Driving assistance device, driving assistance method, and non-transitory computer-readable storage medium

Abstract

This invention relates to driving assistance devices, driving assistance methods, and non-transitory computer-readable storage media. The driving assistance device for a vehicle includes: a notification device disposed within the passenger compartment of the vehicle; and a control device that controls the notification device, wherein the control device is configured to: set an acceleration start point on a merging lane merging with a main lane before a merging start point where lane changing from the merging lane to the main lane is possible, and when the vehicle reaches the acceleration start point, cause the notification device to output an acceleration notification prompting the driver to perform an acceleration operation.

Description

Technical Field

[0001] This invention relates to driving assistance devices, driving assistance methods, and control programs (stored in a non-transitory computer-readable storage medium). Background Technology

[0002] In recent years, given the vulnerable status of traffic participants, there has been a growing effort to provide sustainable transportation systems. To achieve this, research and development related to driver assistance and autonomous driving technologies are underway to further improve the safety and convenience of transportation.

[0003] Merging from a merging lane to the main lane on highways and other similar routes is a stressful maneuver for drivers. JP2019-26060A discloses a driver assistance device for vehicles capable of adaptive cruise control to maintain a safe distance from the vehicle in front. In this device, when a following vehicle is present after merging into the main lane, the driver assistance device corrects the acceleration to increase the following distance.

[0004] However, in the driver assistance device disclosed in JP2019-26060A, vehicle speed is controlled via adaptive cruise control. Therefore, if the set target speed is low, the vehicle will change lanes at a low speed towards the main lane, making lane changes difficult. The success of merging operations largely depends on whether the vehicle reaches sufficient speed in the merging lane. Therefore, if the driver can be prompted to accelerate appropriately in the merging lane, merging operations become relatively easy. Summary of the Invention

[0005] In view of the above background, one aspect of the present invention is to provide a driving assistance device, driving assistance method and control program that can prompt the driver to accelerate appropriately when the vehicle is in a merging lane.

[0006] To achieve the above objectives, one aspect of the present invention provides a driving assistance device for a vehicle, the driving assistance device comprising: a notification device disposed within the passenger compartment of the vehicle; and a control device controlling the notification device, wherein the control device is configured to: set an acceleration start point on a merging lane merging with a main lane before a merging start point where lane changing from the merging lane to the main lane is possible, and when the vehicle reaches the acceleration start point, cause the notification device to output an acceleration notification prompting the driver to perform an acceleration operation.

[0007] Another aspect of the present invention provides a driving assistance method for a vehicle, wherein the driving assistance method is executed by a computer and includes the following steps: setting an acceleration start point on a merging lane merging with a main lane before a merging start point where a lane change from the merging lane to the main lane is possible; and when the vehicle reaches the acceleration start point, causing a notification device to output an acceleration notification prompting the driver to perform an acceleration operation.

[0008] Another aspect of the present invention provides a non-transitory computer-readable storage medium including a stored control program configured to cause a computer to execute a driving assistance method for a vehicle, the driving assistance method including the steps of: setting an acceleration start point on a merging lane merging with a main lane before a merging start point where a lane change from the merging lane to the main lane is possible; and when the vehicle reaches the acceleration start point, causing a notification device to output an acceleration notification prompting the driver to perform an acceleration operation.

[0009] According to the above aspects of the present invention, a driving assistance device, driving assistance method and control program can be provided that can prompt the driver to accelerate appropriately when the vehicle is in a merging lane. Attached Figure Description

[0010] Figure 1 This is a configuration diagram of a driving assistance device according to an embodiment;

[0011] Figure 2 This is an explanatory diagram of the merging lane;

[0012] Figure 3 It is a three-dimensional view showing the vehicle's cabin; and

[0013] Figure 4 This is a flowchart illustrating the process of driver assistance control performed by the control device. Detailed Implementation

[0014] Hereinafter, the implementation methods of the driving assistance device, driving assistance method and control program will be described with reference to the accompanying drawings.

[0015] like Figure 1 As shown, a driving assistance device 1 is installed in vehicle 2. Vehicle 2 may be, for example, a four-wheeled vehicle.

