Vehicle driving assistance method and driving assistance device

Abstract

According to the present invention, a driving assistance method and a driving assistance device for a vehicle are provided, which determine whether a lane change for driving along a set driving path, i.e., a path following lane change, can be assisted by autonomous lane change control. When it is determined that the path following lane change cannot be assisted by autonomous lane change control, the driver is notified that a lane change based on autonomous lane change control cannot be performed, and a lane change in a direction opposite to the direction in which the vehicle is moving in the path following lane change assisted by autonomous lane change control is prohibited.

Description

Technical Field

[0001] The invention relates to a driving assistance method and a driving assistance device for a vehicle. Background Art

[0002] It is known that there is a device for assisting lane changes by using road network information corresponding to road map data to determine a driving route, storing the restriction level for restricting lane changes in correspondence between each lane of the road and the position on the lane, acquiring the driving position of a vehicle, and based on the acquired driving position of the vehicle, referring to the restriction level in the driving route, prompting lane change information for driving along the driving route (Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-76614

[0006] Problems to be solved by the invention

[0007] In the above-mentioned prior art, when the vehicle reaches the position where lane change is recommended, the lane change is instructed by voice. However, the driver cannot correctly understand what kind of control can be performed on the vehicle based on the lane change instruction by voice alone. Therefore, in the above-mentioned prior art, there is a problem that the control that the driver understands based on the voice is inconsistent with the control that the driving assistance device can actually perform. Summary of the invention

[0008] The present invention aims to solve the problem of providing a vehicle driving assistance method and a vehicle driving assistance device that can make the executable control recognized by the driver consistent with the actually executable control.

[0009] The present invention solves the above-mentioned problem by the following processing: determining whether a lane change for driving along a set driving path, i.e., a path-following lane change, can be assisted by autonomous lane change control; when it is determined that the path-following lane change cannot be assisted by autonomous lane change control, notifying the driver that the lane change based on the autonomous lane change control cannot be performed; and even if the execution conditions for executing the lane change based on the autonomous lane change control are met, prohibiting the lane change assisted by the autonomous lane change control in the direction opposite to the direction in which the vehicle is moving in the path-following lane change.

[0010] Effects of the Invention

[0011] According to the present invention, it is possible to make the executable control recognized by the driver and the actually executable control consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a block diagram showing a driving assistance system including the driving assistance device of the present invention.

[0013] Figure 2 Yes means Figure 1 A front view of a portion of an input device.

[0014] Figure 3 is a plan view showing a lane change based on autonomous lane change control.

[0015] Figure 4 It is a plan view showing a lane change to an adjacent lane based on the overtaking assist control.

[0016] Figure 5 It is a plan view showing a lane change to the original driving lane based on autonomous lane change control.

[0017] Figure 6 It is a plan view showing lane change based on lane-keeping assist control.

[0018] Figure 7 Yes means Figure 1 Block diagram of the state transition of the driving assistance device.

[0019] Figure 8 Yes means Figure 1 A flowchart showing an example of the sequence of information processing in a driving assistance system.

[0020] Fig. 9 It means use Figure 1 The illustrated driving assistance system is a plan view of an example of a driving scene in which the autonomous driving control is executed.

[0021] Fig.10 Yes means Figure 8 Flowchart of an example of a subroutine of step S20 in . DETAILED DESCRIPTION

[0022] The following describes an embodiment of the present invention based on the accompanying drawings. In addition, the following description is based on the premise that vehicles travel on the left side in countries with laws for driving on the left side. In countries with laws for driving on the right side, vehicles travel on the right side, so the left and right symmetry in the following description is replaced.

[0023] (Structure of driving assistance system)

[0024] Figure 1: is a block diagram representing the driving assistance system 1 of the present invention. The driving assistance system 1 of the present embodiment is an on-vehicle system, which can be used for private cars that travel to the destination set by the occupants of the vehicle (hereinafter also referred to as "the vehicle") through autonomous driving control, and can also be used for vehicles dispatched in a vehicle dispatch service, for example. The vehicle dispatch service refers to the allocation of vehicles to users that transport users from the boarding point to the disembarkation point, and examples thereof include: the dispatch of manned and unmanned taxis, the dispatch of vehicles used for pick-up services at airports, stations, hotels, etc., and the dispatch of vehicles used for car rental or sharing services. There are no particular restrictions on the users of the vehicle dispatch service as long as they can pay appropriately for the service.

[0025] like Figure 1 As shown, the driving assistance system 1 includes: a camera device 11, a distance measuring device 12, map information 13, a vehicle position detection device 14, a navigation device 15, a vehicle control device 16, an input device 17, an output device 18 and a driving assistance device 19. The devices included in the driving assistance system 1 are connected via a CAN (Controller Area Network) or other vehicle-mounted LAN and can send and receive information to each other.

[0026] The camera device 11 is a device for recognizing objects around the vehicle through images, and is, for example, a camera with an image pickup element such as a CCD, an ultrasonic camera, an infrared camera, or the like. A plurality of camera devices 11 can be provided on a vehicle, for example, they can be arranged at the front grille of the vehicle, the lower part of the left and right door mirrors, and near the rear bumper. Thus, the blind spot when recognizing objects around the vehicle can be reduced. In addition, the camera device 11 includes a driver monitor for photographing the driver.

[0027] The distance measuring device 12 is a device for calculating the relative distance and relative speed between the vehicle and the object, and can be, for example, a radar device such as a laser radar, a millimeter wave radar (LRF, etc.), a LiDAR (light detection and ranging) unit, an ultrasonic radar, or a sonar. A plurality of distance measuring devices 12 can be provided on a vehicle, for example, they can be arranged in front, on the right side, on the left side, and on the rear of the vehicle. Thus, the relative distance and relative speed to the objects around the vehicle can be accurately calculated.

[0028] The objects detected by the camera device 11 and the distance measuring device 12 are lane boundaries, center lines, road markings, median strips, guardrails, curbs, side walls of highways, road markings, traffic lights, crosswalks, construction sites, accident sites, traffic restrictions, etc. In addition, the objects also include obstacles that may affect the driving of the vehicle, such as cars (other vehicles), motorcycles, bicycles, pedestrians, etc. The detection results of the camera device 11 and the distance measuring device 12 are obtained by the driving assistance device 19 at specified time intervals.

[0029] In addition, the detection results of the camera device 11 and the distance measuring device 12 can be integrated or synthesized by the driving assistance device 19, thereby supplementing the missing information of the detected object. For example, based on the position of the vehicle, that is, the vehicle position information obtained by the vehicle position detection device 14 described later, and the relative position (distance and direction) between the vehicle and the object, the position information of the object can be calculated by the driving assistance device 19. The calculated position information of the object is integrated by the driving assistance device 19 with the detection results of the camera device 11 and the distance measuring device 12, and the map information 13 and other information to become the environmental information around the vehicle. In addition, the detection results of the camera device 11 and the distance measuring device 12 and the map information 13 can also be used to identify the objects around the vehicle and predict their movements.

[0030] The map information 13 is information used for generating a driving route and / or controlling driving, and includes road information, facility information, and their attribute information. The road information and road attribute information include: road width, road curvature and curvature radius, shoulder structure, road traffic regulations (speed limit, whether lane changes are possible), road confluence and branch points, lane increase / decrease positions, and other information. The map information 13 of this embodiment is high-precision map information that can grasp the movement trajectory of each lane, including two-dimensional position information and / or three-dimensional position information in each map coordinate, road / lane boundary information in each map coordinate, road attribute information, lane up / down information, lane identification information, destination lane information, etc. In addition, high-precision maps are also called HD (High-Definition) maps.

[0031] The road / lane boundary information of the high-precision map information is information indicating the boundary between the road on which the vehicle is traveling and other roads. The road on which the vehicle is traveling refers to the road used for the vehicle to travel, and the shape of the road is not particularly limited. The boundaries exist on the left and right relative to the direction of travel of the vehicle, and the shape is not particularly limited. The boundaries include road surface markings, road structures, etc. Road surface markings include lane dividing lines, center lines, etc. Road structures include central dividing strips, guardrails, curbs, tunnels, side walls of highways, etc. In addition, at locations such as intersections where the boundary of the road cannot be clearly determined, a boundary is set in advance on the road. The boundary is fictitious and is not an actual road surface marking or road structure.

[0032] The map information 13 is stored in a readable state in a recording medium of an on-vehicle device including the driving assistance device 19 or a server on a network. The driving assistance device 19 acquires the map information 13 as necessary.

[0033] The vehicle position detection device 14 is a positioning system for detecting the current position of the vehicle. It is not particularly limited and a known device can be used. The vehicle position detection device 14 calculates the current position of the vehicle based on radio waves received from satellites used for the GPS (Global Positioning System). In addition, the vehicle position detection device 14 can also estimate the current position of the vehicle based on the vehicle speed information obtained from the vehicle speed sensor and the acceleration information obtained from the acceleration sensor and the gyro sensor, and calculate the current position of the vehicle by comparing the estimated current position with the map information 13.

[0034] The navigation device 15 is a device that calculates a driving route from the current position of the vehicle detected by the vehicle position detection device 14 to the destination set by the driver with reference to the map information 13. The navigation device 15 uses, for example, the road information and facility information of the map information 13 to retrieve a driving route for the vehicle to reach the destination from the current position. The driving route includes at least information on the road, driving lane, and driving direction of the vehicle, and is displayed in a linear form, for example. Depending on the search conditions, there may be a plurality of driving routes. The driving route calculated by the navigation device 15 is output to the driving assistance device 19.

[0035] The vehicle control device 16 is an on-board computer such as an electronic control unit (ECU) and electronically controls on-board devices that restrict the driving of the vehicle. The vehicle control device 16 includes a vehicle speed control device 161 that controls the driving speed of the vehicle and a steering control device 162 that controls the steering operation of the vehicle. The vehicle speed control device 161 and the steering control device 162 autonomously control the operation of these drive devices and steering devices according to the control signal input from the driving assist device 19. As a result, the vehicle can autonomously travel according to the set driving path.

