Follow-up driving support device, follow-up driving support method, and computer program

Abstract

To stop proposing follow-up traveling without an operation by an occupant of a vehicle when the occupant does not want to use follow-up traveling.SOLUTION: A follow-up traveling support device comprises: an information acquisition part 15 for acquiring information about nearby vehicles 30 in the vicinity of an own vehicle 20; a preceding vehicle selection part 16 for selecting a preceding vehicle which is suitable as a follow-up object for the own vehicle on the basis of the information about the nearby vehicles; and a proposal part 17 for proposing follow-up traveling of the own vehicle to the preceding vehicle to the occupant of the own vehicle. The proposal part stops proposing follow-up traveling if follow-up traveling is not started although follow-up traveling is proposed.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a following driving support device, a following driving support method, and a computer program. [Background technology]

[0002] Patent Document 1 describes that when there is a preceding vehicle ahead of the host vehicle, following travel control is performed to follow the preceding vehicle while maintaining a set inter-vehicle distance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-034917 A Summary of the Invention [Problem to be solved by the invention]

[0004] In following driving, the windshield effect of the preceding vehicle reduces the air resistance acting on the vehicle traveling behind the preceding vehicle, and the fuel consumption or power consumption of the following vehicle is reduced. At this time, the effect of reducing the air resistance varies depending on the characteristics of the preceding vehicle. For example, if the preceding vehicle is a large vehicle, the effect of reducing the air resistance is greater than if the preceding vehicle is a small vehicle.

[0005] For this reason, it is desirable to suggest to the vehicle occupants that they should follow the vehicle ahead so that the effect of following the vehicle ahead can be maximized. However, if the suggestion to follow the vehicle ahead is continuously made to the vehicle occupants who do not wish to follow the vehicle ahead, the vehicle occupants may feel bothered by such a suggestion. In addition, it is inconvenient for the vehicle occupants to perform an operation to cancel the suggestion to follow the vehicle ahead.

[0006] In view of the above problem, an object of the present invention is to discontinue suggestions for follow-up driving when a vehicle occupant does not wish to follow-up driving, without requiring any operation by the occupant. [Means for solving the problem]

[0007] The gist of the present disclosure is as follows.

[0008] (1) A follow-up driving assistance device comprising an information acquisition unit that acquires information about surrounding vehicles around the vehicle, a preceding vehicle selection unit that selects a suitable preceding vehicle as a target for the vehicle to follow based on the information about the surrounding vehicles, and a proposal unit that proposes to an occupant of the vehicle that the vehicle follow the preceding vehicle, wherein if the following driving is not initiated despite the proposal of following driving, the proposal unit cancels the proposal of following driving.

[0009] (2) The following driving support device according to (1) above, wherein the suggestion unit cancels the suggestion to follow the vehicle if the following driving is not started until the suggestion to follow the vehicle has been continued for a predetermined time.

[0010] (3) The following driving support device according to (2) above, wherein the suggestion unit is configured to lengthen the predetermined time period as the suitability of the preceding vehicle as a subject to be followed increases.

[0011] (4) The following driving support device according to (1) above, wherein the suggestion unit stops suggesting the following driving when the following driving has not been started despite the following driving being suggested a predetermined number of times.

[0012] (5) The following driving support device according to (4) above, wherein the suggestion unit increases the predetermined number of times as the suitability of the preceding vehicle as a subject to be followed increases.

[0013] (6) The following driving support device according to any one of (1) to (5) above, wherein the suggestion unit does not make the suggestion to drive along with the vehicle in the next or subsequent trips if the situation in which the following driving is not started despite the suggestion to drive along with the vehicle continues for a predetermined number of trips.

[0014] (7) A following driving support device as described in any one of (1) to (6) above, wherein the proposal unit continues to propose following driving when it is difficult for the vehicle to move behind the leading vehicle, even if the following driving is not started despite the proposal of following driving.

[0015] (8) A following driving support method executed by a computer, comprising: acquiring information about nearby vehicles around a host vehicle; selecting a suitable preceding vehicle as a target for the host vehicle to follow based on the information about the nearby vehicles; suggesting to an occupant of the host vehicle that the host vehicle should follow the preceding vehicle; and, if the following driving is not initiated despite the suggestion of following driving, canceling the suggestion of following driving.