[0016] Vehicle 2 includes a propulsion system 5, a braking system 6, and a steering system 7. The propulsion system 5 is a device for providing driving force to vehicle 2, and includes, for example, a power source and a transmission. The power source includes at least one of an internal combustion engine, such as a gasoline engine or a diesel engine, and an electric motor. The braking system 6 is a device for applying braking force to vehicle 2, and includes, for example, a brake caliper for pressing brake pads against a brake rotor and an electric cylinder for supplying hydraulic pressure to the brake caliper. The steering system 7 is a device for changing the steering angle of the wheels, and includes, for example, a rack and pinion mechanism for steering the wheels and an electric motor for driving the rack and pinion mechanism.

[0017] Vehicle 2 includes an external environment recognition device 10. The external environment recognition device 10 is a device for detecting objects outside the vehicle 2. The external environment recognition device 10 uses sensors to detect objects outside the vehicle 2 by capturing electromagnetic waves or light from the surrounding environment. The external environment recognition device 10 may include, for example, radar 11, lidar 12, and an external camera 13.

[0018] Vehicle 2 includes vehicle sensor 15. Vehicle sensor 15 includes a vehicle speed sensor for detecting the speed of vehicle 2 and an acceleration sensor for detecting the acceleration of vehicle 2. Vehicle sensor 15 may also include a yaw rate sensor for detecting the angular velocity about a vertical axis, a direction sensor for detecting the orientation of vehicle 2, etc.

[0019] Vehicle 2 includes a control unit 17, a communication unit 18, a navigation unit 19, and a notification unit 20 as a human-machine interface (HMI). The communication unit 18 mediates communication between the control unit 17 and the navigation unit 19 and nearby vehicles and a server located outside vehicle 2.

[0020] The navigation device 19 is a device that acquires the current position of the vehicle 2 and provides route guidance to the destination. The navigation device 19 preferably includes a Global Navigation Satellite System (GNSS) receiving unit 21, a map storage unit 22, and a route determination unit 23. The GNSS receiving unit 21 determines the position (latitude and longitude) of the vehicle 2 based on signals received from artificial satellites (positioning satellites). The map storage unit 22 is composed of a known storage device such as flash memory or a hard disk, and stores map information.

[0021] The map information includes road information, such as road types (e.g., highways, toll roads, national roads, and county roads), the number of lanes on each road, the center location of each lane (including three-dimensional coordinates of longitude, latitude, and altitude), the shape of road markings such as road boundaries and lane limits, the presence or absence of sidewalks, curbs, and fences, the location of intersections, the location of merging and branching points for each lane, the location of emergency stopping areas, the width of each lane, and road signs. In addition, the map information may include traffic rules, address information (address and postal code), facility information, and telephone number information.

[0022] In this embodiment, the map information includes information about whether the road is a main lane 101, 102 or a merging lane 103 merging with the main lane 101. For example... Figure 2 As shown, the merging lane 103 includes a merging preparation section 103A and a merging section 103B. The merging section 103B extends parallel to the main lane 101. Vehicle 2 can change lanes into the main lane 101 in the merging section 103B. The merging preparation section 103A is separated from the main lane 101 by a rigid nose 104, such as a wall, and a flexible nose 105, such as a traffic pole. The starting point of the merging section 103B, i.e., the ending point of the merging preparation section 103A, is called the merging start point 107. That is, from the merging start point 107, the merging section 103B begins, and vehicle 2 becomes able to change lanes into the main lane 101. The merging start point 107 is preferably located at the end of the flexible nose 105.

[0023] Merging preparation section 103A is, for example, an entrance ramp of a highway. The starting point of merging preparation section 103A is a pre-defined arbitrary point. When merging lane 103 is an entrance ramp of a highway, for example, the starting point of merging preparation section 103A can be the starting point of the entrance ramp, a toll station, or a branch point after passing through a toll station.

[0024] As information related to merging lane 103, the map information preferably includes the following: whether merging lane 103 is a merging preparation section 103A or a merging section 103B, the location of the starting point of merging preparation section 103A, the location of the merging start point 107 (the location of the ending point of merging preparation section 103A), the length of merging preparation section 103A, the gradient of each point within merging preparation section 103A, and the radius of curvature or curve radius (R) of merging preparation section 103A.

[0025] The notification device 20 notifies occupants of various information via a display and / or voice. The notification device 20 is installed in the passenger compartment 25 of vehicle 2. For example... Figure 1As shown, the notification device 20 preferably includes a display 26 having a liquid crystal display, an organic EL display, etc., a display device 27, and a speaker 28.

