Driving control method and driving control device

Abstract

In the driving control method of the present invention, a driving control device is used to control the driving of the vehicle through at least two automatic driving modes with different driving assistance levels. When the driving control device controls the driving of the vehicle through the first mode, when a leading vehicle is detected traveling in front of the vehicle, the automatic driving mode is changed from the first mode to a second mode with a higher driving assistance level than the first mode.

Description

Technical Field

[0001] The invention relates to a driving control method and a driving control device. Background Art

[0002] The automatic driving mode set by the vehicle control device described in Patent Document 1 includes a first level and a second level in which the degree of driver intervention is lower than the first level. The vehicle control device of Patent Document 1 changes the automatic driving mode to the first level when it is determined that the driving environment when the vehicle is controlled in the second level automatic driving mode is a prescribed driving environment such as driving on a low μ road with snow or ice.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2019 / 003294

[0006] Problems to be solved by the invention

[0007] However, the vehicle control device of Patent Document 1 has a problem in that the assistance level of the automatic driving needs to be lowered from the second level to the first level according to changes in the driving environment. Summary of the invention

[0008] An object of the present invention is to provide a driving control method and a driving control device capable of creating a large number of environments in which a host vehicle can travel at a relatively high driving assistance level.

[0009] The driving control method and driving control device of the present invention solve the above-mentioned problems by switching the automatic driving mode to a mode with a relatively high driving assistance level when a preceding vehicle traveling ahead of the host vehicle is detected.

[0010] Effects of the Invention

[0011] According to the present invention, since the host vehicle travels following the preceding vehicle on the path that the preceding vehicle has already traveled, it is possible to create an environment in which the host vehicle travels in the automatic driving mode with a relatively high driving assistance level. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a block diagram showing the structure of the driving control device according to the first embodiment of the present invention.

[0013] Figure 2 Yes means Figure 1 A flowchart of the procedure of the driving control method of the driving control device shown.

[0014] Figure 3 Yes means Figure 2 FIG. 1 is a diagram showing an example of the positional relationship between the host vehicle and the preceding vehicle in the driving control method shown.

[0015] Figure 4 This is a flowchart showing the procedure of a driving control method of the driving control device according to the second embodiment of the present invention.

[0016] Figure 5 Yes means Figure 4 FIG. 1 is a diagram showing an example of the positional relationship between the host vehicle and the first preceding vehicle and the second preceding vehicle in the driving control method shown.

[0017] Figure 6 It means in Figure 4 FIG. 1 is a diagram showing an example of the positional relationship between the host vehicle and the first and second preceding vehicles when only the first preceding vehicle changes lanes in the driving control method shown.

[0018] Figure 7 It means in Figure 4 FIG. 1 is a diagram showing an example of the positional relationship between the host vehicle and the preceding vehicle and the second preceding vehicle when the first preceding vehicle and the second preceding vehicle change lanes in the driving control method shown. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0020] (First Embodiment)

[0021] based on Figures 1 to 4 A first embodiment will be described.

[0022] Figure 1 1 is a block diagram showing the structure of the driving control device 1 of this embodiment. The driving control device 1 of this embodiment is also an embodiment of the driving control method of the present invention. Figure 1 As shown, the driving control device 1 of the vehicle of the present embodiment comprises: a preceding vehicle detection unit 11, a vehicle position detection device 12, a map database 13, an on-board device 14, a prompt device 15, an input device 16, a drive control device 17, and a control device 18. These devices are connected via an on-board LAN such as a CAN (Controller Area Network) in order to send and receive information to each other.

[0023] The preceding vehicle detection unit 11 detects another vehicle traveling in front of the vehicle, that is, the preceding vehicle. The preceding vehicle detection unit 11 includes either or both of a front camera that captures the front of the vehicle or a front radar that detects the preceding vehicle and obstacles in front of the vehicle. In addition, the preceding vehicle detection unit 11 includes a history information receiving unit 11a that can receive the travel history information of other vehicles. The detection result of the preceding vehicle detection unit 11 is output to the control device 18 at a predetermined time interval.

[0024] The vehicle position detection device 12 is composed of a GPS unit, a gyro sensor, a vehicle speed sensor, etc. The vehicle position detection device 12 detects radio waves sent from multiple communication satellites through the GPS unit, periodically obtains the position information of the target vehicle (the vehicle), and detects the current position of the target vehicle based on the acquired position information of the target vehicle, the angle change information obtained from the gyro sensor, and the vehicle speed obtained from the vehicle speed sensor. The position information of the target vehicle detected by the vehicle position detection device 12 is output to the control device 18 at a predetermined time interval.

[0025] The map database 13 is a memory that stores three-dimensional high-precision map information including location information of various facilities and specific locations, and is configured to be accessible from the control device 18. High-precision digital map information (high-precision map, dynamic map) is stored in the map database 13. In this example, the stored high-precision map information is three-dimensional map information based on the road shape including altitude information detected when the vehicle using the data acquisition is traveling on the actual road. The high-precision map information includes identification information of multiple lanes on the road. The map information in the map database 13 includes three-dimensional location information about roads and / or curved roads and the size of the curve (such as curvature or curvature radius), merging points, branching points, and locations where the number of lanes is reduced. The high-precision map information also includes information related to facilities such as service areas / parking areas.

[0026] The vehicle-mounted devices 14 are various devices mounted on the vehicle and are operated by the driver. The vehicle-mounted devices 14 include a steering wheel 14a. In addition, other vehicle-mounted devices 14 include an accelerator pedal, a brake pedal, a navigation device, a direction indicator, a wiper, a light, an electric horn, and other specific switches. When the vehicle-mounted device 14 is operated by the driver, the information is output to the control device 18.

[0027] The prompt device 15 is, for example, a display included in a navigation device, a display incorporated in a rearview mirror inside the vehicle, a display incorporated in an instrument unit, a head-up display projected onto the front windshield, a speaker included in an audio device, a seat device embedded with a vibrator, etc. The prompt device 15 notifies the driver of the prompt information and lane change information described below in accordance with the control of the control device 18.