[0036] The driving device controlled by the vehicle speed control device 161 includes: an electric motor and / or an internal combustion engine as a driving source, a power transmission device including a drive shaft and an automatic transmission that transmits the output from these driving sources to the driving wheels, and a driving device that controls the power transmission device. In addition, the braking device controlled by the vehicle speed control device 161 is, for example, a braking device for braking the wheels. A control signal corresponding to the set driving speed is input from the driving assist device 19 to the vehicle speed control device 161. The vehicle speed control device 161 generates a signal to control these driving devices based on the control signal input from the driving assist device 19, and sends the signal to the driving device, thereby autonomously controlling the driving speed of the vehicle.

[0037] On the other hand, the steering device controlled by the steering control device 162 includes a steering device for controlling the total steering wheel according to the steering angle of the steering wheel (so-called steering wheel), for example, a steering actuator such as an electric motor mounted on the column shaft of the steering gear. The steering control device 162 autonomously controls the operation of the steering device based on the control signal input from the driving assist device 19, using at least one of the detection results of the camera device 11 and the distance measuring device 12, the map information 13, and the information of the current position obtained by the vehicle position detection device 14, so as to maintain a predetermined lateral position (the position of the vehicle in the left-right direction) relative to the set driving path while driving the vehicle.

[0038] The vehicle control device 16 uses the on-board sensor 163 to detect information required for autonomous control of the vehicle speed control device 161 and the steering control device 162, such as the vehicle's driving speed, acceleration, steering angle, and posture. The on-board sensor 163 is a sensor for detecting the driving state of the vehicle, and includes a vehicle speed sensor, an acceleration sensor, a gyro sensor, a steering angle sensor, an inertial measurement unit (IMU), and the like. In addition, the on-board sensor 163 includes a touch sensor (electrostatic capacitance sensor) that detects the driver's hold on the steering wheel. The vehicle control device 16 outputs the detection results of the on-board sensor 163 to the driving assistance device 19 at a specified time interval.

[0039] The input device 17 is a device for the vehicle occupant to input instructions to the driving assistance device 19, and examples thereof include a touch panel for inputting input by the user's finger contact or a stylus, a microphone for obtaining the user's voice instructions, and a switch mounted on the steering wheel of the vehicle.

[0040] As an example of the input device 17, Figure 2 Indicates a switch mounted on the steering wheel of a vehicle. Figure 2 It is a front view showing a part of the input device 17, showing a group of button switches arranged on the spokes of the steering wheel. Figure 2 The input device 17 shown is a push button switch used when setting the on / off of the autonomous driving control function (autonomous speed control function and autonomous steering control function) of the driving assist device 19. The input device 17 includes a main switch 171, a recovery / acceleration switch 172, a setting / coasting switch 173, a cancel switch 174, a vehicle-to-vehicle adjustment switch 175, and a lane change assist switch 176.

[0041] The main switch 171 is a switch for turning on / off the power supply of the system realizing the autonomous speed control function and the autonomous steering control function of the driving assist device 19. The resume / acceleration switch 172 is a switch for restarting the autonomous speed control at the set speed before stopping (OFF) or increasing the set speed after stopping the autonomous speed control, or starting again through the driving assist device 19 after following the preceding vehicle. The setting / coasting switch 173 is a switch for starting the autonomous speed control at the speed when driving or reducing the set speed. The cancel switch 174 is a switch for stopping (OFF) the autonomous speed control. The inter-vehicle adjustment switch 175 is a switch for setting the inter-vehicle distance with the preceding vehicle, and is a switch for selecting one of the multi-level settings such as short distance, medium distance and long distance. The lane change assist switch 176 is a switch for indicating (confirming) the start of the lane change when the driving assist device 19 confirms the start of the lane change to the driver. Furthermore, after confirming the start of the lane change, by operating the lane change assist switch 176 for longer than a predetermined time, the confirmation of the lane change proposal by the driving assist device 19 can be cancelled.

[0042] In addition, Figure 2In addition to the button switch shown in the figure, a direction indicator lever of a direction indicator or a switch of other vehicle-mounted equipment can also be used as the input device 17. For example, when the driving assistance device 19 proposes whether to automatically change lanes, when the driver operates the direction indicator lever, the lane change is performed in the direction in which the direction indicator lever is operated, rather than the proposed lane change. The input device 17 outputs the input setting information to the driving assistance device 19. In addition, autonomous driving control, autonomous speed control, and autonomous steering control will be described in detail later.

[0043] return Figure 1 The output device 18 is a device for providing necessary information to the vehicle occupants, such as a projector such as a head-up display (HUD), a liquid crystal display installed on the instrument panel, and a display assembled in the rearview mirror inside the vehicle. In addition, the output device 18 includes not only devices that provide information visually, but also devices that provide information by sound such as a speaker of an audio device, and devices that provide information by vibration such as a seat with a vibrator embedded therein.

[0044] The driving assistance device 19 is a device that controls the driving of the vehicle by controlling the devices included in the driving assistance system 1 and making them cooperate, so that the vehicle can travel to the destination set by the vehicle occupant or the user of the vehicle dispatch service. The driving assistance device 19 is, for example, a computer, and includes: a CPU (Central Processing Unit) 191 as a processor, a ROM (Read Only Memory) 192 storing a program, and a RAM (Random Access Memory) 193 that functions as an accessible storage device. The CPU 191 is an action circuit for executing the program stored in the ROM 192 to function as the driving assistance device 19.

[0045] (Function of the control unit)

[0046] The program stored in ROM192 includes a control unit 2 as a functional block for implementing driving control of the vehicle by the driving assistance device 19. The control unit 2 has a function of driving the vehicle by autonomous driving control. Autonomous driving control refers to autonomously controlling the driving action of the vehicle using the driving assistance device 19, and the driving action includes various driving actions such as acceleration, deceleration, starting, parking, turning right or left, lane change, and pulling over. In addition, autonomously controlling the driving action means that the driving assistance device 19 uses the device of the vehicle to control the driving action. That is, the control unit 2 intervenes and controls these driving actions within a predetermined range. The driver performs manual operation for driving actions that are not intervened.

[0047] like Figure 1As shown, the control unit 2 includes an acquisition unit 3, an auxiliary unit 4, a determination unit 5, and a notification unit 6. The auxiliary unit 4 includes a speed control unit 41 and a steering control unit 42. The steering control unit 42 includes a lane keeping unit 421, a lane changing unit 422, a passing unit 423, and a route driving unit 424. Figure 1 For the sake of convenience, each unit is extracted and shown. Hereinafter, the functions realized by each functional block of the control unit 2 will be described.

[0048] The acquisition unit 3 has a function of acquiring information related to the driving state of the vehicle (hereinafter also referred to as "driving information"). Hereinafter, the function of acquiring driving information is also referred to as "driving information acquisition function". For example, the driving assistance device 19 acquires the image of the outside of the vehicle captured by the front camera, rear camera and side camera as the camera device 11 as driving information through the driving information acquisition function of the acquisition unit 3. In addition, the driving assistance device 19 acquires the detection results of the front radar, rear radar and side radar as the distance measuring device 12 as driving information through the driving information acquisition function of the acquisition unit 3. Instead of these or in addition to these, the driving assistance device 19 also acquires the driving speed of the vehicle detected by the vehicle speed sensor as the vehicle-mounted sensor 163 and the image information of the driver's face captured by the in-vehicle camera as driving information.

[0049] The driving assist device 19 acquires the current position information of the vehicle from the vehicle position detection device 14 as driving information through the driving information acquisition function of the acquisition unit 3. In addition, the driving assist device 19 acquires the set destination and the driving route to the destination from the navigation device 15 as driving information through the driving information acquisition function of the acquisition unit 3. Instead of or in addition to these, the driving assist device 19 acquires position information such as the size of the curved road and its curve (for example, curvature or curvature radius), merging point, branch point, toll booth, and lane reduction position from the map information 13 as driving information. Instead of or in addition to these, the driving assist device 19 acquires operation information input by the driver from the input device 17 as driving information.

[0050] The auxiliary unit 4 has a function of autonomously controlling the travel of the vehicle without relying on the operation of the driver. The auxiliary unit 4 includes: a speed control unit 41 having a function of autonomously controlling the travel speed of the vehicle, and a steering control unit 42 having a function of autonomously controlling the steering of the vehicle. Here, autonomously controlling the travel of the vehicle without relying on the operation of the driver is also referred to as "autonomous travel control". In addition, autonomously controlling the travel speed of the vehicle is also referred to as "autonomous speed control", and autonomously controlling the steering of the vehicle is also referred to as "autonomous steering control".

[0051] When the driving assist device 19 detects the vehicle ahead, the vehicle speed set by the driver is used as the upper limit through the autonomous speed control of the speed control unit 41, and the vehicle is controlled in a manner to maintain the vehicle-to-vehicle distance corresponding to the vehicle speed, and the vehicle is made to follow the vehicle ahead. On the other hand, when the vehicle ahead is not detected, the vehicle is driven at a constant speed at the speed set by the driver. The former is also called vehicle-to-vehicle control, and the latter is also called constant speed control. In addition, the speed control unit 41 may also have a function of detecting the speed limit of the road being driven from the road signs using the camera device 11, or obtaining the speed limit from the map information 13, and automatically using the speed limit as the set speed.

[0052] In order to activate the autonomous speed control by the speed control unit 41, first, the driver operates Figure 2 The desired driving speed is inputted by the resume / acceleration switch 172 or the setting / coasting switch 173 of the input device 17 shown. For example, if the setting / coasting switch 173 is pressed while the vehicle is traveling at 70 km / h, the current driving speed is directly set. However, if the driver's desired speed is 80 km / h, the set speed can be increased by pressing the resume / acceleration switch 172 several times. On the contrary, if the driver's desired speed is 60 km / h, the set speed can be decreased by pressing the setting / coasting switch 173 several times. In addition, the vehicle distance desired by the driver is set by the operation Figure 2 The inter-vehicle adjustment switch 175 of the input device 17 shown may be selected from a plurality of levels of settings such as short distance, medium distance, and long distance.