[0026] Display device 27 is an optical device used to provide visual information to the driver. Display device 27 can be composed of light-emitting elements (light sources) such as light-emitting diodes (LEDs) or liquid crystal displays. Display device 27 can be what is known as ambient light. Figure 3 As shown, the display device 27 is disposed in the carriage 25 of the vehicle 2 and extends in a predetermined direction. The display device 27 has multiple display areas divided along its extending direction.

[0027] In this embodiment, the display device 27 includes a first portion 27A and a second portion 27B. The first portion 27A is disposed on a door 29 constituting the side portion of the vehicle compartment 25 and extends in a front-rear direction. The door 29 is disposed on one side of the driver's seat 31. The second portion 27B is disposed on a dashboard 32 constituting the front portion of the vehicle compartment 25 and extends laterally. The front end of the first portion 27A and the right end of the second portion 27B, which are one end of the second portion 27B, are disposed close to each other. Thus, the second portion 27B extends to the left from the front end of the first portion 27A. Preferably, the first portion 27A and the second portion 27B extend linearly in a continuous manner.

[0028] The first part 27A preferably extends in the front-to-back direction above the door liner 34 of the door 29. The second part 27B preferably extends along the upper edge of the instrument panel 35 provided in the instrument panel 32. The left end of the second part 27B is preferably located above the central portion of the instrument panel 35.

[0029] The display device 27 can change the display mode. The display mode includes the light-emitting area, the light-emitting color, and the light-emitting period. For example, the display device 27 can set the display mode so that the light-emitting area moves from the rear to the front. In addition, the display device 27 can change the moving speed of the light-emitting area.

[0030] The display device 27 can be located in the left side of the passenger compartment 25. Preferably, the left-side display device 27 is a mirror image of the right-side display device 27. Alternatively, the display device 27 can be located on the instrument panel 32.

[0031] The display 26 may be a touch panel display. The display 26 is preferably located on the dashboard 32. Alternatively, the display 26 may be located in the instrument panel 35.

[0032] like Figure 1As shown, the control device 17 is a computer including a processor 41 and a memory 42 communicatively connected to the processor 41. The processor 41 preferably includes at least one of, for example, a central processing unit (CPU), a graphics processing unit (GPU), and a reduced instruction set computer (RISC) as its core. The memory 42 stores control programs and various data executed by the processor 41. The memory 42 preferably includes at least one of volatile memory and non-volatile memory. The volatile memory may be, for example, dynamic random access memory (DRAM) or static random access memory (SRAM). The non-volatile memory may be a solid-state drive (SSD), flash memory, a disk storage device, or an optical disk storage device. At least a portion of the control device 17 can be implemented using hardware such as large-scale integrated circuits (LSI), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or a combination of software and hardware. The control device 17 can be composed of a single piece of hardware or multiple pieces of hardware capable of communicating with each other. A portion of the control device 17 can be composed of an external server located outside the vehicle 2.

[0033] The processor 41 implements various applications by executing a control program stored in the memory 42. The control program can be stored on a removable recordable medium such as a DVD or CD-ROM, and can be installed into the memory 42 when the recordable medium is read by a reading device. Furthermore, the control program can be downloaded and installed into the memory 42 via a communication network such as the Internet.

[0034] The driver assistance device 1 is a vehicle system and includes at least a control device 17 and a notification device 20 as its components. Additionally, the driver assistance device 1 may include an external environment recognition device 10, vehicle sensors 15, and a navigation device 19 as its components.

[0035] The control device 17 controls the display device 27 and the speaker 28. The processor 41 functions as the surrounding environment recognition unit 45, the self-vehicle position recognition unit 46, and the notification unit 47 by executing the control program stored in the memory 42.

[0036] The surrounding environment recognition unit 45 recognizes the surrounding environment of vehicle 2. Based on the detection results of the external environment recognition device 10, the surrounding environment recognition unit 45 identifies the surrounding environment (external environment) including obstacles, road shape, lane markings, presence or absence of sidewalks, road markings, etc., that exist around vehicle 2. For example, obstacles include guardrails, utility poles, nearby vehicles, and people such as pedestrians. The surrounding environment recognition unit 45 can obtain the position, speed, acceleration, and other states of nearby vehicles based on the detection results of the external environment recognition device 10.

