Driving assistance method and driving assistance device

Abstract

A processor (10) in which this driving assistance method is used detects traffic regulatory signs (OB1, OB2, OB3) on a travel lane (L1), restricts the content of driving assistance executed in a traffic regulated section (TR) recognized on the basis of information indicated by a traffic regulatory sign (OB1), and, when a host vehicle (V1) changes lanes to a branch lane (BL) that branches from the travel lane while the restriction is in place, cancels the restriction and executes driving assistance for the host vehicle (V1).

Description

Driving assistance method and driving assistance device

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

[0002] A technology is known that sets a predetermined autonomous driving level when a construction section on one side of the first travel path is closed to traffic and a construction section is recognized where one-way alternating traffic is possible using the other side of the second travel path.

[0003] Japanese Patent Application Laid-Open No. 2019-156195

[0004] When the vehicle changes lanes to a branch lane, it is difficult to determine the end point of the restricted traffic section, and appropriate driving assistance may not be possible.

[0005] The problem to be solved by the present invention is to provide appropriate driving assistance when the vehicle changes lanes to a branching lane.

[0006] The present invention solves the above problem by restricting the content of driving assistance performed in restricted traffic sections recognized based on traffic restriction signs on the driving lane, and by lifting the restriction if the vehicle changes lanes from the driving lane to a branch lane branching off during the restriction.

[0007] According to the present invention, appropriate driving assistance can be provided when the host vehicle changes lanes to a branching lane.

[0008] It is a block diagram showing the hardware configuration of a driving assistance system. It is a first flowchart showing the processing procedure of driving assistance. It is a second flowchart showing the processing procedure of driving assistance. It is a diagram explaining an example of driving assistance levels. It is a diagram explaining processing in a branching lane.

[0009] 1 shows the configuration of a driving assistance system 100 including a vehicle driving assistance device 1 according to this embodiment. The driving assistance system 100 includes one or more sensors 2, a host vehicle information acquisition device 3, a traffic regulation information acquisition device 4, and a traffic regulation section determination device 5.

[0010] Multiple sensors 2 are installed on the vehicle, forming a sensor group that works together. Sensor 2 detects the presence or absence of objects around the vehicle, the distance to the objects, and the relative speed and relative acceleration of the objects. Sensor 2 detects one or more of the following: the object's outer shape, whether the object is stationary or moving, the object's size, the object's direction, the number of objects, and the object's location. Objects to be detected include traffic regulation signs. Traffic regulation signs indicate the location of traffic regulation areas. Traffic regulation areas include accident areas, areas to avoid fallen objects, areas to avoid scattered objects, flooded areas, road cave-ins, areas where events are being held, and other areas where normal traffic is restricted. Traffic regulation signs include stationary objects and moving objects. Traffic regulation signs include pylons, road cones, barrels, signs, and construction vehicles placed in traffic regulation areas. Traffic regulation signs include traffic guides, guide robots, and the hand flags they carry near traffic regulation areas. Traffic regulation signs indicate the location of traffic regulation areas by their presence. When traffic regulation signs are physical objects, their distinctive shapes and forms indicate that their location is a traffic-restricted section. For example, traffic regulation signs such as pylons, road cones, and barrels indicate that their location is a construction zone. Traffic regulation signs may also have no distinctive shape and simply indicate information identifying a traffic-restricted section where traffic regulations are in effect. Traffic regulation signs include information displayed on signs or displays on roads, as well as the information itself. Information identifying a traffic-restricted section includes the location of the traffic-restricted section and the date and time the traffic regulation will be implemented. Traffic regulation signs indicate information about traffic-restricted sections that notify of road closures, traffic restrictions, or detours due to marathons or road races. The processor 10 is equipped with a calendar and a clock, and can compare the date and time of the traffic regulation with the time of travel to determine whether the traffic regulation on the road or lane will affect the vehicle. The sensor 2 includes one or more cameras 21 installed on the vehicle. The single or multiple cameras 21 capture images of the vehicle's surroundings in all directions. The camera 21 includes an image sensor having an imaging element such as a CCD, an ultrasonic camera, and an infrared camera.The camera 21 includes at least a front camera that captures images in front of the vehicle, a rear camera that captures images behind or on the rear sides of the vehicle, and left and right side cameras that capture images of the left and right sides of the vehicle, and the left and right front and rear sides of the vehicle. The type of camera 21 is not limited as long as it can capture images in all directions of the vehicle. A single camera 21 mounted on a base with a rotation mechanism may be used, or multiple cameras 21 may be used in combination. The sensor 2 includes a radar device 22 that detects (measures) the presence, position, and position change of objects around the vehicle. The radar device 22 emits electromagnetic waves toward the object and measures the reflected waves to measure the distance and direction to the object. The radar device 22 includes a laser radar, a millimeter-wave radar (LRF), a light detection and ranging (LiDAR) unit, an ultrasonic radar, and a sonar. The sensor 2 also includes a global positioning system (GPS) unit, a gyro sensor, a vehicle speed sensor, and the like, and detects the position of the vehicle at each timing. Each sensor 2 can also acquire information from an in-vehicle device and an external device according to its respective function. The detection information acquired by the sensor 2 is provided to the processor 10. The detection information acquired by the sensor 2 may be provided to the host vehicle information acquisition device 3, the traffic regulation information acquisition device 4, and the traffic regulation section determination device 5. The processor 10 may acquire the detection information directly from the camera 21 and the radar device 22, or may acquire it via the host vehicle information acquisition device 3, the traffic regulation information acquisition device 4, or the traffic regulation section determination device 5, which will be described later.

[0011] The host vehicle information acquisition device 3 calculates the current position, attitude, speed, acceleration, behavior, and traveling direction of the host vehicle based on the detection information acquired from the sensor 2 and / or the host vehicle information acquired from the vehicle, and provides the calculated information to the processor 10. The host vehicle information acquisition device 3 refers to the map information 6 and the lane information 61 to identify the lane in which the host vehicle is traveling. The host vehicle information acquisition device 3 refers to the map information 6 and the lane information 61 to extract branch lanes that branch off from the lane in which the host vehicle is traveling, and identify the position of the branch lane.

