Driving assistance method and driving assistance device

Abstract

To continue driving assistant control even if an own vehicle deviates from a target traveling path while suppressing increase in the volume of stored lane information used for driving assistance control.SOLUTION: A driving support method includes the steps of: acquiring lane information for a first lane L1 of a first road R1 on which an own vehicle 1 is traveling in a range ahead of the own vehicle 1; acquiring lane information for a second lane L2 branching from the first lane L1 ahead of the own vehicle 1 and extending into a second road branching from the first road R1; determining whether or not a position of the own vehicle 1 in a lane width direction has advanced by a predetermined length or more beyond a lane boundary line Lb between the first lane L1 and the second lane L2; and discarding the lane information of the first lane L1 when it is determined that the position of the own vehicle in the lane width direction has advanced by the predetermined length or more beyond the lane boundary line Lb.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 proposes a map information generating device that reduces the capacity of map information generated for use in automatic driving control of a vehicle. This map information generating device generates and outputs route information within a first distance range from the current position of the vehicle, and first map information within a second distance range from the current position of the vehicle that is shorter than the first distance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-184499 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if lane information is acquired only for the target driving route along which the vehicle is scheduled to travel, the lane information cannot be used when the vehicle deviates from the target driving route, and driving assistance control cannot be continued. On the other hand, if lane information other than that for the target driving route is continuously stored, the memory capacity for storing lane information increases. The present invention aims to continue driving assistance control even when the host vehicle deviates from a target driving route, while suppressing an increase in the storage capacity of lane information used for driving assistance control. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a driving assistance method for assisting a host vehicle in traveling along a target traveling route from a current position to a destination based on lane information. The driving assistance method causes a controller to execute the following processes: acquiring lane information of a first lane of a first road on which the host vehicle is traveling in a range ahead of the host vehicle; acquiring lane information of a second lane that branches off from the first lane ahead of the host vehicle and extends to a second road branching off from the first road; determining whether the lane width direction position of the host vehicle has progressed beyond the lane boundary line between the first lane and the second lane by a predetermined length or more; and discarding the lane information of the first lane when it is determined that the lane width direction position has progressed beyond the lane boundary line by the predetermined length or more. Effect of the Invention

[0006] According to the present invention, it is possible to continue driving assistance control even if the host vehicle deviates from the target driving route, while suppressing an increase in the storage capacity of lane information used for driving assistance control of the host vehicle. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a vehicle equipped with a driving assistance device according to an embodiment; [Diagram 2] FIG. 2 is a diagram showing a part of the input device of FIG. [Diagram 3] FIG. 13 is an explanatory diagram of an example of a condition for discarding lane information of a first lane. [Figure 4] FIG. 13 is an explanatory diagram of an example of a condition for discarding lane information of the second lane. [Diagram 5] FIG. 2 is a block diagram illustrating an example of a functional configuration of a route driving support function. [Figure 6] 4 is a flowchart of an example of a driving assistance method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same or similar parts are given the same or similar reference numerals, and duplicated explanations are omitted. Each drawing is a schematic diagram, and may differ from the actual one. The embodiments shown below are examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the devices and methods exemplified in the following embodiments. The technical idea of ​​the present invention can be modified in various ways within the technical scope described in the claims.

[0009] (composition) 1 is a diagram showing an example of a schematic configuration of a vehicle equipped with a driving support device according to an embodiment. The driving support device 10 equipped in the vehicle 1 includes a sensor 11, a positioning device 12, a map database (map DB) 13, an in-vehicle device 14, a navigation system 15, a display device 16, a voice output device 17, an input device 18, a vehicle behavior control device 19, and a controller 20. These devices are connected to each other by, for example, a CAN (Controller Area Network) or other in-vehicle LAN in order to transmit and receive information to and from each other.

[0010] The sensor 11 detects the traveling state of the vehicle 1. For example, the sensor 11 includes cameras such as a front camera that captures an image in front of the vehicle 1, a rear camera that captures an image behind the vehicle 1, and a side camera that captures an image on the left and right sides of the vehicle 1. The sensor 11 also includes radars such as a front radar that detects an obstacle in front of the vehicle 1, a rear radar that detects an obstacle behind the vehicle 1, and a side radar that detects an obstacle on the left and right sides of the vehicle 1. The sensor 11 also includes a vehicle speed sensor that detects the speed of the vehicle 1, a touch sensor (capacitive sensor) that detects the holding of the steering wheel by an occupant (e.g., the driver), and an in-vehicle camera that captures an image of the occupant.

[0011] The positioning device 12 includes a GPS unit, a gyro sensor, a vehicle speed sensor, etc. The positioning device 12 detects radio waves transmitted from a plurality of satellite communications by the GPS unit, and periodically acquires position information of the vehicle 1. The positioning device 12 also detects the current position of the vehicle 1 based on the acquired position information of the vehicle 1, angle change information acquired from the gyro sensor, and vehicle speed acquired from the vehicle speed sensor.