[0037] The self-vehicle location identification unit 46 identifies the location of vehicle 2 (self-vehicle). Preferably, the self-vehicle location identification unit 46 identifies the location of vehicle 2 based on GNSS signals received by GNSS receiving unit 21.

[0038] The notification unit 47 of the control device 17 controls the notification device 20 according to the driving assistance method. The notification unit 47 performs driving assistance control when the vehicle 2 is in the merging preparation section 103A of the merging lane 103. The notification unit 47 determines whether the vehicle 2 is in the merging preparation section 103A of the merging lane 103 based on the position and map information of the vehicle 2 obtained by the self-vehicle position recognition unit 46.

[0039] In driver assistance control, the notification unit 47 of the control device 17 sets an acceleration start point 108 on the merging lane 103 that merges with the main lane 101, before (or upstream of) the merging start point 107 where lane changes from the merging lane 103 to the main lane 101 are possible. The merging start point 107 can be pre-stored in map information. The notification unit 47 can set the position of the front end of the flexible nose 105 stored in the map information as the merging start point 107. In addition, the notification unit 47 can set the position of the front end of the flexible nose 105 identified by the surrounding environment recognition unit 45 as the merging start point 107.

[0040] Preferably, the notification unit 47 sets the acceleration start point 108 as a position offset by a predetermined offset distance LO from the merging start point 107 towards the upstream side, i.e., the start point of the merging lane 103, along the merging lane 103. The offset distance LO is the distance between the acceleration start point 108 and the merging start point 107. The offset distance LO can be a preset value, or it can be set based on the vehicle 2's status information, driver characteristic information, and merging lane information. The section from the acceleration start point 108 to the merging start point 107 can be referred to as the acceleration section.

[0041] Preferably, the notification unit 47 sets the offset distance LO based on the vehicle speed included in the vehicle 2's status information. Preferably, the notification unit 47 sets the offset distance LO such that the lower the vehicle 2's speed is relative to the predetermined target speed, the larger the offset distance LO. The target speed is preferably based on the legal speed limit of the merging preparation section 103A or the main lane 101. For example, the target speed is preferably the same as the legal speed limit, or a value obtained by subtracting 10 km / h from the legal speed limit. The target speed can be obtained from map information or through an external environment recognition unit that identifies signs. Preferably, the notification unit 47 obtains the offset distance LO based on the difference between the vehicle 2's speed and the target speed by using a mapping that defines the relationship between the offset distance LO and the difference between the vehicle 2's speed and the target speed. Thus, the notification unit 47 sets the acceleration start point 108 such that the lower the vehicle 2's speed is relative to the predetermined target speed, the larger the distance between the acceleration start point 108 and the merging start point 107.

[0042] Driver characteristic information includes, for example, the driver's driving characteristics and age. Driving characteristics preferably include information related to the driver's driving speed and acceleration. For example, driving characteristics can be represented as scores, such that a higher score indicates a faster vehicle speed, and a lower score indicates a slower vehicle speed. Preferably, the notification unit 47 sets an offset distance LO such that a smaller driving characteristic score corresponds to a larger offset distance LO. The notification unit 47 can use a mapping that defines the relationship between the driving characteristic score and the offset distance LO to obtain the offset distance LO based on the driving characteristic score. Thus, the notification unit 47 sets the acceleration start point 108 based on the driver characteristic information. The driver characteristic information is preferably stored in the memory 42. The driver characteristic information can be created based on past driving data. Furthermore, the notification unit 47 can set the offset distance LO such that the older the driver, the larger the offset distance LO.

[0043] The merging lane information preferably includes at least one of the radius of curvature and slope of the merging lane 103. The radius of curvature and slope of the merging lane 103 are preferably included in the map information. Preferably, the notification unit 47 sets an offset distance LO such that the smaller the radius of curvature of the merging lane 103, the larger the offset distance LO. Additionally, preferably, the notification unit 47 sets an offset distance LO such that the larger the uphill slope of the merging lane 103, the larger the offset distance LO. The notification unit 47 can use a mapping that defines the relationship between the merging lane information and the offset distance LO to obtain the offset distance LO based on the merging lane information. Thus, the notification unit 47 sets the acceleration start point 108 based on the merging lane information including at least one of the radius of curvature and slope of the merging lane 103.

[0044] In another embodiment, the notification unit 47 can set the position of the front end of the rigid nose 104 as the acceleration start point 108.

