Driving assistance method and driving assistance device

Abstract

Provided is a driving assistance method in which a controller performs first lane maintenance assistance (S4, S7) for controlling a vehicle to travel within the same lane without an occupant touching a steering wheel, and an automatic lane change (S2) for controlling the vehicle to change lanes on the condition that the occupant is touching the steering wheel, wherein the controller performs: processing (S1) for selecting, on the basis of a target route, a target lane in which the vehicle should travel; and processing (S9) for performing second lane maintenance assistance in which, when an automatic lane change from the lane that the vehicle is currently travelling in to a target lane includes a first automatic lane change that is from a first lane to a second lane adjacent to the first lane and a second automatic lane change that is from the second lane to a third lane adjacent to the second lane, the vehicle is controlled to travel within the same lane, from the end of the control for the first automatic lane change to the commencement of control for the second automatic lane change, on the condition that the occupant is touching the steering wheel.

Description

[Technical Field]

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

[0002] The following Patent Document 1 describes a vehicle control device that performs an automated lane change from a first lane to a second lane and an automated lane change from the second lane to a third lane in succession. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-138247 Summary of the Invention [Problem to be solved by the invention]

[0004] An automatic lane change function is known that automatically changes lanes when the occupant is in a hands-on state (including a state in which the occupant is touching the steering wheel) and grips the steering wheel.When a vehicle equipped with such an automatic lane change function performs multiple automatic lane changes in succession, including a first automatic lane change followed by a second automatic lane change, if the occupant is allowed to temporarily take their hands off the steering wheel (a state in which the occupant is not touching the steering wheel) after the first automatic lane change, the occupant may feel annoyed when they are asked to take their hands on the steering wheel again immediately after taking their hands off the steering wheel. The present invention aims to eliminate the annoyance of being required to put the driver into a hands-on state immediately after taking his / her hands off the steering wheel when multiple consecutive lane changes are to be made in a vehicle equipped with an automatic lane change function that requires the driver to be in a hands-on state. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a driving assistance method in which a controller performs a first lane keeping assist that controls the host vehicle so that the host vehicle travels within the same lane even if the occupant is not touching the steering wheel, and an automated lane change that controls the host vehicle so that the host vehicle changes lanes on the condition that the occupant is at least touching the steering wheel. The controller performs a process of selecting a target lane in which the host vehicle should travel based on a preset target route, and a process of executing a second lane keeping assist that controls the host vehicle so that the host vehicle travels within the same lane on the condition that the occupant is at least touching the steering wheel from the completion of the first automated lane change control to the start of the second automated lane change control when the automated lane change from a current lane in which the host vehicle is currently traveling to a target lane includes a first automated lane change from a first lane to a second lane adjacent to the first lane and a second automated lane change from the second lane to a third lane adjacent to the second lane. [Effects of the Invention]

[0006] According to the present invention, when a vehicle equipped with an automatic lane change function that requires a hands-on state is required to make multiple consecutive automatic lane changes, the annoyance of being required to return to a hands-on state immediately after taking your hands off the steering wheel can be eliminated. The objects and advantages of the invention will be realized and attained by means of the elements and combinations set forth in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a vehicle equipped with a driving assistance device according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating a part of the input device of FIG. [Figure 3] FIG. 10 is an example of a state transition diagram of an operation mode of the controller. [Figure 4] FIG. 2 is an explanatory diagram of an automobile lane change performed by the driving assistance device according to the embodiment. [Figure 5] FIG. 2 is an explanatory diagram of an automobile lane change performed by the driving assistance device according to the embodiment. [Figure 6] FIG. 2 is an explanatory diagram of an automobile lane change performed by the driving assistance device according to the embodiment. [Figure 7] FIG. 2 is an explanatory diagram of an automobile lane change performed by the driving assistance device according to the embodiment. [Figure 8] FIG. 2 is a block diagram illustrating an example of a functional configuration of a controller for performing route driving assistance control. [Figure 9] 1 is a flowchart illustrating an example of a driving assistance method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (composition) 1 is a diagram showing an example of a schematic configuration of a vehicle equipped with a driving assistance device according to an embodiment. The driving assistance device 10 equipped in the vehicle 1 includes a sensor 11, a positioning device 12, a map database (map DB) 13, on-board equipment 14, a navigation system 15, a display device 16, an audio output device 17, an input device 18, a vehicle behavior control device 19, and a controller 20. These devices are connected to each other via, for example, a CAN (Controller Area Network) or other on-board LAN for transmitting and receiving information to and from each other.

[0009] The sensor 11 detects the traveling state of the host vehicle 1. For example, the sensor 11 includes cameras that capture images in front of, behind, and on the sides of the host vehicle 1. The sensor 11 also includes radars that detect obstacles in front of, behind, and on the sides of the host vehicle 1. The sensor 11 includes a vehicle speed sensor that detects the speed of the host vehicle 1, a touch sensor that detects whether the occupant is holding the steering wheel, and an occupant monitor that captures images of the occupant. The positioning device 12 includes a GPS unit, a gyro sensor, and the like. The positioning device 12 periodically acquires position information of the host vehicle 1 using the GPS unit. The positioning device 12 also detects the current position of the host vehicle 1 based on the position information of the host vehicle 1, angle change information acquired from the gyro sensor, and the vehicle speed acquired from the vehicle speed sensor.

