Driving assistance method and driving assistance device

Abstract

To provide a driving support method and a driving support device which enable a driver to clearly recognize that a condition for switching automatic driving levels is established.SOLUTION: If a first switching condition for controlling the switching from a driving support mode of a relatively low support level to a driving support mode of a relatively high support level has been established, a specific operation for changing operation of on-vehicle equipment of a vehicle and / or a specific operation for changing behavior of the vehicle are continuously executed.SELECTED DRAWING: Figure 12

Description

[Technical Field]

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

[0002] BACKGROUND ART There is known an information display device that changes an image displayed on a monitor according to the level of autonomous driving, thereby allowing the driver to recognize the level of autonomous driving (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-182624 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-mentioned conventional information display devices, the image corresponding to the autonomous driving level is only displayed on the monitor, which means that when the autonomous driving level changes, the driver cannot clearly recognize that the conditions for switching the autonomous driving level have been met.

[0005] The problem to be solved by the present invention is to provide a driving assistance method and a driving assistance device that allow the driver to clearly recognize that the conditions for switching the autonomous driving level are met. [Means for solving the problem]

[0006] The present invention solves the above problem by continuously executing a specific operation that changes the operation of the vehicle's onboard equipment and / or a specific operation that changes the vehicle's behavior when a first switching condition is met that controls switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a driving assistance method and a driving assistance device that allow the driver to clearly recognize that the conditions for switching the autonomous driving level are met. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an embodiment of a driving assistance device of the present invention; [Figure 2] FIG. 2 is a front view showing a part of the input device of FIG. [Figure 3] 2 is a plan view showing an example of lane change control by the control device of FIG. 1. FIG. [Figure 4] 2 is a block diagram showing an outline of state transitions of the control device of FIG. 1. FIG. [Figure 5] 5(a) and 5(b) are diagrams (part 1) for explaining the support level switching conditions in FIG. 4. FIG. [Figure 6] 5(a) and 5(b) are diagrams (part 2) for explaining the support level switching conditions in FIG. 4. FIG. [Figure 7] 5(a) and 5(b) are diagrams (part 3) for explaining the support level switching conditions in FIG. 4. FIG. [Figure 8] 5(a) and 5(b) are diagrams showing examples of display screens of an in-vehicle device corresponding to the assistance levels of FIG. 4, respectively. [Figure 9] 5(a) and 5(b) are diagrams showing other examples of the display screen of the in-vehicle device corresponding to the assistance levels of FIG. 4. [Figure 10A] 6 is a diagram for explaining the relationship between the support level switching conditions and thresholds in FIG. 5. FIG. [Figure 10B] 10B is a diagram for explaining the relationship between the threshold value of the switching condition in FIG. 10A and hysteresis. FIG. [Figure 11A] FIG. 10B is a diagram (part 1) for explaining a change in the threshold value of the switching condition in FIG. 10A. [Figure 11B] FIG. 10B is a diagram (part 2) for explaining a change in the threshold value of the switching condition in FIG. 10A. [Figure 12] 2 is a flowchart showing an example of a driving assistance control process executed by the driving assistance device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Configuration of driving assistance device> Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of a driving assistance device 1 according to this embodiment. The driving assistance device 1 of this embodiment is also an embodiment for carrying out a driving assistance method according to the present invention.

[0010] 1, the driving assistance device 1 of this embodiment includes a sensor 11, a vehicle position detection device 12, a map database 13, in-vehicle equipment 14, a navigation device 15, a presentation device 16, an input device 17, a drive control device 18, and a control device 19. These devices are connected by, for example, a CAN (Controller Area Network) or other in-vehicle LAN, and can transmit and receive information to and from each other. The sensor 11, the vehicle position detection device 12, the map database 13, the in-vehicle equipment 14, the navigation device 15, the presentation device 16, the input device 17, and the drive control device 18 of this embodiment correspond to a detection unit according to the present invention, and the control device 19 of this embodiment corresponds to a control unit according to the present invention.

[0011] The sensor 11 detects the traveling state of the host vehicle. Examples of the sensor 11 include a front camera, a rear camera, a side camera, and a 360-degree camera that capture images of the surroundings of the host vehicle, a front radar, a rear radar, and a side radar that detect obstacles around the host vehicle, a front LIDAR, a rear LIDAR, and a side LIDAR that detect the distance between the host vehicle and obstacles around the host vehicle, a vehicle speed sensor that detects the vehicle speed, a touch sensor (capacitive sensor) that detects whether the driver is holding the steering wheel, and an in-vehicle camera that captures images of the driver. Note that the sensor 11 may be configured to use one of the above-mentioned multiple sensors, or may be configured to use a combination of two or more types of sensors. The detection results of the sensor 11 are output to the control device 19 at predetermined time intervals.

[0012] The vehicle position detection device 12 includes a GPS unit, a gyro sensor, a vehicle speed sensor, etc. The vehicle position detection device 12 detects radio waves transmitted from multiple satellite communications using the GPS unit and periodically acquires position information of the target vehicle (the vehicle itself). The vehicle position detection device 12 also detects the current position of the target vehicle based on the acquired position information of the target vehicle, angle change information acquired from the gyro sensor, and vehicle speed acquired from the vehicle speed sensor. The position information of the target vehicle detected by the vehicle position detection device 12 is output to the control device 19 at predetermined time intervals.

[0013] The map database 13 is a memory that stores three-dimensional high-precision map information including position information of various facilities and specific points and is accessible from the control device 19. The three-dimensional high-precision map information is three-dimensional map information based on road shapes detected when a data acquisition vehicle travels on actual roads. The three-dimensional high-precision map information is map information that associates, as three-dimensional information, detailed and highly accurate position information such as curved roads and the magnitude of the curves (for example, curvature or curvature radius), road junctions, branching points, toll booths, and locations where the number of lanes decreases, with the map information.

[0014] The in-vehicle devices 14 are various devices mounted on the vehicle and are operated by the driver. Examples of such in-vehicle devices include a steering wheel, an accelerator pedal, a brake pedal, a turn signal, wipers, lights, a horn, and other specific switches. When operated by the driver, the in-vehicle devices 14 output operation information to the control device 19. Furthermore, when a switching condition for the assistance level of the driving assistance mode in the autonomous driving control function is met, the in-vehicle devices 14 execute a specific operation based on a command value from the control device 19. The driving assistance mode in the autonomous driving control function, the switching condition for the assistance level of the driving assistance mode, and the specific operation will be described later.

[0015] The navigation device 15 acquires the current position information of the vehicle from the vehicle position detection device 12, and displays the vehicle's position on a display or the like, superimposing it on map information for guidance. The navigation device 15 also has a navigation function that, when the driver inputs a destination, calculates a route to the destination and guides the driver along the set route. With this navigation function, the navigation device 15 displays the route to the destination on a map on the display, and also notifies the driver of recommended driving behaviors along the route by voice or the like.

[0016] The presentation device 16 includes various displays such as a display provided in the navigation device 15, a display incorporated in a rearview mirror, a display incorporated in a meter section, a head-up display projected on the windshield, etc. The presentation device 16 also includes devices other than displays such as a speaker in an audio device, a seat device with an embedded vibrator, etc. The presentation device 16 notifies the driver of various presentation information under the control of the control device 19.