[0045] When the vehicle 2 reaches the acceleration start point 108, the notification unit 47 of the control device 17 causes the notification device 20 to output an acceleration notification prompting the driver to accelerate. The notification unit 47 preferably controls the speaker 28 to output the acceleration notification as an audio effect or voice. The acceleration notification output from the speaker 28 may be, for example, a voice output such as "Please accelerate." The notification unit 47 preferably controls the display 26 to output the acceleration notification as an image, video, or text. For example, the acceleration notification may be an icon depicting an accelerating vehicle or an icon depicting a depressed accelerator pedal. The notification unit 47 preferably controls the display device 27 to output the acceleration notification as a light source. For example, the acceleration notification output from the display device 27 may be the forward movement of the light-emitting area of ​​the display device 27, the flashing of the light-emitting area, etc.

[0046] When vehicle 2 is located before acceleration start point 108 in merging lane 103 and the distance between vehicle 2 and the vehicle ahead 109 is less than the first target distance, the notification unit 47 of control device 17 causes notification device 20 to output a distance increase notification prompting the driver to increase the distance. Additionally, when vehicle 2 is located in merging lane 103 between acceleration start point 108 and merging start point 107 and the distance between vehicle 2 and the vehicle ahead 109 is less than the second target distance, the notification unit 47 causes notification device 20 to output a distance increase notification. The first target distance is set to be greater than the second target distance.

[0047] The surrounding environment recognition unit 45 identifies the vehicle 109 traveling in front of the vehicle 2 and obtains the distance between the vehicle and the vehicle. The notification unit 47 obtains the distance between the vehicle and the vehicle from the surrounding environment recognition unit 45. The first target distance and the second target distance are preferably preset values.

[0048] The notification unit 47 preferably controls the speaker 28 to output a vehicle spacing increase notification as an audio effect or voice. The vehicle spacing increase notification output from the speaker 28 may be, for example, a voice output such as "Increase vehicle spacing." The notification unit 47 preferably controls the display 26 to output a vehicle spacing increase notification as an image, video, or text. The vehicle spacing increase notification output from the display 26 may be, for example, an icon depicting a vehicle moving to increase vehicle spacing, or an icon depicting a vehicle decelerating. The notification unit 47 preferably controls the display device 27 to output a vehicle spacing increase notification as an illuminated image. For example, the vehicle spacing increase notification output from the display device 27 may be the backward movement of the illuminated area of ​​the display device 27, the flashing of the illuminated area, etc.

[0049] When the distance between vehicle 2 and acceleration start point 108 is less than or equal to a predetermined value, the notification unit 47 of control device 17 preferably causes notification device 20 to output a preparation notification prompting the driver to prepare for acceleration. Notification unit 47 determines the distance between vehicle 2 and acceleration start point 108 based on the position of vehicle 2 obtained by self-vehicle position recognition unit 46 and the position of acceleration start point 108. The predetermined value is preferably a preset value, such as 50m.

[0050] The notification unit 47 preferably controls the speaker 28 so that the speaker 28 outputs the preparation notification as an audio effect or voice. The preparation notification output from the speaker 28 may be, for example, a voice output such as "Approaching the merging point". The notification unit 47 preferably controls the display 26 so that the display 26 outputs the preparation notification as an image, video, or text. The preparation notification output from the display 26 may be, for example, a text output such as "Approaching the merging point".

[0051] The following describes the control process of the driver assistance control performed by the control device 17. The control device 17 initiates driver assistance control when the vehicle 2 enters the merging preparation section 103A. The control device 17 determines whether the vehicle 2 is in the merging preparation section 103A based on the position and map information of the vehicle 2 obtained by the self-vehicle position recognition unit 46.

[0052] like Figure 4 As shown, firstly, the control device 17 sets the acceleration start point 108 (ST1). Preferably, the control device 17 obtains the merging start point 107 from map information and sets the acceleration start point 108 based on the merging start point 107. For example, the control device 17 can obtain the vehicle speed, obtain the offset distance LO based on the vehicle speed, and set the acceleration start point 108 based on the merging start point 107 and the offset distance LO. Alternatively, as mentioned above, the control device 17 can set the acceleration start point 108 based on driver characteristic information or merging lane information.