[0028] The input device 16 is, for example, a push button switch that can perform input by manual operation of the driver, a touch panel arranged on a display screen, or a microphone that can perform input by voice of the driver.

[0029] The drive control device 17 controls the driving of the vehicle. For example, the drive control device 17 controls the action of the drive mechanism for adjusting the acceleration and deceleration and the vehicle speed (including the action of the internal combustion engine in an engine car, the action of the driving motor in an electric car system, and the torque distribution between the internal combustion engine and the driving motor in a hybrid car) and the braking action through the autonomous speed control function. In addition, the drive control device 17 controls the action of the steering actuator through the autonomous steering control function, thereby performing the steering control of the vehicle. For example, the drive control device 17 detects the lane marking of the lane in which the vehicle is traveling, and controls the driving position (lateral position) of the vehicle in the width direction so that it travels in the center of the lane in which the vehicle is traveling. In addition, the drive control device 17 controls the vehicle to overtake the preceding vehicle or change the driving direction, etc. Furthermore, the drive control device 17 performs driving control for turning right or left at intersections, etc. In addition, other known methods can also be used as the driving control method of the drive control device 17.

[0030] The control device 18 is composed of a ROM (Read Only Memory) storing a program for controlling the driving of the vehicle, a CPU (Central Processing Unit) executing the program stored in the ROM, and a RAM (Random Access Memory) functioning as an accessible storage device. In addition, as an operating circuit, an MPU (MicroProcessing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. may be used instead of or in addition to the CPU (Central Processing Unit).

[0031] The control device 18 obtains driving information related to the driving state of the host vehicle. For example, the control device 18 obtains image information of the exterior of the vehicle captured by the front camera and the rear camera, or detection results of the front radar, the rear radar, and the side radar as driving information. In addition, the control device 18 also obtains the vehicle speed information of the host vehicle detected by the vehicle speed sensor and the image information of the driver's face captured by the in-vehicle camera as driving information.

[0032] In addition, the control device 18 obtains information on the current position of the vehicle as driving information from the vehicle position detection device 12. In addition, the control device 18 obtains position information on curved roads and the size of the curve (e.g., curvature or curvature radius), merging points, branch points, toll booths, lane reduction positions, service areas (SA) / parking areas (PA), etc. as driving information from the map database 13. In addition, the control device 18 obtains information on the driver's operation of the onboard device 14 from the onboard device 14 as driving information.

[0033] Furthermore, the control device 18 autonomously controls the speed and steering of the vehicle by using the autonomous driving control function by executing the program stored in the ROM through the CPU. The control device 18 transmits a control instruction based on the autonomous driving control function to the drive control device 17.

[0034] In addition, the control device 18 can set an automatic driving mode corresponding to the driving assistance level (driving assistance level), and can assist the driving of the vehicle by the set automatic driving mode. The driving assistance level is a level indicating the degree of intervention when the driving control device 1 assists the driving of the vehicle through the autonomous driving control function. The higher the driving assistance level, the lower the driver's contribution to the driving of the vehicle. Specifically, the driving assistance level can be set using the definition of SAE J3016 based on the American Automobile Technology Association (SAE: Society of Automotive Engineers). In driving assistance level 0, all driving operations of the vehicle are performed manually by the driver. In driving assistance level 1, the driving operation of the vehicle is mainly manual driving by the driver, but the drive control device 17 appropriately assists the driver's manual driving through any one of the functions such as automatic braking, following, and lane keeping. In driving assistance level 2, the driving operation of the vehicle is mainly manual driving by the driver, but under certain conditions, the drive control device 17 can combine multiple functions such as automatic braking, following, and lane keeping to perform driving assistance. In driving assistance level 3, the drive control device 17 performs all driving tasks, but the driver needs to return to control and prepare for manual driving when there is a request from the driving control device 1. In driving assistance level 4, the driver's manual driving is not required, and the drive control device 17 can perform all driving tasks under specific conditions and monitor the surrounding conditions of the vehicle. In driving assistance level 5, the drive control device 17 can perform all driving tasks under all conditions.

[0035] In addition, the classification of driving assistance levels is not limited to the classification based on the definition of the American Automobile Technology Association, and the driving assistance levels can also be defined based on ISO / TC204 of the International Organization for Standardization (ISO). In addition, the classification of driving assistance levels can also be defined based on other criteria as long as it is appropriately classified according to the degree of intervention of the driving control device 1.

[0036] The control device 18 can set the first mode corresponding to the driving assistance level 2 and the second mode corresponding to the driving assistance level 3 as the automatic driving mode. When the automatic driving mode is set to the first mode, the driver needs to visually monitor the surrounding conditions of the vehicle. The first mode is the handheld mode. The handheld mode refers to a mode in which the autonomous steering control of the control device 18 does not operate when the driver does not hold the steering wheel 14a. In addition, whether the driver holds the steering wheel 14a is detected by a touch sensor (not shown) provided on the steering wheel 14a or a steering torque sensor (not shown) of the EPS.

[0037] In addition, “the driver holds the steering wheel 14 a ” includes not only a state in which the driver tightly grips the steering wheel 14 a , but also a state in which the driver lightly places his hands on the steering wheel 14 a .

[0038] On the other hand, when the automatic driving mode is set to the second mode, the system of the driving control device 1 uses a camera, a radar, etc. to monitor the surrounding conditions of the vehicle. That is, when the automatic driving mode is set to the second mode, the driving environment around the vehicle is automatically monitored by the system of the driving control device 1. In addition, the second mode is the hands-off mode. The hands-off mode refers to a mode in which the steering control of the control device 18 is activated even if the driver takes his hands off the steering wheel 14a. In addition, the steering control of the control device 18 is performed by the drive control device 17 as described above.

[0039] The relationship between the first mode and the second mode is that as long as the second mode has a relatively higher driving assistance level than the first mode, the driving assistance level corresponding to each automatic driving mode is not limited to driving assistance level 2 and driving assistance level 3. In addition, in addition to the first mode and the second mode, the control device 18 can also set other automatic driving modes corresponding to different driving assistance levels. In this embodiment, a mode with a lower driving assistance level than the first mode can be set, and a mode with a higher driving assistance level than the second mode can also be set. It is also possible to set one or more modes between the first mode and the second mode, wherein the driving assistance level is higher than the first mode and the driving assistance level is lower than the second mode.