[0017] The input device 17 is, for example, a button switch that can be manually operated by the driver to input, a touch panel arranged on a display screen, or a microphone that can be used to input by the driver's voice. In this embodiment, the driver can input setting information for the presentation information presented by the presentation device 16 by operating the input device 17. Fig. 2 is a front view showing a part of the input device 17 of this embodiment, and shows an example of a group of button switches arranged on the spokes of a steering wheel, etc.

[0018] The illustrated input device 17 is a button switch used to set ON / OFF, etc., of the autonomous driving control functions (autonomous speed control function and autonomous steering control function) provided in the control device 19. The input device 17 of this embodiment includes a main switch 171, a resume / accelerate switch 172, a set / coast switch 173, a cancel switch 174, a vehicle distance adjustment switch 175, and a lane change assist switch 176.

[0019] The main switch 171 is a switch that turns on / off the power supply to the system that realizes the autonomous speed control function and autonomous steering control function of the control device 19. The resume / accelerate switch 172 is a switch that stops (OFF) the autonomous speed control function and then resumes the autonomous speed control function at the set speed before turning it off, increases the set speed, or stops the vehicle following a preceding vehicle and then restarts it using the control device 19. The set / coast switch 173 is a switch that starts the autonomous speed control function at the traveling speed or decreases the set speed. The cancel switch 174 is a switch that turns off the autonomous speed control function. The distance adjustment switch 175 is a switch that sets the distance from the preceding vehicle and selects one of multiple settings, such as short distance, medium distance, or long distance. The lane change assist switch 176 is a switch that instructs (agrees to) start a lane change when the control device 19 confirms with the driver that the lane change should be started. After accepting the start of a lane change, the acceptance of the lane change suggestion by the control device 19 can be cancelled by pressing the lane change assistance switch 176 for a period longer than a predetermined time.

[0020] In addition to the button switches shown in FIG. 2 , a turn signal lever of a turn signal or other switches of the in-vehicle equipment 14 can also be used as the input device 17. For example, when the control device 19 suggests whether to change lanes through autonomous control, the driver can input consent or permission to the lane change by turning on the turn signal switch. Also, when the control device 19 suggests whether to change lanes through autonomous control, if the driver operates the turn signal lever, the lane change will not be in the suggested lane change, but will instead be in the direction in which the turn signal lever is operated. The setting information input by the input device 17 is output to the control device 19.

[0021] The drive control device 18 controls the traveling of the host vehicle. For example, when the host vehicle travels at a constant speed using the autonomous speed control function, the drive control device 18 controls the operation of the drive mechanism (including the operation of the internal combustion engine in an engine vehicle, the operation of the traction motor in an electric vehicle, and the torque distribution between the internal combustion engine and the traction motor in a hybrid vehicle) and the brake operation to accelerate and decelerate the host vehicle and maintain the traveling speed so that the host vehicle reaches the set speed. Furthermore, when the host vehicle travels following a leading vehicle using the autonomous speed control function, the drive control device 18 controls the operation of the drive mechanism and the brake operation to achieve the acceleration / deceleration and traveling speed so that the distance between the host vehicle and the leading vehicle is constant.

[0022] Furthermore, the drive control device 18 performs steering control of the host vehicle by controlling the operation of the steering actuator in addition to the operation control of the drive mechanism and brakes described above using the autonomous steering control function. For example, when performing lane keeping control using the autonomous steering control function, the drive control device 18 detects lane markers of the host vehicle's lane and controls the host vehicle's traveling position in the width direction so that the host vehicle travels at a predetermined position within the host lane. When performing lane change assistance using the lane change assistance function described below, the drive control device 18 controls the host vehicle's traveling position in the width direction so that the host vehicle changes lanes. Furthermore, when performing right / left turn assistance using the autonomous steering control function, the drive control device 18 performs driving control to turn right or left at an intersection, etc. Note that the drive control device 18 controls the driving of the host vehicle according to instructions from the control device 19 described below. Other known methods may also be used as driving control methods by the drive control device 18.

[0023] The control device 19 includes a ROM (Read Only Memory) that stores a program for controlling the traveling of the vehicle, a CPU (Central Processing Unit) that executes the program stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. Note that, as the operating circuit, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. can be used instead of or in addition to the CPU (Central Processing Unit).

[0024] <<Functions Realized by Control Device 19>> The control device 19 executes a program stored in the ROM using the CPU to realize a driving information acquisition function for acquiring information about the driving state of the vehicle, a driving scene determination function for determining the driving scene of the vehicle, and an autonomous driving control function for autonomously controlling the driving speed and / or steering of the vehicle. Each function of the control device 19 will be described below.

[0025] The driving information acquisition function of the control device 19 is a function for the control device 19 to acquire driving information related to the driving state of the host vehicle. For example, the control device 19 acquires image information of the outside of the host vehicle captured by the front camera, rear camera, and side camera of the sensor 11 as driving information. The control device 19 also acquires detection results from the front radar, rear radar, and side radar as driving information. Furthermore, the control device 19 also acquires vehicle speed information of the host vehicle detected by the vehicle speed sensor of the sensor 11 and image information of the driver's face captured by the in-vehicle camera as driving information.

[0026] Furthermore, the control device 19 acquires current position information of the vehicle as driving information from the vehicle position detection device 12. The control device 19 also acquires a set destination and a route to the destination as driving information from the navigation device 15. Furthermore, the control device 19 acquires position information such as curved roads and the magnitude of the curve (for example, curvature or curvature radius), merging points, branching points, toll booths, and positions where the number of lanes decreases as driving information from the map database 13. In addition, the control device 19 acquires operation information of the in-vehicle device 14 by the driver from the in-vehicle device 14 as driving information. The above is the driving information acquisition function realized by the control device 19.

[0027] The driving scene determination function of the control device 19 is a function that determines the driving scene in which the host vehicle is traveling by referring to a table stored in the ROM of the control device 19. The table stored in the ROM of the control device 19 stores, for each driving scene, driving scenes suitable for, for example, lane changing or overtaking, and the determination conditions for such scenes. The control device 19 determines, by referring to the table stored in the ROM, whether the driving scene in which the host vehicle is traveling is suitable for, for example, lane changing or overtaking.

[0028] For example, assume that four conditions are set as conditions for determining a "scene of catching up with a leading vehicle," namely, "there is a leading vehicle ahead," "the speed of the leading vehicle is less than the set speed of the vehicle," "the vehicle reaches the leading vehicle within a predetermined time," and "the direction of the lane change does not satisfy a lane change prohibition condition." In this case, the control device 19 determines whether the vehicle satisfies the above conditions based on, for example, the detection results of the forward camera and forward radar included in the sensor 11, the vehicle speed of the vehicle detected by the vehicle speed sensor, and the position information of the vehicle from the vehicle position detection device 12. If the above conditions are satisfied, the control device 19 determines that the vehicle is in a "scene of catching up with a leading vehicle." The above is the driving scene determination function realized by the control device 19.

[0029] The autonomous driving control function of the control device 19 is a function that allows the control device 19 to autonomously control the driving of the vehicle without relying on the driver's operation. The autonomous driving control function of the control device 19 includes an autonomous speed control function that autonomously controls the driving speed of the vehicle, and an autonomous steering control function that autonomously controls the steering of the vehicle. The autonomous speed control function and the autonomous steering control function of this embodiment will be described below.

