041] Therefore, the path obstruction prediction unit 41 may predict whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping midway while entering ahead of the own vehicle Vh, based on the amount of protrusion d2 of the body of the other vehicle Vo into the own vehicle lane Lh. Furthermore, the path obstruction prediction unit 41 may predict whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping while entering ahead of the host vehicle Vh, based on the amount d3 by which the body of the other vehicle Vo protrudes from the stop line SL. The stop line SL is a stop line on the intersecting lane Lc installed just before the intersection C. For example, if the overhang amounts d2 and d3 are equal to or greater than the thresholds, it is highly likely that another vehicle Vo will enter between the host vehicle Vh and the preceding vehicle Vf, and it is predicted that the other vehicle Vo will stop midway as it enters ahead of the host vehicle Vh, thereby obstructing the path of the straight-moving vehicle m2 and the pedestrian m3.

[0042] For example, the controller 19 may predict whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping midway while entering in front of the host vehicle Vh, based on the angle θ between the fore-and-aft direction of the body of the other vehicle Vo and the direction of the intersecting lane Lc. For example, if the angle θ is greater than or equal to the threshold value, it is highly likely that another vehicle Vo will enter between the host vehicle Vh and the preceding vehicle Vf, and it is predicted that the other vehicle Vo will stop midway as it enters in front of the host vehicle Vh, thereby obstructing the path of the straight-moving vehicle m2 and the pedestrian m3.

[0043] For example, when the preceding vehicle Vf starts from a stopped state, the controller 19 may predict, based on the behavior of the other vehicle Vo in accordance with the start of the preceding vehicle Vf, whether the other vehicle Vo will obstruct the path of the straight-moving vehicle m2 or the pedestrian m3 by stopping while entering in front of the host vehicle Vh. 5(a), if the protrusion amounts d2 and d3 of the body of the other vehicle Vo or the angle θ between the body of the other vehicle Vo and the intersecting lane Lc are smaller than threshold values, or if the other vehicle Vo does not exhibit behavior that matches the start of the preceding vehicle Vf, the path obstruction prediction unit 41 does not predict that the other vehicle Vo will stop midway while entering ahead of the host vehicle Vh and obstruct the path of the straight-moving vehicle m2 or the pedestrian m3.

[0044] See Figure 6(b). In the driving scene in Figure 6(b), a host vehicle Vh is traveling in the host lane Lh, following a leading vehicle Vf, on a road with multiple lanes in each direction, including at least the host lane Lh and its adjacent lane La. The planned traveling lane in which the host vehicle Vh is scheduled to travel is the host lane Lh in which the host vehicle Vh is currently traveling. Another vehicle Vo is about to change lanes from the adjacent lane La and move onto the host lane Lh.

[0045] In such a driving scenario, the other vehicle Vo may stop midway while entering in front of the host vehicle Vh, thereby blocking the path of moving bodies m2 and m3 other than the other vehicle Vo. For example, the other vehicle Vo may block the path of a following vehicle m5 that is traveling straight in the adjacent lane La. In addition, the other vehicle Vo may block the path of a motorcycle m5 that is traveling in the host vehicle Vh's lane Lh and attempting to overtake the host vehicle Vh.

[0046] Therefore, the path obstruction prediction unit 41 may predict whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping midway while entering ahead of the own vehicle Vh, based on the amount of protrusion d4 of the body of the other vehicle Vo into the own vehicle lane Lh. For example, if the amount of overhang d4 is equal to or greater than the threshold, it is highly likely that another vehicle Vo will enter between the host vehicle Vh and the preceding vehicle Vf, and it is predicted that the other vehicle Vo will stop midway as it enters in front of the host vehicle Vh, thereby obstructing the path of the following vehicle m4 and motorcycle m5.

[0047] For example, the controller 19 may predict whether the other vehicle Vo will obstruct the path of a moving body other than the other vehicle Vo by stopping midway while entering in front of the host vehicle Vh, based on the angle θ between the fore-and-aft direction of the body of the other vehicle Vo and the direction of the host vehicle lane Lh or the adjacent lane La. For example, if the angle θ is greater than or equal to the threshold value, it is highly likely that another vehicle Vo will enter between the host vehicle Vh and the preceding vehicle Vf, and it is predicted that the other vehicle Vo will stop midway as it enters in front of the host vehicle Vh, thereby obstructing the path of the following vehicle m4 and the motorcycle m5.