[0040] Although not particularly limited, the driving control device 1 of the present embodiment performs an autonomous driving function of an automatic driving mode that can switch between a handheld mode of a first mode and a hands-off mode of a second mode. The autonomous steering control function in the autonomous driving function effectively utilizes the switching of the handheld mode / hands-off mode. The autonomous steering control function is a function of assisting the driver's steering wheel operation by performing steering control of the vehicle by controlling the action of the steering actuator. The autonomous steering control function includes, for example: a lane center maintaining function that controls the steering gear in a manner of driving near the center of the lane; a lane keeping function that controls the lateral position in a manner of driving in the same lane; a lane change assist function that moves from the lane being driven to other lanes; an overtaking assist function that moves forward through the lateral side (adjacent lane) of other vehicles in front; and a route driving assist function that autonomously changes lanes in order to pursue a route to the destination, etc.

[0041] Although not particularly limited, the driving control device 1 of the present embodiment performs the above-mentioned autonomous steering control function in the hands-off mode when any one or more or all of the following conditions are met. In other words, when some or all of the following conditions are met, the autonomous steering function can be performed even in the hands-off mode of the second mode, that is, when the driver takes his hands off the steering wheel.

[0042] As an example, the transition condition to the hands-off mode in the lane center keeping function is shown below.

[0043] The vehicle is being driven on a road reserved for automobiles.

[0044] Driving on a road that is structurally separated from the oncoming lane.

[0045] Equipped with high-precision maps, driving on roads where high-precision map information can be effectively used.

[0046] Drive below the speed limit.

[0047] Driving on a road where the speed limit is a specified speed (e.g. 60 km / h) or higher.

[0048] ·Global Positioning Satellite System: GNSS (Global Navigation Satellite System) signals are available.

[0049] The driver monitoring camera recognizes the driver and detects that the driver is visually recognizing the front.

[0050] The driver faces forward.

[0051] · It is confirmed that there are no toll gates, car-only road exits, merges, intersections, or places with reduced lanes near the current location (e.g., within about 800 meters ahead).

[0052] There is no sharp curve of less than 100R near the current position (e.g., within about 500m ahead).

[0053] The accelerator pedal is not depressed.

[0054] No abnormality was detected by radar, sonar, vehicle perimeter monitoring camera, or driver monitoring camera.

[0055] During execution of the lane center keeping function using the hands-off mode, if at least one of the above conditions is not satisfied, switching to the lane center keeping function using the hand-off mode is executed.

[0056] The conditions for allowing the hands-off mode as the second mode can be defined for each autonomous driving function (lane keeping function, lane change assist function, overtaking assist function, or route driving assist function). Of course, it is a prerequisite that the conditions for enabling the activation of each autonomous driving function are met.

[0057] Next, based on Figure 2 and Figure 3 The procedure of the driving control method of the driving control device 1 is described. Figure 3 3 shows the host vehicle 10 traveling in the first lane 31 and the preceding vehicle 21 traveling in front of the host vehicle 10 .

[0058] like Figure 2 As shown, first, the driving control device 1 determines in step S1 whether the automatic driving mode of the host vehicle 10 is the first mode. When the automatic driving mode of the host vehicle 10 is not the first mode, this control ends.

[0059] On the other hand, when the automatic driving mode of the host vehicle 10 is the first mode, the control moves to step S2. In step S2, the driving control device 1 determines whether the vehicle speed of the host vehicle 10 is above a predetermined speed. When the vehicle speed of the host vehicle 10 is above a predetermined speed, the automatic driving mode is not changed and the control ends.

[0060] In addition, the prescribed speed refers to the upper limit of the speed that the driving control device 1 or the driver can instantly respond to even when the leading vehicle 21 performs an emergency deceleration or emergency stop when the automatic driving mode of the host vehicle 10 is set to the second mode. The prescribed speed can be set through experiments. The "prescribed speed" in this case is a speed of 100 to 130 km / h, which can be defined according to the performance of the host vehicle 10, etc.

[0061] In addition, if Figure 2 As shown by the dotted line, in step S1, when it is determined that the automatic driving mode of the host vehicle 10 is the first mode, the control may be transferred to step S3 described later without passing through step S2.

[0062] In step S2, when it is determined that the speed of the vehicle 10 is less than the prescribed speed, the control moves to step S3. In step S3, the driving control device 1 determines whether the preceding vehicle detection unit 11 detects the preceding vehicle 21 traveling in front of the vehicle 10. That is, the driving control device 1 determines whether the preceding vehicle 21 traveling in front of the vehicle 10 is detected. The preceding vehicle detection unit 11 detects the presence of the preceding vehicle 21 based on the image information captured by the front camera or the detection result of the front radar. The preceding vehicle 21 is a vehicle traveling near the front of the vehicle 10. In addition, the history information receiving unit 11a of the preceding vehicle detection unit 11 receives the driving history information of other vehicles through vehicle-to-vehicle communication, road-to-vehicle communication or other infrastructure information communication units. The driving history information is information that corresponds the position information and time information of other vehicles passing through. The driving history information can be collected at a prescribed period, can be collected based on the transmission from other vehicles, or can be collected within a limited range of positions. Moreover, when the driving history information includes information indicating that other vehicles have traveled at a location in front of the vehicle 10 before a specified time (for example, within a specified time from the current moment), the presence of other vehicles traveling in front of the vehicle 10, that is, the preceding vehicle 21, is detected. When the preceding vehicle 21 is not detected in front of the vehicle 10, the control moves to step S7. Then, in step S7, the driving control device 1 performs control not to change the automatic driving mode to the second mode. The control not to change the automatic driving mode to the second mode includes: control to maintain the automatic driving mode in the first mode, and control to change the automatic driving mode to other modes with a lower driving assistance level than the first mode. Here, "other modes with a lower driving assistance level than the first mode" is, for example, a third mode that only performs part of the driving operation.

[0063] The predetermined time is, for example, 5 seconds, but is not limited thereto, and may be a time of several seconds to several tens of seconds. The predetermined time is preferably a time within 1 minute.