[0030] The autonomous speed control function is a function that, when a preceding vehicle is detected, follows the preceding vehicle while performing vehicle-to-vehicle distance control to maintain a vehicle-to-vehicle distance according to the vehicle speed, with the vehicle speed set by the driver as the upper limit, and when a preceding vehicle is not detected, travels at a constant speed set by the driver. The former is also called vehicle-to-vehicle distance control, and the latter is called constant speed control. The autonomous speed control function may also include a function that detects the speed limit of the road being traveled on from road signs using sensor 11, or obtains the speed limit from map information in map database 13, and automatically sets the set vehicle speed to that speed limit.

[0031] To activate the autonomous speed control function, the driver first operates the resume / accelerate switch 172 or the set / coast switch 173 of the input device 17 shown in FIG. 2 to input the desired driving speed. For example, if the set / coast switch 173 is pressed while the vehicle is traveling at 70 km / h, the current driving speed is set as is. However, if the driver's desired speed is 80 km / h, the driver can simply press the resume / accelerate switch 172 multiple times to increase the set speed. This is because the "+" sign on the resume / accelerate switch 172 indicates that this is a switch that increases the set value. Conversely, if the driver's desired speed is 60 km / h, the driver can simply press the set / coast switch 173 multiple times to decrease the set speed. This is because the "-" sign on the set / coast switch 173 indicates that this is a switch that decreases the set value. The driver can adjust the desired distance between vehicles by operating the distance adjustment switch 175 of the input device 17 shown in FIG. 2 and selecting one of multiple settings such as short distance, medium distance, and long distance.

[0032] Constant speed control, which allows the vehicle to travel at a constant speed set by the driver, is executed when the forward radar or the like of the sensor 11 detects that there is no preceding vehicle ahead in the vehicle's lane. In constant speed control, the drive control device 18 controls the operation of the engine, brakes, and other drive mechanisms while feeding back vehicle speed data from the vehicle speed sensor so as to maintain the set traveling speed.

[0033] Distance control, which follows a preceding vehicle while performing distance control, is executed when the forward radar of the sensor 11 detects the presence of a preceding vehicle ahead in the vehicle's lane. In distance control, the drive control device 18 controls the operation of the engine, brakes, and other drive mechanisms while feeding back data on the distance detected by the forward radar so as to maintain a set distance, with a set travel speed as the upper limit. If the preceding vehicle stops while traveling under distance control, the vehicle stops following the preceding vehicle. If the preceding vehicle starts moving within, for example, 30 seconds after the vehicle stops, the vehicle also starts moving and resumes following travel under distance control. If the vehicle remains stopped for more than 30 seconds, the vehicle does not automatically start moving even if the preceding vehicle starts moving. After the preceding vehicle starts moving, pressing the resume / accelerate switch 172 or depressing the accelerator pedal resumes following travel under distance control.

[0034] On the other hand, the autonomous steering control function is a function for controlling the steering of the vehicle by controlling the operation of the steering actuator. The autonomous steering control function of this embodiment includes: (1) a lane keeping function (lane width direction maintaining function) that controls the steering to drive, for example, near the center of the lane, and supports the driver's steering wheel operation; (2) a lane change assist function that controls the steering when the driver operates the turn signal lever and supports the steering wheel operation required for changing lanes; (3) an overtaking assist function that, when a vehicle slower than a set vehicle speed is detected ahead, asks the driver via a display whether to perform an overtaking operation, and, if the driver operates an acceptance switch, controls the steering to support the overtaking operation; and (4) a route driving assist function that, when the driver has set a destination in a navigation device or the like, asks the driver via a display whether to perform a lane change when the vehicle reaches a lane change point required for traveling along the route, and, if the driver operates an acceptance switch, controls the steering to support the lane change.

[0035] Here, the lane change assist function of the autonomous steering control function will be described. Fig. 3 is a plan view showing an example of lane change control (lane change assist function) executed by the control device 19 of this embodiment. As shown in Fig. 3, when the driver operates the turn signal lever of the host vehicle V1, the control device 19 turns on the turn signal, and when a preset lane change start condition is met, starts a lane change operation (a series of autonomous lane change processes, hereinafter also referred to as LCP). The control device 19 determines whether the lane change start condition is met based on various types of driving information acquired by the sensor 11. The lane change initiation conditions are not particularly limited, but examples include the following: (1) the vehicle is in lane keeping mode in hands-on mode, (2) a hands-on determination is in progress, (3) the vehicle is traveling at a speed of 60 km / h or more, (4) a lane exists in the direction of the lane change, (5) the lane to which the lane change is to be made has space for a lane change, (6) the lane marker type indicates that a lane change is possible, (7) the road curvature radius is 250 m or more, and (8) the lane change has occurred within one second since the driver operated the turn signal lever. Note that if the control device 19 determines that the lane change initiation conditions are met by the lane change assistance function, even without a driver instruction, the control device 19 may suggest to the driver to change lanes by notifying the driver via the presentation device 16.

[0036] The lane-keeping mode in hands-on mode refers to a state in which the autonomous speed control function and the lane-keeping function of the autonomous steering control function are running and the driver's holding of the steering wheel is detected. Also, the hands-on determination status refers to a state in which the driver continues to hold the steering wheel.

[0037] When the lane change start condition is satisfied, the control device 19 initiates a lane change maneuver LCP. As shown in FIG. 3 , the lane change maneuver LCP in this embodiment includes a lateral movement of the host vehicle V1 to the adjacent lane L2 and a lane change maneuver (hereinafter also referred to as LCM) to actually move the host vehicle V1 to the adjacent lane L2. While the lane change maneuver LCP is being executed, the control device 19 displays information indicating that the lane change is being performed by autonomous control to the driver via the display device 16 to alert the driver to the surroundings. When the lane change maneuver LCM is completed, the control device 19 turns off the turn signal and starts executing a lane keeping function in the adjacent lane L2. The lane change maneuver LCP refers to the period from when the turn signal is turned on by operating the turn signal lever until it is turned off, and the lane change maneuver LCM refers to the period from when the host vehicle V1 starts to step on the boundary line between the host lane L1 and the adjacent lane L2 until it stops stepping on the boundary line.

[0038] Incidentally, a plurality of levels are set for the driving assistance mode realized by the autonomous driving control function of this embodiment. The driving assistance mode refers to the form or style of assistance in assisting driving operation. In this embodiment, the level of assistance is referred to as the assistance level. Each assistance level of the driving assistance mode defines the extent to which the control device 19 intervenes in the control of the vehicle's driving operation, in other words, the extent to which the driver's manual operation intervenes. The control device 19 combines autonomous control of driving speed using the autonomous speed control function and autonomous control of steering operation using the autonomous steering control function to realize the driving operation assistance defined for each assistance level when autonomously controlling the driving of the host vehicle.