[0010] 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 map information that is associated as three-dimensional information with detailed and high-precision position information such as curved roads and the size of the curves (for example, curvature or curvature radius), road junctions, branching points, toll booths, and positions where the number of lanes decreases, along with the map information.

[0011] The in-vehicle devices 14 are various devices mounted on the vehicle 1 and are operated by the operation of a passenger (e.g., the driver). 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, superimposing it on map information for navigation. Furthermore, when a destination is set, the navigation system 15 sets a route from the current position of the vehicle 1 to the destination as a target driving route, and executes navigation control to guide the occupant along the target driving route. In this navigation control, the navigation system 15 displays the target driving route on a map on the display and notifies the occupant of the target driving route by voice or the like. The target driving route set by the navigation system 15 is also used in route driving assistance control by the controller 20. The route driving assistance control is control to autonomously drive the vehicle 1 along the target driving route.

[0012] The display device 16 includes various displays provided at positions visible to the occupants. The display device 16 notifies the occupants of various pieces of presentation 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. The audio output device 17 notifies the occupants of various pieces of presentation information under the control of the controller 20. The input device 18 is, for example, a button switch that can be manually operated by the occupant to input information, a touch panel arranged on the display screen, or a microphone that can be used for voice input by the occupant. By operating the input device 18, the occupant can input setting information for the information presented by the display device 16 and the audio output device 17.

[0013] FIG. 2 is a diagram illustrating a portion of the input device 18 according to this embodiment. The input device 18 may be, for example, a group of button switches arranged on the spokes of the steering wheel. The input device 18 is used to turn autonomous driving control by the controller 20 on / off. The input device 18 includes a main switch 181, a resume / accelerate switch 182, a set / coast switch 183, a cancel switch 184, a distance adjustment switch 185, and a lane change assist switch 186. The main switch 181 is a switch that turns autonomous driving control by the controller 20 on / off. The resume / accelerate switch 182 is a switch that sets the autonomous driving control to resume at the set speed before turning off the autonomous driving control after turning it off, or that increases the set speed. The set / coast switch 183 is a switch that starts autonomous driving control. To start autonomous driving control, the autonomous driving control is turned on by the main switch 181, and then the set / coast switch 183 is pressed. The set / coast switch 183 is a switch for lowering the set speed. The cancel switch 184 is a switch for canceling autonomous driving control. The distance adjustment switch 185 is a switch for setting the distance from the vehicle ahead. The lane change assistance switch 186 is a switch for instructing (approving) the start of a lane change when the controller 20 has confirmed with the occupant that the lane change should be started. In addition to the button switches shown in FIG. 2, the turn signal lever of a turn signal or other switches of the in-vehicle equipment 14 can also be used as the input device 18.

[0014] The vehicle behavior control device 19 controls the vehicle behavior of the host vehicle 1. For example, when the host vehicle 1 travels at a constant speed at a set speed under autonomous travel control, the vehicle behavior control device 19 controls the operation of the drive mechanism and the brakes to achieve acceleration / deceleration and travel speed so that the host vehicle 1 reaches the set speed. The vehicle behavior control device 19 also controls the operation of the drive mechanism and the brakes in the same way when the host vehicle 1 travels following a preceding vehicle under autonomous travel control. Note that the control of the operation of the drive mechanism includes the operation of the internal combustion engine in an engine vehicle and the operation of the traction motor in an electric vehicle. In addition, in a hybrid vehicle, it includes the torque distribution between the internal combustion engine and the traction motor. In addition, when the vehicle behavior control device 19 performs autonomous steering control, which will be described later, through autonomous driving control, it controls the operation of the steering actuator in addition to controlling the operation of the drive mechanism and brakes to perform steering control of the vehicle 1.

[0015] The controller 20 is one or more electronic control units (ECUs) for controlling the traveling of the host vehicle 1, and includes a processor 21 and peripheral components such as a storage device 22. The processor 21 may be, for example, a CPU or an MPU. The storage device 22 may include a semiconductor storage device, a magnetic storage device, an optical storage device, or the like. The storage device 22 may include memories such as a register, a cache memory, and a ROM and RAM used as a main storage device. 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.

[0016] The controller 20 realizes a driving information acquisition function that acquires information about the driving state of the host vehicle 1, and executes autonomous driving control that autonomously controls the driving speed and / or steering of the host vehicle 1. The driving information acquisition function is a function that acquires driving information about the driving state of the host vehicle 1. For example, the controller 20 acquires, as driving information, image information of the outside of the vehicle captured by the camera of the sensor 11, detection results by radar, and vehicle speed information from a vehicle speed sensor.