[0012] The traffic regulation information acquisition device 4 recognizes traffic regulation signs around the vehicle, particularly on the vehicle's travel lane, based on the detection information acquired from the sensor 2. The vehicle's travel lane includes the lane the vehicle will travel in the future. The traffic regulation information acquisition device 4 captures the posted information with the camera 21 and recognizes the location of the traffic regulation section and the date and time of the traffic regulation through text recognition processing or graphic recognition processing. The traffic regulation information acquisition device 4 communicates with an external server, such as a roadside device, via the communication device 30 and recognizes the information indicated by the traffic regulation signs, including the date and time when the traffic regulation will be implemented, the location of the traffic regulation section, and detour routes. The traffic regulation information acquisition device 4 provides the information indicated by the recognized traffic regulation signs to the processor 10. The processor 10 may execute the process of recognizing the information indicated by the traffic regulation signs.

[0013] The traffic restriction section determination device 5 identifies the location and range of the traffic restriction section where traffic restriction is imposed based on the content of information indicated by the detected or recognized traffic restriction sign. Although not particularly limited, the traffic restriction section determination device 5 determines that the traffic restriction section is within a predetermined distance from the location where the barrel, which is a traffic restriction sign, is detected. The traffic restriction section defined by the traffic restriction sign and the traffic restriction section recognized by the processor 10 may be the same or different. The processor 10 can define the traffic restriction section taking into account the driving function and driving performance of the vehicle in order to provide appropriate driving assistance. The traffic restriction section may be defined based on the information indicated by the traffic restriction sign, in accordance with the vehicle's performance, driver's skill, and driver's preferences. For example, the processor 10 may define the traffic restriction section for this driving assistance processing by adding a margin to the traffic restriction section defined by the traffic restriction sign. Furthermore, the traffic restriction section determination device 5 has a function to detect a branching lane ahead of the vehicle based on detection information from the sensor 2. The traffic-restricted section determination device 5 extracts characteristics of branch lanes from the image captured by the camera 21 and compares them with pre-stored characteristics to detect the presence and location of a branch lane ahead of the vehicle. Examples of branch lane characteristics include the presence of a lane mark indicating the boundary with the main lane, the presence of a V-shaped lane mark intersection at the connection between the main lane and the branch lane, the presence of a pair of lane marks for the branch lane extending in a direction different from the main lane, and the presence of a pair of lane marks intersecting with the main lane. Additionally, the traffic-restricted section determination device 5 can detect branch lanes ahead of the vehicle by referring to information on the branch area, branch start point, and branch end point of the branch lane, which are included in the high-precision map information of the map information 6 (described later). The traffic-restricted section determination device 5 sends the branch lane detection result to the processor 10. The processor 10 may also perform branch lane detection processing itself based on information obtained from the sensor 2.

[0014] The driving assistance system 100 has map information 6 and lane information 61. The map information 6 and the lane information 61 are recorded in a storage device or an external server that the processor 10 can access via the communication device 30. The map information 6 is high-precision map information. The map information 6 includes lane information 61 that is referenced when performing autonomous lane change control. The lane information 61 includes identification information that identifies each of multiple lanes belonging to a road. The map information 6 and / or the lane information 61 include information about branch lanes that branch off in different directions from the main road, specifically, information about one or more of the position of the branch area of ​​the branch lane, the branch start point of the branch lane, and the branch end point of the branch lane.

[0015] The navigation device 7 refers to the map information 6 and calculates a route to the set destination. This route includes a target trajectory. The calculated route and target trajectory are provided to the vehicle controller 200 and used for autonomous driving control and driving assistance control.

[0016] The vehicle controller 200 includes a steering control device 210 and a drive control device 220. The vehicle controller 200 can perform autonomous driving or manual driving depending on the driving assistance level specified by the processor 10. When the driving assistance level is high, the vehicle controller 200 performs autonomous driving, including autonomous lane change control. Specifically, the vehicle controller 200 acquires command values ​​for autonomous driving control according to a driving plan formulated by the processor 10 of the driving assistance device 1, and controls the host vehicle to travel a route to the destination. The route is composed of a plurality of consecutive target trajectories to which the command values ​​are associated. The command values ​​for driving control are generated by the vehicle controller 200 or the processor 10. The command values ​​include a set speed for driving the vehicle, and the vehicle controller 200 drives the host vehicle according to the set speed. The vehicle controller 200 inputs longitudinal and lateral forces that control the driving position of the host vehicle based on the command values. According to these inputs, the behavior of the vehicle body and the behavior of the wheels are controlled so that the host vehicle autonomously travels a route to the destination. Based on these controls, at least one of the drive actuators and braking actuators of the drive mechanism of the vehicle body controlled by the drive control device 220 and the steering actuator of the steering control device 210, which is activated as needed, operate autonomously, thereby executing autonomous driving control that causes the vehicle to autonomously travel along a target trajectory. Of course, the vehicle controller 200 can also perform driving in accordance with command values ​​based on manual operation by the driver input via the input / output device 20. In particular, when the driving assistance level determined by the processor 10 is low and hands-on driving is required, the vehicle controller 200 does not perform autonomous driving control, but performs driving in accordance with manual operation by the driver input via the input / output device 20. Similarly, when the driving assistance level determined by the processor 10 is low and only manual lane change driving is possible, the vehicle controller 200 does not perform autonomous lane change control, but performs lane change driving in accordance with manual operation by the driver input via the input / output device 20.

[0017] The driving assistance system 100 includes a driving assistance device 1. The driving assistance device 1 includes a processor 10 that includes a ROM (Read Only Memory) 12 that stores a program for executing autonomous driving or manual driving, a CPU (Central Processing Unit) 11 that executes the program stored in the ROM 12, and a RAM (Random Access Memory) 13 that functions as an accessible storage device. The processor 10 implements the driving assistance method using each piece of hardware of the driving assistance system 100. The driving assistance method is used in the processor 10.

