Driving control method and driving control device

Abstract

A processor 10 is configured to: determine, on the basis of map information 5 including lane information and detection information from a sensor 2 of a host vehicle V1, that the host vehicle V1 is in a scenario in which the host vehicle V1 travels in a first lane L1 adjacent to a road shoulder among a plurality of lanes that share the same travel direction and belong to a road approaching an intersection SE provided with a traffic light SG; stop the host vehicle V1 behind a first object PV1 that is stationary ahead of the host vehicle V1 within a prescribed range from the intersection SE when it has been determined, on the basis of the detection information, that the first object PV1 is to be avoided by the host vehicle V1 and that a second object V2 is present within a prescribed distance in front of the first object PV1, and it has been recognized that the traffic light SG is presenting a proceed signal; determine, on the basis of the detection information, whether a lane change condition is satisfied or not satisfied when it is recognized that the traffic light SG is presenting a stop signal; and cause the host vehicle V1 to change lanes to a second lane L2 adjacent to the first lane L1 when the lane change condition is satisfied.

Description

Operation control method and operation control device

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

[0002] A technology is known in which, when changing lanes to overtake a preceding vehicle, if a congested vehicle is detected ahead of the preceding vehicle and an area in which the vehicle can move ahead of the preceding vehicle is not secured, the overtaking control is interrupted and the vehicle is returned behind the preceding vehicle.

[0003] JP 2016-16829 A

[0004] A vehicle behind a leading vehicle cannot determine whether an object in front of the leading vehicle is one that needs to be avoided. As a result, the vehicle either continues to wait behind the leading vehicle or attempts to change lanes to overtake the leading vehicle. However, if the vehicle changes lanes carelessly, it may stop across lanes when returning to its own lane, disrupting traffic flow in adjacent lanes.

[0005] The problem to be solved by the present invention is to reduce disruption to traffic flow in adjacent lanes and to perform driving control to avoid an object ahead.

[0006] The present invention solves the above problem by, when it is determined that a first object stationary in front of the vehicle within a predetermined range of an intersection equipped with traffic lights is an object to be avoided by the vehicle, and that a second object is present at a predetermined distance ahead of the first object, stopping the vehicle behind the first object if it recognizes that the traffic light is displaying a go signal, or changing lanes to a second lane adjacent to the first lane if it recognizes that the traffic light is displaying a stop signal.

[0007] According to the present invention, it is possible to reduce disruption to traffic flow in adjacent lanes and perform driving control to avoid an object ahead.

[0008] Fig. 1 is a block diagram showing a hardware configuration of a driving control system; Fig. 2 is a flowchart showing a processing procedure for driving control; Fig. 3 is a first diagram explaining the details of driving control for avoidance driving; Fig. 4 is a second diagram explaining the details of driving control for avoidance driving; and Fig. 5 is a third diagram explaining the details of driving control for avoidance driving.

[0009] 1 shows the hardware configuration of a driving control system 100 equipped with a vehicle driving control device 1 according to this embodiment. The driving control method is performed by a processor 10 of the driving control device 1 using each piece of hardware in the driving control system 100.

[0010] The driving control system 100 includes one or more sensors 2, a host vehicle information acquisition device 3, an object information acquisition device 4, map information 5, a navigation device 6, and a traffic light recognition device 7.