[0053] When the front radar of the distance measuring device 12 detects that there is no preceding vehicle in front of the lane, the constant speed control is performed. In the constant speed control, the vehicle speed data of the vehicle speed sensor as the vehicle-mounted sensor 163 is fed back, and the operation of the driving mechanism such as the engine and the brake is controlled by the vehicle speed control device 161 to maintain the set driving speed.

[0054] When the front radar of the distance measuring device 12 or the like detects that there is a leading vehicle in front of the lane, the inter-vehicle control is performed. In the inter-vehicle control, the inter-vehicle distance data detected by the front radar is fed back with the set driving speed as the upper limit, and the operation of the driving mechanism such as the engine and brake is controlled by the vehicle speed control device 161 to maintain the set inter-vehicle distance. In addition, when the leading vehicle stops during inter-vehicle control driving, the present vehicle also stops after following the leading vehicle. In addition, after the present vehicle stops, if the leading vehicle starts within, for example, 30 seconds, the present vehicle also starts and starts following driving based on inter-vehicle control again. In the case where the present vehicle stops for more than 30 seconds, the present vehicle will not start automatically even if the leading vehicle starts. After the leading vehicle starts, when the recovery / acceleration switch 172 is pressed or the accelerator pedal is stepped on, the following driving based on inter-vehicle control will start again.

[0055] The autonomous steering control by the steering control unit 42 performs the steering control of the vehicle by controlling the operation of the steering actuator by the steering control device 162 when the conditions specified in the execution of the autonomous speed control described above are satisfied. The steering control unit 42 includes, for example, a lane keeping unit 421, a lane changing unit 422, an overtaking unit 423, and a path driving unit 424.

[0056] The lane keeping unit 421 has a function of controlling the steering actuator through the steering control device 162 so that the vehicle travels near the center of the lane, thereby assisting the driver's steering wheel operation. In addition, the function of the lane keeping unit 421 is also referred to as a "lane keeping function" or a "lane width direction maintaining function". In addition, the control of the lane keeping unit is also referred to as "lane keeping control".

[0057] The lane change unit 422 has a function of changing lanes through autonomous driving control. Hereinafter, the control of changing lanes from the vehicle's own lane to an adjacent lane adjacent to the vehicle's own lane through autonomous driving based on autonomous driving control is also referred to as "autonomous lane change control". Figure 3As shown, when the driver operates the direction indicator lever, the driving assist device 19 lights up the direction indicator through the autonomous lane change control of the lane change unit 422, and when the pre-set lane change start condition is met, a series of lane change processes based on the autonomous driving control, that is, the lane change operation (hereinafter referred to as LCP) is started. In addition, when the lane change assist switch 176 of the input device 17 is operated, the direction indicator is lit to start the LCP when a button operation is performed to confirm the start of the autonomous lane change control. The driving assist device 19 determines whether the lane change start condition is met based on various driving information acquired through the driving information acquisition function of the acquisition unit 3 through the autonomous lane change control. The lane change start condition is not particularly limited, and examples include the following conditions all being met.

[0058] It is a lane keeping mode in handheld mode.

[0059] ·Determine whether the item is in hand.

[0060] Driving at a speed of 60 km / h or more.

[0061] There is a lane in the direction of the lane change.

[0062] ・There is space available for lane change in the lane at the lane change destination.

[0063] The type of lane marking is lane changeable.

[0064] The curvature radius of the road is more than 250m.

[0065] Within 1 second after the driver operates the direction indicator lever.

[0066] In addition, the lane keeping mode of the handheld mode means that the autonomous speed control of the speed control unit 41 and the lane keeping control of the lane keeping unit 421 are being executed, and the state of the driver holding the steering wheel is detected, which will be described in detail later. In addition, determining that the handheld mode is in the state where the driver continues to hold the steering wheel.

[0067] When the lane change start condition is met, the driving assist device 19 starts LCP through the autonomous lane change control of the lane change unit 422. The LCP includes: the lateral movement of the vehicle to the adjacent lane, and the lane change operation (hereinafter referred to as LCM) of actually moving to the adjacent lane. During the execution of LCP, the driving assist device 19 prompts the driver with information indicating that the lane change is automatically performed through the output device 18 to remind the driver to pay attention to the surroundings. When the LCM based on the autonomous lane change control ends, the driving assist device 19 turns off the direction indicator and starts the control based on the lane keeping unit 421 in the adjacent lane.

[0068] The overtaking unit 423 has a function of overtaking the preceding vehicle by autonomous driving control. Hereinafter, the control for overtaking the preceding vehicle by autonomous driving based on autonomous driving control is also referred to as "overtaking assist control". Overtaking assist control is a type of autonomous lane change control, and is an autonomous lane change control in a driving scenario of overtaking the preceding vehicle. Figure 4 As shown, when there is a preceding vehicle slower than the vehicle in front of the present lane and the predetermined overtaking proposal conditions are met, the driving assistance device 19 prompts the driver with overtaking information through the output device 18 through the function of the overtaking unit 423. Here, the overtaking information refers to information used to propose to the driver to overtake the preceding vehicle. In addition, the driving assistance device 19 starts the above-mentioned LCP when the driver confirms the prompt of the overtaking information by operating the lane change assist switch 176 of the input device 17 (equivalent to the confirmation input) and the predetermined overtaking start conditions are met. The confirmation input includes the driver operating the direction indicator lever to the right or left. The driving assistance device 19 determines whether the overtaking proposal conditions and the overtaking start conditions are met based on the various driving information acquired by the acquisition unit 3. In addition, the overtaking assist control may also include a function of starting the LCP for overtaking the preceding vehicle when the driver operates the direction indicator lever even when the overtaking information is not prompted.

[0069] The transcending proposal condition is not particularly limited, and examples thereof include the condition that all of the following conditions are satisfied.

[0070] · It is a lane keeping mode with hands-off mode.

[0071] Driving at a speed of 60 km / h or more.

[0072] There is a lane in the direction of the lane change.

[0073] ・There is room to change lanes after 5 seconds in the lane at the lane change destination.

[0074] The lane marking type is lane changeable.

[0075] The curvature radius of the road is more than 250m.

[0076] The vehicle's speed is more than 5 km / h slower than the set speed.

[0077] The speed of the vehicle ahead is more than 10 km / h slower than the set speed.

[0078] The inter-vehicle distance between the host vehicle and the preceding vehicle is smaller than a threshold value set in advance based on the speed difference between the host vehicle and the preceding vehicle.

[0079] The speed of the preceding vehicle in the lane at the lane change destination satisfies a predetermined condition.

[0080] In addition, the lane keeping mode of the hands-off mode refers to a mode in which the autonomous speed control of the speed control unit 41 and the lane keeping control of the lane keeping unit 421 are in execution, and the driver does not need to hold the steering wheel, which will be described in detail later. In addition, the condition that the speed of the preceding vehicle in the lane of the lane change destination satisfies the prescribed condition applies different conditions according to the type of lane of the lane change destination. For example, on a multi-lane road with left-hand traffic, in the case of changing lanes from the left lane to the right lane, the condition is that the speed of the vehicle in the left lane is faster than the speed of the preceding vehicle in the right lane by about 5 km / h or more. In contrast, on a multi-lane road with left-hand traffic, in the case of changing lanes from the right lane to the left lane, the condition is that the speed difference between the vehicle and the preceding vehicle in the left lane is within about 5 km / h. In addition, the condition regarding the relative speed difference between the vehicle and the preceding vehicle is opposite on a road with right-hand traffic.

[0081] When the driver confirms the presentation of the overtaking information and the predetermined overtaking start condition is satisfied, the driving assistance device 19 starts LCP by lighting the direction indicator through the overtaking assistance control of the overtaking unit 423. The overtaking start condition is not particularly limited, but examples thereof include the following conditions all being satisfied.

[0082] It is a lane keeping mode in handheld mode.

[0083] ·Determine whether the item is in hand.

[0084] Driving at a speed of 60 km / h or more.

[0085] There is a lane in the direction of the lane change.

[0086] ・There is space for lane change in the lane at the destination.

[0087] The lane marking type is lane changeable.

[0088] The curvature radius of the road is more than 250m.

[0089] The vehicle's speed is 5 km / h or more slower than the set speed (when changing lanes from left-hand traffic to the right lane).

[0090] The speed of the vehicle ahead is more than 10 km / h slower than the set speed (when changing lanes from left lane to right lane).

[0091] The speed of the preceding vehicle in the lane at the lane change destination satisfies a predetermined condition.

[0092] Within 10 seconds after the lane change assist switch 176 is operated.

[0093] In addition, the condition that the speed of the preceding vehicle is slower than the set speed by more than 10 km / h can be changed by the driver's setting, and the changed set speed becomes the overtaking start condition. As the changeable speed, for example, in addition to 10 km / h, 15 km / h and 20 km / h can also be selected. In addition, the condition that the speed of the preceding vehicle in the lane of the lane change destination meets the specified condition is the same as the above-mentioned overtaking proposal condition.

[0094] When the overtaking start condition is satisfied, the driving assist device 19 starts LCP through the overtaking assist control, and executes lateral movement and LCM to the adjacent lane. Through the overtaking assist control, the driving assist device 19 prompts the driver through the output device 18 with information indicating that lane changes are automatically made during the execution of LCP, reminding the driver to pay attention to the surroundings. When LCM ends, the driving assist device 19 turns off the direction indicator and starts the lane keeping control of the lane keeping unit 421 in the adjacent lane. In addition, the overtaking unit 423 has a function of proposing to the driver to return to the original lane through the output device 18 when the overtaking proposal condition is satisfied again after overtaking the leading vehicle. In response to this proposal, when the driver operates the lane change assist switch 176 of the input device 17 to confirm and the overtaking start condition is satisfied, as shown in FIG. Figure 5 As shown, the driving assist device 19 starts LCP to return the host vehicle to the original lane through the overtaking assist control.