[0012] The map database 13 is a memory that stores three-dimensional high-precision map information including position information of various facilities and specific points, and is accessible from the controller 20. The three-dimensional high-precision map information is three-dimensional map information based on road shapes detected when an actual road is traveled using a data acquisition vehicle. The three-dimensional high-precision map information is map information in which detailed and highly accurate position information such as curved roads and the magnitude of the curve (e.g., curvature or curvature radius), road junctions, branching points, toll gates, and positions where the number of lanes decreases is associated as three-dimensional information in addition to the map information.

[0013] In addition, the three-dimensional high-precision map information includes, as lane-by-lane information (i.e., lane information), information on lane nodes indicating reference points on lane reference lines (e.g., the center line within a lane) and information on lane links indicating the section configuration of the lane between the lane nodes. The lane node information includes the lane node's identification number, position coordinates, the number of connected lane links, and the identification numbers of the connected lane links. The lane link information includes the lane link's identification number, lane type, lane width, lane boundary type, lane shape, lane division shape, and lane reference line shape. The 3D high precision map information may further include information on the features, such as the types and position coordinates of features on or near the lane, such as traffic lights, stop lines, signs, buildings, utility poles, curbs, and pedestrian crossings, and the identification numbers of lane nodes and lane link identification numbers corresponding to the feature position coordinates.

[0014] The in-vehicle devices 14 are various devices mounted on the vehicle 1 and are operated by the driver of the vehicle. Examples of such in-vehicle devices include a steering wheel, an accelerator pedal, a brake pedal, a turn signal, wipers, lights, a horn, and other specific switches. The navigation system 15 acquires current position information of the vehicle 1 from the positioning device 12, and displays the position of the vehicle 1 on a display or the like by superimposing the position of the vehicle 1 on map information for navigation. The navigation system 15 also has a navigation function that, when a destination is set, sets a route to the destination and guides the occupant along the set route. This navigation function displays the route on a map on the display and informs the occupant of the route by voice or the like. The route set by the navigation system 15 is also used by a route driving assistance function provided in the controller 20. The route driving assistance function is a function that causes the vehicle 1 to autonomously drive to the destination based on the set route.

[0015] The display device 16 includes various displays, such as a display provided in the navigation system 15, a display built into a rearview mirror, a display built into a meter section, a head-up display projected on the windshield, etc. The display device 16 notifies the occupant of various pieces of presented information under the control of the controller 20. The audio output device 17 is a device that outputs auditory information such as a speaker provided in the navigation system 15, a speaker of an audio device, a buzzer, etc. Under the control of the controller 20, the audio output device 17 notifies the occupant of various pieces of presentation information.

[0016] The input device 18 is, for example, a button switch that allows the occupant to manually input information, a touch panel arranged on a display screen, or a microphone that allows the occupant to input information by voice. By operating the input device 18, the occupant can input setting information for the presentation information presented by the display device 16 and the audio output device 17. 2 is a diagram showing a part of the input device 18 of this embodiment. The input device 18 may be, for example, a group of button switches arranged on the spokes of a steering wheel. The input device 18 is used when setting the on / off of an autonomous driving control function provided in the controller 20. The input device 18 includes a main switch 181, a resume / accelerate switch 182, a set / coast switch 183, a cancel switch 184, a vehicle distance adjustment switch 185, and a lane change assist switch 186.

[0017] The main switch 181 is a switch for turning on / off the autonomous driving control function of the controller 20. The resume / accelerate switch 182 is a switch for setting the autonomous driving control function to resume at the set speed before the autonomous driving control function was turned off after it was turned off, or for increasing the set speed. The set / coast switch 183 is a switch for starting the autonomous driving control function. To start the autonomous driving control function, the set / coast switch 183 is pressed after the autonomous driving control function is turned on by the main switch 181. The set / coast switch 183 is also a switch for lowering the set speed. The cancel switch 184 is a switch for canceling the autonomous driving control function. The vehicle distance adjustment switch 185 is a switch for setting the vehicle distance from the preceding vehicle. The lane change assistance switch 186 is a switch for instructing (agreeing to) start lane change when the controller 20 has confirmed with the occupant that the lane change should be started. 2, a turn signal lever of a turn signal or other switches of the in-vehicle device 14 can be used as the input device 18. For example, when the controller 20 suggests whether or not to automatically change lanes, if the occupant operates the turn signal lever, the vehicle will change lanes in the direction in which the turn signal lever was operated, rather than the suggested lane change.