[0064] In addition, the "previous vehicle 21 traveling in front of the present vehicle 10" is not limited to other vehicles that travel ahead of the present vehicle 10 in the first lane 31 in which the present vehicle 10 is currently traveling. That is, the previous vehicle 21 may also be another vehicle traveling in a predetermined lane in which the present vehicle 10 will travel thereafter. For example, in a case where the present vehicle 10 is scheduled to change lanes in a few seconds along a predetermined driving route, if there are other vehicles in the second lane 32 at the lane change destination, the other vehicles can be detected as the "previous vehicle 21 traveling in front of the present vehicle 10". In addition, in a case where the present vehicle 10 is scheduled to turn right or left at a branch road or intersection in a few seconds, if there are other vehicles at the right turn destination or the left turn destination, the other vehicles can be detected as the "previous vehicle 21 traveling in front of the present vehicle 10".

[0065] In addition, the upper limit distance of the detectable distance D from the host vehicle 10 to the preceding vehicle 21 is longer than the upper limit distance of the followable distance from the host vehicle 10 to the preceding vehicle 21 when the following driving of the preceding vehicle 21 is performed using the first mode. In the case of following driving using the first mode with a relatively low driving assistance level, the upper limit distance of the followable distance is set for the purpose of driving the host vehicle 10 in conjunction with the action of the preceding vehicle 21. On the other hand, in the present embodiment, the upper limit distance of the detectable distance D from the preceding vehicle 21 is set for the purpose of confirming that the host vehicle 10 is traveling behind the preceding vehicle 21 and there are no obstacles on the path (lane) to be traveled thereafter. Depending on the purpose, the "upper limit distance of the detectable distance D from the preceding vehicle 21" as a condition for transitioning to the second mode with a relatively high driving assistance level is set to be longer than the upper limit distance of the followable distance.

[0066] Here, "performing the following driving of the preceding vehicle 21" means that the driving control device 1 controls the driving of the host vehicle 10 so as to be linked with the movement of the preceding vehicle 21, and controls the vehicle speed of the host vehicle 10 so as to keep a certain distance between the host vehicle 10 and the preceding vehicle 21. On the other hand, "the host vehicle 10 travels behind the preceding vehicle 21" means that the host vehicle 10 travels from behind the preceding vehicle 21 on the travel path that the preceding vehicle 21 has traveled, regardless of whether the following driving of the preceding vehicle 21 is performed or not. That is, when the host vehicle 10 travels behind the preceding vehicle 21, the following driving of the preceding vehicle 21 may be performed or not.

[0067] In addition, the upper limit distance of the followable distance can be set based on the distance at which the host vehicle 10 and the preceding vehicle 21 can communicate with each other. Therefore, the upper limit distance D of the detectable distance D from the host vehicle 10 to the preceding vehicle 21 that can be detected by the preceding vehicle detection unit 11 of the driving control device 1 can be made longer than the upper limit distance at which the host vehicle 10 and the preceding vehicle 21 can communicate with each other. The upper limit distance of the detectable distance D from the preceding vehicle 21 that can be detected by the preceding vehicle detection unit 11 is, for example, 100 meters, but is not limited thereto. In addition, the upper limit distance at which the host vehicle 10 and the preceding vehicle 21 can communicate with each other is, for example, 50 meters, but is not limited thereto.

[0068] Next, in step S3, when the preceding vehicle 21 is detected in front of the host vehicle 10, the driving control device 1 calculates the reliability of the preceding vehicle 21 in step S4. The reliability of the preceding vehicle 21 is a reference indicating the driving stability of the preceding vehicle 21. The reliability of the preceding vehicle 21 is calculated based on the behavior of the preceding vehicle 21. Specifically, the reliability of the preceding vehicle 21 is calculated based on at least one of the lateral displacement amount, the frequency of acceleration and deceleration, and the flashing frequency of the brake light of the preceding vehicle 21. The lateral displacement amount, the frequency of acceleration and deceleration, and the flashing frequency of the brake light of the preceding vehicle 21 are calculated as values ​​in a predetermined time or a predetermined distance, respectively. The greater the lateral displacement amount of the preceding vehicle 21, the higher the frequency of acceleration and deceleration, or the higher the flashing frequency of the brake light, the more it is evaluated that the driving of the preceding vehicle 21 is unstable and the reliability is lower. On the other hand, the relatively small lateral displacement amount of the preceding vehicle 21, the relatively low frequency of acceleration and deceleration, or the relatively low flashing frequency of the brake light, the more it is evaluated that the driving of the preceding vehicle 21 is stable and the reliability becomes high. The driving control device 1 may assign scores to the lateral displacement amount, acceleration / deceleration frequency, and brake light flashing frequency of the leading vehicle 21 , and calculate the reliability of the leading vehicle 21 based on the total of the scores.

[0069] On the other hand, when the preceding vehicle 21 is not detected in front of the host vehicle 10 in step S3 , the control proceeds to step S7 , and the driving control device 1 performs control not to change the automatic driving mode to the second mode.

[0070] In addition, in step S3, when the preceding vehicle 21 is detected in front of the host vehicle 10, Figure 2As shown by the dotted line, the control moves to step S6, and the driving control device 1 may also change the automatic driving mode from the first mode to the second mode. The driving control device 1 determines that as long as it is the path traveled by the preceding vehicle 21, there is a high possibility that the present vehicle 10 can travel on the path without encountering obstacles / obstructions, and the assistance level of the automatic driving can be improved. In the present embodiment, the condition that the preceding vehicle 21 is detected in front of the present vehicle 10 is used to re-find / produce an environment in which automatic driving in a mode with a relatively high assistance level can be performed. As a result, the driving control device 1 of the present embodiment can increase the conditions that enable the present vehicle 10 to smoothly drive automatically in a state with a high driving assistance level, and can reduce the burden on the driver.