[0017] Furthermore, the controller 20 acquires, as the driving information, current position information of the vehicle 1 from the positioning device 12. The controller 20 acquires, as the driving information, a set destination and a target driving route to the destination from the navigation system 15. The controller 20 acquires, as the driving information, position information such as curved roads and the magnitude of the curves (for example, curvature or curvature radius), merging points, branching points, toll gates, and positions where the number of lanes decreases, as well as map information such as lane information, from the map database 13. The controller 20 acquires, as the driving information, operation information of the in-vehicle device 14 by the occupant from the in-vehicle device 14.

[0018] In the autonomous driving control, the controller 20 autonomously controls the driving of the host vehicle 1 without relying on the operation of the occupant. The autonomous driving control includes autonomous speed control that autonomously controls the driving speed of the host vehicle 1 and autonomous steering control that autonomously controls the steering of the host vehicle 1. In autonomous speed control, when a preceding vehicle is detected, the controller 20 follows the preceding vehicle while performing inter-vehicle control to maintain a distance according to the vehicle speed, with the upper limit set by the occupant's vehicle speed or speed limit. On the other hand, when a preceding vehicle is not detected, the controller 20 performs constant speed driving at the vehicle speed or speed limit set by the occupant. The former is also called inter-vehicle control, and the latter is called constant speed control.

[0019] Constant speed control is performed when the forward radar of the sensor 11 or the like detects that there is no preceding vehicle ahead in the lane in which the host vehicle 1 is traveling. In constant speed control, the vehicle behavior control device 19 controls the operation of drive mechanisms such as the engine and brakes while feeding back vehicle speed data from a vehicle speed sensor so as to maintain a set traveling speed. Vehicle distance control is performed when the forward radar of the sensor 11 or the like detects that there is a preceding vehicle ahead in the lane in which the host vehicle 1 is traveling. In vehicle distance control, the vehicle behavior control device 19 controls the operation of drive mechanisms such as the engine and brakes while feeding back vehicle distance data detected by the forward radar so as to maintain a set inter-vehicle distance, with a set traveling speed as the upper limit.

[0020] In the autonomous steering control, the controller 20 controls the operation of the steering actuator based on the driving information acquired by the driving information acquisition function, thereby performing steering control of the host vehicle 1. The autonomous steering control includes lane keeping control, lane change assist control, overtaking assist control, and route driving assist control. In lane keeping control, the controller 20 controls the steering actuator so that the vehicle travels near the center of the lane, for example, to assist the driver in steering the vehicle.

[0021] In the lane change assist control, the controller 20 turns on the turn signal when the driver operates the turn signal lever, and determines whether predetermined lane change start conditions are met based on various driving information acquired by the driving information acquisition function. If the lane change start conditions are met, the controller 20 starts a lane change operation. In a lane change operation, the controller 20 performs a lane change maneuver to move the vehicle 1 laterally to an adjacent lane (hereinafter sometimes referred to as a "destination lane") to which the lane is to be changed. While the lane change maneuver is being performed, the controller 20 displays information indicating that the lane change is being performed automatically on the display device 16. When the lane change maneuver is completed, the controller 20 turns off the turn signal and starts executing a lane keeping function in the lane after the lane change. The lane change maneuver is completed, for example, when the vehicle 1 reaches within a predetermined distance from the center of the lane after the lane change.

[0022] In overtaking assist control, when the controller 20 detects a preceding vehicle slower than the host vehicle 1 ahead in the lane in which the host vehicle 1 is traveling and when predetermined overtaking suggestion conditions are met, the controller 20 suggests to the occupant that they change lanes using autonomous driving control to overtake the preceding vehicle. Hereinafter, a proposal to change lanes to overtake the preceding vehicle may be referred to as an "overtaking proposal." When the occupant approves the overtaking suggestion by operating the lane change assist switch 186 of the input device 18 and predetermined overtaking execution conditions are met, the controller 20 executes an automated lane change. In the automated lane change, the controller 20 executes a lane change operation so that the host vehicle 1 moves into the destination lane.

[0023] Furthermore, when predetermined lane return suggestion conditions are met after the host vehicle 1 has overtaken the preceding vehicle, the controller 20 suggests to the occupant via the display device 16 that the host vehicle 1 perform a lane change using autonomous driving control and return to the original lane before the overtaking. Hereinafter, the suggestion to return to the original lane after overtaking the preceding vehicle may be referred to as a "lane return suggestion." If the occupant approves the lane return suggestion by operating the lane change assist switch 186 of the input device 18, and predetermined lane return execution conditions are met, the controller 20 executes an automated lane change. In the automated lane change, the controller 20 executes a lane change operation so that the host vehicle 1 moves to the original lane. Hereinafter, the function of the controller 20 that executes overtaking assist control may be referred to as an "overtaking assist function."