[0018] The vehicle behavior control device 19 controls the vehicle behavior of the vehicle 1. For example, when the vehicle 1 travels at a constant speed at a set speed due to the autonomous driving control function, the vehicle behavior control device 19 controls the operation of the drive mechanism and the brake operation to realize the acceleration / deceleration and traveling speed so that the vehicle 1 reaches the set speed. In addition, the vehicle behavior control device 19 also controls the operation of the drive mechanism and the brake in the same manner when the vehicle 1 travels following a preceding vehicle due to the autonomous driving control function. Note that the operation control of the drive mechanism includes the operation of the internal combustion engine in an engine vehicle and the operation of the driving motor in an electric vehicle system. In addition, in a hybrid vehicle, it includes the torque distribution between the internal combustion engine and the driving motor. In addition, when the vehicle behavior control device 19 uses the autonomous driving control function to execute lane keeping control, lane change assistance function, overtaking assistance function, or route driving assistance function described below, it performs steering control of the vehicle 1 by controlling the operation of the steering actuator in addition to controlling the operation of the drive mechanism and brakes.

[0019] The controller 20 is one or more electronic control units (ECUs) for controlling the running of the vehicle 1, and includes a processor 21 and peripheral components such as a storage device 22. The processor 21 may be, for example, a central processing unit (CPU) or a micro-processing unit (MPU). The storage device 22 may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The storage device 22 may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main storage device, and a RAM (Random Access Memory). The functions of the controller 20 described below are realized, for example, by the processor 21 executing a computer program stored in the storage device 22. The controller 20 may be formed of dedicated hardware for executing each information processing described below. For example, the controller 20 may include a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the controller 20 may include a programmable logic device (PLD) such as a field programmable gate array (FPGA).

[0020] The controller 20 realizes a driving information acquisition function for acquiring information about the driving state of the vehicle 1, and an autonomous driving control function for autonomously controlling the driving speed and / or steering of the vehicle 1. The driving information acquisition function of the controller 20 is a function for acquiring driving information about the driving state of the vehicle 1. For example, the controller 20 may acquire image information of the outside of the vehicle captured by the front camera, rear camera, and side camera of the sensor 11 as the driving information. The controller 20 also acquires detection results by the front radar, rear radar, and side radar as the driving information. Furthermore, the controller 20 also acquires vehicle speed information of the vehicle 1 detected by the vehicle speed sensor of the sensor 11 and image information of the face of the occupant captured by the in-vehicle camera as the driving information.

[0021] Furthermore, the controller 20 acquires, as the travel information, current position information of the vehicle 1 from the positioning device 12. The controller 20 also acquires, as the travel information, the set destination and the route to the destination from the navigation system 15. Furthermore, the controller 20 acquires, as driving information, map information from the map database 13, such as position information about curved roads and the magnitude of the curve (e.g., curvature or radius of curvature), merging points, branching points, toll booths, and locations where the number of lanes is reduced, as well as lane information about lanes. In addition, the controller 20 acquires operation information of the in-vehicle device 14 by the occupant from the in-vehicle device 14 as driving information.

[0022] The autonomous driving control function of the controller 20 is a function for autonomously controlling the driving of the vehicle 1 without relying on the operation of the occupant. The autonomous driving control function of the controller 20 includes an autonomous speed control function for autonomously controlling the driving speed of the vehicle 1, and an autonomous steering control function for autonomously controlling the steering of the vehicle 1. The autonomous speed control function and the autonomous steering control function of this embodiment will be described below. Autonomous speed control function The autonomous speed control function is a function that, when a preceding vehicle is detected, follows the preceding vehicle while controlling the vehicle distance so as to maintain a vehicle distance according to the vehicle speed, with the vehicle speed set by the occupant as the upper limit. On the other hand, when a preceding vehicle is not detected, the autonomous speed control function performs constant speed driving at the vehicle speed set by the occupant. The former is also called vehicle distance control, and the latter is called constant speed control. The autonomous speed control function may include a function that detects the speed limit of the road being traveled from road signs using the sensor 11, or obtains the speed limit from map information in the map database 13, and automatically sets the speed limit to the set vehicle speed.

[0023] The constant speed control is executed when the forward radar of the sensor 11 or the like detects that there is no preceding vehicle ahead in the own lane. In the constant speed control, the vehicle behavior control device 19 controls the operation of the drive mechanisms such as the engine and brakes while feeding back the vehicle speed data from the vehicle speed sensor so as to maintain the set traveling speed. The vehicle distance control is executed when the forward radar of the sensor 11 detects the presence of a preceding vehicle ahead in the own lane. In the vehicle distance control, the vehicle behavior control device 19 controls the operation of the drive mechanisms such as the engine and brakes while feeding back the vehicle distance data detected by the forward radar so as to maintain the set vehicle distance with the set travel speed as the upper limit.

[0024] Autonomous steering control function The autonomous steering control function is a function that executes steering control of the vehicle 1 by controlling the operation of the steering actuator based on the driving information acquired by the driving information acquisition function. The autonomous steering control function includes, for example, a lane keeping function, a lane change assist function, an overtaking assist function, and a route driving assist function. The lane keeping function is a function that assists the occupant in steering the vehicle by controlling the steering actuator so that the vehicle stays in the center of the lane, for example.