[0095] The route driving unit 424 has a function of driving the vehicle along the set driving route. The route driving unit 424 drives the vehicle along the set driving route through route driving assistance control. That is, route driving assistance control is a type of autonomous lane change control, which is an autonomous lane change control in a driving scene in which the vehicle is driven along the set driving route. When there is a driving direction change point such as a branch point, a merging point, an exit, a toll booth, etc. on the set driving route, and the distance to the driving direction change point is within a prescribed distance and the prescribed route driving proposal conditions are met, the driving assistance device 19, through the function of the route driving unit 424, prompts the route driving information through the output device 18 and proposes a lane change to the driving direction change point. In addition, when the lane change proposal is confirmed by the operation of the lane change assistance switch 176 and the prescribed route driving start conditions are met, the driving assistance device 19 starts LCP. Here, the operation of the lane change assistance switch 176 may also be the driver's operation of the direction indicator lever. The driving assist device 19 determines whether or not a route driving suggestion condition and a route driving start condition are satisfied based on various types of driving information acquired by the driving information acquisition function of the acquisition unit 3 .

[0096] Furthermore, although the driving route set by the navigation device 15 is set, when the route driving assist control of the route driving unit 424 is not executed or becomes invalid during setting, normal navigation for guiding the driving route is executed by the navigation device 15. In addition, the route driving assist control may include a function of starting the LCP for driving along the driving route when the driver operates the direction indicator lever even when a lane change is not proposed based on the route driving information.

[0097] exist Figure 6 The example shown is an example in which the vehicle is traveling in the right lane of a single-sided three-lane road with left-hand traffic, and changes lanes twice in sequence toward a branch point on the left lane, and moves toward a branch road (also referred to as a branch lane, the same below) extending from the branch point to the left side of the left lane. When the vehicle is within a first prescribed distance from the branch point (for example, approximately 2.5 km to 1.0 km from the branch point) and the route driving proposal conditions are met, the driving assistance device 19 proposes a lane change from the right lane to the center lane based on the route driving information through the route driving assistance control of the route driving unit 424. In addition, the first prescribed distance (also referred to as the lane change proposal interval) is pre-set according to the number of lane changes required to move to the lane where the driving direction change point is located. For example, if Figure 6 As shown, when two lane changes are required from the right lane to the left lane via the center lane, as shown in the example, the section about 2.5 km to 1.0 km before the branch point becomes the first predetermined distance (lane change proposed section).

[0098] In addition, the route travel proposal conditions are not particularly limited, but examples thereof include the following conditions all being satisfied.

[0099] The destination is set by the navigation device 15 .

[0100] · It is a lane keeping mode with hands-off mode.

[0101] Driving at a speed of 60 km / h or more.

[0102] There is a lane in the direction of the lane change.

[0103] The lane marking type is lane changeable.

[0104] The curvature radius of the road is more than 250m.

[0105] Furthermore, in the route travel suggestion conditions, even when there is no space for lane change at the lane change destination, the route travel information is presented in order to notify the driver that a lane change is required along the travel route.

[0106] When the driver confirms the lane change to the branch point and the line driving start condition is satisfied, the driving assistance device 19 lights up the direction indicator and starts LCP through the line driving assistance control of the line driving unit 424. The line driving start condition is not particularly limited, and examples thereof include the following conditions all being satisfied.

[0107] It is a lane keeping mode in handheld mode.

[0108] ·Determine whether the item is in hand.

[0109] When driving at a speed of 60 km / h or more.

[0110] There is a lane in the direction of the lane change.

[0111] ・There is space for lane change in the lane at the destination.

[0112] The lane marking type is lane changeable.

[0113] Driving in the lane change proposal area.

[0114] The radius of road curvature is more than 250m.

[0115] When the line driving start condition is satisfied, the driving assist device 19 starts LCP through the line driving assist control of the line driving unit 424, and performs lateral movement to the center lane and LCM. When LCM is completed, the driving assist device 19 turns off the direction indicator and starts the lane keeping control of the lane keeping unit 421 in the center lane. The driving assist device 19 prompts the driver through the output device 18 to indicate that the lane change is automatically performed during the execution of LCP, so as to remind the driver to pay attention to the surroundings.

[0116] In addition, if Figure 6 As shown, during the execution of lane keeping control in the center lane, the driving assist device 19 lights up the direction indicator and starts the second LCP through the route driving assist control, when the distance to the branch point is within the second predetermined distance (for example, about 2.3km to 700m before the branch point) and the route driving start condition is satisfied, and the lane change from the center lane to the left lane is performed. When the second LCM ends, the driving assist device 19 turns off the direction indicator and starts the lane keeping control of the lane keeping unit 421 in the left lane.

[0117] Furthermore, when the driving assist device 19 is executing lane keeping control on the left lane, when the distance to the branch point is within a third prescribed distance (for example, about 800m to 150m before the branch point) and the route driving start condition is satisfied, the driving assist device 19 lights up the direction indicator through the route driving assist control. The driving assist device 19 starts the steering control from a point beyond the branch point to the branch road through the route driving assist control of the route driving unit 424, and performs a lane change from the left lane to the branch road through the autonomous driving control. The above-mentioned autonomous steering control is used in this steering control. When the lane change to the branch road is completed, the driving assist device 19 turns off the direction indicator and starts the lane keeping control of the lane keeping unit 421 on the branch road.

[0118] Figure 7 This is a block diagram showing the state transition of each function established by the driving assistance device 19 . Figure 7 The system shown is an autonomous driving control system implemented by the driving assistance device 19. Figure 7 The system is shown as OFF and ON. Figure 2 When the main switch 171 is turned on, the system enters a standby state. Figure 2 The autonomous speed control based on the autonomous speed control function is started by turning on the setting / coasting switch 173 or the recovery / acceleration switch 172. Thus, the above-mentioned constant speed control or vehicle-to-vehicle control is started, and the driver only needs to operate the steering wheel without stepping on the accelerator or the brake to make the vehicle run.

[0119] During autonomous speed control execution, when Figure 7 When the condition (1) of is satisfied, the mode is switched to the lane keeping mode of the autonomous steering control / handheld mode. Although the condition (1) is not particularly limited, the following conditions can be illustrated as being satisfied.

[0120] Detects lane markings on both sides of the vehicle.

[0121] The driver holds the steering wheel.

[0122] Drive near the center of the lane.

[0123] The direction indicator does not work.

[0124] The wipers do not operate at high speed (HI).

[0125] If a high-precision map is available, there are no toll gates, exits, merging points, intersections, or points where the number of lanes has been reduced within approximately 200 meters ahead.

[0126] In addition, the hand-held mode is a mode in which the autonomous steering control based on the autonomous steering control function does not operate if the driver does not hold the steering wheel, and the hands-off mode is a mode in which the autonomous steering control based on the autonomous steering control function operates even if the driver removes his hands from the steering wheel. In addition, the driver's holding of the steering wheel is detected by the touch sensor of the vehicle-mounted sensor 163.

[0127] In lane keeping mode of autonomous steering control / handheld mode, when Figure 7 When the condition (2) of is satisfied, the mode is switched to the lane keeping mode of the autonomous steering control / hands-off mode. As the condition (2), the following conditions can be cited as being satisfied.

[0128] The vehicle is traveling on a road reserved for automobiles.

[0129] Driving on a road that is structurally separated from the oncoming lane.

[0130] Driving on roads with high-precision maps.

[0131] ·The vehicle is traveling at a speed below the speed limit.

[0132] GPS signal is valid.

[0133] The driver holds the steering wheel.

[0134] The driver faces forward.

[0135] There are no toll gates, exits, merges, intersections, or places with reduced lanes within about 800 meters ahead.

[0136] There are no sharp turns less than 100R within about 500m ahead.

[0137] Not driving in a tunnel more than 500m from the tunnel entrance.

[0138] The accelerator pedal is not depressed.

[0139] In addition, for example, it is determined based on an image captured by a driver monitoring camera of the imaging device 11 whether the driver is facing forward.

[0140] On the contrary, in the lane keeping mode execution of autonomous steering control / hands-off mode, when Figure 7 When the condition (3) of is satisfied, the mode is switched to the lane keeping mode of the autonomous steering control / handheld mode. The condition (3) is not particularly limited, but the following conditions may be satisfied.

[0141] The vehicle is traveling on a road other than a dedicated lane for automobiles.

[0142] Driving in the oncoming traffic zone.

[0143] Driving on roads without high-precision maps.

[0144] Driving at a speed exceeding the speed limit.

[0145] ·GPS signal cannot be received.

[0146] After the forward look alarm is activated, the driver does not face forward within 5 seconds.

[0147] The driver monitoring camera can no longer detect the driver.

[0148] · There is a toll booth, exit, merge, or lane reduction approximately 800 meters ahead.

[0149] When driving at a speed of less than 40 km / h, there is a sharp curve of less than 100R within 200m ahead.

[0150] When driving at a speed of approximately 40 km / h or more, there is a sharp curve of less than 170R within approximately 200m ahead.

[0151] Driving in a tunnel more than 500m from the tunnel entrance.

[0152] The driver holds the steering wheel and steps on the accelerator pedal.

[0153] The proximity alarm is operating.

[0154] In lane keeping mode of autonomous steering control / hands-off mode, when Figure 7 When the condition (4) is satisfied, the autonomous steering control is terminated and the vehicle is switched to the autonomous speed control. The condition (4) is not particularly limited, but may be any one of the following conditions satisfied.