[0071] Next, the driving control device 1 determines in step S5 whether the reliability of the preceding vehicle 21 is greater than a predetermined value. The predetermined value is a lower limit value of the reliability, indicating that the driving of the preceding vehicle 21 is stable to the extent that the host vehicle 10 can smoothly drive behind the preceding vehicle 21 when the automatic driving mode is set to the second mode. If it is determined that the reliability of the preceding vehicle 21 is less than the predetermined value, the control moves to step S7, and the driving control device 1 performs control so that the automatic driving mode is not switched to the second mode.

[0072] On the other hand, when it is determined in step S5 that the reliability of the preceding vehicle 21 is equal to or greater than the predetermined value, the driving control device 1 changes the automatic driving mode from the first mode to the second mode in step S6 , and the control ends.

[0073] As described above, in the driving control device 1 and the driving control method of the present embodiment, when the driving of the host vehicle 10 is controlled by the first mode, when the preceding vehicle detection unit 11 detects the presence of the preceding vehicle 21 traveling in front of the host vehicle 10, the automatic driving mode is changed from the first mode to the second mode. This is because the driving control device 1 can determine that as long as it is a path that the preceding vehicle 21 has traveled, the possibility of a failure / obstruction when the host vehicle 10 travels on the path is low, and the driving assistance level of the automatic driving can be improved. In this way, according to the situation that the preceding vehicle 21 travels in front of the host vehicle 10, it is inferred that there are no obstacles that hinder the travel of the host vehicle 10, or construction areas that require lane changes, etc. in the planned path for the host vehicle 10 to travel thereafter. Therefore, it can be expected that the host vehicle 10 can improve the driving assistance level of the automatic driving mode and can travel smoothly behind the preceding vehicle 21. That is, the driving control device 1 can increase the conditions under which the host vehicle 10 can travel smoothly in a state where the driving assistance level of the automatic driving mode is relatively high, and can reduce the burden on the driver.

[0074] In addition, when the driving control device 1 controls the driving of the host vehicle 10 in the first mode, when the presence of the preceding vehicle 21 is detected, the reliability of the preceding vehicle 21 is calculated based on the behavior of the preceding vehicle 21. Furthermore, when the calculated reliability of the preceding vehicle 21 is less than a predetermined value, the driving control device 1 does not change the automatic driving mode to the second mode. That is, when the reliability of the preceding vehicle 21 is greater than a predetermined value, the driving control device 1 changes the automatic driving mode to the second mode. Thus, the host vehicle 10 can improve the driving assistance level of the automatic driving mode, and can smoothly travel behind the preceding vehicle 21 with high reliability, that is, stable behavior. In addition, the driving control device 1 determines that the path traveled by the preceding vehicle 21 with a reliability greater than a predetermined value is reliable. The driving control device 1 determines that as long as the path traveled by the preceding vehicle 21 with a reliability greater than a predetermined value is a path traveled by, the possibility of a failure / obstruction occurring when the host vehicle 10 travels on the path is low, and the driving assistance level of the automatic driving can be improved.

[0075] In addition, when the calculated reliability of the preceding vehicle 21 is less than a predetermined value, the driving control device 1 does not change the automatic driving mode to the second mode, but maintains the automatic driving mode in the first mode. Thus, when the reliability of the preceding vehicle 21 is less than the predetermined value, the host vehicle 10 controls driving while maintaining the automatic driving mode in the first mode, so that even if a sudden obstacle / impediment occurs, it can be dealt with flexibly through the manual driving operation of the driver.

[0076] In addition, the driving control device 1 calculates the reliability of the preceding vehicle 21 based on at least one of the lateral displacement of the preceding vehicle 21, the frequency of acceleration and deceleration, and the flashing frequency of the brake lights. Thus, the driving control device 1 can calculate the reliability of the preceding vehicle 21 based on the specific behavior of the preceding vehicle 21. Therefore, in the case where the preceding vehicle 21 is zigzagging, or is frequently and repeatedly accelerating, or is frequently and repeatedly braking to cause the brake lights to flash, it is determined that the reliability of the preceding vehicle 21 is low, and the driving control device 1 does not change the automatic driving mode to the second mode. On the other hand, in the case where the reliability of the preceding vehicle 21 is high, the preceding vehicle 21 does not sway left and right in the center of the first lane 31 and travels at a substantially constant speed, and the frequency of applying sudden brakes is also low, so the host vehicle 10 can smoothly travel behind the preceding vehicle 21 in the state where the automatic driving mode is set to the second mode.

[0077] In addition, the upper limit distance of the detectable distance D from the host vehicle 10 to the preceding vehicle 21 detectable by the driving control device 1 can be set to be longer than the upper limit distance of the followable distance from the host vehicle 10 to the preceding vehicle 21 when the following driving of the preceding vehicle is performed using the first mode. Furthermore, the upper limit distance of the detectable distance D from the host vehicle 10 to the preceding vehicle 21 detectable by the driving control device 1 is set to be longer than the upper limit distance at which the host vehicle 10 and the preceding vehicle 21 can perform inter-vehicle communication. Thus, even if the distance between the host vehicle 10 and the preceding vehicle 21 is so large that the host vehicle 10 cannot follow the preceding vehicle 21, the driving control device 1 can change the automatic driving mode of the host vehicle 10 to the second mode and make the host vehicle 10 travel behind the preceding vehicle 21. That is, even if the host vehicle 10 does not follow the preceding vehicle 21, by traveling behind the detected preceding vehicle 21, it is possible to smoothly travel on the path that the preceding vehicle 21 has traveled in the state where the automatic driving mode is set to the second mode.

[0078] When the driving control device 1 receives the driving history information of another vehicle at the history information receiving unit 11a, and the driving history information includes information indicating that the other vehicle has traveled past a location in front of the host vehicle within a predetermined time, the other vehicle is detected as the preceding vehicle 21 traveling in front of the host vehicle 10. Thus, even when the preceding vehicle 21 cannot be detected by the front camera or the front radar, the driving control device 1 can detect the presence of the preceding vehicle 21 traveling in front of the host vehicle 10. Specifically, the history information receiving unit 11a can detect the presence of the preceding vehicle 21 in a lane in which the host vehicle 10 is scheduled to travel thereafter, that is, a lane of a lane change destination, a lane of a right turn destination, or a lane of a left turn destination of the host vehicle 10.