[0018] The processor 10 limits the content of driving assistance performed in a restricted-traffic section, and releases the restriction on driving assistance if the host vehicle changes lanes from the driving lane to a branching lane while the content of the driving assistance being performed is restricted. The processor 10 executes each function in cooperation with software for realizing at least a function of determining whether the host vehicle is traveling in a restricted-traffic section, a function of determining whether the host vehicle will change lanes to a branching lane, and a function of determining whether to limit the content of driving assistance (whether to maintain or release the restriction) depending on the determination result of the restricted-traffic section, and each hardware shown in FIG.

[0019] The assistance process executed in the driving control of the host vehicle will be described with reference to the flowchart of FIG. 2. The process related to the driving assistance method for the host vehicle is performed by the processor 10. The processor 10 acquires detection information about the surroundings of the host vehicle via the sensor 2 (S1). The detection information includes detection information based on image capture information from the camera 21 and / or detection information based on observation information from the radar device 22. The processor 10 may also acquire the detection information about the surroundings of the host vehicle from a roadside device via the communication device 30. The processor 10 acquires host vehicle information, such as the current position and speed of the host vehicle, from the host vehicle information acquisition device 3 (S2). The processor 10 refers to the detection information from the sensor 2 or the lane information 61 in the map information 6 to acquire lane information about the current lane the host vehicle is traveling in as part of the host vehicle information. The processor 10 refers to the map information 6 and / or the lane information 61 to acquire information about the presence and position of branch lanes branching off from the host vehicle's traveling lane.

[0020] The sensor 2 detects the surroundings of the vehicle and provides the detection information to the processor 10. The processor 10 detects traffic regulation signs on the lane in which the vehicle is traveling using the detection information from the sensor 2. The processor 10 acquires information indicated by the detected traffic regulation signs (S3). The processor 10 may acquire the information indicated by the traffic regulation signs via the traffic regulation information acquisition device 4.

[0021] The processor 10 recognizes the restricted traffic zone based on the information provided by the traffic regulation sign (S4). The information provided by the traffic regulation sign includes at least the location of the restricted traffic zone where traffic is restricted. The location of the restricted traffic zone is identified by one or more of the following information: lane identification information, node information, link information, latitude and longitude, and a linear map based on the latitude and longitude. Specifically, the processor 10 pre-stores the external features of the traffic regulation signs, which are tangible objects placed to indicate construction zones, such as pylons, traffic cones, barrels, signs, construction vehicles, traffic guides, traffic robots, and traffic flags. The processor 10 extracts the external features of the traffic regulation signs obtained from the detection information of the sensor 2, compares the stored external features of the traffic regulation signs with the features of the detected objects, and performs pattern matching to recognize the information provided by the traffic regulation signs and the location of the restricted traffic zone indicated by the traffic regulation signs. For example, the processor 10 recognizes that a pylon is a sign indicating a construction zone and that the location of the pylon is a restricted traffic zone due to construction. Furthermore, while the external shape of a sign or sign itself may not have a specific meaning, the intangible information displayed on the sign or sign may have meaning. Processor 10 acquires information written on the sign or sign via an image captured by camera 21, and recognizes the content of the written text and graphics to acquire information related to the traffic regulation. Processor 10 references pre-stored text and graphic information related to the traffic regulation, and recognizes the location, date, time, and position where the traffic regulation will be implemented based on the text recognized from the captured image. Processor 10 may also acquire the content of the traffic regulation sign directly from a server device external to the vehicle (e.g., a roadside device) via communication device 30.

[0022] The processor 10 determines whether the host vehicle will be traveling through the identified traffic-restricted section (S5). The processor 10 compares the current position of the host vehicle acquired from the sensor 2 and / or the host vehicle information acquisition device 3 with the position information of the traffic-restricted section identified in S4, and determines whether the host vehicle will be traveling through the traffic-restricted section based on whether the current position of the host vehicle belongs to the traffic-restricted section. This determination process is repeatedly executed at a predetermined cycle. If the processor 10 determines that the host vehicle will be traveling through the traffic-restricted section (YES in S5), it turns on a flag indicating that the host vehicle will be traveling through the traffic-restricted section (S6). The processor 10 performs driving assistance for the host vehicle according to the result of the determination of whether the host vehicle will be traveling through the traffic-restricted section. The processor 10 limits the content of the driving assistance to be performed when the host vehicle is traveling through the traffic-restricted section, and does not limit the content of the driving assistance to be performed when the host vehicle is not traveling through the traffic-restricted section (if a restriction is in effect, it cancels the restriction). When the host vehicle transitions from a non-traffic restricted section to a traffic restricted section, the content of the driving assistance is restricted, and when the host vehicle transitions from a traffic restricted section to a non-traffic restricted section, the restriction on the content of the driving assistance is lifted. The level of driving assistance when the content of the driving assistance is restricted is lower than the level of driving assistance when the content of the driving assistance is not restricted (restrictions are lifted). When the content of the driving assistance is not restricted (restrictions are lifted), the level of driving assistance is set to a standard level according to the vehicle performance, and when the content of the driving assistance is restricted, it is set to a reduced level relatively lower than the standard level. When the flag is on (S6), that is, when it is determined that the host vehicle is traveling in a traffic restricted section, the content of the driving assistance to be executed is restricted, and a level of driving assistance lower than that when it is determined that the host vehicle is not traveling in a traffic restricted section is determined (S8). Processor 10 executes driving assistance that is lower than the determined standard level (S9). Even after the execution of low-level driving assistance has begun (S9), processor 10 periodically determines whether the vehicle is traveling in a restricted-traffic section and executes driving assistance at a level appropriate to the determination (S1-S9). When the vehicle is traveling in a restricted-traffic section, it determines that careful driving that takes individual circumstances into consideration is preferable to uniform autonomous control, and lowers the level of driving assistance.On the other hand, if the processor 10 determines that the host vehicle is not traveling in a restricted-traffic section (NO in S5), it turns off the flag indicating that the host vehicle is traveling in a restricted-traffic section (S7). Turning off the flag in S7 includes not turning on the flag, i.e., not performing any special processing. If the flag indicating that the host vehicle is traveling in a restricted-traffic section is off, the normal standard level of driving assistance is maintained (S14). The driver can use the relatively high level of autonomous driving functions provided by the host vehicle.