[0016] (9) A computer program that causes a computer to perform the following operations: obtain information about nearby vehicles around a host vehicle; select a suitable preceding vehicle for the host vehicle to follow based on the information about the nearby vehicles; suggest to an occupant of the host vehicle that the host vehicle follow the preceding vehicle; and, if the following driving is not initiated despite the suggestion to follow the preceding vehicle, cancel the suggestion to follow the preceding vehicle. Effect of the Invention

[0017] According to the present invention, when the vehicle occupant does not wish to have the vehicle follow the obstacle, the suggestion to have the vehicle follow the obstacle can be cancelled without requiring any operation by the vehicle occupant. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic configuration diagram of a vehicle control system including an adaptive cruise control device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of a scene in which a plurality of vehicles are traveling on a motorway. [Diagram 3] FIG. 3 is a functional block diagram of the processor of the ECU. [Figure 4] FIG. 4 is a flowchart showing a control routine for the preceding vehicle selection process in the first embodiment. [Diagram 5] FIG. 5 is a flowchart showing a control routine of the following proposal processing in the first embodiment. [Figure 6] FIG. 6 is a flowchart showing a control routine of the following proposal processing in the second embodiment. [Figure 7] FIG. 7 is a flowchart showing a control routine of the following proposal processing in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, like components are designated by like reference numerals.

[0020] First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

[0021] 1 is a schematic configuration diagram of a vehicle control system 1 including an adaptive cruise control device according to a first embodiment of the present invention. The vehicle control system 1 is mounted on a vehicle and performs various controls of the vehicle.

[0022] 1, the vehicle control system 1 includes a surrounding information detection device 2, a Global Navigation Satellite System (GNSS) receiver 3, a map database 4, a navigation device 5, a vehicle behavior detection device 6, an actuator 7, a human machine interface (HMI) 8, a communication device 9, and an electronic control unit (ECU) 10. The surrounding information detection device 2, the GNSS receiver 3, the map database 4, the navigation device 5, the vehicle behavior detection device 6, the actuator 7, the HMI 8, and the communication device 9 are electrically connected to the ECU 10 via an in-vehicle network or the like that complies with a standard such as a Controller Area Network (CAN).

[0023] The surrounding information detection device 2 acquires data (images, point cloud data, etc.) of the surroundings of a vehicle (host vehicle) and detects surrounding information of the vehicle (for example, surrounding vehicles, lanes, etc.). For example, the surrounding information detection device 2 includes a millimeter wave radar, a camera (for example, a stereo camera), a LIDAR (Laser Imaging Detection And Ranging), an ultrasonic sensor (sonar), or any combination of these. The output of the surrounding information detection device 2, i.e., the surrounding information of the vehicle detected by the surrounding information detection device 2, is transmitted to the ECU 10.

[0024] The GNSS receiver 3 detects the current position of the vehicle (e.g., the latitude and longitude of the vehicle) based on positioning information obtained from multiple (e.g., three or more) positioning satellites. Specifically, the GNSS receiver 3 captures multiple positioning satellites and receives radio waves transmitted from the positioning satellites. The GNSS receiver 3 then calculates the distance to the positioning satellite based on the difference between the transmission time and reception time of the radio waves, and detects the current position of the vehicle based on the distance to the positioning satellite and the position (orbit information) of the positioning satellite. The output of the GNSS receiver 3, i.e., the current position of the vehicle detected by the GNSS receiver 3, is transmitted to the ECU 10. A GPS receiver is an example of a GNSS receiver.

[0025] The map database 4 stores map information. The ECU 10 acquires the map information from the map database 4. Note that the map database may be provided outside the vehicle (for example, a server, etc.), and the ECU 10 may acquire the map information from outside the vehicle.

[0026] The navigation device 5 sets a driving route for the vehicle to the destination based on the current position of the vehicle detected by the GNSS receiver 3, map information in the map database 4, input by a vehicle occupant (e.g., the driver), etc. The driving route set by the navigation device 5 is transmitted to the ECU 10.

[0027] The vehicle behavior detection device 6 detects parameters indicating the behavior of the vehicle. The vehicle behavior detection device 6 includes, for example, a vehicle speed sensor that detects the speed of the vehicle, a steering angle sensor that detects the steering angle of the vehicle (the steering angle of the steered wheels), etc. The output of the vehicle behavior detection device 6, i.e., the parameters detected by the vehicle behavior detection device 6, is transmitted to the ECU 10.

[0028] The actuators 7 operate the vehicle. For example, the actuators 7 include a drive device (e.g., at least one of an internal combustion engine and an electric motor) for accelerating the vehicle, a brake actuator for braking the vehicle, a steering actuator for steering the vehicle, etc. The ECU 10 controls the actuators 7 to control the behavior of the vehicle.