[0079] In addition, the driving control device 1 does not change the automatic driving mode to the second mode when the driving of the host vehicle 10 is controlled by the first mode and the vehicle speed of the host vehicle 10 is above the prescribed speed. Thus, the driving control device 1 can change the automatic driving mode from the first mode to the second mode only when the host vehicle 10 is traveling at a speed within a range in which the host vehicle 10 can travel smoothly in the second mode. That is, when the automatic driving mode is set to the second mode, when the vehicle speed of the host vehicle 10 is traveling at a high speed above the prescribed speed, it is difficult for the driving control device 1 or the driver to immediately respond to a sudden change in the situation such as an emergency stop of the preceding vehicle 21, and therefore the driving control device 1 does not change the automatic driving mode to the second mode.

[0080] In addition, the control of not changing the automatic driving mode to the second mode includes the control of maintaining the automatic driving mode in the first mode and the control of changing the automatic driving mode to another mode with a lower driving assistance level than the first mode.

[0081] Furthermore, the first mode is an automatic driving mode in which the driver needs to visually monitor the surrounding conditions of the host vehicle 10, and the second mode is an automatic driving mode in which the monitoring of the surrounding conditions of the host vehicle is performed by the driving control device 1. Thus, by switching the automatic driving mode from the first mode to the second mode through the driving control device 1, the monitoring burden of the driver can be reduced.

[0082] In addition, the first mode is a hand-held mode in which the steering control of the driving control device 1 does not operate when the driver does not hold the steering wheel 14a, and the second mode is a hand-off mode in which the steering control of the driving control device 1 operates even if the driver takes his hands off the steering wheel. Thus, the driving control device 1 switches the automatic driving mode from the first mode to the second mode, thereby reducing the burden of the driver's driving operation.

[0083] In addition, in the present embodiment, the driving control device 1 may not execute the process of calculating the reliability of the preceding vehicle 21. Figure 2 Steps S4 and S5, and Figure 2 After the preceding vehicle 21 is detected in step S3, the control is transferred to step S6 to change the automatic driving mode to the second mode. In addition, if the preceding vehicle 21 cannot be detected in step S3, the driving control device 1 may transfer the control to step S7 to prohibit the process of changing the automatic driving mode to the second mode. In addition, the driving control device 1 may also transfer the control to step S7 regardless of the speed of the host vehicle 10. Figure 2 After the preceding vehicle 21 is detected in step S3, the automatic driving mode is changed from the first mode to the second mode in step S6. Figure 2 The process of step S2 shown in the figure is skipped (step S2 is skipped), and the process proceeds from step S1 to step S3. Thereafter, as described above, the process of steps S4 and S5 may be skipped, and the process proceeds to step S6.

[0084] In addition, the preceding vehicle detection unit 11 of the driving control device 1 may not include the history information receiving unit 11 a .

[0085] In addition, in this embodiment, Figure 2 In step S6, after the automatic driving mode is changed from the first mode to the second mode, the host vehicle 10 travels behind the preceding vehicle 21. In this case, the host vehicle 10 may follow the preceding vehicle 21 in conjunction with the action of the preceding vehicle 21, or may simply follow the travel path of the preceding vehicle 21 without following the preceding vehicle 21. In addition, the upper limit distance of the detectable distance D from the host vehicle 10 to the preceding vehicle 21 that can be detected by the driving control device 1 may also be consistent with the upper limit distance at which the host vehicle 10 and the preceding vehicle 21 can communicate with each other.

[0086] In addition, the driving control device 1 may estimate the vehicle height of another vehicle traveling ahead of the host vehicle 10, and when the vehicle height of the other vehicle is higher than the vehicle height of the host vehicle 10, the process of not determining that "the preceding vehicle 21 traveling ahead of the host vehicle 10 is detected" is performed in step S3, and the control is transferred to step S7. That is, when the vehicle height of another vehicle traveling ahead is higher than the vehicle height of the host vehicle 10, the other vehicle is excluded from the "previous vehicle 21". This is because, when it is assumed that there is a dropped object or the like in the first lane 31, even if the object does not become an obstacle that hinders the travel of another vehicle with a higher vehicle height, it may become an obstacle that hinders the travel of the host vehicle 10 with a lower vehicle height than the other vehicles. That is, the driving control device 1 considers the possibility that even a path where another vehicle with a higher vehicle height travels without an obstacle is a path that is an obstacle for the host vehicle 10 with a relatively lower vehicle height. In addition, when the host vehicle 10 is a passenger car, the other vehicle with a vehicle height higher than the host vehicle 10 is, for example, a large vehicle such as a truck. The vehicle 10 determines the model of the other vehicle based on the other vehicle information obtained through the inter-vehicle communication with the other vehicle traveling ahead, and estimates the vehicle height of the other vehicle based on the model. In addition, the vehicle 10 determines the model of the other vehicle based on the appearance or license plate information of the other vehicle obtained from the image of the other vehicle traveling ahead taken by the front camera, and estimates the vehicle height of the other vehicle based on the model.

[0087] In addition, when the driving control device 1 determines that the other vehicle traveling in front of the host vehicle 10 is a two-wheeled vehicle, it is also possible to perform processing that does not determine that "the preceding vehicle 21 traveling in front of the host vehicle 10 is detected" in step S3, and move the control to step S7. That is, when the other vehicle traveling in front of the host vehicle is a two-wheeled vehicle, the other vehicle is excluded from the "previous vehicle 21". This is because, when it is assumed that there is a fallen object or the like in the first lane 31, depending on the size of the object, even if it cannot become an obstacle that hinders the travel of other vehicles that are two-wheeled vehicles, it may become an obstacle that hinders the travel of the host vehicle 10. That is, the driving control device 1 considers the possibility that even if a two-wheeled vehicle can travel on a path that avoids an obstacle, there is a possibility that there is an obstacle that cannot be avoided for the host vehicle 10 that is a four-wheeled vehicle. In addition, whether the other vehicle is a two-wheeled vehicle can be determined based on the image captured by the camera.

[0088] (Second Embodiment)

[0089] based on Figures 4 to 7 The second embodiment is described. Figures 1 to 3 The same symbols as those described in the drawings represent the same or similar components or control steps, and therefore repeated descriptions are omitted and the description in the first embodiment is cited.