[0011] A plurality of sensors 2 are provided on the vehicle, forming a sensor group that works in coordination with each other. The sensors 2 detect the presence or absence of objects, including other vehicles, around the vehicle, the distance to the objects, and the relative speed and relative acceleration of the objects. The sensors 2 detect other vehicles traveling in front, behind, on the left and right sides of the vehicle (oncoming lanes, adjacent lanes, and adjacent lanes). The detection information acquired by the sensors 2 is provided to the processor 10. The processor 10 determines the object's position, posture, and movement (speed, acceleration, etc.) and their changes based on the detection information, and performs driving control using the determination results. The sensors 2 include one or more cameras 21 arranged on the vehicle. The cameras 21 capture images of the vehicle's surroundings in all directions. The cameras 21 include image sensors with imaging elements such as CCDs, ultrasonic cameras, and infrared cameras. The cameras 21 include 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 front and rear of the left and right sides of the vehicle. The camera 21 may be of any type, provided it can capture images of the entire vehicle. The sensor 2 includes a radar device 22 that detects (measures) the presence, position, and position changes 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 from the vehicle to the object and the distance between the object and other objects. The radar device 22 includes laser radar, millimeter-wave radar (LRF), a light detection and ranging (LiDAR) unit, ultrasonic radar, and sonar. The sensor 2 also includes a receiver for signals from a global positioning system (GPS) or a global navigation satellite system (GNSS), a gyro sensor, and a vehicle speed sensor, which are used to detect the vehicle's position. Each sensor 2 can also acquire information from on-board devices and external devices according to its respective function. Each sensor 2 transmits the acquired detection information to the vehicle information acquisition device 3, the object information acquisition device 4, or the processor 10 in response to a request or command. The processor 10 may acquire the detection information directly from the camera 21 and the radar device 22, or may acquire the detection information via the host vehicle information acquisition device 3 and the object information acquisition device 4.

[0012] The host vehicle information acquisition device 3 calculates the current position, attitude, speed, acceleration, behavior, and direction of travel of the host vehicle based on the detection information acquired from the sensor 2, and provides the calculated information to the processor 10. The object information acquisition device 4 calculates the position, attitude, speed, acceleration, behavior, and direction of travel of objects, including other vehicles, around the host vehicle based on the detection information acquired from the sensor 2, and provides the calculated information to the processor 10. This information is used for autonomous driving control.

[0013] The driving control system 100 further includes map information 5 having lane information 51. The map information 5 is stored in one or more of the ROM 12, the storage device of the navigation device 6, and the storage device of an external server accessible by the processor 10 via the communication device 30. The map information 5 is high-precision map information that includes lane information 51 that is referenced when executing autonomous lane change control. The lane information 51 includes identification information that identifies each of multiple lanes belonging to a road. The map information 5 includes the positions of traffic lights and the positions of intersections equipped with traffic lights, and the lane information 51 includes identification information for roads entering and exiting each intersection and the lanes belonging to those roads. The lane identification information includes the position of each lane and the relationship between adjacent lanes. By referring to the lane information 51, the processor 10 can determine, based on the driving lane identified based on the current location and the lane identification information, whether the driving lane is the rightmost or leftmost lane among multiple lanes in the same direction, whether the driving lane is adjacent to the shoulder or adjacent to an oncoming lane, and which lane the driving lane is from the right or left among multiple lanes. Note that while this embodiment describes an example of left-hand traffic, it can also be applied to right-hand traffic. The navigation device 6 refers to the map information 5 to calculate a route to a set destination. This route includes a target trajectory in which the traveling lane is identified. The route and target trajectory calculated by the navigation device 6 are provided to the vehicle controller 200 and used for autonomous driving control. The navigation device 6 refers to the lane information 51 in the map information 5 to identify a first lane adjacent to the shoulder of a road that is a road entering an intersection equipped with traffic lights and that belongs to the road and has a common traveling direction. The first lane adjacent to the shoulder is a lane where on-street parking, construction / inspection of facilities, and accident response are likely to occur. Since this road has multiple lanes, there is a second lane adjacent to the first lane. Vehicles traveling in the first lane can change lanes to the second lane. The navigation device 6 determines whether the vehicle will travel in the first lane based on the current position of the vehicle obtained from the sensor 2. The navigation device 6 identifies a scene in which the vehicle travels in the first lane adjacent to the shoulder of the road among multiple lanes with a common traveling direction that belong to a road entering an intersection with traffic lights as a "target scene."When the navigation device 6 determines that the vehicle has encountered a target scene, it notifies the processor 10 of this fact. The processor 10 recognizes the "target scene" and executes driving control for the evasive driving in the "target scene." The processor 10 can also execute processing to identify the "target scene." The driving control system 100 is equipped with a traffic light recognition device 7. The traffic light recognition device 7 uses a camera 21 to identify the color of the traffic light, refers to legal information of each country / region, and recognizes the content of the traffic control command, such as proceed, stop, or caution, associated with each color. The traffic light recognition device 7 may obtain the content of the signal displayed by the traffic light ahead on the road on which the vehicle is traveling from a roadside device via a communication device 30. The signal recognition result is provided to the processor 10.