[0039] The assistance level in this embodiment can be set based on the driving automation levels defined in, for example, SAE J3016: SEP2016, Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles published by the Society of Automotive Engineers (SAE). For example, assistance level 0 defined by the SAE is a level at which the driver performs all driving tasks required for driving operations. Similarly, assistance level 1 is a level at which the control device 19 continuously performs either autonomous speed control or autonomous steering control (but not both simultaneously) in a specific limited area, and the driver either controls the vehicle's traveling speed or steers the vehicle by steering (but not both simultaneously). Similarly, assistance level 2 is a level at which the control device 19 continuously performs autonomous speed control and autonomous steering control in a specific limited area, and the driver either controls the vehicle's traveling speed or steers the vehicle by steering (but not both simultaneously). Similarly, assistance level 3 is a level at which the control device 19 continuously performs all driving tasks in a limited area. Similarly, at assistance level 4, the control device 19 performs all driving tasks and responds to cases where it is difficult to continue control continuously within a limited area. Similarly, at assistance level 5, the control device 19 performs all driving tasks and responds to cases where it is difficult to continue control continuously and without limit.

[0040] Assistance level 1 set in this embodiment corresponds to, but is not limited to, the control device 19 controlling the traveling speed of the vehicle by autonomous speed control. Similarly, assistance level 2 corresponds to, but is not limited to, the control device 19 controlling the steering of the vehicle by autonomous steering control in addition to autonomous speed control. Assistance level 2 includes a hands-on mode (assistance level 2β) and a hands-off mode (assistance level 2α). Hands-on mode refers to a state in which autonomous steering control does not operate unless the driver holds the steering wheel, and hands-off mode refers to a state in which autonomous steering control operates even if the driver takes their hands off the steering wheel. Furthermore, assistance level 2 set in this embodiment executes autonomous speed control and autonomous steering control in eyes-on mode, but is not limited to.

[0041] Assistance level 3 set in this embodiment corresponds to, but is not limited to, the control device 19 performing autonomous speed control and autonomous steering control in eyes-off mode in addition to assistance level 2. Eyes-on mode refers to a state in which autonomous speed control and autonomous steering control do not operate unless the driver's monitoring of the surroundings (particularly the front) is detected. In eyes-on mode, the driver is imaged using an in-vehicle camera and the driver's line of sight and facial direction are monitored. If the driver is not in a situation suitable for monitoring the surroundings, such as if the driver's line of sight is averted from the front or the driver's face is not facing forward, the control device 19 activates a forward attention warning. In contrast, eyes-off mode refers to a state in which the control device 19 monitors the surroundings under certain conditions, thereby activating autonomous speed control and autonomous steering control, even if the driver's monitoring of the surroundings is not detected.

[0042] At assistance level 2 of this embodiment, the control device 19 controls driving operations, but the driver monitors the surroundings and determines vehicle behavior in eyes-on mode, so the driver has the initiative in driving. In contrast, at assistance level 3 of this embodiment, in addition to controlling driving operations, the control device 19 monitors the surroundings and determines vehicle behavior in eyes-off mode, so the initiative in driving is temporarily transferred to the control device 19.

[0043] <<State transition of driving assistance device>> FIG. 4 is a block diagram showing an outline of the state transitions of each function established in the control device 19. The system shown in FIG. 4 refers to an autonomous driving control system realized by the control device 19. When the main switch 171 in FIG. 2 is turned ON from the system OFF state shown in FIG. 4, the system enters a standby state. When the set / coast switch 173 or the resume / accelerate switch 172 in FIG. 2 is turned ON from this standby state, the autonomous speed control (assistance level 1) of the driving assistance mode is activated. This starts the constant speed control or vehicle distance control described above, and the driver can drive the vehicle by simply operating the steering wheel without stepping on the accelerator or brake. The system OFF state and standby state correspond to a manual driving mode in which the driver performs driving operations, and the system ON state corresponds to a driving assistance mode in which the driver's driving operations are assisted by the autonomous driving control system of the control device 19.

[0044] When the vehicle transitions from the manual driving mode to the driving assistance mode, the control device 19 controls the switching of the assistance level in the driving assistance mode. The control for switching the assistance level is executed when the establishment conditions (hereinafter also referred to as the switching conditions) of each assistance level are satisfied. The establishment conditions for the switching control are not particularly limited, but may be a combination of road conditions and geographical conditions such as whether the vehicle is traveling on a highway exclusively for motor vehicles, whether the vehicle is traveling on a road structurally separated from oncoming lanes, whether the vehicle is traveling on a road with a high-precision map, whether there is a toll booth, exit, merging point, intersection, or point where the number of lanes decreases within a predetermined range ahead, whether lane markers on both sides of the vehicle are detected, and whether the vehicle is traveling near the center of the lane, as well as environmental conditions such as whether the vehicle is traveling at or below the speed limit, whether the wipers are operating at high speed (HI), whether the driver is holding the steering wheel, whether the accelerator pedal is depressed, whether the driver has applied the brakes, whether a lane change is being performed by the driver, and whether the driver can be detected by the driver monitor camera, and other conditions.

[0045] 5 to 7 are diagrams illustrating the switching conditions for the assistance level. FIGS. 5(a) and 5(b) show scenes in which vehicle speed is used as a switching condition from assistance level 2α to assistance level 3. For example, assume that a vehicle speed of 70 km / h is set as a threshold Th1 as a switching condition. When the vehicle speed S of the host vehicle V1 detected by the sensor 11 exceeds 70 km / h, at which it is preferable for the driver to monitor the surroundings, the switching condition for assistance level 2α is met. As shown in FIG. 5(a), assistance level 2α is implemented while the host vehicle V1 is traveling at a vehicle speed of 70 km / h or higher. On the other hand, when the vehicle speed S of the host vehicle V1 detected by the sensor 11 falls below 70 km / h, the switching condition for assistance level 3 is met. As shown in FIG. 5(b), assistance level 3, in which the control device 19 monitors the surroundings, is implemented while the host vehicle V1 is traveling at a vehicle speed less than 70 km / h.

[0046] 6(a) and 6(b) show scenes in which road conditions are used as the switching condition from assistance level 2α to assistance level 3. For example, suppose that the detection of a construction section is set as the switching condition. It is difficult for the vehicle to recognize the surrounding environment near the construction section, so it is preferable for the driver to monitor the surroundings. Therefore, when the sensor 11 detects a construction section around the host vehicle V1, the switching condition to assistance level 2α is met. As shown in FIG. 6(a), assistance level 2α is executed while the host vehicle V1 is traveling to the side of the construction section. In contrast, once the host vehicle V1 passes through the construction section, it becomes easier to recognize the surrounding environment of the vehicle, so the control device 19 can monitor the surroundings. Therefore, when the construction section is no longer detected by the sensor 11, the switching condition to assistance level 3 is met. As shown in FIG. 6(b), assistance level 3 is executed after the host vehicle V1 passes through the construction section.

[0047] 7(a) and 7(b) illustrate a scene in which a driving situation-related condition is used as a switching condition from assistance level 2β to assistance level 3. The scenes shown in FIGS. 7(a) and 7(b) illustrate a scene in which a left turn is required ahead on the driving route, and the driver performs a lane change from the current lane to the lane for the left turn (see the black arrow). In this case, the detection of a lane change due to the driver's driving operation is set as the switching condition. When an input value by the driver, such as the operation of the turn signal lever or the steering wheel of the in-vehicle device 14, is detected, the switching condition for assistance level 2β is met. As shown in FIG. 7(a), while the host vehicle V1 is changing lanes, priority is given to the driver's driving operation, and assistance level 2β of the hands-on mode is executed. In contrast, once the driver completes the lane change of the host vehicle V1, priority is no longer given to the driver's driving operation. Therefore, once the host vehicle V1 completes the lane change, the switching condition for assistance level 3 is met. As shown in FIG. 7(b), after changing lanes to a lane for turning left, assistance level 3 is implemented.