[0024] In the route driving assistance control, when predetermined route driving suggestion conditions are met at a point a predetermined distance d0 before a driving direction change point such as a branch point, merging point, exit, or toll booth on the target driving route set by the navigation system 15, the controller 20 suggests to the occupant that a lane change be performed by autonomous driving control to drive the host vehicle 1 along the target driving route. Hereinafter, the suggestion of a lane change to drive the host vehicle 1 along the target driving route may be referred to as a "route driving suggestion." When the occupant accepts the route driving suggestion by operating the lane change assistance switch 186 of the input device 18 and predetermined route driving execution conditions are met, the controller 20 executes an automated lane change. In the automated lane change, the controller 20 executes a lane change operation so that the host vehicle 1 moves into the destination lane. Hereinafter, the function of the controller 20 that executes the route driving assistance control may be referred to as a "route driving assistance function."

[0025] 3 is an example of a state transition diagram of the operation mode (hereinafter simply referred to as "operation mode") of the controller 20. When the main switch 181 is turned from off to on, the autonomous driving control enters a standby state, and when the set / coast switch 183 or the resume / accelerate switch 182 is turned on in the standby state, the autonomous speed control starts. This starts the constant speed control or vehicle distance control described above. If condition (1) is met while autonomous speed control is being executed, the operation mode transitions to lane keeping mode of hands-on mode. Hands-on mode is an operation mode in which the controller 20 executes autonomous steering control on the condition that the occupant is at least touching the steering wheel. In hands-on mode, autonomous steering control does not operate unless the occupant is at least touching the steering wheel. Alternatively, if the touch of the steering wheel cannot be detected while autonomous steering control is in operation, the autonomous steering control is stopped or interrupted. Whether or not the occupant is touching the steering wheel can be determined by, for example, detecting touch at one or more points on the touch sensor of the sensor 11 provided on the steering wheel. Detected Alternatively, the condition may be that the occupant is gripping the steering wheel. Whether or not the occupant is gripping the steering wheel may be determined when a pressure sensor provided on the steering wheel detects a value equal to or greater than a predetermined value. The lane keeping mode is an operating mode in which the controller 20 executes lane keeping control. The lane keeping control executed in the lane keeping mode of the hands-on mode is an example of the "second lane keeping assist" described in the claims. For example, condition (1) may be that all of the following conditions are met. Lane markers on both sides of vehicle 1 are detected. The passenger is holding the steering wheel. - Driving near the center of the lane. -Turn indicators are not working.

[0026] When condition (2) is satisfied in the lane keeping mode of the hands-on mode, the operation mode transitions to the hands-off mode. The hands-off mode is an operation mode in which the controller 20 executes lane keeping control even if the occupant takes their hands off the steering wheel (i.e., even if the occupant is not touching the steering wheel). The lane keeping control executed in the hands-off mode is an example of the "first lane keeping assist" described in the claims. For example, condition (2) may be that all of the following conditions are met. Vehicle 1 is driving on a motorway. High-definition maps are available. · The GPS signal is valid. The passenger is holding the steering wheel. When condition (3) is met in the hands-off mode, the operation mode transitions to the lane keeping mode of the hands-on mode. For example, condition (3) may be that any of the following conditions is met. Vehicle 1 is traveling on a road other than a highway. High-definition maps are not available. -GPS signal cannot be received.

[0027] When condition (4) is satisfied in the hands-off mode, the operation mode transitions to the lane change mode of the hands-on mode. The lane change mode is an operation mode in which the controller 20 executes lane change assist control, overtaking assist control, and route driving assist control. That is, the controller 20 executes an automated lane change on the condition that the occupant is at least touching the steering wheel. The hands-on mode in the lane change mode may have a lower threshold for determining whether the occupant is touching the steering wheel compared to the hands-on mode in the lane keeping mode. For example, condition (4) may be that any of the following conditions is met. The controller 20 presents an overtaking suggestion, a lane return suggestion, or a route driving suggestion, and the occupant operates the lane change assistance switch 186. The passenger operated the turn signal lever. When condition (5) is met in the lane change mode of the hands-on mode, the operation mode transitions to the lane keeping mode of the hands-on mode. For example, condition (5) may be that any of the following conditions is met. - The occupant failed to initiate a lane change operation within the specified time after operating the lane change assist switch 186 in response to an overtaking suggestion or lane return suggestion. - After the driver operated the lane change assist switch 186 in response to the proposed route, he was unable to initiate a lane change operation and approached the fork in the road too close. A lane change maneuver is completed.

[0028] Therefore, when the lane change operation is completed during an automated lane change, the operation mode transitions to the lane keeping mode of the hands-on mode. When condition (2) is met in the lane keeping mode of the hands-on mode, the operation mode transitions to the hands-off mode. As a result, the occupant can use the lane keeping assistance provided by the controller 20 even if they take their hands off the steering wheel. The other conditions (6) to (9) shown in FIG. 3 will be described later. In an automated lane change using route driving assist control, when the lane in which the vehicle 1 should currently travel (hereinafter sometimes referred to as the "target lane") is set in order to travel along the target driving route set by the navigation system 15, there may be one or more lanes between the lane in which the vehicle 1 is currently traveling (hereinafter sometimes referred to as the "current lane") and the target lane, and automated lane changes across multiple lanes may be performed consecutively from the current lane to the target lane. In the following description, automated lane changes across multiple lanes may be referred to as "multiple automated lane changes."