[0014] The driving control system 100 includes a vehicle controller 200. The vehicle controller 200 is equipped with a steering control device 210 and a drive control device 220. The vehicle controller 200 acquires command values ​​for autonomous driving control according to a driving plan formulated by the processor 10 of the driving control device 1, and controls the host vehicle to travel along a route to a destination. The route is composed of a series of target trajectories to which command values ​​are associated. The target trajectory includes trajectories for lateral movement and / or lane changes to avoid approaching other vehicles or objects. The trajectory for lateral movement is calculated based on a target lateral position to avoid approaching other vehicles or objects. The command values ​​for driving control are generated by the vehicle controller 200 or the processor 10. The command values ​​are vehicle control command values ​​for driving the host vehicle along the target trajectory. The command values ​​include a set speed (including an upper limit speed and an applicable 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 to 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 vehicle autonomously travels along a route to the destination. Based on these controls, at least one of the drive actuator and the brake actuator 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, and autonomous driving control is executed to make the vehicle autonomously travel along a target trajectory. Furthermore, the vehicle controller 200 can execute driving according to command values ​​based on manual operation by the driver input via the input / output device 20.

[0015] The driving control device 1 included in the driving control system 100 controls autonomous driving of the vehicle to travel along a target trajectory. The driving control device 1 of this embodiment controls driving, including avoidance driving to avoid an object ahead of the vehicle. The processor 10 included in the driving control device 1 includes a ROM (Read Only Memory) 12 storing a program for controlling autonomous 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 control method using each hardware of the driving control system 100. The processor 10 executes each function by cooperating with the hardware shown in FIG. 1 and software for realizing a function to recognize when the vehicle encounters a predetermined target scene, a function to determine whether a first object and / or a second object are objects to be avoided, and an autonomous driving function to execute driving control of avoidance driving, including lane changes, depending on the content of traffic lights. In this embodiment, "lane change" includes a lane change from the first lane to the second lane and a lane change from the second lane to the first lane.

[0016] The autonomous driving control process will be described with reference to the flowchart in FIG. 2. The processor 10 acquires detection information from the sensor 2, which includes the camera 21 and the radar device 22 (S1). The detection information includes detection information based on the image capture information from the camera 21 and detection information based on the observation information from the radar device 22. The processor 10 acquires host vehicle information, such as the host vehicle's current position and speed, from the host vehicle information acquisition device 3 (S2). The processor 10 references the detection information from the sensor 2 and map information 5 containing lane information 51 (S3) to identify the host vehicle's traveling lane (S4). The processor 10 then references the map information 5 containing the lane information 51 to confirm that the host vehicle's traveling lane belongs to a road leading to an intersection equipped with traffic lights (S5). Furthermore, the processor 10 confirms that the host vehicle's traveling lane is the first lane adjacent to the shoulder of multiple lanes sharing a common traveling direction (S6). If S5-S6 are satisfied, the processor 10 determines that the host vehicle's traveling situation is a target situation for executing this driving control. If not (NO in S5, NO in S6), the process returns to S1 and repeats the processes from S1 onwards. The processes of S2 to S6 may be executed by the navigation device 6, and the decision made by the navigation device 6 may be obtained.