[0155] The lane markings on both sides of the vehicle are not detected for a certain period of time.

[0156] The driver is operating the steering wheel.

[0157] The wipers operate at high speed (HI).

[0158] In addition, the driver's operation of the steering wheel is determined by detecting the torque applied to the steering wheel through the vehicle-mounted sensor 163.

[0159] In addition, during lane keeping mode execution in autonomous steering control / hands-off mode, when Figure 7 When the condition (5) is satisfied, the autonomous steering control and the autonomous speed control are terminated and the vehicle is switched to the standby state. The condition (5) is not particularly limited, but any one of the following conditions may be satisfied.

[0160] The driver applied the brakes.

[0161] The driver operated Figure 2 The cancel switch 174.

[0162] The door of your vehicle is open.

[0163] The driver's seat belt was unfastened.

[0164] The seat occupancy sensor detects that the driver has left the driver's seat.

[0165] The selector lever is in a position other than "D" or "M".

[0166] The parking brake is applied.

[0167] The vehicle's anti-skid device is OFF.

[0168] The anti-skid device has been activated.

[0169] Snow mode is turned ON.

[0170] The emergency brake is applied.

[0171] After the vehicle was stopped by speed control, it remained stopped for about 3 minutes.

[0172] Detects poor vision of the front camera that cannot correctly recognize objects due to dirt, backlight, rain / fog, etc.

[0173] The front radar detected obstruction or radio wave failure.

[0174] The forward radar detected an axis deviation.

[0175] The side radar detected obstruction or radio wave failure.

[0176] Side radar detected axis deviation.

[0177] In autonomous steering control / handheld mode, when Figure 7 When the condition (6) is satisfied, the autonomous steering control is terminated and the vehicle is switched to the autonomous speed control. The condition (6) is not particularly limited, but the condition (6) may be any one of the following conditions satisfied.

[0178] Unable to detect lane markings on both sides of the vehicle.

[0179] The driver operated the steering wheel.

[0180] The driver operated the direction indicator lever.

[0181] The wipers operate at high speed (HI).

[0182] ·It becomes a toll booth section when a high-precision map is available.

[0183] Detects poor vision of the front camera that cannot correctly recognize objects due to dirt, backlight, rain / fog, etc.

[0184] In addition, during autonomous steering control / handheld mode execution, when Figure 7 When the condition (7) is satisfied, the autonomous steering control and the autonomous speed control are terminated and the vehicle is switched to the standby state. The condition (7) is not particularly limited, but any one of the following conditions may be satisfied.

[0185] The driver applied the brakes.

[0186] The driver operated Figure 2 The cancel switch 174.

[0187] The door of your vehicle is open.

[0188] The driver's seat belt was unfastened.

[0189] The seat occupancy sensor detects that the driver has left the driver's seat.

[0190] The selector lever is in a position other than "D" or "M".

[0191] The parking brake is applied.

[0192] The vehicle's anti-skid device is OFF.

[0193] The anti-skid device has been activated.

[0194] Snow mode is turned ON.

[0195] The emergency brake is applied.

[0196] After the vehicle was stopped by speed control, it remained stopped for about 3 minutes.

[0197] The forward radar detected obstruction or radio wave failure.

[0198] The forward radar detected an axis deviation.

[0199] During autonomous speed control execution, when Figure 7 When the condition (8) is satisfied, the system switches to the standby state. The condition (8) is not particularly limited, but any one of the following conditions can be exemplified.

[0200] The driver applied the brakes.

[0201] The driver operated Figure 2 The cancel switch 174.

[0202] The door of your vehicle is open.

[0203] The driver's seat belt was unfastened.

[0204] The seat occupancy sensor detects that the driver has left the driver's seat.

[0205] The selector lever is in a position other than "D" or "M".

[0206] The parking brake is applied.

[0207] The vehicle's anti-skid device is OFF.

[0208] The anti-skid device has been activated.

[0209] Snow mode is turned ON.

[0210] The emergency brake is applied.

[0211] After the vehicle was stopped by speed control, it remained stopped for about 3 minutes.

[0212] The front radar detected obstruction or radio wave failure.

[0213] The forward radar detected an axis deviation.

[0214] In lane keeping mode of autonomous steering control / hands-off mode, when Figure 7 When the condition (9) of is satisfied, the mode is switched to the lane change mode of the autonomous steering control / handheld mode. The condition (9) is not particularly limited, and examples thereof include the satisfaction of any of the following conditions.

[0215] The system proposes a lane change based on the overtaking assist control of the overtaking unit 423 or the line driving assist control of the line driving unit 424 , and the driver operates the lane change assist switch 176 .

[0216] The driver operated the direction indicator lever to execute autonomous lane change control.

[0217] During lane change mode execution in autonomous steering control / handheld mode, when Figure 7 When the condition (10) is satisfied, the mode is switched to the lane keeping mode of the autonomous steering control / handheld mode. The condition (10) is not particularly limited, but the following conditions may be satisfied.

[0218] ·Before LCP started, the speed limit was exceeded.

[0219] Before the LCP starts, the driver holds the steering wheel and presses the accelerator pedal.

[0220] When the lane change assist switch 176 is pressed during a lane change proposal with a slow vehicle ahead, LCP cannot be started within 10 seconds.

[0221] After the lane change assist switch 176 is pressed during a lane change proposal for following the driving route, the LCP cannot be started and the vehicle approaches the branch point too close.

[0222] After LCP is activated, LCM cannot be started within 5 seconds.

[0223] Start LCP, the vehicle speed is below about 50 km / h before starting LCM.

[0224] After LCP, before starting LCM, the space in the adjacent lane required for lane change is no longer available.

[0225] The driver canceled the LCM operation before it started.

[0226] Lane markings are not detected before LCM starts.

[0227] Before LCM starts, it is determined that there is no adjacent lane in the lane change direction or there is no adjacent lane within a certain distance ahead.

[0228] Before the LCM starts, it is determined that there is a curve with a radius of curvature of more than 250m within a certain distance ahead.

[0229] Before LCM starts, it is determined that there is a line dividing the lane ahead within a certain distance, and that lane changes to the adjacent lane are prohibited.

[0230] Before LCM starts, the side radar detects shielding or radio wave obstruction.

[0231] Before LCM starts, the side radar detects axis deviation.

[0232] Handheld alarm action.

[0233] The driver stopped the direction indicator.

[0234] ·LCP has ended.

[0235] In addition, the handheld alarm will be activated when any of the following conditions are met.

[0236] The driver does not hold the steering wheel within about 2 seconds after LCP is activated.

[0237] The driver does not hold the steering wheel within about 2 seconds after pressing the lane change assist switch 176 during lane change proposal when there is a slow vehicle ahead.

[0238] The driver does not hold the steering wheel within about 2 seconds after pressing lane change assist switch 176 in a lane change proposal for following the driving route.

[0239] In addition, if the main switch 171 is turned OFF in any of the autonomous steering control / hands-off mode, autonomous steering control / handheld mode, autonomous speed control, and standby mode, the system is turned OFF.

[0240] Next, refer to Figure 8 The travel control process according to the present embodiment will be described. Figure 8 1 is an example of a flowchart showing the driving control process of the present embodiment. In addition, the driving assistance device 19 performs the driving control process described below at a predetermined time interval. In addition, in the following description, the driving assistance device 19 performs autonomous speed control through the function of the speed control unit 41, and performs autonomous steering control through the function of the steering control unit 42. In addition, the driving assistance device 19 performs lane change assistance control through the function of the lane change unit 422, performs overtaking assistance control through the function of the overtaking unit 423, and performs route driving assistance control through the function of the route driving unit 424.

[0241] First, in Figure 8 In step S1, it is determined whether the main switch 171 of the driving assist device 19 is turned on (ON). If the main switch 171 is turned off (OFF), step S1 is repeated until it is turned on. If the main switch 171 is turned on, the process proceeds to step S2 to determine whether the driving speed is set by the driver. If the driving speed is not set, the process returns to step S1 and steps S1 and S2 are repeated until the driving speed is set. In addition, the driver sets the driving speed by operating the Figure 2 This is done by inputting a desired travel speed using the resume / accelerate switch 172 or the set / coast switch 173 of the input device 17 shown.

[0242] After the travel speed is set, autonomous speed control starts. In step S3, the front radar as the distance measuring device 12 is used to detect whether there is a preceding vehicle in front of the lane where the vehicle is traveling. If there is a preceding vehicle, the process proceeds to step S4 to perform inter-vehicle control. If there is no preceding vehicle, the process proceeds to step S5 to perform constant speed control. As a result, the driver can drive the vehicle at a desired speed without stepping on the accelerator or the brake by simply operating the steering wheel.

[0243] During the execution of the inter-vehicle control of step S4 or the constant speed control of step S5, in step S6, it is determined whether the condition (1) for switching to the lane keeping mode of the autonomous steering control / handheld mode is satisfied. If the condition (1) is satisfied, the process proceeds to step S7, and if the condition (1) is not satisfied, the process returns to step S3.

[0244] In step S7, the front radar (distance measuring device 12) for detecting obstacles in front of the vehicle is used to detect whether there is a preceding vehicle in front of the lane in which the vehicle is traveling. If there is a preceding vehicle, the process proceeds to step S8 to execute the inter-vehicle control / lane keeping mode. If there is no preceding vehicle, the process proceeds to step S9 to execute the constant speed control / lane keeping mode.

[0245] During the execution of the vehicle-to-vehicle control / lane keeping mode of step S8 or the constant speed control / lane keeping mode of step S9, in the subsequent step S10, it is determined whether the condition (2) for switching to the above-mentioned autonomous steering control / hands-off mode is met. If condition (2) is met, the process proceeds to step S11; if condition (2) is not met, the process returns to step S3. In step S11, in which the condition (2) for switching to the autonomous steering control / hands-off mode is met, a front radar (ranging device 12) for detecting obstacles in front of the vehicle is used to detect whether there is a preceding vehicle in front of the lane in which the vehicle is traveling. If there is a preceding vehicle, the process proceeds to step S12 to execute vehicle-to-vehicle control / lane keeping mode / hands-off. If there is no preceding vehicle, the process proceeds to step S13 to execute constant speed control / lane keeping mode / hands-off.