[0025] When the set / coast switch 183 is pressed after the autonomous driving control function is turned on by the main switch 181, the controller 20 judges whether or not a predetermined autonomous driving control start condition is satisfied. If it is judged that the autonomous driving control start condition is satisfied, the controller 20 executes the lane keeping function of the autonomous steering control function. Alternatively, when an autonomous driving control start condition is satisfied after the autonomous driving control function is turned on by the main switch 181, the controller 20 waits for the set / coast switch 183 to be pressed. When the set / coast switch 183 is pressed, the controller 20 starts the autonomous driving control and executes the lane keeping function of the autonomous steering control function.

[0026] Lane change assistance function The lane change assist function turns on the turn signal when the driver operates the turn signal lever, and when a predetermined lane change start condition is met, starts a lane change operation, which is a series of processes for changing lanes on a vehicle. The lane change assist function determines whether or not the predetermined lane change start condition is met based on various driving information acquired by the driving information acquisition function. The lane change assist function starts a lane change operation when the lane change start conditions are met. In the lane change operation, the vehicle 1 is moved laterally to the adjacent lane, and when the movement to the adjacent lane is completed, the turn signal is turned off and the lane keeping function in the adjacent lane is started.

[0027] Overtaking Assistance Function The overtaking support function presents overtaking information to the occupant via the display device 16 when there is a preceding vehicle slower than the vehicle 1 ahead in the own lane and when a predetermined overtaking suggestion condition is satisfied. Here, the overtaking information is information for suggesting to the occupant to overtake the preceding vehicle. When the occupant accepts the overtaking information presented by operating the lane change support switch 186 of the input device 18 and a preset overtaking start condition is satisfied, the overtaking support function turns on the turn signal and starts the above-mentioned lane change operation. Based on various driving information acquired by the driving information acquisition function, the overtaking support function judges whether the overtaking suggestion condition and the overtaking start condition are satisfied.

[0028] Route driving support function The route driving assistance function presents route driving information on the display device 16 and suggests a lane change to the driving direction change point when a branch point, junction point, exit, toll gate, or other driving direction change point exists on the set route, the distance to the driving direction change point is within a predetermined distance, and predetermined route driving suggestion conditions are satisfied. In addition, the route driving assistance function starts a lane change operation when the lane change suggestion is accepted by operating the lane change assistance switch 186 and predetermined route driving start conditions are satisfied. The route driving assistance function determines whether or not the route driving suggestion conditions and the route driving start conditions are met based on various driving information acquired by the driving information acquisition function.

[0029] These autonomous steering control functions perform driving assistance control of the vehicle 1 by executing steering control of the vehicle 1 based on map information acquired by the driving information acquisition function. Therefore, if map information of only the lanes of the route on which the vehicle 1 is scheduled to travel is acquired, the map information cannot be used if the vehicle 1 deviates from the route, and driving assistance control cannot be continued. For this reason, in addition to map information of lanes of the route along which vehicle 1 is scheduled to travel, map information of lanes other than those of the route along which vehicle 1 is scheduled to travel is also acquired.

[0030] Referring to Fig. 2, it is assumed that a vehicle 1 is traveling on a first lane L1 of a first road R1. The number of lanes is increased by dividing the first lane L1 into a second lane L2 and the first lane L1 at a point ahead of the vehicle 1. For example, the second lane L2 may be a lane that branches off from the first road R1 and extends to a second road (not shown) that runs in a different direction from the first road R1, and the second road can be reached by traveling a not-so-long distance (e.g., 1.5 km) from the point where the first lane L1 and the second lane L2 divide. In the following description, a section in which the number of lanes increases as a result of the first lane L1 splitting into the second lane L2 and the first lane L1 will be referred to as a "lane increase section S1."

[0031] If the route that the vehicle 1 is scheduled to travel, as set by the navigation system 15, recommends continuing traveling on the first road R1 rather than heading toward the second road, the controller 20 acquires map information (e.g., lane information) for a predetermined distance (e.g., 7 km) ahead of the vehicle 1, not only for the first lane L1 but also for the second lane L2. Similarly, if the route along which vehicle 1 is planned to travel recommends traveling toward the second road, map information is obtained for a predetermined distance ahead of vehicle 1 for not only the second lane L2 but also the first lane L1.

[0032] However, if map information for both the first lane L1 and the second lane L2 is continuously acquired and stored, the storage capacity for storing the map information increases. For example, assume that map information for both lanes is retained until the first lane L1 and the second lane L2 split and it becomes impossible to change lanes, and when this point is reached, the map information for the lane in which the vehicle 1 is not traveling is deleted. In this case, if a point where the route splits is found ahead while the map information for both lanes is being retained, map information for the new lane must be added and retained, which increases the storage capacity.

[0033] In order to reduce the storage capacity, it is conceivable to delete the map information of the first lane L1 when, for example, a turn signal for changing lanes from the first lane L1 to the second lane L2 is turned on. However, if the vehicle continues to travel on the first lane L1 after the turn signal is turned on by the driver's driving operation, it becomes necessary to reacquire the map information of the first lane L1, which increases the processing load for reacquiring the map information.