[0017] In the target scene (YES in S5-S6), processor 10 acquires detection information of objects around the host vehicle from sensor 2 of the host vehicle (S7). Although the presence of a first object may block acquisition of a detection signal, preventing sufficient detection information from being obtained about a second object in front of the first object, processor 10 determines that the second object is in front of the first object and acquires the distance between the first object and the second object. Based on the detection information, processor 10 recognizes that a stationary first object exists in front of the host vehicle within a predetermined range upstream from the intersection, and that a second object exists within a predetermined distance ahead of the first object (S8). Processor 10 acquires detection information of the first object (S9). Based on the detection information of the first object, processor 10 determines whether the first object is an object to be avoided that must be avoided by the host vehicle (S10). An object to be avoided is an object whose area of ​​existence interferes with at least a portion of the vehicle's travel area as it moves along a route toward the destination. Specifically, the object to be avoided is a stationary object with attributes such as a parked vehicle, a construction site, an installation, or an unreachable area that the host vehicle must avoid (i.e., if the host vehicle does not avoid the object, the host vehicle will not be able to reach the destination). The object to be avoided does not include vehicles or objects temporarily stopped at a traffic light or otherwise waiting to resume movement. Processor 10 calculates the lateral position of the first object relative to the first lane from the detection information of the first object and determines whether the first object is an object to be avoided based on the lateral position. When the distance between the first object and the boundary with the shoulder of the first lane (the edge of the first lane on the shoulder side) is less than a predetermined distance, processor 10 determines that the first object is not an object attempting to travel in the first lane but is an object to be avoided that has moved to the shoulder so as not to obstruct the roadway. Furthermore, when the lateral position of the reference point of the first object is deviated by a predetermined amount or more toward the shoulder of the first lane, processor 10 determines that the first object is not an object attempting to travel in the first lane but is an object to be avoided. The reference point is the center of gravity or the center of the vehicle width of the first object. The predetermined amount as a threshold for determining the lateral position relative to the first lane can be set based on the lateral position of the road when the vehicle is normally traveling on the first lane. Furthermore, the processor 10 determines that the first object is an object to be avoided when it is confirmed to be in a stationary state, i.e., there has been no change in position in the vehicle width direction or the vehicle length direction for a predetermined period of time or more.Furthermore, the processor 10 may perform a pattern matching process on the image of the first object captured by the camera 21 with a pre-stored image feature pattern of each object to determine the attributes of the first object, and determine whether the first object is an object to be avoided based on the attributes. If the first object is a vehicle and an object to be avoided, the first object can be determined to be a parked vehicle. If an object indicating a construction site (e.g., a cone) or a no-entry sign is detected around the first object, the first object can be determined to be a construction site. In addition, if the processor 10 obtains detection information that the first object, a vehicle, has its hazard lights on, it determines that the stopped state is likely to continue and determines that the first object is an object to be avoided. If the first object, a vehicle, has its turn signal lights on, it determines that the stopped state is likely to be released and determines that the first object is not an object to be avoided. Note that the method for determining whether a first object is an object to be avoided can also be applied to determining whether a second object is an object to be avoided. If the first object is not an object to be avoided (NO in S10), the first object is a moving object traveling in the first lane, and therefore the host vehicle is stopped behind the first object (S13).