[0048] Furthermore, for example, when the preceding vehicle Vf starts from a stopped state, the controller 19 may predict, based on the behavior of the other vehicle Vo in accordance with the start of the preceding vehicle Vf, whether the other vehicle Vo will obstruct the path of the following vehicle m4 or the two-wheeled vehicle m5 by stopping while entering in front of the host vehicle Vh. 6(a), if the amount of protrusion d4 of the body of the other vehicle Vo or the angle θ between the body of the other vehicle Vo and the lanes Lh and La is smaller than a threshold, or if the other vehicle Vo does not exhibit behavior that matches the start of the preceding vehicle Vf, the path obstruction prediction unit 41 does not predict that the other vehicle Vo will stop midway while entering ahead of the host vehicle Vh and thereby obstruct the paths of the following vehicle m4 or the motorcycle m5.

[0049] 3, when it is predicted that the other vehicle Vo will stop on its way to enter ahead of the host vehicle Vh and thereby block the path of a moving body other than the other vehicle Vo, the target inter-vehicle distance setting unit 42 sets the target inter-vehicle distance Dt to a second distance D2 that is longer than the normal first distance D1. Conversely, when it is not predicted that the other vehicle Vo will stop on its way to enter ahead of the host vehicle Vh and thereby block the path of a moving body other than the other vehicle Vo, the target inter-vehicle distance setting unit 42 sets the target inter-vehicle distance Dt to the normal first distance D1. In the following explanation, when another vehicle Vo stops while entering in front of the host vehicle Vh, blocking the path of a moving body other than the other vehicle Vo, this will be referred to simply as "obstruction of the path of another moving body by the other vehicle Vo."

[0050] At this time, the target inter-vehicle distance setting unit 42 determines whether the preceding vehicle Vf is moving. If the preceding vehicle Vf is not moving, even if the other vehicle Vo is allowed to enter ahead of the host vehicle Vh, the other vehicle Vo may not be able to move forward sufficiently, and the path obstruction by the other moving body may not be resolved. Therefore, when another vehicle Vo is predicted to block the path of another moving object and the preceding vehicle Vf is moving, the target inter-vehicle distance setting unit 42 sets the target inter-vehicle distance Dt to the second distance D2.When the preceding vehicle Vf is not moving, the target inter-vehicle distance Dt is set to the normal first distance D1.

[0051] When the other vehicle Vo has finished entering between the host vehicle Vh and the preceding vehicle Vf (i.e., when the host vehicle Vh has finished entering the planned driving lane in which the host vehicle Vh is planned to travel), the target inter-vehicle distance setting unit 42 returns the target inter-vehicle distance Dt to the normal first distance D1. For example, the target inter-vehicle distance setting unit 42 may return the target inter-vehicle distance Dt to the normal first distance D1 when a predetermined time has elapsed since the other vehicle Vo finished entering between the host vehicle Vh and the preceding vehicle Vf.

[0052] The target driving trajectory generation unit 43 calculates a target driving trajectory for the host vehicle Vh to travel based on the current position and attitude of the host vehicle Vh, a target driving route to the destination set by the navigation device 16, and the surrounding environment of the host vehicle Vh. For example, it generates a route space map that represents the route around the host vehicle Vh and the presence or absence of objects, and a risk map that quantifies the risk of the driving area, and generates the target driving trajectory based on the motion characteristics of the host vehicle Vh, the route space map, and the risk map.

[0053] When a preceding vehicle Vf is present ahead of the host vehicle Vh, the target traveling trajectory generating unit 43 generates a target vehicle speed profile so that the inter-vehicle distance between the preceding vehicle Vf and the host vehicle Vh becomes the target inter-vehicle distance Dt. In addition, the target driving trajectory generating unit 43 may generate a target vehicle speed profile so that the host vehicle Vh stops just before the intersection C when it is predicted that another vehicle Vo will obstruct the path of another moving body and it is determined that the preceding vehicle is moving. At this time, the target driving trajectory generating unit 43 may generate a target vehicle speed profile so that the stopping position when it is predicted that another vehicle Vo will obstruct the path of another moving body and it is determined that the preceding vehicle is moving will be a position closer to the current position of the vehicle Vh than the stopping position when it is not predicted that another vehicle Vo will obstruct the path of another moving body or it is not determined that the preceding vehicle is moving.