[0034] Therefore, in order to reduce the above-mentioned processing load while suppressing an increase in memory capacity for storing map information, the controller 20 of this embodiment deletes the map information of the first lane L1 at the time when the vehicle 1 crosses the lane boundary line Lb between the first lane L1 and the second lane L2 when changing lanes from the first lane L1 to the second lane L2. By deleting the map information for the first lane L1 at such a timing, the memory capacity required to store the map information can be reduced compared to the case where the map information for the first lane L1 and the second lane L2 is continued to be stored as described above. In addition, since the vehicle 1 has crossed the lane boundary line Lb and traveled a predetermined distance or more, it is unlikely that the driver will subsequently operate the vehicle in the first lane L1, which reduces the processing load of reacquiring map information by continuing to drive in the first lane L1 after deleting the map information for the first lane L1.

[0035] For example, when the vehicle 1 changes lanes from the first lane L1 to the second lane L2, the controller 20 deletes the map information of the first lane L1 at the timing when the position P1 of the vehicle 1 crosses the lane boundary line Lb and the lane width direction position of the position P1 advances toward the second lane L2 by a predetermined length or more (i.e., the timing when the position P1 is in the second lane L2 and the lane width direction distance d2 between the position P1 and the lane boundary line Lb increases to a predetermined length or more). For example, the position P1 of the vehicle 1 may be the center of the vehicle 1 (e.g., the center of gravity position or the geometric center of the vehicle body). The predetermined length may be a value such as 30 cm.

[0036] Referring to FIG. 4, when the vehicle 1 continues traveling on the first lane L1 without changing lanes to the second lane L2, the map information of the second lane L2 is deleted at the timing when the position P1 of the vehicle 1 passes a lane increase completion point P2, which is a point where the lane width w1 of the second lane L2, which increases in the lane increase section S1, increases and reaches a threshold value or more. For example, the threshold value may be set according to the lane width of the first lane L1. For example, the threshold value may be set to a value equal to the lane width of the first lane L1, or may be set to a value obtained by subtracting a predetermined margin from the lane width of the first lane L1. By deleting the map information for the second lane L2 at such a timing, the memory capacity required to store the map information can be reduced compared to the case where the map information for the first lane L1 and the second lane L2 is continued to be stored as described above. In addition, since the vehicle 1 continues to travel in the first lane L1 even after passing the lane increase completion point P2, it is unlikely that the driver will subsequently change lanes to the second lane L2 due to the driving operation of the vehicle 1. This makes it possible to suppress the processing load of re-acquiring map information caused by changing lanes to the second lane L2 after the map information of the second lane L2 is deleted.

[0037] 5 is a block diagram of an example of the functional configuration of the route driving support function. The controller 20 functions as a map information acquisition unit 30, a navigation information acquisition unit 31, a self-location information acquisition unit 32, a map information processing unit 33, a lane change request determination unit 34, a surrounding situation recognition unit 35, a lane change possibility determination unit 36, and a lane change state management unit 37. The map information acquiring unit 30 acquires map information from the map database 13 or a communication device (not shown). For example, the map information acquiring unit 30 may acquire high-precision three-dimensional map information and map information for navigation as the map information. The navigation information acquisition unit 31 acquires route information relating to a route from the current position to a destination from the navigation system 15. The self-position information acquisition unit 32 acquires current position information on the current position of the vehicle 1 from the positioning device 12 .

[0038] The map information processing unit 33 acquires, from the map information acquisition unit 30, three-dimensional high-precision map information of a predetermined range in the vicinity of the current position of the vehicle 1. The lane change request determination unit 34 determines whether or not there is a request for a lane change due to the route driving assistance function. The surrounding condition recognition unit 35 recognizes the surrounding conditions of the vehicle 1. For example, the surrounding condition recognition unit 35 recognizes objects present around the vehicle 1 (for example, adjacent vehicles that are other vehicles traveling in adjacent lanes, a vehicle preceding the vehicle 1, a following vehicle, and obstacles on the lane) and lane boundary lines (for example, lane marks, etc.) as the surrounding conditions. The surrounding condition recognition unit 35 outputs surrounding environment information to the lane change feasibility determination unit 36 ​​and the lane change state management unit 37.

[0039] The lane change feasibility determination unit 36 ​​determines whether or not a lane change is possible using the route driving assistance function based on the surrounding conditions of the vehicle 1 and the internal state of the vehicle 1. For example, the lane change feasibility determination unit 36 ​​determines whether or not the above-mentioned route driving start condition is satisfied. If the route driving start condition is satisfied, the lane change is permitted using the route driving assistance function, and if not satisfied, the lane change is prohibited. The route travel start condition may be, for example, that all of the following conditions are met. The lane keeping function is active. Hands-on evaluation is currently underway. - Driving at a speed of 60km / h or more. There is a lane in the direction you want to change lanes. -There is space to change lanes in the lane you are about to change lanes into. -The type of lane markings indicates that lane changes are possible. - The vehicle is traveling within a specified distance to the branch point. - The curvature radius of the road is less than 250m.