[0018] Through the processing of S7-S10, in the above-mentioned "target scene," if the presence of a first object to be avoided, stationary in front of the vehicle within a predetermined range from the intersection, is detected based on the detection information, and if it is determined that a second object exists within a predetermined distance ahead of the first object (YES in S10), the signal of the traffic light ahead is recognized (S11). If it is recognized that the traffic light is displaying a proceed signal (NO in S12), the vehicle is stopped behind the first object (S13). If it is recognized that the traffic light is displaying a stop signal (YES in S12), the process proceeds to S14. When the traffic light is displaying a stop signal, the processor 10 acquires detection information from the sensor 2 (S14). Specifically, it acquires detection information of a vehicle traveling in the second lane and approaching the vehicle from behind (S15). Then, the predefined lane change conditions are referenced (S16). The lane change conditions are experimentally set based on at least one or more pieces of information, including the vehicle type (large vehicle, standard vehicle, compact vehicle), vehicle performance, the performance or accuracy of the vehicle's sensor 2, and the attributes of the road to which the vehicle is traveling (highway, motorway, urban road). The lane change conditions are pre-stored in ROM 12 of processor 10. Processor 10 constantly monitors whether the lane change conditions are met at a predetermined interval during autonomous driving control (S14-S17). Processor 10 determines whether the lane change conditions are met (S17) based on detection information (S14) obtained when it is determined that a first object is stationary in front of the vehicle within a predetermined range from an intersection and a second object is present within a predetermined distance ahead of the first object in the target scene, and a stop signal is recognized by a traffic light (YES in S12). When the traffic light is displaying a stop signal, if the processor 10 detects a rear vehicle approaching the host vehicle from behind in the second lane based on the rear vehicle detection information obtained in S15, it determines whether the lane change conditions are met or not based on the relative distance and relative speed of the rear vehicle to the host vehicle (S17). The proximity between the host vehicle and the rear vehicle may be evaluated using an index based on the time to collision (TTC). If the lane change conditions are not met (NO in S17), the process returns to S14 and waits for a timing when a lane change is possible. If the lane change conditions are met (YES in S17), the process calculates a driving plan for changing lanes from the first lane to the second lane (S18).The driving plan includes a target trajectory, a set vehicle speed and a steering amount at each point on the target trajectory. The processor 10 executes a lane change to move the host vehicle from the first lane to the second lane based on the driving plan including the lane change (S19).

[0019] When avoiding at least the first object, if the traffic light is recognized as indicating a stop signal, the system determines whether the lane change condition is satisfied or not based on the detection information. This prevents the host vehicle from getting too close to the rear vehicle in the second lane where the host vehicle plans to change lanes. In other words, since the system confirms in advance that the lane change condition is satisfied when the stop signal is displayed, disruption of traffic flow can be prevented even if the host vehicle changes lanes from the first lane to the second lane. In particular, by confirming in advance that the lane change condition is satisfied for the rear vehicle approaching the host vehicle from behind in the second lane, a sufficient inter-vehicle distance is ensured between the host vehicle and the rear vehicle in the second lane, thereby preventing disruption of traffic flow even if the host vehicle changes lanes to the second lane. Whether the lane change is satisfied or not is determined based on the proximity calculated from the relative distance and / or relative speed of the rear vehicle to the host vehicle based on the detection information. When a first object and a second object to be avoided are present in a target scene formed upstream (in front of) an intersection, the processor 10 determines whether a lane change condition is satisfied when it recognizes that a traffic light ahead of the host vehicle is displaying a stop signal, and then executes a lane change to move the host vehicle from the first lane to the second lane. When it recognizes that the traffic light is displaying a stop signal, this is a timing when the traffic light's stop signal is predicted to block traffic flow in the second lane. When the traffic light is displaying a proceed signal, entering or stopping the host vehicle in the second lane disrupts traffic flow, but when the traffic light is displaying a stop signal, the host vehicle is less likely to disrupt traffic flow in the second lane. The processor 10 determines whether a lane change condition is satisfied when the traffic light is displaying a stop signal, and changes lanes from the first lane to the second lane only when the lane change condition is satisfied. According to this driving control, it is possible to overtake the first object and the second object and avoid the first object and the second object while suppressing disruption of traffic flow in the second lane. Note that in this embodiment, the lane change to move the host vehicle from the first lane to the second lane is a first driving control to avoid the first object and the second object. The subsequent lane change to move the host vehicle from the second lane to the first lane is also a second driving control to avoid the first object and the second object.The avoidance maneuver to avoid the first object and the second object is a maneuver in which the host vehicle traveling in the first lane changes lanes to the second lane, overtakes the first object and the second object, and then returns to the first lane. The driving control involving the avoidance maneuver to avoid the first object and the second object includes a first lane change driving control to move the host vehicle from the first lane to the second lane, and a second lane change driving control to move the host vehicle from the second lane to the first lane. This second driving control is executed based on detection information measured during the execution of the first lane change driving control to move the host vehicle from the first lane to the second lane. This detection information includes the lateral position of the second object relative to the first lane, measured during the execution of the first driving control.