[0090] based on Figures 4 to 7 The procedure of the driving control method of the driving control device 1 is described. Figures 5 to 7 , the vehicle 10 traveling in the first lane 31, the first preceding vehicle 41 as a preceding vehicle traveling in front of the vehicle 10, and the second preceding vehicle 42 traveling in front of the first preceding vehicle 41 are shown. The first preceding vehicle 41 is another vehicle traveling in the first lane 31 and traveling directly in front of the vehicle 10.

[0091] Figure 4 : is a flowchart showing the control sequence of the second embodiment. Figure 4 As shown, the driving control device 1 determines in step S3 whether the first preceding vehicle 41 as the preceding vehicle traveling in the first lane 31 is detected. If the first preceding vehicle 41 is not detected, the control returns to step S1, and the processing after step S1 is executed again. On the other hand, if the first preceding vehicle 41 is detected, the driving control device 1 changes the automatic driving mode from the first mode to the second mode in step S6.

[0092] After the driving control device 1 changes the automatic driving mode to the second mode in step S6, in step S11, Figure 5 As shown, it is determined whether the second preceding vehicle 42 is detected in front of the first preceding vehicle 41 in the first lane. If the second preceding vehicle 42 is not detected, the control returns to step S1, and the processing after step S1 is executed again.

[0093] In step S11, when the second preceding vehicle 42 is detected, the control moves to step S12, and the driving control device 1 determines whether the first preceding vehicle 41 maintains driving in the first lane 31. When it is determined that the first preceding vehicle 41 maintains driving in the first lane 31 without changing lanes, the control returns to step S1, and the processing after step S1 is executed again.

[0094] In step S11, if it is determined that the first leading vehicle 41 does not maintain the driving in the first lane 31, that is, Figure 6 or Figure 7 As shown, when the first preceding vehicle 41 changes lanes to the second lane 32 which is another lane adjacent to the first lane 31 , control proceeds to step S13 . In step S13 , the driving control device 1 determines whether the second preceding vehicle 42 maintains traveling in the first lane 31 .

[0095] In step S13, if it is determined that the second preceding vehicle 42 does not change lanes and maintains traveling in the first lane 31, control proceeds to step S14. In step S14, the driving control device 1 causes the host vehicle 10 to travel behind the second preceding vehicle 42. In this case, Figure 6 As shown, the vehicle 10 shortens the inter-vehicle distance between the vehicle 10 and the second preceding vehicle 42 to a predetermined distance and follows the second preceding vehicle 42. In addition, the vehicle 10 may also drive behind the second preceding vehicle 42 in the first lane 31 while maintaining the original inter-vehicle distance (inter-vehicle distance when the first preceding vehicle 41 changes lanes) with the second preceding vehicle 42 without following the second preceding vehicle 42. That is, the vehicle 10 may drive in conjunction with the movement of the second preceding vehicle 42 and follow the second preceding vehicle 42, or may drive simply along the driving path of the second preceding vehicle 42 without following the second preceding vehicle 42.

[0096] In addition, in step S13, if it is determined that the second preceding vehicle 42 does not maintain the driving in the first lane 31, that is, the second preceding vehicle 42 changes lanes to the second lane 32, the control moves to step S15. In step S15, the driving control device 1 causes the host vehicle 10 to drive behind the first preceding vehicle 41 while performing a lane change to the second lane 32 so that the host vehicle 10 can follow the first preceding vehicle 41 and the second preceding vehicle 42 to change lanes. Then, as shown in FIG. Figure 7 As shown, the driving control device 1 causes the host vehicle 10 to travel behind the first preceding vehicle 41 in the second lane 32. In this case, the host vehicle 10 may follow the first preceding vehicle 41 in conjunction with the movement of the first preceding vehicle 41, or may simply travel along the travel path of the first preceding vehicle 41 without following the first preceding vehicle 41.

[0097] As described above, in the driving control device 1 and the driving control method of the present embodiment, the first preceding vehicle 41 and the second preceding vehicle 42 traveling ahead of the first preceding vehicle 41 are detected in the first lane 31, and it is determined whether the first preceding vehicle 41 and the second preceding vehicle 42 are maintaining the traveling in the first lane 31. When it is determined that the first preceding vehicle 41 changes lanes to the second lane 32 and the second preceding vehicle 42 maintains the traveling in the first lane 31, the driving control device 1 causes the host vehicle 10 to travel behind the second preceding vehicle 42 instead of causing the host vehicle 10 to travel behind the first preceding vehicle 41. The driving control device 1 determines that even when the first preceding vehicle 41 changes lanes, as long as the second preceding vehicle 42 traveling ahead of the first preceding vehicle 41 is traveling in the same first lane 31 as the host vehicle 10, it is highly likely that the host vehicle 10 can travel in the first lane 31 without any obstacle. Thus, even when the first preceding vehicle 41 changes lanes, the host vehicle 10 can smoothly travel behind the second preceding vehicle 42 while maintaining the automatic driving mode in the second mode.

[0098] Furthermore, when the driving control device 1 determines that both the first preceding vehicle 41 and the second preceding vehicle 42 have changed lanes to the second lane 32, the host vehicle 10 changes lanes to the second lane 32 following the first preceding vehicle 41 and the second preceding vehicle 42. That is, the driving control device 1 causes the host vehicle 10 to travel behind the first preceding vehicle 41 and change lanes to the second lane 32. This is because, when both the first preceding vehicle 41 and the second preceding vehicle 42 have changed lanes, there is a high possibility that an obstacle or a construction area exists in the first lane 31.

[0099] In addition, Figure 4 In the driving control method shown in FIG. 1 , the driving control device 1 may also be configured to Figure 4 Between step S3 and step S6 shown in FIG. Figure 2 As shown in steps S4 and S5, the reliability of the first preceding vehicle 41 is calculated, and it is determined whether the reliability of the first preceding vehicle 41 is greater than a predetermined value. Figure 4 In steps S12 and S13 shown in the figure, after detecting that the first preceding vehicle 41 changes lanes and the second preceding vehicle 42 maintains driving in the first lane 31, the reliability of the second preceding vehicle 42 is calculated, and it is determined whether the reliability of the second preceding vehicle 42 is greater than a predetermined value. That is, when the reliability of the second preceding vehicle 42 is less than the predetermined value, the driving control device 1 can adjust the automatic driving mode from the second mode to the first mode.