[0040] The lane change state management unit 37 determines, based on the determination result of the lane change request determination unit 34, whether or not the above-mentioned route driving suggestion conditions are satisfied when a lane change is requested by the route driving assistance function. The route travel suggestion condition may be, for example, that all of the following conditions are satisfied. The lane keeping function is active. A destination is set in the navigation system15. - Driving at a speed of 60km / h or more. There is a lane in the direction you want to change lanes. -The type of lane markings indicates that lane changes are possible. -The road curvature radius is 250m or more.

[0041] When the route travel suggestion conditions are satisfied, the lane change state management unit 37 presents route travel information on the display device 16 and / or the audio output device 17 and suggests a lane change. When the lane change suggestion is accepted by operating the lane change assistance switch 186 and a predetermined route travel start condition is satisfied, the lane change permission determination unit 36 ​​determines whether or not the lane change is permitted. When the lane change is permitted, the lane change state management unit 37 starts the lane change operation. If the occupant does not consent to the lane change, or if the lane change permission determination unit 36 ​​does not permit the lane change, the lane change state management unit 37 maintains the current driving lane without performing a lane change operation. The vehicle behavior control device 19 executes steering control of the vehicle 1 by controlling the operation of the steering actuator based on a command from the lane change state management unit 37 .

[0042] FIG. 6 is a flowchart of an example of a driving assistance method according to the embodiment. In step S1, the map information processing unit 33 acquires, from the map information acquisition unit 30, three-dimensional high-precision map information of a predetermined range around the current position of the vehicle 1, based on the route information acquired by the navigation information acquisition unit 31 and the self-position information acquired by the self-position information acquisition unit 32. Specifically, the map information processing unit 33 acquires three-dimensional high-precision map information of the first lane L1 on which the vehicle 1 is currently traveling, within a range from the current position to a predetermined distance ahead. The predetermined distance may be, for example, 7 km.

[0043] In step S2, the map information processor 33 determines whether or not a lane increase section S1 exists within a predetermined distance d1 [km] ahead of the current position of the vehicle 1 on the first lane based on the acquired map information. The predetermined distance d1 may be, for example, 2 [km]. If a lane increase section S1 exists (step S2: Y), the process proceeds to step S4. If the lane increase section S1 does not exist (step S2: N), the 3D high-precision map information of only the first lane L1 has been acquired. In this case, the process proceeds to step S3, and the map information processing unit 33 holds the 3D high-precision map information of only the first lane L1. Then, the process ends.

[0044] In step S4, the map information processor 33 acquires three-dimensional high-precision map information of the second lane L2 within a range from the current position to a predetermined distance ahead. The predetermined distance may be, for example, 7 km. In step S5, the map information processing unit 33 determines whether the route information acquired by the navigation information acquisition unit 31 recommends traveling in the first lane L1 or the second lane L2. If the second lane L2 is recommended (step S5: Y), the process proceeds to step S6. If the first lane L1 is recommended (step S5: N), the process proceeds to step S11.

[0045] In step S6, the lane change request determination unit 34 determines that there is a request to change lanes to the second lane L2 based on the determination result of the map information processing unit 33. The lane change state management unit 37 determines whether or not the route travel suggestion conditions are satisfied, and if the route travel suggestion conditions are satisfied, suggests to the occupant to change lanes to the second lane L2. The lane change state management unit 37 determines whether or not an occupant is interfering with the lane change to the second lane L2.

[0046] For example, the lane change state management unit 37 determines whether the occupant has accepted the lane change suggestion. If the occupant does not accept the suggestion, it is determined that there is occupant interference, and if the occupant accepts the suggestion, it is determined that there is no occupant interference. For example, if the occupant does not operate the lane change assistance switch 186 while traveling for a predetermined time (e.g., 30 [seconds]) or a predetermined distance (e.g., 700 [m]) after the lane change suggestion, it may be determined that the occupant has not accepted the suggestion. Also, for example, it may be determined that there is occupant interference when the occupant intervenes in steering or operates a turn signal at an inappropriate time. If there is no occupant interference (step S6: N), the process proceeds to step S7. If there is occupant interference (step S6: Y), the process proceeds to step S11.

[0047] In step S7, the lane change possibility determination unit 36 ​​determines whether there is a reason not to proceed into the second lane L2. For example, the lane change possibility determination unit 36 ​​may determine whether a route travel start condition is satisfied. The lane change possibility determination unit 36 ​​may determine that there is a reason not to proceed into the second lane L2 when the route travel start condition is not satisfied, and may determine that there is no reason when the condition is satisfied. If there is no reason not to proceed into the second lane L2 (step S7: N), the process proceeds to step S8. If there is a reason not to proceed into the second lane L2 (step S7: Y), the process proceeds to step S11.