[0053] Next, the control device 17 sets the first target vehicle spacing as the target vehicle spacing (ST2). Then, the control device 17 determines whether the vehicle spacing between vehicle 2 and the vehicle ahead 109 is greater than or equal to the first target vehicle spacing (ST3). If the vehicle spacing between vehicle 2 and the vehicle ahead 109 is less than the first target vehicle spacing (ST3: No), the control device 17 controls the notification device 20 to issue a vehicle spacing increase notification (ST4).

[0054] Then, if the distance between vehicle 2 and the vehicle ahead 109 is greater than or equal to the first target distance (ST3: Yes), or if step ST4 has been performed, the control device 17 determines whether vehicle 2 has reached the acceleration start point 108 (ST5). Preferably, the position of vehicle 2 is obtained by the self-vehicle position recognition unit 46.

[0055] If vehicle 2 does not reach acceleration start point 108 (ST5: No), return to step ST3, and control device 17 repeats the processing of steps ST3 to ST5.

[0056] When vehicle 2 reaches acceleration start point 108 (ST5: Yes), control device 17 sets the second target vehicle spacing as the target vehicle spacing (ST6). Next, control device 17 determines whether the vehicle spacing between vehicle 2 and the vehicle in front 109 is greater than or equal to the second target vehicle spacing (ST7). If the vehicle spacing between vehicle 2 and the vehicle in front 109 is less than the second target vehicle spacing (ST7: No), control device 17 controls notification device 20 to issue a vehicle spacing increase notification (ST8).

[0057] If the distance between vehicle 2 and the vehicle ahead 109 is greater than or equal to the second target distance (ST7: Yes), the control device 17 determines whether the vehicle speed is less than or equal to the speed limit of the main lane 101 (ST9). Preferably, the control device 17 obtains the vehicle speed from the vehicle sensor 15 and obtains the speed limit of the main lane 101 from map information. If the vehicle speed is less than or equal to the speed limit of the main lane 101 (ST9: Yes), the control device 17 controls the notification device 20 to output an acceleration notification (ST10).

[0058] If step ST8 or ST10 has been performed, or if the vehicle speed exceeds the speed limit of the main lane 101 (ST9: No), the control device 17 determines whether vehicle 2 has reached the merging start point 107 (ST11). If vehicle 2 has not reached the merging start point 107 (ST11: No), the process returns to step ST7, and the control device 17 repeats the processes of steps ST7 to ST10. If vehicle 2 has reached the merging start point 107 (ST11: Yes), the control device 17 terminates the driver assistance control.

[0059] According to the embodiment, a driving assistance device 1 can be provided that prompts the driver to accelerate appropriately in the merging lane 103. The driver can accelerate at an appropriate time in the merging lane 103 based on the acceleration notification. The control device 17 controls at least one of the display 26, the display device 27, and the speaker 28 to execute the acceleration notification, thereby prompting the driver to accelerate at a position prior to the merging start point 107.

[0060] Since the acceleration start point 108 is set before the merging start point 107, the driver accelerates earlier based on the acceleration notification. This allows the driver's vehicle 2 to accelerate earlier than the following vehicle. Therefore, the reaction delay of the following vehicle can be used to increase the distance between the driver's vehicle 2 and the following vehicle. Furthermore, because the driver begins acceleration before the merging start point 107, vehicle 2 is able to reach sufficient speed when changing lanes.

[0061] In the area prior to acceleration start point 108, control device 17 issues a vehicle spacing increase notification based on a first target vehicle spacing greater than the second target vehicle spacing. Therefore, the driver can increase the distance to the vehicle ahead 109 based on this notification. This ensures sufficient distance between the vehicle ahead 109 and vehicle 2 at acceleration start point 108. Consequently, the driver can accelerate at acceleration start point 108 without worrying about the vehicle ahead 109.

[0062] The acceleration start point 108 can be changed based on the vehicle 2's speed, driver characteristics, and merging lane information. Therefore, when the vehicle 2's speed is low, for example, by issuing an acceleration notification in advance, sufficient time can be ensured for the driver to accelerate. Additionally, for drivers who are not adept at acceleration, an acceleration notification can be issued in advance. Furthermore, when the merging lane 103 has an uphill slope or a small radius of curvature, an acceleration notification can be issued in advance.

[0063] After vehicle 2 reaches the merging zone 103B, the control device 17 does not cause the notification device 20 to issue an acceleration notification or a vehicle spacing increase notification, so the driver can concentrate on changing lanes to the main lane 101.