[0246] In step S14, it is determined whether the driver has operated the direction indicator lever. If the direction indicator lever has been operated, condition (9) for switching to the lane change mode of the autonomous steering control / handheld mode is satisfied, and the process proceeds to step S15. In step S15, the lane change assist control is executed. After the lane change assist control in step S15 is completed, the process returns to step S3. If the driver has not operated the direction indicator lever in step S14, the process proceeds to step S16.

[0247] In step S16, it is determined whether there is a preceding vehicle that is slower than the set speed. If there is a preceding vehicle that is slower than the set speed, it is determined whether condition (9) is satisfied. If condition (9) is satisfied, the lane change mode of the autonomous steering control / handheld mode is switched to step S17. In step S17, the overtaking assist control is executed. After the overtaking assist control in step S17 is completed, the process returns to step S3. If there is no preceding vehicle that is slower than the set speed in step S16, the process proceeds to step S18.

[0248] In step S18, it is determined whether a driving route to the destination is set in the navigation device 15. If no driving route is set, the process returns to step S1. In step S18, if a driving route to the destination is set in the navigation device 15, the process proceeds to step S19. In step S19, it is determined whether the specified distance from the driving direction change point, such as a branch point on the driving route, has been reached. In step S19, if the specified distance from the driving direction change point has been reached, it is determined whether condition (9) is satisfied. If condition (9) is satisfied, the process switches to the lane change mode of the autonomous steering control / handheld mode and the process proceeds to step S20. In step S20, route driving assist control is executed. After the route driving assist control in step S20 is completed, the process returns to step S3. In step S19, if the specified distance from the driving direction change point has not been reached, the process returns to step S1.

[0249] In addition, Figure 8 In the flowchart, the need for lane change assist control, overtaking assist control, and route driving assist control is judged in turn, but in fact the need for each control is judged in parallel. When other auxiliary controls need to be executed during the execution of any auxiliary control, it is necessary to adjust whether to execute each auxiliary control and determine the auxiliary control to be executed first.

[0250] (Route Driving Assist Control)

[0251] use Fig. 9 The route-based driving assist control according to the present embodiment will be described. Fig. 9 It is a plan view showing an example of a driving scene in which autonomous driving control is performed using the driving assistance system 1 . Fig. 9 The direction of vehicle movement on the road shown is determined by Fig. 9 The direction indicated by the lower right arrow A is from the lower side toward the upper side of the drawing. Fig. 9 The road shown has a lane L1 on the right side in the traveling direction and a lane L2 on the left side in the traveling direction. Lane L2 branches at a branch position B into lane L2 as a main lane and lane L3 as a branch lane.

[0252] exist Fig. 9In the driving scenario shown, it is assumed that the vehicle V is traveling at position P1 in lane L2. In addition, it is assumed that the destination Px set by the driver exists in front of the driving direction of lane L3, and the driving path toward the destination Px is set by the navigation device 15. In this case, in order to travel along the driving path, the vehicle V needs to change lanes from lane L2 to lane L3 and enter lane L3 as a branch lane. In order to make the vehicle V enter lane L3, the driving assistance device 19, for example, makes the vehicle V travel from position P1 to position P2 along trajectory T1, starts the first LCP at position P2 in lane L2, and makes the vehicle V travel along trajectory T2, and ends the LCP at position P3 in lane L3.

[0253] exist Fig. 9 In the driving scenario shown, since the angle α between the main lane L2 and the branch lane L3 is large, the vehicle V needs to significantly slow down and turn left with a large steering angle in order to enter the branch lane L3. In this way, in a driving scenario where the behavior of the vehicle V changes significantly, a lane change using autonomous lane change control (hereinafter also referred to as "autonomous lane change") cannot be performed, so the driving assistance device 19 notifies the driver in advance that the autonomous lane change cannot be performed. For example, Fig. 9 In the driving scenario shown, when the host vehicle V reaches the notification position X, the driver is notified that the autonomous lane change cannot be performed. The notification is performed using the output device 18. The driver who is notified that the autonomous lane change cannot be performed understands that all autonomous lane changes cannot be performed, and attempts to change lanes from the main lane L2 to the branch lane L3 by manual operation.

[0254] In this way, Fig. 9 In the driving scenario shown, the driving assistance device 19 notifies the driver that an autonomous lane change cannot be executed. However, in this driving scenario, the autonomous lane change that cannot be executed is only the autonomous lane change from the main lane L2 to the branch lane L3 based on the route driving assistance control of the route driving unit 424. That is, even after passing the notification position X, the autonomous lane change based on the autonomous lane change control of the lane change unit 422 and the autonomous lane change based on the overtaking assistance control of the overtaking unit 423 can be executed. Therefore, when the driver inputs the direction indicator lever to the right after passing the notification position X, the autonomous lane change from the lane L2 to the lane L1 is executed by the function of the lane change unit 422. That is, although the driver understands that all autonomous lane changes cannot be executed between the notification position X and the branch position B, in fact, the autonomous lane change from the lane L2 to the lane L1 can be executed, so there is a discrepancy between the control that the driver recognizes as executable and the control that is actually executable.

[0255] Therefore, in the route driving assistance control of the present embodiment, in addition to the functions of the acquisition unit 3 and the assistance unit 4, the functions of the determination unit 5 and the notification unit 6 are also used, so that after notifying the driver that the autonomous lane change cannot be performed, the executable control recognized by the driver is made consistent with the actually executable control, thereby suppressing the driver's discomfort caused by the inconsistency between the two. The functions of the determination unit 5 and the notification unit 6 are described below.

[0256] The determination unit 5 has a function of determining whether a path following lane change is required. A path following lane change is a lane change required for traveling along a set driving path. The determination unit 5 determines whether a lane change is required to follow the driving path using road information from the map information 13, information on the current position of the vehicle V obtained from the vehicle position detection device 14, and information on the driving path obtained from the navigation device 15.

[0257] Specifically, first, based on the road information of the map information 13 and the information of the current position of the vehicle V, it is determined whether the number of lanes of the road ahead of the driving direction of the road on which the vehicle V is traveling has increased. For example, when the road on which the vehicle V is traveling is divided into a main lane and a branch lane ahead of the current position of the vehicle V, it is determined that the number of lanes of the road has increased. As another example, when other lanes merge with the main lane on which the vehicle V is traveling ahead of the current position of the vehicle V, it is determined that the number of lanes of the road has increased. In addition, as another example, when there is an intersection ahead of the vehicle V, when the lane on which the vehicle V is traveling is divided into a straight lane and a right turn lane in front of the intersection, it is determined that the number of lanes of the road has increased. In contrast, when there is a bridge ahead of the vehicle V, when the lane on which the vehicle V is traveling merges with the adjacent lane in front of the bridge as the width decreases, it is determined that the number of lanes of the road has decreased. In addition, when there is no branch position and a merging position of the lanes ahead of the current position of the vehicle V, it is determined that the number of lanes of the road has not changed.

[0258] Next, the driving assistance device 19 determines whether the vehicle V needs to enter the added lane in order to head toward the set destination based on the information of the current position of the vehicle V obtained from the vehicle position detection device 14 and the driving path obtained from the navigation device 15. For example, in a case where the road on which the vehicle V is traveling branches into a main lane and a branch lane in front of the current position of the vehicle V, when a driving path for traveling on the main lane is set, it is determined that the vehicle V does not need to enter the added lane. That is, it is determined that a path-following lane change is not required. In contrast, in a case where the road on which the vehicle V is traveling branches into a main lane and a branch lane in front of the current position of the vehicle V, when a driving path for entering a branch lane is set, it is determined that the vehicle V needs to enter the added lane, i.e., the branch lane. That is, it is determined that a path-following lane change is required.

[0259] Instead of or in addition to these, the lane of the road on which the vehicle V is traveling may be determined based on the road information and the current position of the vehicle V, and the determined lane may be compared with the lane in which the vehicle V is traveling after traveling along the driving path. When it is determined that the lane in which the vehicle V is traveling is the same as the lane in which the vehicle V is traveling after traveling along the driving path, or when the vehicle V can follow the driving path even if it continues traveling in the lane currently traveling, it is determined that a path-following lane change is not required. In contrast, when it is determined that the vehicle V cannot follow the driving path if it continues traveling in the lane currently traveling, it is determined that a path-following lane change is required. In addition, when a position requiring a lane change is pre-set in the driving path generated by the navigation device 15, it is determined that a path-following lane change is required when the vehicle V approaches the pre-set lane change position.

[0260] exist Fig. 9 In the driving scenario shown, since the vehicle V is traveling at position P1 in lane L2, the road on which the vehicle V is traveling branches into the main lane L2 and the branch lane L3 at the branch position B in front of the current position of the vehicle V, i.e., position P1. Therefore, the number of lanes on the road increases. In addition, the driving path toward the destination Px is set to enter the branch lane L3. Therefore, the driving assistance device 19 determines that the vehicle V needs to change lanes from lane L2 to lane L3 (i.e., determines that a path following lane change is required). In contrast, for example, when the destination Px is set in front of lane L1, a driving path is set to travel on the main lane, i.e., lane L1 or lane L2. Therefore, even if the vehicle V continues to travel on lane L2, it can follow the driving path, so it is determined that a path following lane change is not required.

[0261] The above-mentioned determination of whether the path following the lane change is necessary (for example, the determination of the increase in the number of lanes) is performed within a range of a predetermined distance from the current position of the host vehicle V. The predetermined distance can be set to an appropriate value within a range in which the driver is not confused about whether the guidance of the driving assistance device 19 is appropriate. The predetermined distance is, for example, 500 to 1500 meters. If the predetermined distance is set longer than this, the driving distance to the lane change position will become longer, and the driver will be confused about whether the guidance of the driving assistance device 19 is appropriate, resulting in discomfort.