[0054] The vehicle speed control unit 44 controls the vehicle speed of the host vehicle Vh so that the host vehicle Vh travels at a speed that conforms to the target vehicle speed profile generated by the target travel trajectory generation unit 43. Specifically, the vehicle speed control unit 44 drives the accelerator opening actuator and the brake control actuator of the actuator 17 to generate driving force and braking force for the host vehicle Vh so that the vehicle speed of the host vehicle Vh conforms to the target vehicle speed profile. Furthermore, when the host vehicle Vh is stopped because it is predicted that the other vehicle Vo will block the path of another moving body and it is determined that the preceding vehicle is moving, the vehicle speed control unit 44 may maintain the stopped state of the host vehicle Vh and wait for the other vehicle Vo to enter between the host vehicle Vh and the preceding vehicle Vf. Also, even if the host vehicle Vh is already stopped at the time it is predicted that the other vehicle Vo will block the path of another moving body and it is determined that the preceding vehicle is moving, the vehicle speed control unit 44 may maintain the stopped state of the host vehicle Vh and wait for the other vehicle Vo to enter between the host vehicle Vh and the preceding vehicle Vf.

[0055] The steering angle control unit 45 controls the steering angle so that the host vehicle Vh travels on the target travel trajectory. Specifically, the vehicle speed control unit 44 drives the steering actuator of the actuator 17 to steer the steered wheels so that the host vehicle Vh travels on the target travel trajectory. Furthermore, when the host vehicle Vh is stopped because it is predicted that another vehicle Vo will obstruct the path of another moving object and it is determined that a preceding vehicle is moving, the steering angle control unit 45 controls the steering angle so that the host vehicle Vh stops while maintaining the orientation of the body of the host vehicle Vh. For example, when the host vehicle Vh is stopped, the steering angle is returned to the neutral position. As a result, for example, as shown in Figures 2(a), 2(b), 4(a) and 4(b), when the vehicle Vh turns left at an intersection C following the preceding vehicle Vf, the vehicle Vh can indicate its intention to give way to the other vehicle Vo by not changing the direction of the vehicle body even when the left turn signal is flashed.

[0056] When the vehicle control unit 36 predicts that another vehicle Vo will obstruct the path of another moving body and determines that the preceding vehicle is moving, and performs the control to give way to the other vehicle Vo described above (i.e., control to set the target inter-vehicle distance Dt to the second distance D2, control to move the stopping position of the vehicle Vh closer at the intersection C, control to maintain the stopped state and wait for the other vehicle Vo to enter, control not to change the direction of the vehicle body), the vehicle control unit 36 may inform the occupants of the vehicle Vh that they will give way to the other vehicle Vo. This reduces the discomfort felt by the occupants of the host vehicle Vh when the host vehicle Vh is not being driven to follow the preceding vehicle Vf. For example, visual information (e.g., a text message, an image, a video, a graphic, an icon, etc.) indicating that the host vehicle Vh will give way to the other vehicle Vo may be displayed on the display device 18.

[0057] (operation) FIG. 7 is a flowchart of an example of a driving assistance method according to the embodiment. In step S1, the surrounding vehicle detection unit 40 detects a preceding vehicle Vf located immediately in front of the host vehicle Vh. The surrounding vehicle detection unit 40 also detects another vehicle Vo that may enter between the host vehicle Vh and the preceding vehicle Vf from a lane different from the host vehicle Vh's current lane Lh.

[0058] In step S2, the path obstruction prediction unit 41 determines whether the protrusion amount d1, d2, d3, or d4 of the other vehicle Vo is equal to or greater than a threshold. It may also determine whether the angle θ between the other vehicle Vo and the lane is equal to or greater than a threshold. If the protrusion amount d1, d2, d3, or d4 or the angle θ is not equal to or greater than the threshold (step S2: N), the process proceeds to step S4. If the protrusion amount d1, d2, d3, or d4 or the angle θ is equal to or greater than the threshold (step S2: Y), the process proceeds to step S3. In step S3, the target inter-vehicle distance setting unit 42 determines whether the preceding vehicle Vf is moving. If the preceding vehicle Vf is moving, the target inter-vehicle distance setting unit 42 sets the target inter-vehicle distance Dt to the second distance D2. Then, the process ends.