[0064] This embodiment is not limited to the above configuration and can be modified in various ways. For example, it can be configured to allow the driver to select the offset distance LO. A selection switch can be provided on the instrument panel 32, etc., to allow selection of the offset distance LO.

[0065] The control unit 17 can perform forward vehicle following control, also known as adaptive cruise control. In this control unit 17, the propulsion device 5 and braking device 6 are controlled based on the target vehicle speed and target distance, such that the distance to the vehicle ahead 109 becomes the target distance. In this case, the aforementioned driver assistance control can be performed simultaneously with forward vehicle following control. When a distance increase notification is issued based on driver assistance control during forward vehicle following control, the driver preferably operates a switch to increase the target distance for forward vehicle following control. Furthermore, the control unit 17 can set either a first or second target distance set in driver assistance control as the target distance for forward vehicle following control. Thus, the forward vehicle following control performed by the control unit 17 can maintain the distance at the first target distance before the acceleration start point 108 and maintain the distance at the second target distance between the acceleration start point 108 and the merging start point 107.

[0066] When an acceleration notification is issued based on driver assistance control during forward vehicle follow control, the driver should preferably depress the accelerator pedal to overtake the forward vehicle follow control and accelerate vehicle 2. When the accelerator pedal is depressed during forward vehicle follow control, the control device 17 should preferably control the propulsion device 5 according to the amount of accelerator pedal depressed, thereby overtaking the forward vehicle follow control. Additionally, the control device 17 can change the target speed of the forward vehicle follow control to a predetermined merging speed upon reaching the acceleration start point, thereby accelerating vehicle 2 under forward vehicle follow control. The merging speed is preferably a value obtained, for example, by reducing the speed limit of the main lane 101 by 10 km / h to 30 km / h.

[0067] The above implementation method can be described as follows.

[0068] One embodiment is a driving assistance device 1 for a vehicle 2, the driving assistance device 1 including: a notification device 20 disposed in the passenger compartment 25 of the vehicle 2; and a control device 17 controlling the notification device 20, wherein the control device is configured to: set an acceleration start point 108 on a merging lane 103 merging with the main lane 101 before a merging start point 107 where lane changes can be made from the merging lane 103 to the main lane 101, and when the vehicle 2 reaches the acceleration start point 108, cause the notification device 20 to output an acceleration notification prompting the driver to perform an acceleration operation.

[0069] Based on this aspect, a driving assistance device 1 can be provided that prompts the driver to accelerate appropriately in the merging lane 103. The driver can then accelerate at an appropriate time in the merging lane 103 based on the acceleration notification. Furthermore, since the acceleration start point 108 is set before the merging start point 107, the driver performs the acceleration operation at a relatively early time based on the acceleration notification. This allows the driver's vehicle 2 to accelerate earlier than the following vehicle. Therefore, the reaction delay of the following vehicle can be utilized to increase the distance between the driver's vehicle 2 and the following vehicle.

[0070] In the above embodiment, when vehicle 2 is located before acceleration start point 108 on merging lane 103 and the distance between vehicle 2 and the vehicle in front 109 is less than the first target distance, control device 17 can cause notification device 20 to output a distance increase notification prompting the driver to increase the distance. When vehicle 2 is located between acceleration start point 108 and merging start point 107 on merging lane 103 and the distance between vehicle 2 and the vehicle in front 109 is less than the second target distance, control device 17 can cause notification device 20 to output a distance increase notification, and the first target distance is set to be greater than the second target distance.

[0071] Based on this, the driver can increase the distance between vehicle 2 and the vehicle in front 109 before vehicle 2 reaches the acceleration start point 108, based on the distance increase notification. This ensures sufficient distance between vehicle 2 and vehicle 109 at the acceleration start point 108. Therefore, the driver can accelerate at the acceleration start point 108 without worrying about vehicle 109.

[0072] In the above embodiment, the control device 17 can set the acceleration start point 108 so that the lower the speed of the vehicle 2 is relative to the predetermined target speed, the greater the distance between the acceleration start point 108 and the merging start point 107.

[0073] Based on this, when the vehicle 2 is traveling at a low speed, an acceleration notification is given in advance, thereby ensuring that the driver has sufficient time to accelerate.

[0074] In the above embodiment, the control device 17 can set the acceleration start point 108 based on driver characteristic information.