[0023] Here, the details of driving assistance will be described with reference to FIG. 4. When the details of driving assistance are not limited and the level of driving assistance is high, driving requiring relatively few operations from the driver is performed. When the details of driving assistance are limited and the level of driving assistance is low, driving requiring relatively many operations from the driver is performed. In other words, when the level of driving assistance is high, the burden on the driver is light, and when the level of driving assistance is low, the burden on the driver is heavy. In FIG. 4, a relatively low level of driving assistance is designated driving assistance level A, and a relatively high level of driving assistance is designated driving assistance level B (>A). The low level of driving assistance level A is performed when it is determined that the host vehicle is traveling in a traffic-restricted section and the details of driving assistance are restricted, while the high level of driving assistance level B is performed when it is determined that the host vehicle is not traveling in a traffic-restricted section and the restrictions on the details of driving assistance are lifted. Driving assistance at driving assistance level A requires hands-on driving, which requires the driver to drive the vehicle themselves. Driving assistance at driving assistance level B allows hands-off driving, in which the host vehicle drives autonomously. Furthermore, in driving assistance at driving assistance level A, only lane changes manually performed by the driver are permitted, and autonomous lane change control is prohibited. In driving assistance at driving assistance level B, autonomous driving including autonomous lane change control is permitted. Note that lane changes manually performed by the driver and lane keep control to maintain the lateral position within the driving lane can be performed at both driving assistance levels A and B.

[0024] As described above, in this embodiment, when the host vehicle is traveling in a restricted-traffic section, the type of driving assistance to be implemented is limited, and a lower level of driving assistance is determined than when the host vehicle is not traveling in a restricted-traffic section. In a restricted-traffic section due to construction, construction machinery, tools, and construction workers are present, and in a restricted-traffic section due to flooding or a sinkhole, drainage machinery and detour guides are present. Paying close attention to all of these objects and workers and controlling speed and driving position is considered to require delicate recognition and consideration of individual situations, rather than autonomous control based on predetermined standards. Furthermore, in restricted-traffic sections, some lanes are prohibited from entry, making it difficult to recognize the drivable area referenced in autonomous driving. For this reason, the type of driving assistance to be implemented in restricted-traffic sections is limited, the level of driving assistance is lowered, and manual driving is performed rather than autonomous driving. On the other hand, when the host vehicle is not traveling in a restricted-traffic section, the type of driving assistance to be implemented is not limited, and a higher level of driving assistance is determined than when the host vehicle is traveling in a restricted-traffic section. Specifically, when it is determined that the host vehicle is traveling in a traffic-restricted section, the processor 10 requests hands-on driving as a relatively low level of driving assistance. In addition to this, or independently of this, when it is determined that the host vehicle is traveling in a traffic-restricted section, the processor 10 commands the prohibition of autonomous lane change control as a relatively low level of driving assistance. This allows driving based on the driver's judgment only when the host vehicle is traveling in a traffic-restricted section. On the other hand, when it is determined that the host vehicle is not traveling in a traffic-restricted section, the processor 10 allows hands-off driving as a relatively high level of driving assistance. In addition to this, or independently of this, when it is determined that the host vehicle is not traveling in a traffic-restricted section, the processor 10 executes autonomous lane change control. This allows the host vehicle to perform autonomous driving when not traveling in a traffic-restricted section, thereby reducing the driver's driving burden.

[0025] Returning to FIG. 2 , the process of providing a low level of driving assistance when the host vehicle is traveling in a restricted-traffic section (S9) and subsequent processes will be described. Processor 10 determines whether the host vehicle will change lanes to a branching lane (S10). If it is determined that the host vehicle will change lanes to a branching lane (YES in S10), it determines that the host vehicle is not traveling in a restricted-traffic section and turns off a flag indicating that the host vehicle is traveling in a restricted-traffic section (S12). If it is determined that the host vehicle will not change lanes to a branching lane (NO in S10), the determination result in step S6 is maintained, and the flag indicating that the host vehicle is traveling in a restricted-traffic section remains on (S6). If the flag indicating that the host vehicle is traveling in a restricted-traffic section is turned off (S12), the restriction on the content of driving assistance is lifted, and the level of driving assistance for the host vehicle is determined to be relatively high according to the determination result (S13). When it is determined that the host vehicle is changing lanes into a branching lane, the processor 10 releases the restriction on the content of the driving assistance, raises the driving assistance level, and executes the high level of driving assistance (S14). Even after the execution of the high level of driving assistance has started (S14), the processor 10 periodically determines whether the host vehicle is traveling in a restricted traffic section and executes the driving assistance at a level corresponding to the determination (S1-S14). The high driving assistance level is a standard level that can be used depending on the vehicle performance.

[0026] Even if traffic restrictions due to construction or the like are in place on the main lane on which the vehicle is traveling, if the vehicle changes lanes to a branch lane, the branch lane is no longer a separate road from the main lane, and therefore there is a high possibility that the traffic restrictions will no longer be in place. The present invention focuses on this point, and when the vehicle changes lanes from a main lane including a traffic-restricted section to a branch lane, it is determined that the traffic-restricted section has ended and a flag indicating that the vehicle is traveling in the traffic-restricted section is turned off. This allows the end of the traffic-restricted section to be determined quickly and appropriately based on the determination that the vehicle has changed lanes to a branch lane, even if it has been determined that the vehicle is traveling in a traffic-restricted section on the main lane. As a result, the driving assistance level that was reduced because the vehicle was traveling in a traffic-restricted section can be restored to its original high level. Specifically, turning off the flag indicating that the vehicle is traveling in a traffic-restricted section enables hands-off driving and / or lane changes by autonomous control, thereby reducing the driver's burden at an early stage. Since careful driving is preferred in traffic-restricted sections, the driving assistance level is lowered to require hands-on driving or driver-operated lane changes. Driving at a low level of driving assistance places a greater burden on the driver, so it is preferable to shorten the driving time and driving distance for which the driving assistance level is lowered. Increasing the driving assistance level allows the vehicle's autonomous driving functions to be utilized, allowing occupants to utilize hands-off driving and autonomous lane-changing functions. By quickly determining the end of a traffic-restricted section, the processor 10 of this embodiment can shorten the driving time and driving distance in the traffic-restricted section and shorten the driving time and driving distance at which the driving assistance level is lowered. In this method, by regarding the trigger of changing lanes from the main lane to a branch lane as a change in the traffic regulation situation, the method appropriately determines the passage of the end of the traffic-restricted section and quickly restores the driving assistance level.