[0262] When the determination unit 5 determines that a path following lane change is not required, the determination unit 5 instructs the assisting unit 4 to execute or continue the lane keeping control of the lane keeping unit 421. On the other hand, when the determination unit 5 determines that a path following lane change is required, the determination unit 5 determines whether the path following lane change can be assisted by the autonomous lane change control. Specifically, the driving assist device 19 determines whether the execution conditions for executing the autonomous lane change are satisfied through the function of the determination unit 5.

[0263] The conditions for executing the autonomous lane change are conditions that allow the lane change to be performed without causing discomfort or unpleasantness to passengers including the driver, and conditions that do not cause significant changes in the front-rear and left-right directions of the vehicle V during the autonomous lane change. Figure 7 The conditions (1) for transitioning to autonomous steering control / handheld mode, and (9) for transitioning to lane change mode are shown.

[0264] Execution conditions include, for example: lane markings on both sides of the vehicle V are detected; the driver holds the steering wheel; the vehicle V is traveling near the center of the lane; the direction indicator is not operating; the wipers are not operating at high speed (HI) (i.e., no heavy rain or snow is observed around the vehicle V); driving on a road for which a high-precision map can be used (especially for the road on which the vehicle V travels from the start to the end of the autonomous lane change, high-precision map information can be used); when a high-precision map can be used, there are no toll booths, exits, merging points, intersections, or points where the number of lanes decreases within approximately 200 meters ahead; the road on which the vehicle V travels from the start to the end of the autonomous lane change has not been registered on the high-precision map as a road on which autonomous lane changes cannot be performed. The information includes: the vehicle V is traveling at a speed within a specified range (for example, a speed of 1 to 30 km / h and 40 to 70 km / h); the GPS signal is valid; the radius of curvature of the road on which the vehicle V is traveling from the start of the autonomous lane change to the end is greater than a specified value (for example, 200 to 1000 m); there is no sharp turn of less than 100R within approximately 500 m ahead; the vehicle is not traveling in a tunnel more than 500 m from the tunnel entrance; a lane change is proposed by the route driving assist control of the route driving unit 424, and the driver operates the lane change assist switch 176; the driver operates the direction indicator lever to execute the autonomous lane change control; there is space in the adjacent lane for the vehicle V to enter the adjacent lane, etc.

[0265] In addition, the execution conditions include that the behavior of the vehicle V is within a range that can be controlled by autonomous lane change control during autonomous lane change execution. The range that can be controlled by autonomous lane change control is a range set by at least one of the acceleration, deceleration, and lateral acceleration of the vehicle V, and appropriate values ​​can be set for each of the acceleration, deceleration, and lateral acceleration within a range that does not cause discomfort to passengers including the driver. In addition, the reason why the behavior of the vehicle V deviates from the range that can be controlled by autonomous lane change control is the shape of the road on which the vehicle V is traveling. Therefore, roads where the behavior of the vehicle V changes greatly can also be pre-registered in the high-precision map information as roads where autonomous lane changes cannot be performed.

[0266] Furthermore, the execution condition includes: the distance from the current position of the host vehicle V to the position where lane change is not possible is longer than the driving distance required for executing LCP or LCM (for example, 700 to 1500 meters). Fig. 9 In the driving scenario shown, position Y is the position where the main lane L2 and the branch lane L3 are separated. The distance from the current position of the vehicle V to the position where lane change is not possible is Fig. 9The distance D along the travel direction (direction of arrow A) of the road along which the host vehicle V is traveling is shown. After passing position Y, the host vehicle V cannot change lanes from the main lane L2 to the branch lane L3. Therefore, the host vehicle V needs to change lanes before reaching position Y.

[0267] In addition, changing lanes before reaching position Y means that, when looking down at the vehicle V, the entire body of the vehicle V is included in the branch lane L3 before the rear end of the body of the vehicle V reaches position Y. That is, LCM only needs to be completed before the rear end of the body of the vehicle V reaches position Y, and LCP does not necessarily need to be completed.

[0268] In addition, the execution conditions may also include: when the road on which the host vehicle V is traveling merges with a different road ahead of the traveling direction of the host vehicle V after the path following lane change ends, the distance from the end position of the path following lane change to the merging position of the road is less than a specified distance (for example, 50 to 500 meters), and the speed limit of the road entered by the host vehicle V is set to be lower than the speed limit of the road on which the host vehicle V was traveling when the path following lane change started. For example, Fig. 9 The main lane L2 shown is a dedicated road for automobiles, and the branch lane L3 does not meet the execution condition when it merges with the general road about 200 meters ahead of the position P3. This is because the speed limit of the general road is usually set lower than the speed limit of the lane L2 that the host vehicle V traveled when the lane change started, and the host vehicle V needs to slow down significantly 200 meters before entering the general road.

[0269] Furthermore, the execution condition may also include: when there is an intersection ahead of the vehicle V in the driving direction on the road where the vehicle V is traveling after the path following lane change is completed, the distance from the end position of the path following lane change to the intersection is less than a specified distance (for example, 50 to 500 meters). Fig. 9 The main lane L2 shown is a dedicated road for automobiles. If there is an intersection about 300m ahead of the position P3 of the branch lane L3, the execution condition is not met. This is because in order to enter the intersection, the driving speed needs to be reduced to a slow speed (for example, 5 to 20 km / h), so the vehicle V needs to slow down significantly 300m before the intersection.

[0270] When it is determined that the execution conditions of the autonomous lane change are met, the auxiliary unit 4 determines that the path following lane change can be assisted by the autonomous lane change control. Moreover, the autonomous lane change is executed as the path following lane change through the route driving auxiliary control of the route driving unit 424. In contrast, when it is determined that the execution conditions of the autonomous lane change are not met, it is determined that the path following lane change cannot be assisted by the autonomous lane change control. In this case, the path following lane change is performed through manual operation of the driver. At this time, in order to urge the driver to change lanes through manual operation, the driver is notified of the situation that the autonomous lane change cannot be performed through the function of the auxiliary unit 4. The notification is performed using an output device 18 such as a display or a speaker in the instrument panel. The notification can also be performed by the function of the notification unit 6.

[0271] In addition, the assisting unit 4 notifies the driver that the lane change based on the autonomous lane change control cannot be performed, and prohibits the lane change in the opposite direction to the direction in which the host vehicle V moves in the path following lane change by assisting the autonomous lane change control. The direction in which the host vehicle V moves in the path following lane change refers to the steering direction of the host vehicle V, which is the direction in which the steering wheel is rotated when the lane change is performed. Fig. 9 In the driving scenario shown, since the lane change is made from the main lane L2 to the branch lane L3, the direction in which the host vehicle V moves in the path following lane change is left. Therefore, after the host vehicle V passes the notification position X, the assisting unit 4 does not assist the lane change to the right relative to the driving direction by autonomous lane change control before the host vehicle V passes the branch position B. The prohibition of the autonomous lane change to the right may be until the LCM or LCP of the host vehicle V ends, or until the host vehicle V reaches the position Y where the main lane L2 and the branch lane L3 branch.

[0272] In addition, the assisting unit 4 may also disable the functions of the lane change unit 422, the overtaking unit 423, and the line driving unit 424 in order to prohibit the assistance based on the autonomous lane change control. In this case, the autonomous lane change caused by the driver's operation such as the operation of the lane change assist switch 176 and the operation of the direction indicator lever is not performed. In addition, the lane change is not proposed to the driver by any of the functions of the lane change unit 422, the overtaking unit 423, and the line driving unit 424. That is, regardless of the driving scene, it is in a state where all autonomous lane changes cannot be performed. At this time, the functions of the speed control unit 41 and the lane keeping unit 421 may remain valid or invalid.

[0273] Next, refer to Fig.10 , explaining the processing in route driving assistance control. Fig.10 yes Figure 8 The subroutine of step S20 in the flowchart shown. Fig.10 The subroutine shown is just an example and is not limited to this. In addition, the CPU (processor) 191 of the driving assistance device 19 executes the processing described below at predetermined time intervals.

[0274] First, in step S31, the driving route generated by the navigation device 15 is acquired through the function of the acquisition unit 3 and set as the driving route. In the following step S32, the vehicle control device 16 is used to make the vehicle V travel along the driving route through the function of the route driving unit 424. In the following step S33, the map information 13 and the vehicle position detection device 14 are used through the function of the route driving unit 424 to determine whether the number of lanes of the road ahead in the driving direction of the road on which the vehicle V is traveling has increased. In the case where it is determined that the number of lanes of the road ahead in the driving direction of the road on which the vehicle V is traveling has increased, the process proceeds to step S34. In contrast, in the case where it is determined that the number of lanes of the road ahead in the driving direction of the road on which the vehicle V is traveling has not changed or has decreased, the process returns to step S3.

[0275] In step S34, based on the information of the current position of the host vehicle V and the driving path, it is determined whether the host vehicle V needs to enter the additional lane in order to head toward the set destination. If it is determined that the host vehicle V needs to enter the additional lane, the process proceeds to step S35. On the other hand, if it is determined that the host vehicle V does not need to enter the additional lane, the process returns to step S3.

[0276] In step S35, the function of the assisting unit 4 (particularly the route driving unit 424) determines whether the lane change can be assisted by the autonomous lane change control. The map information 13 and the detection results of the vehicle-mounted sensor 163 are used in this determination. If it is determined that the lane change can be assisted by the autonomous lane change control, the process proceeds to step S36 to execute the autonomous lane change. On the other hand, if it is determined that the lane change cannot be assisted by the autonomous lane change control, the process proceeds to step S37.