[0029] In this embodiment, the vehicle control system 1 functions as an advanced driving assistance system (ADAS) and realizes a predetermined driving assistance function by controlling the actuator 7. The predetermined driving assistance function includes, for example, an adaptive cruise control (ACC) that automatically controls the speed of the vehicle depending on the presence or absence of a preceding vehicle, a lane keeping assist (LKA) that automatically controls the steering of the vehicle so that the vehicle is kept within the lane, or a lane tracing assist (LTA).

[0030] The HMI 8 transmits and receives information between the vehicle and a vehicle occupant (e.g., the driver). The HMI 8 has an output unit (e.g., a display, a speaker, a vibration unit, etc.) that provides information to the vehicle occupant, and an input unit (e.g., a touch panel, an operation button, an operation switch, a microphone, etc.) that inputs information by the vehicle occupant. The output of the ECU 10 is notified to the vehicle occupant via the HMI 8, and the input from the vehicle occupant is transmitted to the ECU 10 via the HMI 8. The HMI 8 is an example of an input device, an output device, or an input / output device. Note that a mobile terminal (a smartphone, a tablet terminal, etc.) of the vehicle occupant may be connected to the ECU 10 in a wired or wireless manner so as to be communicable with the ECU 10 and function as the HMI 8. The HMI 8 may also be integrated with the navigation device 5.

[0031] The communication device 9 is capable of communicating with the outside of the vehicle, and enables communication between the vehicle and the outside of the vehicle. For example, the communication device 9 includes a wide-area communication device that enables wide-area communication between the vehicle and the outside of the vehicle (e.g., a server) via a communication network such as a carrier network or the Internet network, an inter-vehicle communication device that enables inter-vehicle communication between the vehicle and surrounding vehicles using a predetermined frequency band, and a road-to-vehicle communication device that enables road-to-vehicle communication between the vehicle and a roadside unit using the predetermined frequency band.

[0032] The ECU 10 executes various controls of the vehicle. As shown in Fig. 1, the ECU 10 includes a communication interface 11, a memory 12, and a processor 13. The communication interface 11 and the memory 12 are connected to the processor 13 via signal lines. Note that, although one ECU 10 is provided in this embodiment, multiple ECUs may be provided for each function.

[0033] The communication interface 11 has an interface circuit for connecting the ECU 10 to an in-vehicle network. The ECU 10 is connected to other in-vehicle devices via the communication interface 11.

[0034] The memory 12 includes, for example, a volatile semiconductor memory and a non-volatile semiconductor memory. The memory 12 stores programs, data, etc. that are used when the processor 13 executes various processes.

[0035] The processor 13 includes one or more central processing units (CPUs) and their peripheral circuits. The processor 13 may further include an arithmetic circuit such as a logical arithmetic unit or a numerical arithmetic unit.

[0036] In order to reduce the amount of fuel or electricity required for a vehicle to travel, it is effective to reduce the air resistance during travel. One method for reducing air resistance during travel is "follow-up driving," in which a vehicle follows a preceding vehicle. In following-up driving, the windbreak effect of the preceding vehicle reduces the air resistance acting on a vehicle traveling behind the preceding vehicle. Platoon driving, in which multiple vehicles travel in a convoy, is one example of following-up driving.

[0037] Fig. 2 is a diagram showing an example of a scene in which a plurality of vehicles are traveling on a motorway. In the example of Fig. 2, five surrounding vehicles 30 are traveling around the host vehicle 20. In such a situation, the plurality of vehicles (the five surrounding vehicles 30) are candidates for a preceding vehicle of the host vehicle 20 in following traveling.

[0038] When the host vehicle performs following-traveling, it is desirable to select a preceding vehicle in the following-traveling so that the effect obtained by following-traveling is as large as possible. Therefore, in this embodiment, the ECU 10 provided in the host vehicle functions as a following-traveling support device that supports the following-traveling of the host vehicle, and suggests appropriate following-traveling of the preceding vehicle to the occupants of the host vehicle.

[0039] 3 is a functional block diagram of the processor 13 of the ECU 10. In this embodiment, the processor 13 has an information acquisition unit 15, a preceding vehicle selection unit 16, and a proposal unit 17. The information acquisition unit 15, the preceding vehicle selection unit 16, and the proposal unit 17 are functional modules that are realized by the processor 13 of the ECU 10 executing a program stored in the memory 12 of the ECU 10. Note that these functional modules may each be realized by a dedicated arithmetic circuit provided in the processor 13.