[0027] Although not particularly limited, in this embodiment, after it is determined that the host vehicle will change lanes to the branching lane (YES in S10), a process for confirming that no traffic regulation sign is present in the branching lane can be executed. FIG. 3 shows the overall process in which a process S11 for confirming that no traffic regulation sign is present in the branching lane is added after S10 (YES in S10) in the flowchart of FIG. 2 . When the processor 10 detects a traffic regulation sign indicating the presence of a traffic regulation section in the branching lane where the host vehicle will change lanes (YES in S11), the processor 10 determines that the host vehicle is traveling in a traffic regulation section and keeps the flag on (S6), even if it is determined that the host vehicle will change lanes to the branching lane (YES in S10). In other words, even if the determination condition that the host vehicle will change lanes to the branching lane and will not be traveling in a traffic regulation section is satisfied, the processor 10 cancels such determination and maintains the flag on state executed in S6, that is, the determination result that the host vehicle is traveling in a traffic regulation section. On the other hand, if no traffic restriction sign is detected in the branch lane where the host vehicle is changing lanes (NO in S11), the processor 10 determines that the host vehicle is not traveling in a traffic-restricted section and turns off the flag (S12). That is, the processor 10 changes the flag-on determination performed in S6 to a flag-off determination. When the host vehicle changes lanes from a main lane including a traffic-restricted section to a branch lane, the processor 10 predicts that the host vehicle is not traveling in a traffic-restricted section, but prepares for the possibility that a traffic-restricted section may also be set in the branch lane. In this embodiment, when the host vehicle changes lanes, the processor 10 first confirms that there is no traffic restriction sign in the branch lane, and then determines that the host vehicle is not traveling in a traffic-restricted section and turns off the flag (NO in S11 to S12). In this way, when performing the processing of S11, the processor 10 determines that the host vehicle is not traveling in a traffic-restricted section only when the host vehicle changes lanes to the branch lane and there is no traffic restriction sign in the branch lane. When the vehicle changes lanes to a branch lane, the processor 10 checks in advance whether there is a restricted-traffic section in the branch lane and verifies the determination result for the main lane early on. This increases the reliability of the determination result and prevents the determination result of traveling through a restricted-traffic section from being changed (the flag being turned off or on) due to an erroneous prediction.As a result, the end of the traffic-restricted section can be determined early while ensuring the accuracy of the determination results.

[0028] Next, a method for determining whether the host vehicle will change lanes to a branching lane will be described. The processor 10 determines whether the host vehicle will change lanes to a branching lane based on the positional relationship between the host vehicle's current position obtained by the host vehicle information acquisition device 3 and the branching lane located in the host vehicle's traveling direction. The processor 10 references the map information 6 and / or the lane information 61 to obtain the positional relationship between the host vehicle and the branching lane and determines whether the host vehicle will change lanes to the branching lane. The map information 6 and / or the lane information 61 include one or more of the branching lane's attributes, location, location area, and branching position. The branching position includes the branching end point and / or branching start point of the branching lane. The processor 10 also obtains the positional relationship between the host vehicle and the branching lane based on the captured image obtained from the camera 21 or the observation information obtained from the radar device 22 and determines whether the host vehicle will change lanes to the branching lane.

[0029] FIG. 5 shows an example of a branch lane. FIG. 5 shows a branch lane BL branching off to the left from the main line L1, which is the lane in which the host vehicle V1 (T1) is currently traveling at time T1, in the direction of travel (the Y-axis direction in the figure). Multiple traffic regulation signs OB1 (shown as circular shapes) are arranged along the extension direction of the main line L1. The traffic regulation signs OB1 are, for example, pylons, and the section of the main line L1 where the traffic regulation signs OB1 are arranged is a traffic regulation section TR. The main line L1 shown in FIG. 5 includes the traffic regulation section TR, and the host vehicle V1 (T1) travels in the traffic regulation section TR of the main line L1, which is the travel lane. The processor 10 sets a flag to ON to indicate that the host vehicle V1 (T1) is traveling in the traffic regulation section TR. The branch lane BL is a physically separate lane from the main line L1 and the adjacent lane L2. The branch lane BL is connected to the main line L1 at an angle. The main lane L1 is defined by a pair of lane marks LMTR and LMTL, each having a predetermined width in the road width direction (the X-axis direction in the figure), and the branch lane BL is defined by a pair of lane marks LMBR and LMBL, each having a predetermined width in the road width direction. The pair of lane marks LMTR and LMTL and the pair of lane marks LMBR and LMBL each define different lanes. The branch lane BL is not included in the main lane L1.

[0030] The area where the main lane L1 and the branch lane BL connect is called the branch area. Figure 5 illustrates a branch area BR1, indicated by a triangular dashed line including the connection between the main lane L1 and the branch lane BL, and a branch area BR2 where the main lane L1 and the branch lane BL connect. The branch area BR1 is an area including the branch lane BL and a portion of the main lane TL as seen from the host vehicle V1 (T1) traveling on the main lane L1. The processor 10 detects the branch area BR1 ahead of the host vehicle V1 (T1) based on changes in the shape of the road structure using captured images and observation information acquired from the sensor 2 of the host vehicle V1 (T1). The processor 10 can also detect the branch area BR1 including the portion where the branch lane BL is formed by referring to the map information 6 and / or lane information 61. When the current position of the host vehicle V1 (T1) obtained as the host vehicle position information approaches the branch region BR1 within a predetermined distance or within a predetermined TTC, or when the current position of the host vehicle V1 (T1) belongs to the branch region BR1, the processor 10 determines that the host vehicle V1 (T1) will change lanes from the main lane L1, which is the driving lane, to the branch lane BL. Furthermore, the processor 10 can determine that the host vehicle V1 (T1) will change lanes to the branch lane BL based on the fact that the branch lane BL exists in the traveling direction of the current position of the host vehicle obtained by the host vehicle information acquisition device 3 on the route to the destination of the host vehicle calculated by the navigation device 7 and that the branch lane BL is part of the route.