[0075] Based on this, and according to the driver's characteristics, an acceleration notification will be given at an appropriate time.

[0076] In the above embodiment, the control device 17 can set the acceleration start point 108 based on merging lane information including at least one of the radius of curvature and gradient of the merging lane 103.

[0077] According to this aspect, an acceleration notification shall be given at an appropriate time, based on at least one of the radius of curvature and gradient of the merging lane 103.

[0078] In the above embodiment, when the distance between vehicle 2 and acceleration start point 108 is less than or equal to a predetermined value, control device 17 can cause notification device 20 to output a preparation notification prompting the driver to prepare for acceleration.

[0079] Based on this, drivers can prepare for acceleration operations based on preparation notices.

[0080] Another embodiment is a driving assistance method for vehicle 2, wherein the driving assistance method is executed by a computer and includes the following steps: setting an acceleration start point 108 on a merging lane 103 merging with the main lane 101 before a merging start point 107 where a lane change can be made from the merging lane 103 to the main lane 101; and when vehicle 2 reaches the acceleration start point 108, causing the notification device 20 to output an acceleration notification prompting the driver to perform an acceleration operation.

[0081] Based on this, a driving assistance method can be provided that prompts the driver to accelerate appropriately on the merging lane 103.

[0082] Another embodiment is a non-transitory computer-readable storage medium including a stored control program configured to cause a computer to execute a driving assistance method for vehicle 2, the driving assistance method including the steps of: setting an acceleration start point 108 on a merging lane 103 merging with the main lane 101 before a merging start point 107 where a lane change can be made from the merging lane 103 to the main lane 101; and when vehicle 2 reaches the acceleration start point 108, causing a notification device 20 to output an acceleration notification prompting the driver to perform an acceleration operation.

[0083] According to this aspect, a control program can be provided for causing a computer to execute a driving assistance method that prompts the driver to accelerate appropriately on the merging lane 103.

Claims

1. A driving assistance device for a vehicle, the driving assistance device comprising: A notification device, wherein the notification device is installed inside the passenger compartment of the vehicle; and Control device, the control device controls the notification device. The control device is configured as follows: On the merging lane that merges with the main lane, an acceleration start point is set before the merging start point where lane changes from the merging lane to the main lane are possible, and When the vehicle reaches the acceleration start point, the notification device outputs an acceleration notification prompting the driver to accelerate.

2. The driving assistance device according to claim 1, wherein, When the vehicle is located before the acceleration start point on the merging lane, and the distance between the vehicle and the vehicle in front is less than a first target distance, the control device causes the notification device to output a distance increase notification prompting the driver to increase the distance. When the vehicle is located between the acceleration start point and the merging start point on the merging lane, and the distance between the vehicle and the vehicle ahead is less than the second target distance, the control device causes the notification device to output a notification indicating an increase in the distance. The first target vehicle spacing is set to be greater than the second target vehicle spacing.

3. The driving assistance device according to claim 1, wherein, The control device sets the acceleration start point such that the lower the vehicle's speed is relative to the predetermined target speed, the greater the distance between the acceleration start point and the merging start point.

4. The driving assistance device according to claim 1, wherein, The control device sets the acceleration start point based on driver characteristic information.

5. The driving assistance device according to claim 1, wherein, The control device sets the acceleration start point based on merging lane information, including at least one of the merging lane's radius of curvature and gradient.

6. The driving assistance device according to claim 1, wherein, When the distance between the vehicle and the acceleration start point is less than or equal to a predetermined value, the control device causes the notification device to output a preparation notification prompting the driver to prepare for acceleration.

7. A driving assistance method for a vehicle, wherein, The driving assistance method will be executed by a computer and includes the following steps: On the merging lane that merges with the main lane, an acceleration start point is set before the merging start point where a lane change from the merging lane to the main lane is possible; and When the vehicle reaches the acceleration start point, the notification device outputs an acceleration notification prompting the driver to accelerate.

8. A non-transitory computer-readable storage medium including a stored control program configured to cause a computer to perform a driving assistance method for a vehicle, the driving assistance method comprising the following steps: On the merging lane that merges with the main lane, an acceleration start point is set before the merging start point where a lane change can be made from the merging lane to the main lane. as well as When the vehicle reaches the acceleration start point, the notification device outputs an acceleration notification prompting the driver to accelerate.

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