[0277] In step S37, the driver is notified that the lane change cannot be performed by the autonomous lane change control through the function of the assisting unit 4 or the notifying unit 6. In the following step S38, the lane change in the direction opposite to the direction in which the vehicle moves during the path following lane change is prohibited by the function of the assisting unit 4. In this case, the path following lane change is performed by the manual operation of the driver. Then, after the processing of step S36 and step S38 is completed, the process returns to step S3.

[0278] (Embodiment of the present invention)

[0279] As described above, according to the present embodiment, a driving assistance method for a vehicle is provided. In the driving assistance method for a vehicle using a processor that executes autonomous lane change control, when the processor performs a lane change for traveling along a set driving path, i.e., a path following lane change, it is determined whether the path following lane change can be assisted by the autonomous lane change control. When it is determined that the path following lane change cannot be assisted by the autonomous lane change control, the driver is notified that the lane change based on the autonomous lane change control cannot be performed, and the lane change in the direction opposite to the direction in which the vehicle moves in the path following lane change is prohibited from being assisted by the autonomous lane change control. Thus, the executable control recognized by the driver can be made consistent with the actually executable control. In addition, the occurrence of a situation in which the driver feels uncomfortable due to the inconsistency between the executable control recognized by the driver and the actually executable control can be suppressed.

[0280] In addition, according to the vehicle driving assistance method of the present embodiment, when determining whether the autonomous lane change control can assist the path following the lane change, the processor determines whether the execution condition for enabling the lane change based on the autonomous lane change control to be executed is satisfied, and when it is determined that the execution condition is satisfied, it is determined that the autonomous lane change control can assist the path following the lane change, and when it is determined that the execution condition is not satisfied, it is determined that the autonomous lane change control cannot assist the path following the lane change. In this way, it is possible to more accurately determine whether the autonomous lane change can be executed.

[0281] In addition, according to the vehicle driving assistance method of the present embodiment, the execution condition includes: high-precision map information can be used for the road on which the vehicle is traveling from the start to the end of the lane change based on the autonomous lane change control. Therefore, it can be more accurately determined whether the autonomous lane change can be performed.

[0282] In addition, according to the vehicle driving assistance method of the present embodiment, the execution condition includes any one of the following conditions: the radius of curvature of the road on which the vehicle is traveling from the start to the end of the lane change based on the autonomous lane change control is greater than a specified value; the road is not registered in the high-precision map information as a road on which lane change based on the autonomous lane change control cannot be performed; the driving speed of the vehicle is within a specified range; the behavior of the vehicle is within a range that can be controlled by the autonomous lane change control during the execution of the lane change based on the autonomous lane change control. In this way, it is possible to more accurately determine whether the autonomous lane change can be performed.

[0283] In addition, according to the vehicle driving assistance method of the present embodiment, the range is set by at least one of the acceleration, deceleration, and lateral acceleration of the vehicle. This makes it possible to more accurately determine whether autonomous lane change can be performed.

[0284] In addition, according to the vehicle driving assistance method of the present embodiment, the execution condition includes any one of the following conditions: when the road on which the vehicle is traveling merges with a different road ahead of the vehicle in the driving direction after the path following lane change ends, the distance from the end position of the path following lane change to the merging position of the road is less than a prescribed distance, and the speed limit of the road the vehicle enters is set to be lower than the speed limit of the road the vehicle has traveled on when the path following lane change starts; and when there is an intersection ahead of the vehicle in the driving direction on the road on which the vehicle is traveling after the path following lane change ends, the distance from the end position of the path following lane change to the intersection is less than a prescribed distance. In this way, it is possible to more accurately determine whether the autonomous lane change can be performed.

[0285] In addition, according to the present embodiment, a driving assistance device for a vehicle is provided, comprising: a determination unit, which determines whether the path following lane change can be assisted by autonomous lane change control when a lane change for traveling along a set driving path, i.e., a path following lane change, is performed; and an assistance unit, which, when the determination unit determines that the path following lane change cannot be assisted by the autonomous lane change control, notifies the driver that the lane change based on the autonomous lane change control cannot be performed, and prohibits the autonomous lane change control from assisting the lane change in the direction opposite to the direction in which the vehicle moves during the path following lane change. Thus, the executable control recognized by the driver can be made consistent with the actually executable control. In addition, the occurrence of a situation in which the driver feels uncomfortable due to the inconsistency between the executable control recognized by the driver and the actually executable control can be suppressed.

[0286] Explanation of symbols

[0287] 1: Driving assistance system

[0288] 11: Camera device

[0289] 12: Distance measuring device

[0290] 13: Map information

[0291] 14: Vehicle position detection device

[0292] 15: Navigation device

[0293] 16: Vehicle control device

[0294] 161: Vehicle speed control device

[0295] 162: Steering Controls

[0296] 163: Vehicle Sensors

[0297] 17: Input Device

[0298] 171: Main switch

[0299] 172: Resume / acceleration switch

[0300] 173: Setting / slide switch

[0301] 174: Cancel switch

[0302] 175: Workshop adjustment switch

[0303] 176: Lane change assist switch

[0304] 18: Output device

[0305] 19: Driving assistance device

[0306] 191: CPU (processor)

[0307] 192: ROM

[0308] 193: RAM

[0309] 2: Control Department

[0310] 3: Get the department

[0311] 4: Auxiliary Department

[0312] 41: Speed ​​control unit

[0313] 42: Steering control unit

[0314] 421: Lane Keeping Department

[0315] 422: Lane Change Department

[0316] 423: Beyond Department

[0317] 424: Route driving department

[0318] 5: Judgment Department

[0319] 6: Notification Department

[0320] A: Arrow (driving direction)

[0321] B: Branch location

[0322] D: Distance

[0323] L1, L2: Lane (main lane)

[0324] L3: Lane (branch lane)

[0325] P1, P2, P3: Location

[0326] Px: Destination

[0327] T1, T2: Trajectory

[0328] X: Notification location

[0329] V: This vehicle

Claims

1. A driving assistance method for a vehicle, using a processor for performing autonomous lane change control, wherein: The processor performs the following processing: When performing a lane change for traveling along a set driving route, namely, a path following lane change, determining whether the path following lane change can be assisted by the autonomous lane change control, When it is determined that the path following lane change cannot be assisted by the autonomous lane change control, the driver is notified that the lane change based on the autonomous lane change control cannot be performed, and even if the execution conditions for executing the lane change based on the autonomous lane change control are met, a lane change assisted by the autonomous lane change control in a direction opposite to the direction in which the vehicle is moving in the path following lane change is prohibited.

2. The vehicle driving assistance method according to claim 1, wherein: The processor performs the following processing: In the case of determining whether the path following lane change can be assisted by the autonomous lane change control, determining whether the execution condition is satisfied, When it is determined that the execution condition is satisfied, it is determined that the path following lane change can be assisted by the autonomous lane change control, When it is determined that the execution condition is not satisfied, it is determined that the path following lane change cannot be assisted by the autonomous lane change control.

3. The vehicle driving assistance method according to claim 2, wherein: The execution condition includes that high-precision map information is available for a road on which the vehicle travels from the start to the end of the lane change by the autonomous lane change control.

4. The vehicle driving assistance method according to claim 2, wherein: The execution condition includes at least one of the following conditions: a curvature radius of the road on which the vehicle is traveling from the start to the end of the lane change based on the autonomous lane change control being greater than or equal to a predetermined value; The road is not registered in high-precision map information as a road on which lane change by the autonomous lane change control is not possible; The driving speed of the vehicle is within the prescribed range; The behavior of the vehicle is within a range controllable by the autonomous lane change control during execution of the lane change based on the autonomous lane change control.

5. The vehicle driving assistance method according to claim 4, wherein: The range is set based on at least one of acceleration, deceleration, and lateral acceleration of the vehicle.

6. The vehicle driving assistance method according to claim 2, wherein: The execution condition includes at least one of the following conditions: When the road on which the vehicle is traveling merges with a different road ahead in the traveling direction of the vehicle after the path following lane change ends, the distance from the end position of the path following lane change to the merging position of the roads is less than a predetermined distance, and the speed limit of the road entered by the vehicle is set to be lower than the speed limit of the road on which the vehicle has traveled when the path following lane change starts; If there is an intersection ahead in the traveling direction of the vehicle on the road on which the vehicle travels after the path following lane change is completed, the distance from the end position of the path following lane change to the intersection is less than or equal to a predetermined distance.

7. The vehicle driving assistance method according to any one of claims 1 to 6, wherein: When it is determined that the path following lane change cannot be assisted by the autonomous lane change control, the processor does not execute the overtaking assist control even if a condition for starting the overtaking assist control for overtaking a preceding vehicle by autonomous traveling based on the autonomous traveling control is satisfied.

8. The vehicle driving assistance method according to any one of claims 1 to 6, wherein: The processor does not execute a lane change by the autonomous lane change control due to the operation of the driver when it is determined that the path following lane change cannot be assisted by the autonomous lane change control.

9. The vehicle driving assistance method according to any one of claims 1 to 6, wherein: The processor determines whether the path following lane change can be assisted by autonomous lane change control based on the shape of the road pre-registered in map information when performing the path following lane change. When it is determined that the path following lane change cannot be assisted by the autonomous lane change control based on the shape of the road, a lane change based on the autonomous lane change control is not performed from the current position of the vehicle to a position where the vehicle cannot perform the path following lane change.

10. A driving assistance device for a vehicle, comprising: a determination unit that determines whether, when a lane change for traveling along a set driving route, i.e., a route-following lane change, is performed, the route-following lane change can be assisted by autonomous lane change control; an assisting unit which, when the determining unit determines that the path following lane change cannot be assisted by the autonomous lane change control, notifies the driver that the lane change based on the autonomous lane change control cannot be performed, and prohibits assisting the lane change in a direction opposite to the direction in which the vehicle is moving during the path following lane change by the autonomous lane change control even if an execution condition for enabling the lane change based on the autonomous lane change control is satisfied.

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