[0029] Referring to FIG. 4, an example is shown of a situation in which multiple lane changes are performed consecutively from a current lane to a target lane. A first road R1 on which the host vehicle 1 is currently traveling has lanes L1, L2, and L3. Lane L1 is the current lane on which the host vehicle 1 is currently traveling. For example, the first road R1 may be a main road. A second road R2 branches off from the first road R1 at a branch point Pj1, and an exit lane Lo leading to the second road R2 branches off from lane L3 on the first road R1. For example, the second road R2 may be a branch road. The lane change section SL is a section where a lane change is possible between lane L3 and exit lane Lo. The lane change section SL begins at a starting point Ps where the exit lane Lo occurs, and ends at a branch point Pj1 where the first road R1 and the second road R2 are physically separated, or where a structure (wall or median strip) between the first road R1 and the second road R2 makes it impossible to change lanes between lane L3 and exit lane Lo.

[0030] For example, assume that the navigation system 15 sets a target driving route for exiting from a first road R1 to a second road R2. In the route driving assistance control, the exit lane Lo is set as the target lane. When the host vehicle 1 reaches a point P0 that is a predetermined distance d0 before the branch point Pj1, which is the driving direction change point, the controller 20 presents a route driving proposal to the occupant. If the occupant accepts the route driving proposal, a first automated lane change from the current lane L1 to lane L2, a second automated lane change from lane L2 to lane L3, and a third automated lane change from lane L3 to the target lane Lo are executed consecutively. In this case, for example, if the hands-off mode is initiated after the first lane change and the occupant takes their hands off the steering wheel, and then the occupant is required to put their hands on for the second lane change, the occupant may feel annoyed. The same applies to subsequent lane changes.

[0031] Therefore, when an automated lane change from the current lane L1 to the target lane Lo requires a first automated lane change from the first lane to the second lane adjacent to the first lane, and a second automated lane change from the second lane to the third lane adjacent to the second lane, the controller 20 operates in the lane keeping mode of the hands-on mode from the completion of control of the first automated lane change to the start of control of the second automated lane change. This prevents the occupant from taking their hands off the steering wheel between the first automated lane change and the second automated lane change, eliminating the inconvenience of being required to maintain a hands-on state for the second automated lane change immediately after taking their hands off the steering wheel.

[0032] In FIG. 4, the dashed dotted line and the dashed double dotted line schematically show the travel path of the host vehicle 1 when an automated lane change is performed from the current lane L1 to the target lane Lo. Points P1s, P2s, and P3s indicate the start points of the first to third automated lane change controls, respectively. Each automated lane change control may start, for example, when a predetermined route driving execution condition is satisfied. Points P1e, P2e, and P3e indicate the end points of the first to third automated lane change controls, respectively. Each automated lane change control may end, for example, when the distance between the center of the driving lane after the lane change and the vehicle 1 becomes equal to or less than a predetermined distance. After each automated lane change control is completed, lane keeping control is executed until the next automated lane change control starts (in the example of FIG. 4, between completion point P1e and start point P2s and between completion point P2e and start point P3s).

[0033] The dashed-dotted line schematically shows the driving trajectory when the controller 20 is operating in hands-off mode, and the dashed-two-dotted line schematically shows the driving trajectory when the controller 20 is operating in hands-on mode. The controller 20 maintains the hands-on mode from the start point P1s of the first automated lane change control to the completion point P3e of the third automated lane change control. Therefore, the controller 20 operates in the lane keeping mode of the hands-on mode from the completion point P1e of the first automated lane change control to the start point P2s of the second automated lane change control, and from the completion point P2e of the second automated lane change control to the start point P3s of the third automated lane change control. When the host vehicle 1 reaches the target lane Lo and the third automated lane change control is completed at the completion point P3e, the controller 20 enters hands-off mode.

[0034] See FIG. 5. When the route driving proposal is approved in the route driving assistance control, the controller 20 may complete the automated lane change to lane L3 on the first road R1 that branches off to the exit lane Lo as quickly as possible. This is to ensure that the vehicle travels along the target driving route. As a result, the distance traveled from the completion of the second automated lane change from lane L2 to lane L3 to the start of the third automated lane change from lane L3 to the exit lane Lo may be long. In this case, it is preferable to operate the controller 20 in hands-off mode to reduce the burden on the occupants. Therefore, when the control of the automated lane change from lane L2 to lane L3 is completed at a point that is a predetermined distance d1 before the start point Ps where the exit lane Lo branches off from lane L3, the controller 20 may execute lane keeping control in the hands-off mode after the control of the automated lane change from lane L2 to lane L3 is completed. In this case, the controller 20 may execute the automated lane change from lane L3 to the exit lane Lo after transitioning to the lane change mode of the hands-on mode at a point that is a predetermined distance d2 before the start point Ps.