[0031] The processor 10 identifies another branch region BR2. The branch region BR2 is a travel region from the branch start point STP to the branch end point EDP. In FIG. 5, the region in which the host vehicle V1 (T1) travels from the branch start point STP to the branch end point EDP is shown as the branch region BR2. The branch start point STP is a point where a lane mark LMTL defining the left side of the main line L1 intersects with a lane mark LMBL defining the left side of the branch lane BL. The processor 10 detects the branch start point STP, where the lane mark LMTL defining the main line intersects with a lane mark LMBL defining the branch lane BL, based on an image captured by a camera 21 capturing an image ahead of the host vehicle V1 (T1). When observed from the host vehicle V1 (T1) heading toward the branch region BR2, the intersection of the lane mark LMTL and the lane mark LMBL at the branch start point STP appears to form a "V" shape. The processor 10 uses the "V" shape of the lane mark as a characteristic point to detect the existence and location of the branch start point STP based on the image captured by the camera 21. Furthermore, depending on the road, only the lane mark LMTL' at the portion of the lane mark LMTL on the main line L1 that connects to the branch lane BL may be different, for example, a dashed line instead of a solid line, as shown in FIG. 5 . Based on the change in the appearance of the lane mark LMTL and LMTL' on the main line L1, the processor 10 detects the branch start point STP where the lane mark LMTL defining the main line L1 intersects with the lane mark LMBL defining the branch lane BL. Furthermore, the processor 10 can detect the branch start point STP by referring to map information and / or lane information 61.

[0032] The branch end point EDP is a point downstream (in the direction of travel of the vehicle) of the branch start point STP where the lane mark LMTL defining the left side of the main line L1 intersects with the lane mark LMBR defining the right side of the branch lane BL. The processor 10 can detect the branch end point EDP, where the lane mark LMTL defining the main line L1 intersects with the lane mark LMBR defining the branch lane BL, based on an image captured by a camera 21 capturing an image ahead of the vehicle V1 (T1). When observed from the vehicle V1 (T1) heading toward the branch area BR2, the intersection of the lane mark LMTL and the lane mark LMBR appears to form a "V" shape. The processor 10 can detect the branch end point EDP based on the image captured by the camera 21, using this "V" shape as a characteristic point. On some roads, only the lane mark LMTL' of the main line L1, which connects to the branch lane BL, may be different, for example, a solid line or a dashed line. The processor 10 can detect a branch end point EDP where the lane mark LMTL defining the main line L1 intersects with the lane mark LMBR defining the branch lane BL, based on changes in the appearance of the lane markings LMTL and LMTL' on the main line L1. Furthermore, the processor 10 can also detect the branch end point EDP by referring to map information and / or lane information 61. Note that while Figure 5 shows an example of a branch lane BL extending to the left of the main line L1 in the direction of travel, the same can be applied to a branch lane BL extending to the right of the main line L1 in the direction of travel.

[0033] The processor 10 detects the branch region BR1 or BR2 and determines that the host vehicle V1 (T1) has changed lanes when the host vehicle V1 (T1) reaches the branch region BR1 or BR2. The processor 10 determines that the host vehicle V1 (T1) has changed lanes when the current position of the host vehicle V1 (T1) detected by the sensor 2 approaches the branch region BR1 or BR2 within a predetermined distance (or within a predetermined TTC). The predetermined distance / predetermined TTC is a short distance that allows for determination of arrival. Based on the positional relationship between the branch region BR1 or BR2 and the host vehicle V1, the processor 10 determines that the host vehicle V1 has changed lanes to the branch lane BL and turns off a flag indicating that the host vehicle V1 is traveling through the traffic-restricted section TR. The host vehicle V1's lane change to the branch lane BL is used as a trigger to determine the end of travel through the traffic-restricted section TR. This allows the control of the driving assistance content to be released and the reduced level of driving assistance to be quickly switched back to the original high level, thereby reducing the burden on the driver. In principle, when the processor 10 determines that the host vehicle has approached or entered the branch area BR1 and changed lanes to the branch lane, it determines that the host vehicle is not traveling in the traffic-restricted section TR and turns off the determination flag for traveling in the traffic-restricted section TR. Even in this case, the processor 10 checks in advance whether traffic restriction signs OB2 and OB3 are present in the branch lane, as performed in S11 of FIG. 3 . In FIG. 5, the traffic restriction signs OB2 and OB3 are shown as virtual entities to illustrate the locations of the traffic restriction signs to be detected. When the processor 10 detects traffic restriction signs OB2 and OB3 in the branch lane, even if it determines that the host vehicle will change lanes to the branch lane BL, it determines that the host vehicle will continue traveling in the traffic-restricted section without turning off the determination flag for traveling in the traffic-restricted section TR and keeps the determination flag on. This makes it possible to prevent the determination of whether or not to drive through a restricted traffic section from being turned on and off, and to continue providing driving assistance appropriate to the situation.

[0034] The processor 10 detects a branch start point STP of the branch lane BL and determines that the host vehicle V1 (T1) has changed lanes when the host vehicle V1 (T1) reaches the branch start point STP. FIG. 5 shows a state in which the host vehicle V1 (T2) reaches the branch start point STP at a timing T2 after the timing T1. The host vehicle V1 (T2) reaching the branch start point STP means that the branch start point STP belongs to the location area of ​​the host vehicle V1 (T2). In other words, the state in which the host vehicle V1 (T2) reaches the branch start point STP includes all states from when the host vehicle V1 (T2) approaches the branch start point STP (the leading edge of the host vehicle overlaps with the branch start point STP) to when the host vehicle V1 (T2) passes the branch start point STP (the trailing edge of the host vehicle overlaps with the branch start point STP). In addition, from the viewpoint of increasing the certainty that the host vehicle V1 (T2) has changed lanes to the branch start point STP, it is preferable to define the state in which the host vehicle V1 (T2) has reached the branch start point STP as the state in which the host vehicle V1 (T2) has passed the branch start point STP. When the host vehicle V1 (T2) has reached the branch start point STP, the processor 10 determines that the host vehicle V1 (T2) has changed lanes to the branch lane and turns off a flag indicating that the host vehicle V1 (T2) is traveling in a traffic-restricted section TR. This makes it possible to determine at an early stage (upstream in the traveling direction) whether the host vehicle V1 (T2) will change lanes, thereby appropriately determining the end point of the traffic-restricted section and switching (returning) the reduced driving assistance level to the original high level at an early stage, thereby reducing the burden on the driver.