[0040] The information acquisition unit 15 acquires information about the surrounding vehicles around the host vehicle. For example, the information acquisition unit 15 acquires information about the surrounding vehicles from the surrounding vehicles around the host vehicle via vehicle-to-vehicle communication.

[0041] The preceding vehicle selection unit 16 selects a preceding vehicle suitable as a target to be followed by the host vehicle based on information about the surrounding vehicles. For example, the preceding vehicle selection unit 16 extracts preceding vehicle candidates traveling in the same direction as the host vehicle from among the surrounding vehicles based on information about the surrounding vehicles, and calculates the suitability of each preceding vehicle candidate as a target to be followed. Then, the preceding vehicle selection unit 16 selects the preceding vehicle candidate with the highest suitability as the preceding vehicle.

[0042] The suggestion unit 17 suggests to the occupant of the host vehicle that the host vehicle should follow the preceding vehicle. For example, the suggestion unit 17 suggests following the preceding vehicle by notifying the occupant of the host vehicle of the preceding vehicle selected by the preceding vehicle selection unit 16 via the HMI 8. However, if following the preceding vehicle is continuously suggested to the occupant of the host vehicle who does not wish to follow the preceding vehicle, the occupant of the host vehicle may feel bothered by such suggestions.

[0043] For this reason, when follow-up driving is not started in response to the suggestion of follow-up driving, the suggestion unit 17 stops the suggestion of follow-up driving. In other words, when follow-up driving is not started despite the suggestion of follow-up driving, the suggestion unit 17 stops the suggestion of follow-up driving. In this way, when the occupant of the host vehicle does not wish to follow-up driving, the suggestion of follow-up driving can be stopped without requiring any operation by the occupant.

[0044] For example, if following-driving is not started within a predetermined time period after the suggestion of following-driving is started, the suggestion unit 17 stops the suggestion of following-driving. In other words, if following-driving is not started before the suggestion of following-driving continues for a predetermined time period, the suggestion unit 17 stops the suggestion of following-driving. This makes it possible to prevent the suggestion of following-driving from being continued to an occupant of the host vehicle who does not wish to follow.

[0045] The above-mentioned control process flow will be described in detail below with reference to Fig. 4 and Fig. 5. Fig. 4 is a flowchart showing a control routine for the preceding vehicle selection process in the first embodiment. This control routine is repeatedly executed by the processor 13 of the ECU 10 at a predetermined execution interval.

[0046] First, in step S101, the preceding vehicle selection unit 16 determines whether or not the execution condition for follow-up driving is satisfied. The execution condition for follow-up driving is determined in advance, and is satisfied, for example, when the ACC is activated. The ACC is activated in response to an operation by an occupant of the host vehicle. The execution condition for follow-up driving may be, for example, that the host vehicle is traveling on a motorway at a speed equal to or greater than a predetermined value. If it is determined in step S101 that the execution condition for follow-up driving is satisfied, this control routine proceeds to step S102.

[0047] In step S102, the information acquisition unit 15 acquires information about the surrounding vehicles around the vehicle through vehicle-to-vehicle communication. Specifically, the information acquisition unit 15 communicates with the surrounding vehicles located within the communication range of the vehicle-to-vehicle communication, and receives information about the surrounding vehicles from the surrounding vehicles. For example, the information transmitted from the surrounding vehicles through the vehicle-to-vehicle communication includes the current positions (latitude and longitude) of the surrounding vehicles, the traveling azimuth of the surrounding vehicles, the speed of the surrounding vehicles, the vehicle width and vehicle length of the surrounding vehicles, etc.

[0048] After step S102, in step S103, the preceding vehicle selection unit 16 extracts preceding vehicle candidates traveling in the same direction as the host vehicle from among the surrounding vehicles, based on the information on the surrounding vehicles.

[0049] Next, in step S104, the preceding vehicle selection unit 16 calculates the suitability of each preceding vehicle candidate as a vehicle to be followed. Basically, the larger the forward projection area of ​​the preceding vehicle candidate, the smaller the air resistance acting on the host vehicle when the host vehicle follows the preceding vehicle candidate, and the greater the effect obtained by following the preceding vehicle candidate. For this reason, the preceding vehicle selection unit 16 calculates the suitability of the preceding vehicle candidate as a vehicle to be followed, for example, based on the forward projection area of ​​the preceding vehicle candidate. The forward projection area is calculated based on the vehicle width and vehicle length using a map or the like, and the suitability is increased as the forward projection area is larger. Note that the vehicle width and vehicle height of the surrounding vehicle may be transmitted to the host vehicle via vehicle-to-vehicle communication, and the forward projection area may be calculated by multiplying the vehicle width by the vehicle height, or the forward projection area of ​​the surrounding vehicle may be transmitted to the host vehicle via vehicle-to-vehicle communication.