[0020] As described in the description of S8 in FIG. 2 , although processor 10 can detect the presence of a second object in front of the first object, the presence of the first object may prevent processor 10 from acquiring sufficient detection information about the second object. Even if processor 10 determines whether the second object is moving at a certain detection timing while traveling in the first lane, it may not be possible to determine whether the second object is a continuously stationary object (a target to be avoided) or an object that temporarily stops but then starts moving (a non-target to be avoided). Because it is unclear whether the second object is a target to be avoided, the host vehicle behind the first object may not be able to plan where to return to in the first lane after moving to the second lane to avoid the first object. If the host vehicle changes lanes recklessly, the host vehicle may stop straddling lanes when moving from the second lane to the first lane, disrupting traffic flow in the second lane. On the other hand, if the host vehicle changes lanes with a lateral movement and does not overtake the first object to be avoided, the host vehicle may have to remain stopped behind the first object.

[0021] While the host vehicle is changing lanes, the processor 10 acquires detection information of a second object located behind (further ahead of) the first object to be avoided, and guides the host vehicle to an appropriate position on the first lane that is planned based on the detection information. If it is possible to determine whether the second object is an object to be avoided based on the detection information, an appropriate position on the first lane can be identified based on this determination. This prevents the host vehicle from being unable to return to the first lane after changing lanes to the second lane and becoming stuck across lanes. In this way, the host vehicle changing lanes to avoid the first object can avoid disrupting traffic flow in the second lane and avoid being forced to wait for a long time behind the object to be avoided, and can avoid the first object at the appropriate time and return to an appropriate location on the first lane. In addition, in the target scene, when it is determined that there is a first object to be avoided and a second object in front of it, and the traffic light displays a proceed signal, the traffic volume and traffic speed in the second lane are greater than when a stop signal is displayed, making it difficult to change lanes into the second lane without disrupting the traffic flow in the second lane.

[0022] When the lane change is initiated in S19, the lateral position of the vehicle changes. This causes a shift in the positional relationship between the first object and the second object relative to the vehicle, allowing processor 10 to acquire detection information of the second object through the first object (S20). While the lane change is being performed, processor 10 determines whether the second object is an object to be avoided. Specifically, processor 10 calculates the lateral position of the second object relative to the first lane based on the detection information of the second object (S21), and determines whether the second object is an object to be avoided, such as a parked vehicle, based on the lateral position (S22). For example, when the distance between the shoulder of the first lane and the second object is less than a predetermined distance, processor 10 determines that the second object is not an object that will continue traveling in the first lane, but is an object to be avoided, such as a parked vehicle. Furthermore, when the lateral position of the reference point of the second object is deviated by more than a predetermined amount toward the shoulder of the first lane, processor 10 determines that the second object is not an object that will continue traveling in the first lane, but is an object to be avoided. The method for determining whether a first object is a target for avoidance is used as the method for determining whether a second object is a target for avoidance. To avoid repetition, the above-mentioned description of the method for determining whether a first object is a target for avoidance is also used here as the description of the method for determining whether a second object is a target for avoidance. If the second object is a target for avoidance (YES in S22), the host vehicle must avoid the second object in addition to the first object. The processor 10 causes the host vehicle, which moved to the second lane due to the lane change started in S19, to change lanes from the second lane to the first lane (return) and move in front of the second object (S23). If the second object in front of the first object is also a target for avoidance, the host vehicle can avoid getting stuck behind the target for avoidance by overtaking the first and second objects and getting in front of the second object. On the other hand, if the second object is not a target for avoidance (NO in S22), the host vehicle must follow the second object and travel in the first lane. Therefore, the processor 10 causes the host vehicle, which has moved to the second lane due to the lane change started in S19, to change lanes from the second lane to the first lane (return to the original lane) and move it behind the second object (S24). In this way, if the first object is an object to be avoided but the second object is not an object to be avoided, for example, a moving vehicle, the processor 10 causes the host vehicle to get behind the second object.This can prevent the vehicle from being controlled to overtake the second object and cut in line.