[0048] The fulfillment of switching conditions and the switching control of assistance levels are not limited to the above-mentioned scenarios. For example, if the conditions for autonomous steering control are met while executing autonomous speed control (assistance level 1) as shown in Figure 4, the system switches to autonomous speed control, autonomous steering control, and hands-on mode (assistance level 2β). If the conditions for hands-off mode are met while executing autonomous speed control, autonomous steering control, and hands-on mode (assistance level 2β), the system switches to autonomous speed control, autonomous steering control, and hands-off mode (assistance level 2α). Conversely, if the conditions for hands-off mode are no longer met while executing autonomous speed control, autonomous steering control, and hands-off mode (assistance level 2α), the system stops hands-off mode and switches to autonomous speed control, autonomous steering control, and hands-on mode (assistance level 2β). Also, if the conditions for autonomous steering control are no longer met while executing autonomous speed control, autonomous steering control, and hands-on mode (assistance level 2β), the system stops autonomous steering control and switches to autonomous speed control (assistance level 1). If the conditions for autonomous speed control are no longer met while autonomous speed control (assistance level 1) is being executed, the driving assistance mode is switched to manual driving mode and the system enters standby mode. Note that if the main switch 171 in Fig. 2 is turned off while in any of assistance level 3, assistance level 2α, assistance level 2β, assistance level 1, and standby mode, the system will be turned off.

[0049] In this way, the transition of the assistance level in the driving assistance mode or the transition from the driving assistance mode to the manual driving mode is autonomously controlled by the control device 19 when the conditions for switching control are met. However, in the transition from assistance level 2 to assistance level 3, as described above, the driving initiative is temporarily handed over from the driver to the control device 19. Therefore, if the switching conditions for assistance level 3 are met while assistance level 2α or assistance level 2β is being executed, the system may not immediately transition to assistance level 3 but may be in a standby state, and may transition only when the driver agrees or permits the switching control to assistance level 3. The method for the driver to agree or permit is not particularly limited, and may be configured to, for example, press a start switch for assistance level 3.

[0050] As described above, the control device 19 of this embodiment controls the switching of the assistance level of the driving assistance mode autonomously or with the driver's consent when the switching condition for the assistance level is met. When controlling the switching of the assistance level, if the driver cannot clearly recognize that the switching condition from assistance level 2α to assistance level 3 is met, for example, the control is performed autonomously to switch to assistance level 3, and even though the eyes-off mode is being executed, the driver may continue to monitor the surroundings without noticing the transition, or may continue autonomous driving control at assistance level 2α without consenting or permitting the switching control to assistance level 3.

[0051] The prior art documents cited in the prior art documents describe displaying an image on a monitor according to the autonomous driving level. However, if only an image is displayed on a monitor, there is a problem in that unless the driver consciously watches the monitor when the autonomous driving level changes, the driver cannot clearly recognize the change in the image according to the autonomous driving level, i.e., that the conditions for switching the autonomous driving level have been met.

[0052] Therefore, in the driving assistance device 1 according to this embodiment, when a condition for switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is met, specific operations such as changing the operation of the vehicle's on-board devices or changing the vehicle's behavior are continuously performed so that the driver can clearly recognize that the condition for switching the autonomous driving level is met. Hereinafter, an embodiment of driving assistance control using the control device 19 will be described with reference to Figures 5 to 9.

[0053] 5 to 7, when the conditions for switching from assistance level 2α or assistance level 2β to assistance level 3 are met, the control device 19 transmits a command to execute a specific operation to the in-vehicle device 14, the presentation device 16, the drive control device 18, etc., and changes the operation of the in-vehicle devices and the behavior of the vehicle at assistance level 2α or assistance level 2β. At this time, in order to enable the driver to more clearly recognize the transition status of the assistance level, the specific operation may be continued while the control device 19 is executing switching control when the conditions for switching from assistance level 2α or assistance level 2β to assistance level 3 are met, and the specific operation may be canceled (stopped) after the switching control to assistance level 3 is completed.

[0054] The specific action that changes the operation of the in-vehicle device or the behavior of the vehicle is, for example, a visual change that is given to the driver. Because visual changes are easily noticeable even when the driver is concentrating on driving operations, it is easy for the driver to recognize that the conditions for switching to assistance level 3 have been met. Taking the example of using interior lighting in the vehicle, when the conditions for switching to assistance level 3 are met, the control device 19 sends a command to the lights, which are the in-vehicle devices 14, to execute a specific action, thereby changing the overall atmosphere of the vehicle interior by increasing the brightness and saturation of the lights compared to when they were on at assistance level 2α or assistance level 2β, appropriately combining on and off to create a sense of dynamism, or projecting a specific pattern into the vehicle interior. In addition to the lights mentioned above, visual changes may also be given by, for example, changing the swing behavior of the windshield wipers or controlling the speed so that they swing at specific intervals.

[0055] The control device 19 may also change the visual information presented to the driver using the presentation device 16. FIGS. 8(a) and 8(b) are diagrams showing an example of a display screen of a display serving as the presentation device 16 arranged on the instrument panel. As shown in FIG. 8(a), while assistance level 2α is being executed, the visual information presented to the driver may include, for example, a vehicle speed display S related to the driving information of the host vehicle V1, a hands mode display H related to the assistance level information, and an eyes mode display E. In contrast, at assistance level 3, the control device 19 performs both the driving operation and the surroundings monitoring, and therefore the display related to the driving information of the host vehicle V1 is unnecessary for the driver. Therefore, when the condition for switching to assistance level 3 is met and assistance level 3 is being executed, a destination display D unrelated to the driving information, such as an estimated time of arrival at the destination, may be displayed instead of the display related to the driving information, such as the vehicle speed display S, as shown in FIG. 8(b).

[0056] 9(a) and 9(b) are diagrams showing other examples of the display screen of the display as presentation device 16 arranged on the instrument panel. As shown in FIG. 9(a), while assistance level 2α is being executed, visual information to be presented to the driver includes, for example, a vehicle speed display S related to the driving information of the host vehicle V1, a hands mode display H related to the assistance level information, an eyes mode display E, etc., and in addition, a driving route guide N for the host vehicle V1 is displayed. In contrast, when the condition for switching to assistance level 3 is met and assistance level 3 is being executed, the visual information may be changed by displaying an around-view image V of the surroundings of the host vehicle V1, as shown in FIG. 9(b), instead of the vehicle speed display S related to the driving information of the host vehicle V1 and the driving route guide N.

[0057] The around-view image V displayed while assistance level 3 is being implemented is an image of the surroundings of the host vehicle V1 captured by the front camera, rear camera, and side camera serving as sensors 11. In addition to the around-view image V, which displays a bird's-eye view of the surroundings of the host vehicle V1, a partial image Vf captured by the front camera, for example, may be displayed in a reduced size. The around-view image V and the partial image Vf are part of the operation information of the surroundings monitoring by the control device 19 executed at assistance level 3. By continuously displaying these images, the driver can recognize that the eyes-off mode at assistance level 3 is operating. Note that at assistance levels 2α and 2β, the driver must monitor the surroundings themselves, so it is not preferable to continuously display images such as the around-view image V and the partial image Vf while the host vehicle V1 is traveling.