[0035] See FIG. 6. Before the host vehicle 1 reaches a point a predetermined distance d0 before the branch point Pj1, the current lane L1 may branch off from the main road at the branch point Pj2. In this case, the route driving assistance control presents a route driving suggestion at a point Px a predetermined distance d0 before the branch point Pj2. As a result, the distance between the branch point Pj1 and the point P1e at which the control of the first automated lane change from the current lane L1 to lane L2 is completed may be longer than the predetermined distance d0. In this case, the travel distance from the completion of the first automated lane change to lane L2 to the start of the second automated lane change from lane L2 to lane L3 may be longer. In this case, it is preferable to operate the controller 20 in hands-off mode to reduce the burden on the occupants. Therefore, if the distance between the branch point Pj1 and the completion point P1e of the control of the first automated lane change from the current lane L1 to the lane L2 is longer than the predetermined distance d0, the controller 20 may execute lane keeping control in the hands-off mode after the completion of the control of the automated lane change from the current lane L1 to the lane L2. In this case, the controller 20 may start the control of the automated lane change from the lane L2 to the lane L3 at the point P0 that is the predetermined distance d0 before the branch point Pj1.

[0036] See Figure 7. Lane L3 on the first road R1 may separate from the first road R1 and become the exit lane Lo of the second road. In this case, when the second lane change from lane L2 to lane L3 is completed, the vehicle reaches the target lane Lo, completing multiple lane changes from the current lane L1 to the target lane Lo. Therefore, when the second lane change is completed, the controller 20 transitions to the hands-off mode.

[0037] 8 is a block diagram of an example of a functional configuration for performing route driving assistance control in the controller 20. The controller 20 includes a map information acquisition unit 31, a navigation information acquisition unit 32, a self-location information acquisition unit 33, a surrounding situation recognition unit 34, a lane change proposal determination unit 35, a lane change feasibility determination unit 36, a lane change status management unit 37, and a lane keeping control unit 38. The map information acquisition unit 31 acquires map information from the map database 13 or a communication device (not shown). The navigation information acquisition unit 32 acquires route information related to a target driving route to a destination from the navigation system 15. The self-position information acquisition unit 33 acquires current position information related to the current position of the host vehicle 1 from the positioning device 12. The surrounding situation recognition unit 34 recognizes the situation around the host vehicle 1 (e.g., other vehicles and white lines) based on the driving information. In particular, the surrounding situation recognition unit 34 recognizes the distance d between the host vehicle 1 and another vehicle on the destination lane in the direction of the lane extension. For example, the distance d may be the inter-vehicle distance or the inter-vehicle time between the host vehicle 1 and another vehicle in the direction of the lane extension.

[0038] The lane change proposal determination unit 35 selects a target lane when the host vehicle 1 reaches a point P0 a predetermined distance d0 before the driving direction change point for driving along the target driving route. The lane change proposal determination unit 35 determines whether the route driving proposal conditions are satisfied. For example, the route driving proposal conditions may include the following conditions: - Route driving assistance function is enabled. The lane in which the vehicle 1 is currently traveling is different from the target lane. Lane change to the target lane is possible (for example, lane markings do not prohibit lane changes, the curvature radius of the road is greater than or equal to a threshold, etc.). When the route travel proposal conditions are satisfied, the lane change proposal determination unit 35 sets a proposal point where a route travel proposal is to be presented. When the host vehicle 1 reaches the proposal point, the lane change proposal determination unit 35 outputs a route travel proposal request to the lane change state management unit 37.

[0039] When the lane change proposal determination unit 35 outputs a route travel proposal request, the lane change state management unit 37 outputs route travel information to the display device 16 and the audio output device 17 to present the route travel proposal to the occupant. When the proposed route is presented, the lane change possibility determination unit 36 ​​determines whether or not predetermined conditions for executing the route are met. For example, the conditions for executing the route may include the following conditions. - Route driving assistance function is enabled. The lane in which the vehicle 1 is currently traveling is different from the target lane. The distance d between the host vehicle 1 and another vehicle on the destination lane in the direction of the lane extension is equal to or greater than the distance threshold Dp. -It is possible to change lanes to the target lane. If the route travel execution conditions are satisfied, the lane change state management unit 37 turns on the turn signal and executes a lane change operation. Also, on the condition that the route travel execution conditions are satisfied, the lane change state management unit 37 starts a lane change operation so that the host vehicle 1 moves into the destination lane.