[0023] The movement of the host vehicle in the above process will be explained based on Figures 3(a), 3(b), and 3(c). In each figure in Figure 3, the avoidance target is a parked vehicle. Figure 3(a) shows an example of a target scenario in which driving control is executed. Figure 3(a) shows two lanes, L1 and L2, on one of the inbound and outbound lanes, separated by a dividing line LD. The other inbound or outbound lane is omitted. The dividing line LD may be composed of a median strip or the like. The number of lanes is not limited. In Figure 3(a), the host vehicle V1 (T1) is traveling in the first lane L1, which is located closest to the shoulder (opposite the dividing line LD) of multiple lanes L1 and L2 that share the same traveling direction. An intersection SE with a traffic light SG is located ahead of the first lane L1, and the road including the first lane L1 and the second lane L2 connects to the intersection SE. In the target scene, the processor 10 detects a first object PV1 in front of the host vehicle V1 (T1) traveling in lane L1 at time T1 within a predetermined range RD upstream (-Y direction in the figure) from the intersection SG in the opposite direction to the host vehicle's traveling direction (Y direction in the figure). The processor 10 then recognizes that the first object PV1 is an object to be avoided by the host vehicle V1 and that the second object V2 is located within a predetermined distance M ahead of the first object PV1 based on the detection information, including the lateral position of the first object PV1. The predetermined distance M is not particularly limited, but can be set to approximately 5 m–20 m, taking into account typical vehicle lengths. Figure 3(a) illustrates a situation in which a second object V2, such as a parked vehicle (avoidance object) or a vehicle temporarily stopped due to a traffic jam or stoplight, is located in front of the first object PV1. Figure 3(a) illustrates an example of the detection area AR of the sensor 2 of the host vehicle V1. Even within the detection area AR, the sensor 2 cannot obtain sufficient detection information about the second object V2 due to the obstruction of the first object PV1 ahead. Although the presence of the second object V2 and its temporary behavior (stopped or moving) can be detected, the processor 10 cannot measure the lateral position of the second object V2 relative to the first lane L1. When the traffic light SG ahead is displaying a stop signal (STOP), the processor 10 confirms that the lane change conditions are met and changes the host vehicle V1 (T1) from the first lane L1 to the second lane L2. In Figure 3(b), the lateral position of the host vehicle V1 (T1) that has started to change lanes shifts toward the second lane L2.As the host vehicle V1 (T2) moves away laterally from the first lane L1, its positional relationship with the first object PV1 changes, enabling the sensor 2 to acquire detection information for the second object V2. The processor 10 is then able to calculate the lateral position of the second object V2 relative to the first lane L1 during a lane change. The processor 10 measures the distance W1 between the second object V2 and the lane mark SD on the shoulder of the road. If the distance W1 is less than a predetermined value, the processor 10 determines that the second object V2 is an object to be avoided. If the distance W1 is equal to or greater than the predetermined value, the processor 10 determines that the second object V2 is not an object to be avoided. The distance W1 is not particularly limited, and if the second object V2 is a vehicle, it can be set to approximately 0.3 m to 0.7 m, taking into account passengers getting on and off. The processor 10 determines the target points TP1 and TP2 for the host vehicle V1 (T2) depending on whether the second object V2 is an object to be avoided. If the second object V2 is a target to be avoided, a target point TP1 is set in front of the second object V2. If the second object V2 is not a target to be avoided, a target point TP2 is set behind the second object V2. The target point TP1 is set so that the host vehicle does not cross the stop line at the intersection SE. If it is determined that the host vehicle will cross the stop line, the target point TP1 is not set and the host vehicle is made to wait. The target point TP2 is set in front of the first object PV1, and the host vehicle V1 is made to wait until there is enough space between the first object PV1 and the second object V2 for the host vehicle V1 to enter. Since the second object V2 is not a target to be avoided, the host vehicle V1 starts moving immediately, and the waiting time is shorter than the traffic light cycle. Figure 3(c) shows the host vehicle V1 (T3) at timing T3 when it moves to the target point TP2, which was set when the second object V2 was not a target to be avoided. When encountering a situation in which a stationary first object PV1 and a second object V2 exist side by side (in tandem), conventionally, the host vehicle V1 would not know whether the second object V2 in front of the first object PV1 is an object to be avoided, and would either continue to wait behind the parked vehicle of the first object PV1, or would recklessly change lanes, disrupting traffic flow in the second lane L2. By having the host vehicle V1 change lanes when the traffic light SG displays a stop signal STOP in a situation in which a stationary first object PV1 and a second object V2 exist side by side in the target scene, as in the present driving control, the waiting time is limited to a finite time corresponding to the signal cycle time, and disruption of traffic flow in the second lane L2 can be suppressed.In the timing diagram of FIG. 3, time passes in the order of T1, T2, and T3.