[0050] In addition, the suitability of the preceding vehicle candidate as a follow-up target may be calculated based on parameters other than the frontal projection area (e.g., the relative speed between the vehicle and the preceding vehicle candidate, the vehicle speed stability of the preceding vehicle candidate, etc.). In addition, the suitability does not necessarily need to be calculated as a detailed numerical value. For example, the suitability may be expressed as two levels (large and small) or three levels (large, medium and small).

[0051] Next, in step S105, the preceding vehicle selection unit 16 selects the preceding vehicle candidate with the highest suitability as the preceding vehicle. If there are multiple preceding vehicle candidates with the same suitability, for example, the preceding vehicle candidate closest to the vehicle itself is selected as the preceding vehicle. Also, if only one surrounding vehicle is extracted as the preceding vehicle candidate, this surrounding vehicle is selected as the preceding vehicle. After step S105, this control routine ends.

[0052] On the other hand, if it is determined in step S101 that the conditions for performing following driving are not satisfied, this control routine proceeds to step S106. In step S106, the preceding vehicle selection unit 16 resets the proposal flag F to zero. After step S106, this control routine ends.

[0053] In step S102, the information acquisition unit 15 may acquire information about the surrounding vehicles around the host vehicle based on the output of the surrounding information detection device 2 or via road-to-vehicle communication.

[0054] 5 is a flowchart showing a control routine of the following proposal processing in the first embodiment. This control routine is repeatedly executed by the processor 13 of the ECU 10 at a predetermined execution interval.

[0055] First, in step S201, the suggestion unit 17 determines whether or not the preceding vehicle selected by the preceding vehicle selection unit 16 has been changed. If it is determined that the preceding vehicle has been changed, this control routine proceeds to step S202.

[0056] In step S202, the proposal unit 17 sets the proposal flag F to 1. After step S202, this control routine proceeds to step S203. On the other hand, if it is determined in step S201 that the preceding vehicle has not been changed, this control routine skips step S202 and proceeds to step S203.

[0057] In step S203, the proposal unit 17 determines whether or not the proposal flag F is set to 1. If it is determined that the proposal flag F is set to 1, this control routine proceeds to step S204.

[0058] In step S204, the suggestion unit 17 suggests to an occupant (e.g., a driver) of the host vehicle that the host vehicle follow the preceding vehicle. For example, the suggestion unit 17 suggests following the preceding vehicle by notifying the occupant of the host vehicle of the preceding vehicle selected by the preceding vehicle selection unit 16 via the HMI 8. For example, when the surrounding vehicles 30 of the host vehicle 20 are displayed on the display of the HMI 8 as shown in FIG. 2, the suggestion unit 17 displays the surrounding vehicle 30 selected as the preceding vehicle in a display mode (e.g., transparency, brightness, color (hue), color brightness, color saturation, etc.) different from that of the other surrounding vehicles 30. The suggestion unit 17 may notify the occupant of the host vehicle of the preceding vehicle by voice via a speaker of the HMI 8.

[0059] Next, in step S205, the suggestion unit 17 determines whether or not the host vehicle has started following the preceding vehicle. For example, the suggestion unit 17 determines that following travel has started when the host vehicle is located behind the preceding vehicle on the same lane and the distance between the host vehicle and the preceding vehicle is equal to or less than a predetermined value. This determination is made, for example, based on the output of the surrounding information detection device 2. In addition, when the preceding vehicle is located in a lane different from the host vehicle, the suggestion unit 17 may determine that following travel has started when the host vehicle starts to change lanes to the lane of the preceding vehicle. This determination is made, for example, based on the output of the steering angle sensor of the vehicle behavior detection device 6. In addition, the suggestion unit 17 may determine that following travel has started when an occupant of the host vehicle approves the proposal for following travel via the HMI 8.

[0060] If it is determined in step S205 that following driving has not started, this control routine proceeds to step S206. In step S206, the proposal unit 17 determines whether or not a predetermined time has elapsed since the proposal of following driving was started. In other words, the proposal unit 17 determines whether or not the proposal of following driving has continued for a predetermined time. If it is determined in step S206 that the predetermined time has not elapsed, this control routine ends.

[0061] On the other hand, if it is determined in step S205 that the following driving has started, or if it is determined in step S206 that the predetermined time has elapsed, this control routine proceeds to step S207. In step S207, the suggestion unit 17 stops suggesting following driving. For example, the suggestion unit 17 stops notifying the occupants of the host vehicle of the preceding vehicle.