[0100] In the driving control method of the second embodiment, similarly to the first embodiment, regardless of the vehicle speed of the host vehicle 10, Figure 4 After the first preceding vehicle 41 is detected in step S3, the automatic driving mode is changed from the first mode to the second mode in step S6. Figure 4 Step S2 is shown.

[0101] Explanation of symbols

[0102] 1: Driving Controls

[0103] 10: This vehicle

[0104] 11: Forward vehicle detection unit

[0105] 11a: History information receiving unit

[0106] 12: Vehicle position detection device

[0107] 13: Map Database

[0108] 14: Vehicle Equipment

[0109] 15: Prompt device

[0110] 16: Input Device

[0111] 17: Drive control device

[0112] 14a: Steering wheel

[0113] 18: Control Device

[0114] 21: Vehicle ahead

[0115] 31: First lane

[0116] 32: Second lane

[0117] 41: First preceding vehicle (preceding vehicle)

[0118] 42: Second vehicle ahead

[0119] D: Detectable distance

Claims

1. A driving control method, using a driving control device to control the driving of a vehicle through at least two automatic driving modes with different driving assistance levels, wherein: The at least two automatic driving modes include a first mode and a second mode having a higher driving assistance level than the first mode, The driving control device, when controlling the driving of the host vehicle using the first mode, switches the automatic driving mode from the first mode to the second mode when a preceding vehicle traveling in front of the host vehicle is detected within an upper limit distance of a detectable distance from the host vehicle to the preceding vehicle. The driving control device is capable of executing following driving of the preceding vehicle when the host vehicle is controlled using the first mode and the distance from the host vehicle to the preceding vehicle is within an upper limit of a following distance, The upper limit distance of the detectable distance is longer than the upper limit distance of the followable distance.

2. The driving control method according to claim 1, wherein: The driving control device performs the following processing: In a case where the driving of the host vehicle is controlled using the first mode, when the preceding vehicle is detected, the reliability of the preceding vehicle is calculated based on the behavior of the preceding vehicle, When the reliability of the leading vehicle is less than a predefined specified value, the automatic driving mode is not switched to the second mode.

3. The driving control method according to claim 2, wherein: The driving control device maintains the automatic driving mode at the first mode when the reliability of the leading vehicle is less than the predetermined value.

4. The driving control method according to claim 2 or 3, wherein: The driving control device calculates the reliability of the preceding vehicle based on at least any one of an amount of lateral displacement of the preceding vehicle, a frequency of acceleration and deceleration, and a flashing frequency of a brake light.

5. The driving control method according to claim 1, wherein: The upper limit distance of the followable distance is a distance at which vehicle-to-vehicle communication is possible between the host vehicle and the preceding vehicle.

6. The driving control method according to any one of claims 1 to 3, wherein: The driving control device receives driving history information of other vehicles, and if the received driving history information includes information that the other vehicle has passed a location in front of the vehicle within a specified time, the other vehicle is detected as the preceding vehicle traveling in front of the vehicle.

7. The driving control method according to any one of claims 1 to 3, wherein: The driving control device does not switch the automatic driving mode to the second mode when the driving of the host vehicle is controlled by the first mode and when the vehicle speed of the host vehicle is equal to or higher than a predetermined speed.

8. The driving control method according to any one of claims 1 to 3, wherein: The first mode is an automatic driving mode that requires the driver to visually monitor the surrounding conditions of the vehicle. The second mode is an automatic driving mode in which the driving control device monitors the surrounding conditions of the host vehicle.

9. The driving control method according to any one of claims 1 to 3, wherein: The first mode is a handheld mode in which the steering control of the driving control device does not operate when the driver does not hold the steering wheel. The second mode is a hands-off mode in which the steering control of the driving control device is activated even when the driver takes his hands off the steering wheel.

10. The driving control method according to any one of claims 1 to 3, wherein: When the vehicle height of another vehicle traveling ahead of the host vehicle is higher than the vehicle height of the host vehicle, the other vehicle is excluded from the preceding vehicles.

11. The driving control method according to any one of claims 1 to 3, wherein: When the other vehicle traveling ahead of the host vehicle is a two-wheeled vehicle, the other vehicle is excluded from the preceding vehicle.

12. The driving control method according to any one of claims 1 to 3, wherein: The driving control device performs the following processing: When the driving of the host vehicle is controlled by the first mode, when a first preceding vehicle as the preceding vehicle is detected in a first lane in which the host vehicle is traveling, the automatic driving mode is changed from the first mode to the second mode, Furthermore, when a second preceding vehicle traveling ahead of the first preceding vehicle in the first lane is detected, it is determined whether the first preceding vehicle and the second preceding vehicle are traveling in the first lane. When it is determined that the first leading vehicle changes lanes to a lane different from the first lane and the second leading vehicle maintains traveling in the first lane, the host vehicle travels behind the second leading vehicle; When it is determined that the first leading vehicle and the second leading vehicle have changed lanes to the other lane, the host vehicle is caused to travel behind the first leading vehicle and the lane change is executed to the other lane.

13. A driving control device comprising: a control device for controlling driving of the host vehicle in at least two automatic driving modes including a first mode and a second mode having a higher driving assistance level than the first mode; a preceding vehicle detection unit for detecting a preceding vehicle traveling in front of the host vehicle, The control device, when controlling the driving of the host vehicle in the first mode, switches the automatic driving mode from the first mode to the second mode when the preceding vehicle detection unit detects the preceding vehicle within an upper limit of a detectable distance from the host vehicle to the preceding vehicle, The control device is capable of executing following driving of the preceding vehicle when the host vehicle is controlled in the first mode and the distance from the host vehicle to the preceding vehicle is within an upper limit of a following distance, The upper limit distance of the detectable distance is longer than the upper limit distance of the followable distance.

Images