[0058] The specific action that changes the operation of the in-vehicle devices or the vehicle behavior may be an auditory change provided to the driver. The auditory change allows the driver to notice that the conditions for switching to assistance level 3 have been met without changing his or her line of sight or posture, and is therefore less likely to interfere with driving operations. For example, in the case of using switch or operation sounds for turn signals, audio, air conditioning, etc., when the conditions for switching to assistance level 3 are met, the control device 19 sends a command to execute a specific action to each device, such as the turn signals, audio, or air conditioning, which are the in-vehicle devices 14, and changes the sound emitted from each device by increasing the volume, changing the tone, or lengthening the sound duration compared to when the device was operating at assistance level 2α or assistance level 2β. Alternatively, the voice quality or tone of the agent device installed in the vehicle may be changed, or a specific sound effect may be played to notify the driver that the conditions for switching to assistance level 3 have been met.

[0059] The specific operation may be a change that the driver perceives. The change that the driver perceives is a change related to the ride comfort of the vehicle, and is a change that the driver can easily sense intuitively when the conditions for switching to assistance level 3 are met. At assistance level 3, the driving initiative is temporarily transferred to the control device 19, allowing the driver to prioritize ride comfort and ease over vehicle operability. Therefore, when the conditions for switching to assistance level 3 are met, the control device 19 sends a command to execute a specific operation to the drive control device 18, and controls the vehicle's driving behavior to provide a more comfortable ride than when assistance level 2α or assistance level 2β is being executed. For example, the vehicle's ride comfort can be made milder by increasing the acceleration / deceleration rate or steering speed, or by making the suspension more flexible. Furthermore, to expand the driver's operating range, spatial comfort may be changed by adjusting the height or fore-and-aft position of the steering wheel or the angle of the seat.

[0060] In this way, by changing the operation of the in-vehicle devices or the behavior of the vehicle, the vehicle can actively notify the driver that the conditions for switching from assistance level 2α or assistance level 2β to assistance level 3 have been met, allowing the driver to easily recognize that the switching conditions have been met. The specific action for changing the operation of the in-vehicle devices or the behavior of the vehicle may be any one of the above-mentioned visual changes, auditory changes, and bodily changes, or a combination of two or more changes. The specific action may be configured to continue for a predetermined time between the satisfaction of the conditions for switching to assistance level 3 and the execution of switching control, or may be configured to continue even after the execution of switching control to assistance level 3. Furthermore, the specific action may be configured to be autonomously canceled at a predetermined timing, or may be canceled when the driver performs a stop operation.

[0061] FIG. 10A is a diagram illustrating the relationship between the switching conditions for the assistance level and thresholds. The upper diagram in FIG. 10A shows the passage of traveling time of the host vehicle V1, the lower diagram in FIG. 10A shows the change in the vehicle speed S of the host vehicle V1 over time, and the middle diagram in FIG. 10A shows the transition state of the assistance level in response to the change in the vehicle speed S of the host vehicle V1. The control device 19 of this embodiment notifies the driver that the switching condition from assistance level 2α or assistance level 2β to assistance level 3 is met by executing a specific operation. Here, as in FIGS. 5(a) and 5(b), for example, when vehicle speed is used as the switching condition, as shown in FIG. 10A, it is assumed that a vehicle speed of 70 km / h is set as threshold Th1 of the first switching condition for controlling switching from assistance level 2α to assistance level 3, and that a vehicle speed of 70 km / h is also set as threshold Th2 of the second switching condition for controlling switching from assistance level 3 to assistance level 2α. In this case, if the host vehicle V1 is traveling at a speed of around 70 km / h, the condition for switching to assistance level 3 is met and a specific operation is executed every time the vehicle speed falls below 70 km / h (see t2, t5). However, if the condition for switching to assistance level 3 is met and not met frequently, the specific operation is also frequently executed and canceled, which may be annoying to the driver.

[0062] For this reason, the control device 19 of this embodiment provides hysteresis to the switching condition between support level 2α or support level 2β and support level 3, as shown in Fig. 10B. For example, the threshold value Th1fa (=65 km / h) of the first switching condition when controlling switching from support level 2α or support level 2β to support level 3 is set relatively high compared to the threshold value Th2 (=70 km / h) of the second switching condition when controlling switching from support level 3 to support level 2α or support level 2β. Note that setting the threshold value Th1fa of the first switching condition relatively high does not mean a large or small numerical value, but means increasing the difficulty of establishing the switching condition when controlling switching to support level 3. In the scene shown in Fig. 11A, hysteresis is provided to the threshold value Th2 (=70 km / h) of the second switching condition for controlling switching from support level 3 to support level 2α, and the threshold value Th1 (=70 km / h) of the first switching condition for controlling switching from support level 2α to support level 3, and the threshold value Th1 (=70 km / h) for controlling switching from support level 2α to support level 3 is changed to a threshold value Th1fa (=65 km / h). This prevents the switching condition between support level 3 and support level 2α from being met and not being met frequently again.

[0063] 11B is a diagram showing a scene in which the threshold value Th1fa itself of the first switching condition for controlling switching from support level 2α to support level 3 is changed in accordance with the elapsed time α since the completion of switching control from support level 3 to support level 2α in the scene shown in Fig. 11A. The threshold value Th1fa of the first switching condition for controlling switching from support level 2α to support level 3 is set to a vehicle speed of 65 km / h, whereas when the elapsed time α since the completion of switching control from support level 3 to support level 2α exceeds a predetermined value T, the threshold value Th1fa of the first switching condition for controlling switching from support level 2α to support level 3 is changed to a threshold value Th1fb (=vehicle speed 60 km / h) (see t5).

[0064] As shown in FIG. 11B , when the vehicle speed of the host vehicle V1, which has been traveling at a speed less than 70 km / h, increases to 70 km / h or more at time t1, the control device 19 switches from support level 3 to support level 2α. At this time, the control device 19 determines whether the time α1 that has elapsed since time t1, when the control device 19 switched to support level 2α, is greater than a predetermined value T. The predetermined value T is not particularly limited, but is a value, such as one minute, for determining whether the vehicle speed due to the traveling environment of the host vehicle V1 is in a state where support level 2α should be maintained. If the time α1 that has elapsed since time t1 is less than the predetermined value T, that is, if the vehicle speed again becomes less than the threshold value Th1fa (=65 km / h) within a short time after the control device 19 switched to support level 2α and the condition for switching to support level 3 is met, a specific operation is executed at time t2, and the control device 19 switches to support level 3.

[0065] At t3, when the vehicle speed of the host vehicle V1 again reaches 70 km / h or higher, the control unit 19 switches from support level 3 to support level 2α. At this time, the control unit 19 also determines whether the elapsed time α2 since t3, when the control unit 19 switched to support level 2α, is greater than a predetermined value T. If the elapsed time α2 since t3 is greater than the predetermined value T, that is, if a certain amount of time has passed since the control unit 19 switched to support level 2α, it can be determined that the driving environment of the host vehicle V1 is suitable for maintaining the current vehicle speed. Therefore, it is easier to respond to subsequent changes in vehicle speed by maintaining support level 2α rather than by switching to support level 3 again. Therefore, when the elapsed time α2 exceeds the predetermined value T, the control unit 19 changes the threshold value Th1fa itself to a relatively higher value Th1fb.