[0040] The lane keeping control unit 38 executes lane keeping control and controls the host vehicle 1 so that the host vehicle 1 travels within the same lane. For example, the steering actuator may be controlled so that the host vehicle 1 travels near the center of the lane, or a driving force difference or braking force difference may be applied between the left and right wheels. The lane keeping control unit 38 determines whether or not condition (6) is met when the control of the first automatic lane change is completed (i.e., when the lane change operation is completed) of the first automatic lane change from the first lane to the second lane adjacent to the first lane, and the second automatic lane change from the second lane to the third lane adjacent to the second lane, which are consecutively executed in the route driving assist control. For example, condition (6) may be that all of the following conditions are met: The distance between the first automatic lane change control completion point and the branch point Pj1 is equal to or shorter than the predetermined distance d0. The driving lane after the first automatic lane change is not an adjacent lane to the target lane, or the distance from the completion point of the first automatic lane change control to the start point Ps of the lane change section SL is less than or equal to d1. If all of the conditions (6) are met, the lane keeping control unit 38 maintains the lane keeping mode of the hands-on mode. When the lane keeping mode of the hands-on mode is maintained after the first automatic lane change control is completed and condition (7) is satisfied, the lane change state management unit 37 turns on the turn signal and starts the second automatic lane change control (i.e., starts the lane change operation). Condition (7) may be a route travel execution condition.

[0041] Furthermore, when the first automatic lane change control is completed, the lane keeping control unit 38 determines whether or not the condition (8) is satisfied. For example, the condition (8) may be that any of the following conditions is satisfied. The distance between the first automatic lane change control completion point and the branch point Pj1 is not equal to or less than the predetermined distance d0. The driving lane after the first automatic lane change is the lane adjacent to the target lane, and the distance from the completion point of the first automatic lane change control to the start point Ps of the lane change section SL is longer than d1. If all of the conditions (8) are met, the lane keeping control unit 38 transitions the operation mode to the hands-off mode. If the driving lane after the first automatic lane change is the lane adjacent to the target lane and the controller 20 is operating in the hands-off mode, the lane keeping control unit 38 determines whether or not the condition (9) is satisfied when the control of the first automatic lane change is completed. For example, the condition (9) may be the following example condition. The vehicle 1 has reached a point a predetermined distance d2 before the start point Ps of the lane change section SL. If the condition (9) is met, the lane keeping control unit 38 transitions the operation mode to the lane keeping mode of the hands-on mode.

[0042] When all of the multiple lane change operations from the current lane L1 to the target lane Lo are completed, the lane keeping control unit 38 transitions the operation mode to the lane keeping mode of the hands-on mode, and then transitions to the hands-off mode when the condition (2) is met. The vehicle behavior control device 19 controls the operation of the steering actuator based on commands from the lane change state management unit 37 and the lane keeping control unit 38, thereby performing steering control of the host vehicle 1.

[0043] 9 is a flowchart of an example of the driving assistance method according to the embodiment. In step S1, the lane change proposal determination unit 35 selects a target lane in which the vehicle should currently travel in order to travel along the target travel route. In step S2, the lane change state management unit 37 Lane change Execute. In step S3, the lane change suggestion determination unit 35 determines whether the route driving support function is enabled. If the route driving support function is enabled (step S3: Y), the process proceeds to step S5. If the route driving support function is not enabled (step S3: N), the process proceeds to step S4. In step S4, the lane keeping control unit 38 transitions the operation mode to the hands-off mode, after which the process ends. In step S5, the lane change proposal determination unit 35 determines whether the host vehicle 1 has reached the target lane. If the host vehicle 1 has not reached the target lane (i.e., the lane in which the host vehicle 1 is currently traveling is not the target lane) (step S5: Y), the process proceeds to step S6. If the host vehicle 1 has reached the target lane (step S5: N), the process proceeds to step S4.

[0044] In step S6, the lane keeping control unit 38 determines whether the distance between the completion point of the automated lane change control in step S2 and the branch point Pj1 is equal to or less than a predetermined distance d0. If the distance between the completion point and the branch point Pj1 is equal to or less than the predetermined distance d0 (step S6: Y), the process proceeds to step S8. If the distance between the completion point and the branch point Pj1 is not equal to or less than the predetermined distance d0 (step S6: N), the process proceeds to step S7. In step S7, the lane keeping control unit 38 transitions the operation mode to the hands-off mode, after which the process returns to step S2. In step S8, the lane keeping control unit 38 determines whether the driving lane in which the vehicle 1 is currently traveling is an adjacent lane to the target lane. If the driving lane is an adjacent lane to the target lane (step S8: Y), the process proceeds to step S10. If the driving lane is not an adjacent lane to the target lane (step S8: N), the process proceeds to step S9. In step S9, the lane keeping control unit 38 maintains the operation mode in the lane keeping mode of the hands-on mode, after which the process returns to step S2. In step S10, the lane keeping control unit 38 determines whether the distance from the completion point of the automated lane change control in step S2 to the start point Ps of the lane change section SL is d1 or less. If the distance from the completion point to the start point Ps is d1 or less (step S10: Y), the process proceeds to step S9. If the distance from the completion point to the start point Ps is not d1 or less (step S10: N), the process proceeds to step S7.