[0048] In step S8, the lane change state management unit 37 starts a lane change operation from the first lane L1 to the second lane L2. Map information and surrounding environment information for proceeding to the second lane L2 are sent to the vehicle behavior control device 19, which calculates a target steering angle and controls the operation of the steering actuator to make the vehicle 1 change lanes. In step S9, the map information processing unit 33 determines whether the position P1 of the vehicle 1 has passed the lane boundary line Lb and the lane width direction position of the position P1 has advanced a predetermined length or more toward the second lane L2. If the position P1 has passed the lane boundary line Lb and the lane width direction position has advanced a predetermined length or more toward the second lane L2 (step S9: Y), the process proceeds to step S10. If not (step S9: N), the process returns to step S9. In this case, the map information of both the first lane L1 and the second lane L2 is held until the position P1 has passed the lane boundary line Lb and the lane width direction position has advanced a predetermined length or more toward the second lane L2.

[0049] In step S10, the map information processing unit 33 deletes the map information of the first lane L1. Then, the process ends. Note that the processes in steps S9 and S10 may be executed by the lane change state management unit 37 using the surrounding environment information. On the other hand, if the first lane L1 is recommended (step S5: N), if there is interference from an occupant (step S6: Y), or if there is a reason not to proceed to the second lane L2 (step S7: Y), in step S11, the lane change status management unit 37 decides to travel in the first lane L1 (i.e., not to change lanes to the second lane).

[0050] In step S12, the map information processing unit 33 determines whether the vehicle 1 has traveled along the first lane L1 and passed the lane increase completion point P2. If the vehicle 1 has passed the lane increase completion point P2 (step S12: Y), the process proceeds to step S13. If the vehicle 1 has not yet passed the lane increase completion point P2 (step S12: N), the process returns to step S12. In this case, the map information for both the first lane L1 and the second lane L2 is held until the vehicle 1 passes the lane increase completion point P2. In step S13, the map information processing unit 33 deletes the map information of the second lane L2. Then, the process ends. Note that the processes in steps S12 and S13 may be executed by the lane change state management unit 37 using the surrounding environment information.

[0051] Even if the first lane L1 is recommended (step S5: N), if the vehicle 1 proceeds to the second lane L2 due to the driving operation of the occupant, it may be determined whether the position P1 of the vehicle 1 crosses the lane boundary line Lb and the lane width direction position of the position P1 has progressed toward the second lane L2 by a predetermined length or more. When the lane width direction position of the position P1 has progressed toward the second lane L2 by the predetermined length or more, the map information of the first lane L1 may be deleted.

[0052] (Effects of the embodiment) (1) The driving assistance device 10 assists the vehicle 1 in traveling along a target traveling route from a current position to a destination based on lane information. The controller 20 executes the following processes: acquiring lane information of a first lane of a first road on which the vehicle 1 travels in a range ahead of the vehicle 1; acquiring lane information of a second lane that branches off from the first lane ahead of the vehicle 1 and extends to a second road branching off from the first road; determining whether the lane width direction position of the vehicle 1 has progressed beyond the lane boundary line between the first lane and the second lane by a predetermined length or more; and discarding the lane information of the first lane when it is determined that the lane width direction position has progressed beyond the lane boundary line by the predetermined length or more.

[0053] This makes it possible to reduce the memory capacity required to store map information, compared to the case where map information for the first lane and the second lane is continually stored. In addition, since the vehicle 1 has crossed the lane boundary line and traveled a predetermined distance or more, it is unlikely that the driver will subsequently operate the vehicle in the first lane. Therefore, the processing load of re-acquiring map information caused by continuing to drive in the first lane after deleting the map information for the first lane can be suppressed.

[0054] (2) The controller 20 may execute a process of determining whether or not the vehicle 1 traveling in the first lane has passed a lane increase completion point, which is a point at which the lane width of the second lane branching off from the first lane increases and reaches or exceeds a threshold value, and a process of discarding lane information of the second lane if it is determined that the vehicle 1 traveling in the first lane has passed the lane increase completion point. This makes it possible to reduce the memory capacity required to store map information, compared to the case where map information for the first lane and the second lane is continually stored. In addition, since the vehicle 1 continues to travel in the first lane even after passing the lane increase completion point, it is unlikely that the driver will subsequently change lanes to the second lane. Therefore, it is possible to suppress the processing load of re-acquiring map information caused by changing lanes to the second lane after deleting the map information of the second lane.

[0055] (3) The controller 20 executes a process of determining whether or not it is necessary to change lanes from the first lane to the second lane based on the target driving route, and a process of determining whether or not to change lanes to the second lane if it is determined that it is necessary to change lanes to the second lane.When changing lanes to the second lane, the controller 20 may determine whether or not the lane width direction position of the vehicle 1 has progressed beyond the lane boundary line by a predetermined length or more. As a result, when a lane change is made to the second lane in accordance with the target driving route, the map information for the first lane is deleted, making it possible to reduce the memory capacity required to hold the map information.