[0066] In the scene shown in FIG. 11B , when the elapsed time α2 from t3, when switching control to support level 2α, exceeds a predetermined value T, the threshold value Th1fa (=65 km / h) is changed to a threshold value Th1fb (=60 km / h) to make it difficult to switch control from support level 2α to support level 3. If the threshold value Th1fa remains at 65 km / h at t5, when the speed of the host vehicle V1 becomes less than 65 km / h, the switching condition for support level 3 is met and a specific operation is executed. In contrast, if the threshold value Th1fb is changed to 60 km / h, the switching condition for support level 3 can be prevented from being met at t5, and support level 2α can be continued from t3 to t6. In this way, by changing the threshold value Th1 for switching control from support level 2α to support level 3 to the relatively high threshold values ​​Th1fa and Th1fb, the switching condition for support level 3 can be prevented from being met frequently and the specific operation can be prevented from being repeatedly executed.

[0067] 11B, the threshold values ​​Th1fa and Th1fb are changed to two values, 65 km / h and 60 km / h, but the control device 19 may set the change amount of the threshold value Th1fa to be successively larger as the elapsed time α increases after switching control from assistance level 3 to assistance level 2α or assistance level 2β. In the scene shown in FIG. 11B, the vehicle speed set for the threshold value Th1fb is slowed as the elapsed time α2 from t3, when switching control from assistance level 3 to assistance level 2α is performed, is increased, and switching control to assistance level 3 again is suppressed. Since switching control from a driving assistance mode with a relatively high assistance level to a driving assistance mode with a relatively low assistance level is likely due to a change in the driving environment of the host vehicle V1, the driving behavior of the vehicle can be stabilized by suppressing the switching control of the assistance level until the change in the driving environment settles down.

[0068] When changing the threshold value Th1 of the first switching condition for switching from assistance level 2α or assistance level 2β to assistance level 3, the control device 19 may set the threshold value Th1fa based on the driving environment conditions of the host vehicle V1. The driving environment conditions of the host vehicle V1 include the driving conditions of other vehicles traveling around the host vehicle V1. For example, when the host vehicle V1 is traveling near an interchange or junction, the number of other vehicles around the host vehicle V1 increases, temporarily slowing the vehicle speed, making it easier for the switching condition for assistance level 3 to be met. However, when the host vehicle V1 passes near an interchange or junction, the number of other vehicles traveling around the host vehicle V1 decreases, which may increase the vehicle speed of the host vehicle V1. In such a case, in order to prevent the switching condition for assistance level 3 from being frequently met, it is preferable to perform switching control to assistance level 3 when the vehicle speed remains slow even after passing near an interchange or junction.

[0069] Furthermore, even if the lane in which the host vehicle V1 is currently traveling is congested, causing the vehicle speed to temporarily slow down and the switching condition for assistance level 3 to be met, if the overtaking lane is clear, traffic flow may improve and the vehicle speed of the host vehicle V1 may increase. For this reason, it is preferable to detect the congestion status of not only the lane in which the host vehicle V1 is currently traveling but also the overtaking lane, and to perform switching control to assistance level 3 when it is determined that the number of other vehicles traveling around the host vehicle V1 has increased and the vehicle speed will remain slow. In this way, based on the traveling conditions of other vehicles traveling around the host vehicle V1, the threshold value Th1 is changed so that the switching condition for assistance level 3 is met when the driving environment conditions become favorable for switching control.

[0070] The driving environment conditions of the host vehicle V1 may include the operating conditions of the sensors 11 and the natural environment conditions in which the host vehicle V1 is driving. This is to control switching to assistance level 3 in a stable situation where the surrounding environment of the host vehicle V1 can be recognized normally. For example, when only a detection value from one of the multiple sensors 11, such as a front camera that detects lane markers on the road surface, a front lidar, and a 360-degree camera, can be confirmed, the detectability of the surrounding environment has decreased, so it is not desirable for the control device 19 to control switching to assistance level 3, in which the control device 19 monitors the periphery. Therefore, when detection values ​​from all sensors can be confirmed, the threshold value Th1 is changed so that the switching condition to assistance level 3 is met.

[0071] Incidentally, in cases where detection ability is reduced due to road conditions such as lane markers being blurred or difficult to detect due to contrast with the road surface, or when the surrounding conditions cannot be recognized due to bad weather such as rain or fog, or when driving on a road with few streetlights at night, it is preferable to change threshold value Th1 so that the condition for switching to assistance level 3 is met when the surrounding environment of the host vehicle V1 can be recognized normally and the situation becomes stable. By changing threshold value Th1 based on the driving environment conditions of the host vehicle V1, it is possible to perform switching control of the assistance level according to the driving environment conditions of the host vehicle V1.

[0072] <<Driving assistance control processing>> Next, the driving assistance control process of this embodiment will be described with reference to Fig. 5 and Fig. 12. Fig. 12 is a flowchart showing an example of the driving assistance control process executed by the driving assistance device 1 of this embodiment. The driving assistance control process described below is executed at predetermined time intervals by the driving assistance device 1. In addition, the following description will be given assuming that the driving assistance mode is executed at assistance level 2α by the autonomous driving control function of the control device 19. Note that the description will be given assuming that a vehicle speed of 70 km / h is set as the threshold value Th1 of the first switching condition for switching control from assistance level 2α to assistance level 3, and that when switching control to assistance level 3 is performed, when the driver presses the activation switch for assistance level 3.

[0073] First, in step S1 of Fig. 12, the speed of the host vehicle V1 is detected based on an input value from the sensor 11. Next, in step S2, the control device 19 determines whether or not the condition for switching to assistance level 3 is met. If the vehicle speed of the host vehicle V1 is less than 70 km / h, it is determined that the condition for switching to assistance level 3 is met, and the process proceeds to step S3. In response to this, step S2 is repeated for a predetermined time until the vehicle speed becomes less than 70 km / h, that is, until the condition for switching to assistance level 3 is met.

[0074] If it is determined in step S2 that the conditions for switching to assistance level 3 are met, then in step S3, the control device 19 sends a command to execute a specific operation to the in-vehicle equipment 14, the presentation device 16, and the drive control device 18, thereby changing the operation of the in-vehicle equipment and the behavior of the vehicle.

[0075] In the next step S4, the control device 19 determines whether or not the driver has consented to the switch control to assistance level 3. If the driver has pressed the activation switch for assistance level 3, it is determined that the driver has consented to the switch control to assistance level 3, and the process proceeds to step S5. On the other hand, if the driver has not pressed the activation switch for assistance level 3, it is determined that the driver has not consented to the switch control to assistance level 3, and step S4 is repeated for a predetermined period of time.