[0059] In step S4, the target inter-vehicle distance setting unit 42 sets the target inter-vehicle distance Dt to the normal first distance D1. If a stopped preceding vehicle Vf is detected in step S1, the path obstruction prediction unit 41 determines in step S5 whether the preceding vehicle Vf has started moving. If the preceding vehicle Vf has started moving (step S5: Y), the process proceeds to step S7. If the preceding vehicle Vf has not started moving (step S5: N), the process proceeds to step S6. If a moving preceding vehicle Vf is detected in step S1, steps S5 to S8 may be omitted, in which case the target inter-vehicle distance Dt is set to the first distance D1.

[0060] In step S6, the vehicle speed control unit 44 maintains the state in which the host vehicle Vh is stopped behind the leading vehicle Vf, after which the process returns to step S2. In step S7, the path obstruction prediction unit 41 determines whether the other vehicle Vo has started. That is, it determines whether the other vehicle Vo has started in conjunction with the start of the preceding vehicle Vf. If the other vehicle Vo has not started (step S7: N), the process ends. In this case, the target inter-vehicle distance Dt is set to the first distance D1. If the other vehicle Vo has started (step S7: Y), the process proceeds to step S8.

[0061] In step S8, the target inter-vehicle distance setting unit 42 sets the target inter-vehicle distance Dt to a second distance D2 that is longer than the normal first distance D1. This causes the host vehicle Vh to wait in a stopped state until the inter-vehicle distance between the host vehicle Vh and the moving preceding vehicle Vf reaches the second distance D2. When the inter-vehicle distance to the preceding vehicle Vf reaches the second distance D2, the vehicle speed control unit 44 transmits the signal following the preceding vehicle Vf. Alternatively, the vehicle speed control unit 44 may maintain the stopped state of the host vehicle Vh and wait for the other vehicle Vo to enter between the host vehicle Vh and the preceding vehicle Vf.

[0062] (Effects of the embodiment) (1) The controller 19 detects a preceding vehicle Vf of the host vehicle Vh and controls the vehicle speed of the host vehicle Vh so that the inter-vehicle distance between the preceding vehicle Vf and the host vehicle Vh becomes a target inter-vehicle distance. The controller 19 executes the following processes: detecting another vehicle Vo that may enter between the host vehicle Vh and the preceding vehicle Vf from a lane different from the lane the host vehicle Vh is currently traveling in; predicting whether the other vehicle Vo will block the path of a moving body other than the other vehicle Vo by stopping on the way to enter in front of the host vehicle Vh; determining whether the preceding vehicle Vf is moving; and setting the target inter-vehicle distance to a predetermined first distance when the other vehicle Vo is not predicted to block the path of the moving body or when it is not determined that the preceding vehicle Vf is moving; and setting the target inter-vehicle distance to a second distance longer than the first distance when it is predicted that the other vehicle Vo will block the path of the moving body and it is determined that the preceding vehicle Vf is moving.

[0063] This allows the other vehicle Vo to easily enter ahead of the host vehicle Vh, eliminating the possibility of the other vehicle Vo stopping to obstruct the path of other moving bodies. Also, when the other vehicle Vo stops midway while entering ahead of the host vehicle Vh, it gives way to the other vehicle Vo only if the other vehicle Vo obstructs the path of the other moving body, eliminating the possibility of the other vehicle Vo obstructing the path of the other moving body without excessively restricting the travel of the host vehicle Vh.

[0064] (2) When there is a possibility that another vehicle Vo may enter between the vehicle Vh and the preceding vehicle Vf at an intersection, the controller 19 may set the stopping position at the intersection when it predicts that the other vehicle Vo will obstruct the path of the moving body and determines that the preceding vehicle Vf is moving to be closer than the stopping position when it does not predict that the other vehicle Vo will obstruct the path of the moving body or when it does not determine that the preceding vehicle Vf is moving. This makes it easier for the other vehicle Vo to enter ahead of the host vehicle Vh, and also enables the host vehicle Vh to indicate to the other vehicle Vo its intention to give way.

[0065] (3) When the controller 19 predicts that another vehicle Vo will obstruct the path of the moving body and determines that the preceding vehicle Vf is moving, the controller 19 may stop the host vehicle Vh and wait for the other vehicle Vo to enter between the host vehicle Vh and the preceding vehicle Vf. This makes it easier for the other vehicle Vo to enter ahead of the host vehicle Vh, and also enables the host vehicle Vh to indicate to the other vehicle Vo its intention to give way.