[0062] After step S207, in step S208, the proposal unit 17 resets the proposal flag F to 0. After step S208, this control routine ends.

[0063] Note that instead of continuously proposing to the occupant of the vehicle the following driving, the suggestion unit 17 may intermittently suggest to the occupant of the vehicle the following driving. In this case, for example, in step S206, the suggestion unit 17 determines whether the number of times the following driving has been proposed has reached a predetermined number. That is, if following driving has not been started despite the following driving being proposed a predetermined number of times, the suggestion unit 17 stops proposing following driving. This makes it possible to prevent the following driving from being continuously proposed to the occupant of the vehicle who does not wish to follow driving.

[0064] Second Embodiment The configuration and control of the follow-up driving support device according to the second embodiment are basically the same as those of the follow-up driving support device according to the first embodiment, except for the points described below. Therefore, the second embodiment of the present invention will be described below, focusing on the differences from the first embodiment.

[0065] As described above, if the following driving is not started until the following driving suggestion is continued for a predetermined time, the suggestion unit 17 stops the following driving suggestion. That is, the longer the predetermined time, the longer the time for encouraging the occupants of the vehicle to follow the following driving. Also, the higher the suitability of the preceding vehicle as a subject to be followed, the greater the effect obtained by following the preceding vehicle, and the greater the merit of following the preceding vehicle.

[0066] Therefore, in the second embodiment, the suggestion unit 17 lengthens the continuous suggestion time (predetermined time) until the suggestion of follow-up driving is stopped, the higher the suitability of the preceding vehicle selected by the preceding vehicle selection unit 16 as a follow-up target. This makes it possible to suggest follow-up driving to the vehicle occupants with an appropriate strength according to the effect obtained by follow-up driving.

[0067] In the second embodiment, as in the first embodiment, the control routine of the preceding vehicle selection process in Fig. 4 is executed. Meanwhile, in the second embodiment, the control routine of the following proposal process in Fig. 6 is executed instead of the control routine of the following proposal process in Fig. 5. Fig. 6 is a flowchart showing the control routine of the following proposal process in the second embodiment. This control routine is repeatedly executed at a predetermined execution interval by the processor 13 of the ECU 10.

[0068] 5, in step S301, the suggestion unit 17 determines whether or not the preceding vehicle selected by the preceding vehicle selection unit 16 has been changed. If it is determined that the preceding vehicle has been changed, this control routine proceeds to step S302.

[0069] In step S302, similarly to step S202 in FIG.

[0070] Next, in step S303, the proposing unit 17 sets the predetermined time based on the suitability of the preceding vehicle as a target to be followed, selected by the preceding vehicle selecting unit 16. Specifically, the proposing unit 17 lengthens the predetermined time as the suitability is higher. The proposing unit 17 acquires the value already calculated by the preceding vehicle selecting unit 16 in step S104 of FIG. 4 as the suitability of the preceding vehicle as a target to be followed.

[0071] After step S303, the control routine proceeds to step S304. On the other hand, if it is determined in step S301 that the preceding vehicle has not been changed, the control routine skips steps S302 and S303 and proceeds to step S304.

[0072] Steps S304 to S309 are executed in the same manner as steps S203 to S208 in Fig. 5. At this time, the value set in step S303 is used as the predetermined time in step S306.

[0073] As in the first embodiment, the suggestion unit 17 may stop suggesting follow-up driving if follow-up driving has not been started despite the follow-up driving being suggested a predetermined number of times. In this case, the suggestion unit 17 increases the number of suggestions (predetermined number of times) until the suggestion of follow-up driving is stopped, the higher the suitability of the preceding vehicle selected by the preceding vehicle selection unit 16 as a follow-up target. This makes it possible to suggest follow-up driving to the vehicle occupants with an appropriate strength according to the effect obtained by follow-up driving.

[0074] <Third embodiment> The configuration and control of the following driving support device according to the third embodiment are basically the same as those of the following driving support device according to the first embodiment, except for the points described below. Therefore, the following description of the third embodiment of the present invention will focus on the differences from the first embodiment.

[0075] As described above, if following driving is not started despite the suggestion of following driving, it is determined that the vehicle occupants do not wish to follow the preceding vehicle, and the suggestion of following driving is canceled. However, even if the vehicle occupants wish to follow driving, if it is difficult for the host vehicle to move behind the preceding vehicle, following driving is not started. In such a situation, it is not appropriate to cancel the suggestion of following driving against the will of the vehicle occupants.