[0076] If the result of the determination in step S4 is that the driver agrees to the switch control to assistance level 3, then in step S5 the control device 19 executes the switch control from assistance level 2α to assistance level 3. In the following step S6, the control device 19 determines whether or not the switch control to assistance level 3 has been completed. If it is determined that the switch control to assistance level 3 has been completed, the process proceeds to step S7. On the other hand, if it is determined that the switch control to assistance level 3 has not been completed, the process proceeds to step S8, and if a predetermined time has elapsed, the process proceeds to step S7.

[0077] If it is determined in step S6 that the switching control to assistance level 3 has been completed, or if a predetermined time has elapsed in step S8, the control device 19 sends a command to cancel the specific operation to the in-vehicle equipment 14, the presentation device 16, and the drive control device 18 in step S7.

[0078] As described above, according to the driving assistance method and driving assistance device 1 of this embodiment, when driving assistance is provided by autonomous driving control by switching between driving assistance modes with multiple assistance levels, if a first switching condition for controlling switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is met, a specific operation for changing the operation of the vehicle's on-board equipment and / or a specific operation for changing the behavior of the vehicle is continuously executed. This allows the driver to clearly recognize that the condition for switching the driving assistance level is met.

[0079] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, when the first switching condition is met, the specific operation is continued for a predetermined time, and after completing the switching control from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level, the specific operation is canceled, so that the driver can more clearly recognize the transition status of the driving assistance level.

[0080] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, the threshold value of the first switching condition is set relatively higher than the threshold value of the second switching condition for controlling switching from a driving assistance mode with a relatively high assistance level to a driving assistance mode with a relatively low assistance level, thereby preventing the switching condition to the driving assistance mode with a relatively high assistance level from being met frequently and preventing the specific operation from being repeatedly executed.

[0081] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, the threshold value of the first switching condition is set higher the longer the elapsed time after completing the switching control from a driving assistance mode with a relatively high assistance level to a driving assistance mode with a relatively low assistance level, thereby stabilizing the vehicle's driving behavior.

[0082] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, the threshold value of the first switching condition is set based on the vehicle's driving environment conditions, which include at least one of the driving conditions of other vehicles driving around the vehicle, the operating conditions of sensors provided in the vehicle, and the natural environment conditions in which the vehicle is driving. This makes it possible to perform switching control of the assistance level according to the driving environment conditions of the host vehicle V1.

[0083] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, the specific operation includes at least one of a visual change, an auditory change, and a bodily change that is given to the driver due to the operation of the vehicle's onboard equipment and / or the vehicle's behavior. This allows the vehicle to actively notify the driver that the switching condition has been met. As a result, the driver can easily recognize that the switching condition has been met.

[0084] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, the visual changes include at least one of changes in the lighting inside the vehicle cabin, the display of driving information, the display of the surrounding conditions, and the operation control of the wipers. Visual changes are easily noticeable even when the driver is concentrating on driving operations, making it easier for the driver to recognize that the conditions for switching to a driving assistance mode with a relatively high level of assistance have been met.

[0085] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, the auditory changes include at least one of a change in volume and a change in tone of the operation sound of the vehicle's on-board devices. The auditory changes do not interfere with driving operations because the driver can recognize that the conditions for switching to a driving assistance mode with a relatively high assistance level have been met without changing his or her line of sight or posture.

[0086] Furthermore, according to the driving assistance method and driving assistance device 1 of this embodiment, the perceptual changes include at least one of changes in vehicle acceleration / deceleration control, steering control, suspension control, and steering wheel position control, making it easier for the driver to intuitively notice that the conditions for switching to a driving assistance mode with a relatively high level of assistance have been met.

[0087] It should be noted that the above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, the elements disclosed in the above embodiments are intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0088] 1...Driving assistance device 11...Sensor 12...Vehicle position detection device 13...Map database 14…In-vehicle equipment 15...Navigation device 16...Presentation device 17...Input device 18...Drive control device 19...Control device V1: Your vehicle

Claims

1. A driving assistance method executed by a processor, which assists driving of a vehicle through autonomous driving control by switching between driving assistance modes having a plurality of assistance levels, The processor: A driving assistance method in which, when a first switching condition for controlling switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is met, the changed state of at least one of a change in lighting inside the vehicle's cabin or a change in wiper operation control of the vehicle is continued for a predetermined period of time.

2. A driving assistance method executed by a processor, which assists driving of a vehicle through autonomous driving control by switching between driving assistance modes having a plurality of assistance levels, The processor: When a first switching condition for controlling switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is satisfied, the driving assistance method continues the changed state of at least one of the tone or sound duration of the operation sound of the vehicle's on-board equipment for a predetermined period of time.

3. A driving assistance method executed by a processor, which assists driving of a vehicle through autonomous driving control by switching between driving assistance modes having a plurality of assistance levels, The processor: A driving assistance method in which, when a first switching condition for controlling switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is met, the changed state of at least one of changes in acceleration / deceleration control of the vehicle, changes in steering control, changes in suspension control, or changes in steering wheel position control is maintained for a predetermined period of time.

4. A driving assistance method executed by a processor, which assists driving of a vehicle through autonomous driving control by switching between driving assistance modes having a plurality of assistance levels, The processor: a driving assistance method for changing a display of the vehicle's speed and route guidance from a display of an around-view image of the surroundings of the vehicle to a display of an around-view image of the surroundings of the vehicle when a first switching condition for controlling switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is satisfied, and maintaining the changed state for a predetermined time.

5. The processor:

5. The driving assistance method according to claim 1, wherein when the first switching condition is met, continuation of the changed state is started, and switching control from the driving assistance mode with a relatively low assistance level to the driving assistance mode with a relatively high assistance level is completed, continuation of the changed state is canceled even if the predetermined time has not elapsed.

6. The processor: The driving assistance method according to any one of claims 1 to 5, wherein the threshold value of the first switching condition is set relatively low compared to the threshold value of a second switching condition that controls switching from a driving assistance mode in which the assistance level is relatively high to a driving assistance mode in which the assistance level is relatively low.

7. The processor:

7. The driving assistance method according to claim 6, wherein the threshold value of the first switching condition is set lower as the elapsed time after completion of switching control from the driving assistance mode with the relatively high assistance level to the driving assistance mode with the relatively low assistance level increases.

8. The processor:

8. The driving assistance method according to claim 6 or 7, wherein the threshold value of the first switching condition is set based on driving environment conditions of the vehicle, including at least one of driving conditions of other vehicles driving around the vehicle, operating conditions of sensors provided in the vehicle, and natural environment conditions in which the vehicle is driving.

9. A driving assistance device that supports vehicle driving through autonomous driving control by switching between driving assistance modes having a plurality of assistance levels, a detection unit that detects that a first switching condition for controlling switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is satisfied; A driving assistance device comprising: a control unit that, when the first switching condition is met, continues the changed state of at least one of the change in the lighting inside the vehicle's cabin or the change in the operation control of the wipers of the vehicle for a predetermined period of time.

10. A driving assistance device that supports vehicle driving through autonomous driving control by switching between driving assistance modes having a plurality of assistance levels, a detection unit that detects that a first switching condition for controlling switching from a driving assistance mode with a relatively low assistance level to a driving assistance mode with a relatively high assistance level is satisfied; A driving assistance device comprising: a control unit that, when the first switching condition is met, continues the changed state of at least one of the change in tone or the change in sound duration of the operation sound of the vehicle's on-board equipment for a predetermined period of time.

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