[0066] (4) When the controller 19 predicts that another vehicle Vo will obstruct the path of the moving body and determines that the preceding vehicle Vf is moving, the controller 19 may stop the host vehicle Vh while maintaining the orientation of the vehicle body. This allows the host vehicle Vh to indicate to the other vehicle Vo its intention to give way. [Explanation of symbols]

[0067] 10...driving assistance device, 11...object sensor, 12...vehicle sensor, 13...positioning device, 14...map database, 15...communication device, 16...navigation device, 17...actuator, 18...display device, 19...controller, 19a...processor, 19b...storage device, 30...object detection unit, 31...host vehicle position estimation unit, 32...map acquisition unit, 33...detection integration unit, 34...object tracking unit, 35...in-map position calculation unit, 36...vehicle control unit, 40...surrounding vehicle detection unit, 41...path obstruction prediction unit, 42...target inter-vehicle distance setting unit, 43...target driving trajectory generation unit, 44...vehicle speed control unit, 45...steering angle control unit, C...intersection, m1...intersecting vehicle, m2...straight-moving vehicle, m3...pedestrian, m4, m5...following vehicle, Vf...leading vehicle, Vh...host vehicle, Vo...other vehicle

Claims

1. A driving assistance method for detecting a vehicle ahead of a host vehicle and controlling a vehicle speed of the host vehicle so that a vehicle-to-vehicle distance between the vehicle ahead and the host vehicle becomes a target vehicle-to-vehicle distance, A process of detecting another vehicle that may enter between the host vehicle and the preceding vehicle from a lane different from the lane in which the host vehicle is currently traveling; a process of predicting whether the other vehicle will obstruct a path of a moving body other than the other vehicle by stopping midway in the path of the other vehicle; a process of determining whether the preceding vehicle is moving; a process of setting the target inter-vehicle distance to a predetermined first distance when it is not predicted that the other vehicle will obstruct the path of the moving body or when it is not determined that the preceding vehicle is moving, and setting the target inter-vehicle distance to a second distance longer than the first distance when it is predicted that the other vehicle will obstruct the path of the moving body and it is determined that the preceding vehicle is moving; A driving assistance method characterized in that the controller executes the above.

2. 2. The driving assistance method according to claim 1, wherein the controller, when there is a possibility that the other vehicle will enter between the host vehicle and the preceding vehicle at the intersection, sets a stopping position at the intersection when it predicts that the other vehicle will obstruct the path of the moving body and determines that the preceding vehicle is moving to be closer than a stopping position when it does not predict that the other vehicle will obstruct the path of the moving body or when it does not determine that the preceding vehicle is moving.

3. 3. The driving assistance method according to claim 1, wherein the controller, when predicting that the other vehicle will obstruct the path of the moving body and determining that the preceding vehicle is moving, stops the host vehicle and waits for the other vehicle to enter between the host vehicle and the preceding vehicle.

4. The driving assistance method according to any one of claims 1 to 3, characterized in that the controller stops the vehicle while maintaining the orientation of the vehicle body when it predicts that the other vehicle will obstruct the path of the moving body and determines that the leading vehicle is moving.

5. A driving assistance device including a controller that detects a vehicle preceding a host vehicle and controls a vehicle speed of the host vehicle so that a vehicle-to-vehicle distance between the preceding vehicle and the host vehicle becomes a target vehicle-to-vehicle distance, the controller comprising: A process of detecting another vehicle that may enter between the host vehicle and the preceding vehicle from a lane different from the lane in which the host vehicle is currently traveling; a process of predicting whether the other vehicle will obstruct a path of a moving body other than the other vehicle by stopping midway in the path of the other vehicle; a process of determining whether the preceding vehicle is moving; a process of setting the target inter-vehicle distance to a predetermined first distance when it is not predicted that the other vehicle will obstruct the path of the moving body or when it is not determined that the preceding vehicle is moving, and setting the target inter-vehicle distance to a second distance longer than the first distance when it is predicted that the other vehicle will obstruct the path of the moving body and it is determined that the preceding vehicle is moving; A driving assistance device characterized by executing the above.

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