[0056] (4) The controller 20 executes a process of determining whether or not it is necessary to change lanes from the first lane to the second lane based on the target driving route, and a process of determining whether or not to change lanes to the second lane if it is determined that it is necessary to change lanes to the second lane. If it is determined that the lane will not be changed to the second lane, the controller 20 may determine whether or not the vehicle 1 has traveled in the first lane and passed the lane increase completion point. As a result, when driving continues on the first lane without following the target driving route, the map information for the second lane is deleted, making it possible to reduce the memory capacity required to hold the map information.

[0057] (5) The controller 20 executes a process to determine whether or not it is necessary to change lanes from the first lane to the second lane based on the target driving route, and if it determines that it is not necessary to change lanes to the second lane, it may determine whether or not the vehicle 1 is traveling in the first lane and has passed the lane increase completion point. As a result, when driving continues on the first lane according to the target driving route, the map information for the second lane is deleted, making it possible to reduce the memory capacity required to hold the map information.

[0058] (6) The controller 20 executes a process to determine whether the vehicle 1 is moving toward the second lane due to steering by the occupant, and if it determines that the vehicle 2 is moving toward the second lane, it may determine whether the lane width direction position of the vehicle 1 has crossed the lane boundary line and traveled a predetermined distance or more. As a result, when the vehicle changes lanes to the second lane without following the target driving route, the map information for the first lane is deleted, making it possible to reduce the memory capacity required to hold the map information. [Explanation of symbols]

[0059] 1...vehicle, 10...driving assistance device, 11...sensor, 12...positioning device, 13...map database, 14...in-vehicle equipment, 15...navigation system, 16...display device, 17...audio output device, 18...input device, 19...vehicle behavior control device, 20...controller, 21...processor, 22...storage device, 30...map information acquisition unit, 31...navigation information acquisition unit, 32...self-position information acquisition unit, 33...map information processing unit, 34...lane change request determination unit, 35...surrounding situation recognition unit, 36...lane change feasibility determination unit, 37...lane change state management unit

Claims

1. A driving assistance method for assisting a host vehicle in traveling along a target traveling route from a current position to a destination based on lane information, comprising: A process of acquiring lane information of a first lane of a first road on which the host vehicle is traveling, the first lane information being obtained in a range ahead of the host vehicle; A process of acquiring lane information of a second lane branching off from the first lane ahead of the host vehicle, the second lane extending onto a second road branching off from the first road; A process of determining whether or not the lane width direction position of the host vehicle has traveled a predetermined length or more beyond the lane boundary line between the first lane and the second lane; a process of discarding the lane information of the first lane and retaining the lane information of the second lane when it is determined that the lane width direction position has passed the lane boundary line by the predetermined length or more; A driving assistance method comprising: causing a controller to execute the above steps.

2. A process of determining whether or not the host vehicle traveling on the first lane has passed a lane increase completion point, which is a point where the lane width of the second lane branching off from the first lane increases and reaches a threshold value or more; discarding the lane information of the second lane when it is determined that the host vehicle has traveled along the first lane and passed the lane increase completion point; The driving support method according to claim 1, further comprising causing the controller to execute the following steps:

3. The controller: A process of determining whether or not it is necessary to change lanes from the first lane to the second lane based on the target driving route; a process of determining whether or not to change lanes to the second lane when it is determined that it is necessary to change lanes to the second lane; and when it is determined that the vehicle should change lanes to the second lane, determining whether the lane width direction position of the vehicle has progressed beyond the lane boundary line by more than the predetermined length.

4. The controller: A process of determining whether or not it is necessary to change lanes from the first lane to the second lane based on the target driving route; a process of determining whether or not to change lanes to the second lane when it is determined that it is necessary to change lanes to the second lane; and when it is determined not to change lanes to the second lane, determining whether the host vehicle has traveled in the first lane and passed the lane increase completion point.

5. The controller executes a process of determining whether or not it is necessary to change lanes from the first lane to the second lane based on the target driving route; The driving assistance method according to claim 2 , further comprising the step of determining whether the host vehicle has traveled along the first lane and passed the lane increase completion point when it is determined that there is no need to change lanes to the second lane.

6. The controller executes a process of determining whether the vehicle is moving toward the second lane due to steering by an occupant, The driving assistance method according to claim 5, further comprising the steps of: when it is determined that the vehicle is traveling toward the second lane, determining whether the lane width direction position of the vehicle has progressed beyond the lane boundary line by more than the specified length.

7. A driving assistance device that assists a host vehicle in traveling along a target traveling route from a current position to a destination based on lane information, A process of acquiring lane information of a first lane of a first road on which the host vehicle is traveling, the first lane information being obtained in a range ahead of the host vehicle; A process of acquiring lane information of a second lane branching off from the first lane ahead of the host vehicle, the second lane extending onto a second road branching off from the first road; A process of determining whether or not the lane width direction position of the host vehicle has progressed beyond a lane boundary line between the first lane and the second lane by a predetermined length or more; a process of discarding the lane information of the first lane and retaining the lane information of the second lane when it is determined that the lane width direction position has progressed beyond the lane boundary line by a predetermined length or more; A driving assistance device comprising a controller that executes the above.

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