[0076] For this reason, in the third embodiment, even if following driving is not started despite the suggestion of following driving, when it is difficult for the host vehicle to move behind the leading vehicle, the suggestion unit 17 continues the suggestion of following driving. This makes it possible to prevent the suggestion of following driving from being stopped against the will of the vehicle occupants.

[0077] In the third embodiment, as in the first embodiment, the control routine of the preceding vehicle selection process in Fig. 4 is executed. Meanwhile, in the third embodiment, the control routine of the following proposal process in Fig. 7 is executed instead of the control routine of the following proposal process in Fig. 5. Fig. 7 is a flowchart showing the control routine of the following proposal process in the third embodiment. This control routine is repeatedly executed at a predetermined execution interval by the processor 13 of the ECU 10.

[0078] Steps S401 to S406 are executed in the same manner as steps S201 to S206 in Fig. 5. If it is determined in step S406 that the predetermined time has elapsed, this control routine proceeds to step S407.

[0079] In step S407, the suggestion unit 17 determines whether it is difficult for the host vehicle to move behind the preceding vehicle. For example, when the preceding vehicle is located behind the host vehicle, the suggestion unit 17 determines that it is difficult for the host vehicle to move behind the preceding vehicle. In addition, when there is no space of a predetermined distance behind the preceding vehicle in the lane in which the preceding vehicle is traveling, the suggestion unit 17 determines that it is difficult for the host vehicle to move behind the preceding vehicle. In addition, when the distance from the current position of the host vehicle to the merging point or the branching point is within a predetermined distance, the suggestion unit 17 determines that it is difficult for the host vehicle to move behind the preceding vehicle. The determination in step S407 is made based on, for example, the output of the surrounding information detection device 2, the output of the GNSS receiver 3, information received from surrounding vehicles via vehicle-to-vehicle communication, information received from a roadside device via road-to-vehicle communication, and the like.

[0080] If it is determined in step S407 that it is difficult for the host vehicle to move behind the leading vehicle, this control routine ends. On the other hand, if it is determined in step S407 that it is not difficult for the host vehicle to move behind the leading vehicle, this control routine proceeds to step S408. In this case, the suggestion unit 17 stops proposing follow-up driving in step S408, and resets the suggestion flag F to zero in step S409. After step S409, this control routine ends.

[0081] <Fourth embodiment> The configuration and control of the follow-up driving support device according to the fourth embodiment are basically the same as the configuration and control of the follow-up driving support device according to the first embodiment, except for the points described below. Therefore, the following description of the fourth embodiment of the present invention will focus on the differences from the first embodiment.

[0082] If the occupant of the host vehicle has no intention of following the vehicle, it is assumed that the occupant of the host vehicle will continue to ignore the suggestion to follow the vehicle. In such a case, repeating the suggestion to follow the vehicle and then canceling the suggestion may cause discomfort to the occupant of the vehicle.

[0083] For this reason, in the fourth embodiment, if a situation where following driving is not started despite the suggestion of following driving continues for a predetermined number of trips, the suggestion unit 17 does not suggest following driving in the next trip and thereafter. This makes it possible to prevent the following driving from being repeatedly suggested to the occupants of the vehicle who have no intention of following driving. Note that a trip refers to the period from when the ignition switch of the vehicle is turned on to when the ignition switch of the vehicle is turned off.

[0084] In the fourth embodiment, similarly to the first embodiment, the control routine of the preceding vehicle selection process in FIG. 4 and the control routine of the following proposal process in FIG. 5 are executed. In the fourth embodiment, the execution condition of the following-traveling used in the judgment of step S101 in FIG. 4 includes that the situation where following-traveling is not started despite the proposal of following-traveling has not continued for a predetermined number of trips. In other words, if the situation where following-traveling is not started despite the proposal of following-traveling has continued for a predetermined number of trips, it is determined that the execution condition of the following-traveling is not satisfied. As a result, the proposal flag F is reset to zero in step S106 in FIG. 4, and the proposal of following-traveling by the proposal unit 17 is prohibited.

[0085] <Other embodiments> Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

[0086] For example, the vehicle in which the following driving support device is installed may be a manually driven vehicle that does not have a driving support function. In this case, the acceleration and deceleration of the vehicle during following driving is controlled by the driver of the vehicle. Also, the vehicle in which the following driving support device is installed may be a fully automated vehicle in which the acceleration, steering, and deceleration (braking) of the vehicle are all performed automatically. In this case, when the vehicle occupant accepts the proposal for following driving via the HMI 8, following driving is automatically started.