[0035] When determining that the host vehicle V1 (T2) has changed lanes to the branch lane BL based on the arrival of the host vehicle V1 (T2) at the branch start point STP, the processor 10 confirms in advance that a traffic-restricted section does not exist in the branch lane BL. Specifically, the processor 10 determines the direction in which the branch lane BL exists and the direction in which the branch lane BL extends based on the position of the branch start point STP of the branch lane BL. This determination is preferably made before the host vehicle V1 (T2) enters the branch lane BL, when the host vehicle V1 (T2) is traveling on the main lane L1 and approaches the branch start point STP. In the example shown in FIG. 5, the branch lane BL extends diagonally to the left (X direction in the figure) of the traveling direction of the host vehicle V1 (T1) or the host vehicle V1 (T2) (Y-axis direction in the figure). The location of the traffic regulation sign in the branch lane BL is not particularly limited. If the host vehicle V1 (T1) is located along the branch lane BL, the processor 10 determines that a restricted traffic section exists in the branch lane BL even if the traffic restriction sign OB2 is detected upstream of the branch lane BL (closer to the host vehicle V1) or the traffic restriction sign OB3 is detected downstream of the branch lane BL (farther from the host vehicle V1). The processor 10 determines that the host vehicle V1 (T1) or V1 (T2) is not traveling in a restricted traffic section only if the traffic restriction sign OB2 and / or OB3 indicating the presence of a restricted traffic section are not detected in the direction of the branch lane BL. In other words, if the host vehicle V1 (T1) is traveling on the main lane L1 and at least the traffic restriction sign OB2 is detected from the main lane L1 in the direction of the branch lane BL, the processor 10 maintains the determination that the host vehicle V1 is traveling in a restricted traffic section even if the host vehicle V1 (T2) reaches the branch start point STP. In principle, the processor 10 turns off the flag indicating that the vehicle V1 (T2) is traveling in a traffic-restricted section when the vehicle V1 (T2) reaches the branch start point STP and changes lanes from the main road L1, which includes the traffic-restricted section, to a branch lane BL, which is another road. Even in this case, the processor 10 checks in advance whether or not traffic restriction signs OB2 and OB3 are present in the branch lane BL, which includes the branch start point STP, as performed in S11 of FIG. 3.When a traffic restriction sign is detected in the branch lane BL including the branch start point STP, even if the host vehicle V1 is determined to change lanes to the branch lane, the processor 10 maintains the determination result from traveling on the main lane L1 that the host vehicle V1 is traveling in the traffic restriction section TR, without determining that the host vehicle V1 is not traveling in a traffic restriction section. In other words, the processor 10 determines that the host vehicle is traveling in a traffic restriction section without turning off the determination flag for traveling in a traffic restriction section, and maintains the determination flag on. This prevents the determination flag for traveling in a traffic restriction section from being turned on or off, allowing driving assistance appropriate for the situation to be continued. In addition, the host vehicle V1 can travel in the traffic restriction section of the branch lane BL with a low level of driving assistance, allowing the driver to drive carefully through the operation. From a similar perspective, processor 10 determines the direction in which the branch lane BL exists based on the position of the branch start point STP of the branch lane BL, and if no traffic restriction signs OB2, OB3 are detected in the direction in which the branch lane BL exists, determines that the host vehicle V1 will not be traveling in the traffic restriction section TR when the host vehicle V1 reaches the branch start point STP. This makes it possible to quickly determine the end point of the traffic restriction section while confirming that the branch lane BL does not include the traffic restriction section, and to switch from a low level of driving assistance to a high level of driving assistance and perform driving control based on the determination that the host vehicle is not traveling in the traffic restriction section.

[0036] The processor 10 detects the branch end point EDP of the branch lane BL and determines that the host vehicle V1 (T1) has changed lanes when the host vehicle V1 (T1) reaches the branch end point EDP. FIG. 5 shows a state in which the host vehicle V1 (T3) reaches the branch end point EDP at timing T3, which is later than timing T2. The host vehicle V1 (T3) reaching the branch end point EDP means that the branch end point EDP belongs to the location area of ​​the host vehicle V1 (T3). In other words, the state in which the host vehicle V1 (T3) reaches the branch end point EDP includes all states from when the host vehicle V1 (T3) approaches the branch end point EDP (the leading edge of the host vehicle overlaps with the branch end point EDP) to when the host vehicle V1 (T3) passes the branch end point EDP (the trailing edge of the host vehicle overlaps with the branch end point EDP). In addition, from the viewpoint of increasing the reliability of the determination that the host vehicle V1 (T3) has changed lanes to the branch end point EDP, it is preferable to define the state in which the host vehicle V1 (T3) has reached the branch start point STP as the state in which the host vehicle V1 (T3) has passed the branch start point STP. When the host vehicle V1 (T3) has reached the branch end point EDP, the processor 10 determines that the host vehicle has changed lanes to the branch lane and turns off a flag indicating that the host vehicle is traveling in a restricted-traffic section. When the state in which the host vehicle V1 (T3) has reached the branch end point EDP is detected, the possibility that the host vehicle V1 (T3) will return to the main lane L1 is extremely low. In other words, it is possible to determine with high accuracy that the host vehicle V1 (T3) will change lanes to the branch lane BL. The host vehicle V1, traveling upstream of the branch region BR2, i.e., near the branch start point STP, may proceed into the branch lane BL, but the possibility of continuing traveling on the main lane L1 without proceeding into the branch lane BL cannot be ruled out. Based on the host vehicle V1 (T3) reaching the branch end point EDP, the processor 10 can accurately determine whether the host vehicle V1 will change lanes into the branch lane BL. This allows the host vehicle V1 (T2) to accurately determine the end point of the traffic-restricted section based on the host vehicle V1 (T2) moving from the main lane L1, which includes a traffic-restricted section, to another branch lane BL. As a result, the restrictions on driving assistance set for traveling in the traffic-restricted section can be lifted, and the reduced level of driving assistance can be switched back to the original high level (standard level) in a timely manner, reducing the burden on the driver.