[0045] (Effects of the embodiment) (1) The controller 20 performs a first lane keeping assist that controls the host vehicle 1 so that the host vehicle 1 travels within the same lane even if the occupant is not touching the steering wheel, and an automated lane change that controls the host vehicle 1 so that the host vehicle 1 changes lanes on the condition that the occupant is at least touching the steering wheel. The controller 20 executes a process of selecting a target lane in which the host vehicle 1 should travel based on a preset target route, and a process of executing a second lane keeping assist that controls the host vehicle 1 so that the host vehicle 1 travels within the same lane on the condition that the occupant is at least touching the steering wheel from the completion of the first automated lane change control to the start of the second automated lane change control, when the automated lane change from the current lane in which the host vehicle 1 is currently traveling to the target lane includes a first automated lane change from the first lane to a second lane adjacent to the first lane and a second automated lane change from the second lane to a third lane adjacent to the second lane. This means that the occupant does not have to take their hands off the steering wheel between the first and second lane changes, eliminating the annoyance of being required to take their hands off the steering wheel to make the second lane change immediately after taking their hands off the steering wheel.

[0046] (2) When the target lane is an exit lane for entering a second road branching off from a first road on which the vehicle 1 is currently traveling, and the second lane change is an automatic lane change from the second lane, which is a lane on the first road branching off to the exit lane, to the third lane, which is an exit lane, and control of the first lane change is completed at a point that is more than a predetermined distance before the branch point where the exit lane branches off from the second lane, the controller 20 may perform first lane keeping assistance after control of the first lane change is completed. As a result, if the distance traveled between the completion of the first automatic lane change control and the start of the second automatic lane change control is long, the first lane keeping assist will be executed even if the driver takes their hands off the steering wheel, thereby reducing the burden on the occupants.

[0047] All examples and conditional terms described herein are intended for educational purposes to aid the reader in understanding the present invention and the concepts provided by the inventor for the advancement of technology, and should be construed without limitation to the specifically described examples and conditions above, and the configuration of examples herein for illustrating the advantages and disadvantages of the present invention. Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0048] 1... Vehicle, 10... Driving assistance device, 11... Sensor, 12... Positioning device, 13... Map DB, 14... In-vehicle equipment, 15... Navigation system, 16... Display device, 17... Audio output device, 18... Input device, 19... Vehicle behavior control device, 20... Controller

Claims

1. A driving assistance method in which a controller performs a first lane keeping assistance that controls the host vehicle so that the host vehicle travels in the same lane even if an occupant is not touching the steering wheel when a predetermined condition is satisfied, and an automated lane change that controls the host vehicle so that the host vehicle changes lanes on the condition that the occupant is at least touching the steering wheel, A process of selecting a target lane in which the host vehicle should travel based on a preset target route; a process of starting control of the first automated lane change after executing the first lane keeping assist by satisfying the predetermined condition, when the automated lane change from a current lane in which the host vehicle is currently traveling to the target lane includes a first automated lane change from a first lane to a second lane adjacent to the first lane, and a second automated lane change from the second lane to a third lane adjacent to the second lane, and maintaining execution of a second lane keeping assist that controls the host vehicle to travel in the same lane on condition that the occupant is at least in contact with the steering wheel, from the completion of control of the first automated lane change to the start of control of the second automated lane change, even if the predetermined condition is satisfied between the completion of control of the first automated lane change and the start of control of the second automated lane change; A driving assistance method characterized by causing the controller to execute the above.

2. 2. The driving assistance method according to claim 1, wherein the target lane is an exit lane for entering a second road branching off from a first road on which the host vehicle is currently traveling, the second automated lane change is an automated lane change from the second lane, which is a lane on the first road branching off to the exit lane, to the third lane, which is the exit lane, and the control of the first automated lane change is completed at a point that is a predetermined distance or more before a branch point where the exit lane branches off from the second lane.

3. A driving assistance device including a controller that performs a first lane keeping assistance that controls a host vehicle so that the host vehicle travels in the same lane even if an occupant is not touching a steering wheel when a predetermined condition is satisfied, and an automated lane change that controls the host vehicle so that the host vehicle changes lanes on the condition that the occupant is at least touching the steering wheel, The controller A process of selecting a target lane in which the host vehicle should travel based on a preset target route; a process of starting control of the first automated lane change after executing the first lane keeping assist by satisfying the predetermined condition, when the automated lane change from a current lane in which the host vehicle is currently traveling to the target lane includes a first automated lane change from a first lane to a second lane adjacent to the first lane, and a second automated lane change from the second lane to a third lane adjacent to the second lane, and maintaining execution of a second lane keeping assist that controls the host vehicle to travel in the same lane on condition that the occupant is at least in contact with the steering wheel, from the completion of control of the first automated lane change to the start of control of the second automated lane change, even if the predetermined condition is satisfied between the completion of control of the first automated lane change and the start of control of the second automated lane change; A driving assistance device characterized by executing the above.

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