[0087] Furthermore, a computer program that causes a computer to realize the functions of each unit of the processor 13 of the ECU 10 may be provided in a form stored in a computer-readable recording medium. The computer-readable recording medium is, for example, a magnetic recording medium, an optical recording medium, or a semiconductor memory.

[0088] In addition, the above-described embodiments can be implemented in any combination. For example, when the third embodiment is combined with the second embodiment, steps S302 and S303 in FIG. 6 are executed instead of step S402 in the control routine of the following proposal process in FIG. [Explanation of symbols]

[0089] 10 Electronic Control Unit (ECU) 13 Processors 15 Information acquisition department 16 Leading vehicle selection section 17 Proposal Department 20 Vehicle 30 Nearby vehicles

Claims

1. An information acquisition unit that acquires information about surrounding vehicles around the host vehicle; a preceding vehicle selection unit that selects a preceding vehicle suitable as a follow-up target for the host vehicle based on information about the surrounding vehicles; a suggestion unit that suggests to an occupant of the host vehicle that the host vehicle should follow the preceding vehicle; Equipped with When the following driving is not started despite the suggestion of the following driving, the suggestion unit cancels the suggestion of the following driving; The following driving support device, wherein the suggestion unit continues to suggest following driving when it is difficult for the host vehicle to move behind the preceding vehicle, even if following driving is not started despite the suggestion of following driving.

2. The following driving support device according to claim 1 , wherein the suggestion unit stops suggesting the following driving when the following driving is not started until the suggestion of the following driving is continued for a predetermined time.

3. An information acquisition unit that acquires information about surrounding vehicles around the host vehicle; a preceding vehicle selection unit that selects a preceding vehicle suitable as a follow-up target for the host vehicle based on information about the surrounding vehicles; a suggestion unit that suggests to an occupant of the host vehicle that the host vehicle should follow the preceding vehicle; Equipped with The suggestion unit stops the suggestion of following the vehicle if the following driving has not started until the suggestion of following the vehicle has been continued for a predetermined time, The suggestion unit is configured to lengthen the predetermined time period as the suitability of the preceding vehicle as a vehicle to be followed increases.

4. 2. The following driving support device according to claim 1, wherein the suggestion unit is configured to stop suggesting the following driving when the following driving has not been started despite the following driving being suggested a predetermined number of times.

5. An information acquisition unit that acquires information about surrounding vehicles around the host vehicle; a preceding vehicle selection unit that selects a preceding vehicle suitable as a follow-up target for the host vehicle based on information about the surrounding vehicles; a suggestion unit that suggests to an occupant of the host vehicle that the host vehicle should follow the preceding vehicle; Equipped with The suggestion unit stops suggesting the following driving when the following driving has not been started despite the following driving being suggested a predetermined number of times, The suggestion unit increases the predetermined number of times as the suitability of the preceding vehicle as a target to be followed increases.

6. 6. The following driving support device according to claim 1, wherein the suggestion unit is configured to not make the suggestion to follow the vehicle in a next or subsequent trip if a situation in which the following driving is not started despite the suggestion to follow the vehicle continues for a predetermined number of trips.

7. 6. The following driving support device according to claim 3, wherein the suggestion unit continues to suggest the following driving when it is difficult for the host vehicle to move behind the preceding vehicle, even if the following driving is not started despite the suggestion of the following driving.

8. A method for assisting following vehicles, the method comprising: Obtaining information about surrounding vehicles around the host vehicle; selecting a preceding vehicle suitable as a follow-up target for the host vehicle based on information about the surrounding vehicles; Proposing to an occupant of the host vehicle that the host vehicle follow the preceding vehicle; If the following driving has not been started despite the suggestion of the following driving, canceling the suggestion of the following driving; Even if the following driving is not started despite the suggestion of following driving, when it is difficult for the host vehicle to move behind the preceding vehicle, the suggestion of following driving is continued. The following driving support method includes:

9. Obtaining information about surrounding vehicles around the host vehicle; selecting a preceding vehicle suitable as a follow-up target for the host vehicle based on information about the surrounding vehicles; Proposing to an occupant of the host vehicle that the host vehicle follow the preceding vehicle; If the following driving has not been started despite the suggestion of the following driving, canceling the suggestion of the following driving; Even if the following driving is not started despite the suggestion of following driving, when it is difficult for the host vehicle to move behind the preceding vehicle, the suggestion of following driving is continued. A computer program that causes a computer to execute the following:

Images