[0037] In principle, when the processor 10 determines that the host vehicle V1 (T3) has reached the branch end point EDP and changed lanes to the branch lane, it determines that the host vehicle is not traveling in the traffic-restricted section TR and turns off the determination flag for traveling in the traffic-restricted section TR. Even in this case, the processor 10 checks in advance whether traffic restriction signs OB2 and OB3 are present in the branch lane BL including the branch end point EDP, as performed in S11 of FIG. 3 described above. When the processor 10 detects a traffic restriction sign OB3 near the branch end point EDP or a traffic restriction sign OB2 upstream of the branch end point EDP, the processor 10 does not turn off the determination flag for traveling in the traffic-restricted section TR even if it determines that the host vehicle V1 (T3) will change lanes to the branch lane. In this case, the processor 10 determines that the host vehicle V1 (T3) is traveling in the traffic-restricted section and keeps the determination flag on. This prevents the determination flag for traveling in the traffic-restricted section from being turned on or off repeatedly, allowing driving assistance appropriate for the situation to be continued.

[0038] Incidentally, the condition for turning off the flag indicating travel in a traffic-restricted section may be a requirement that the host vehicle be a predetermined distance away from a state in which no traffic restriction signs are detected. In the example shown in FIG. 5, when the host vehicle changes lanes to the branch lane BL, and traffic restriction signs are no longer detected on either side of the host vehicle, and then the host vehicle arrives at the planned traffic restriction end point CHP, which is a predetermined distance DTH away, it is determined that the traffic restriction section has ended, and the flag indicating travel in a traffic-restricted section is turned off. In this way, if the condition is set to be a distance of at least a predetermined distance from the traffic restriction sign, the driving assistance level is not restored unless the host vehicle travels at least the predetermined distance. In contrast, in this embodiment, when the host vehicle changes lanes from the main lane L1 to the branch lane BL, it is determined that the host vehicle is not traveling in a traffic-restricted section. The positions of the branch regions BR1 and BR2 for determining lane changes, the branch start point STP, and the branch end point EDP are all located upstream of the planned traffic restriction end point CHP, allowing for early determination of whether the host vehicle is traveling in a traffic-restricted section.

[0039] 100... driving assistance system, 1... driving assistance device, 10... processor, 11... CPU, 12... ROM, 13... RAM, 20... input / output device, 30... communication device, 2... sensor, 21... camera, 22... radar device, 3... vehicle information acquisition device, 4... traffic regulation information acquisition device, 5... traffic regulation section determination device, 6... map information, 61... lane information, 7... navigation device, 200... vehicle controller, 210... steering control device, 220... drive control device

Claims

1. A driving assistance method used in a processor to execute driving assistance for a host vehicle, wherein the processor detects a traffic regulation sign on the driving lane of the host vehicle, restricts the content of driving assistance executed in a traffic regulation section recognized based on the traffic regulation sign, and when the host vehicle changes lanes to a branch lane that branches off from the driving lane during the restriction, releases the restriction.

2. The driving assistance method according to claim 1, wherein when the traffic regulation sign is detected in the branch lane, even if it is determined that the host vehicle changes lanes to the branch lane, the processor determines that the host vehicle travels through the traffic regulation section.

3. The driving assistance method according to claim 1 or 2, wherein the processor detects a branch area of the branch lane, and when the host vehicle reaches the branch area, determines that the host vehicle changes lanes.

4. The driving assistance method according to claim 1 or 2, wherein the processor detects an end point of the branch of the branch lane, and when the host vehicle reaches the end point of the branch, determines that the host vehicle changes lanes.

5. The driving assistance method according to claim 4, wherein when the traffic regulation sign is detected at the end point of the branch of the branch lane, even if it is determined that the host vehicle changes lanes to the branch lane, the processor determines that the host vehicle travels through the traffic regulation section.

6. The driving assistance method according to claim 1, wherein the processor detects a start point of the branch of the branch lane, and when the host vehicle reaches the start point of the branch, determines that the host vehicle changes lanes.

7. The driving assistance method according to claim 6, wherein the processor determines the direction in which the branch lane exists based on the position of the start point of the branch of the branch lane, and when the traffic regulation sign is detected in the direction in which the branch lane exists, even if it is determined that the host vehicle changes lanes to the branch lane, the processor determines that the host vehicle travels through the traffic regulation section.

8. The driving assistance method according to claim 6, wherein the processor determines the direction in which the branch lane exists based on the position of the start point of the branch of the branch lane, and when the traffic regulation sign is not detected in the direction in which the branch lane exists, determines that the host vehicle does not travel through the traffic regulation section when it reaches the start point of the branch.

9. The driving support method according to any one of claims 1 to 8, wherein when the processor determines that the host vehicle is traveling in the traffic control section, the processor executes the driving support at a lower level than when it is determined that the host vehicle is not traveling in the traffic control section.

10. The driving support method according to claim 9, wherein when the processor determines that the host vehicle is traveling in the traffic control section, the processor executes a hands-on driving request and / or a prohibition of autonomous lane change control as the driving support at a relatively low level.

11. The driving support method according to claim 9 or 10, wherein when the processor determines that the host vehicle is not traveling in the traffic control section, the processor executes hands-off driving permission and / or autonomous lane change control execution as the driving support at a relatively high level.

12. A driving support device including a processor that executes driving support for a host vehicle, wherein the processor detects a traffic control sign on the driving lane of the host vehicle, restricts the content of the driving support executed in a traffic control section recognized based on the traffic control sign, and releases the restriction when the host vehicle changes lanes to a branch lane that branches from the driving lane during the restriction.

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