[0024] 4(a), 4(b), and 4(c) will be used to explain the processing performed when multiple second objects V2 are present. The host vehicle V1 shown in each diagram in FIG. 4 is shown in a state in which the host vehicle V1 is in the process of or has completed the lane change from the first lane L1 to the second lane L2, which was initiated in S19 in FIG. 2. When multiple second objects V2a, V2b, and V2c are detected lined up ahead of the first object PV1, which is an avoidance target, the processor 10 measures the lateral positions of the closest second object V2a, the next closest second object V2b, and the next closest second object V2c relative to the first lane L1 in accordance with the order in which the host vehicle V1 approaches, and sequentially determines whether each of the second objects V2a, V2b, and V2c is an avoidance target based on the measured lateral positions. Because accurate lateral position measurement is not possible unless the host vehicle V1 approaches the second objects V2a, V2b, and V2c, the processor 10 sequentially determines whether the second objects V2a, V2b, and V2c are objects to be avoided as the host vehicle V1 moves forward. Even after the lateral position moves to the second lane L2, the processor 10 continues to determine whether the second objects V2a, V2b, and V2c are objects to be avoided. When the processor 10 detects a second object V2a, V2b, or V2c that is not an object to be avoided, the processor 10 changes lanes of the host vehicle V1 from the second lane L2 to the first lane L1, and moves the host vehicle V1 behind the second object V2a, V2b, or V2c that was initially determined not to be an object to be avoided. As shown in FIG. 4(a), if all of the second objects V2a, V2b, and V2c lined up in front of the first object V1P, which is the object to be avoided, are not to be avoided, a target point TP is set in front of the first object V1P and behind the second object V2a, and the host vehicle V1 is moved to the target point TP by changing lanes from the second lane L2 to the first lane L1. In this example, the second object V2a is the first object determined not to be a target to be avoided. FIG. 4(b) shows a method for setting the target point TP for the host vehicle V1 when the second objects V2 include both objects that are to be avoided and objects that are not to be avoided. FIG. 4(b) shows the second object V2aP, which is a target to be avoided, and the second objects V2b and V2c, which are not to be avoided. Of the second objects V2b and V2c determined not to be a target to be avoided, the second object V2b is the first object determined not to be a target to be avoided.When the processor 10 first detects a second object V2b that is not an avoidance target among the multiple second objects V2, the processor 10 changes lanes of the host vehicle V1 from the second lane L2 to the first lane L1 and moves the host vehicle V1 to a target point TP behind the second object V2b. The host vehicle V1 overtakes the second object V2aP that is an avoidance target and moves to an appropriate position without cutting in front of the second object V2b that is not an avoidance target. FIG. 4(c) shows a method of setting the target point TP for the host vehicle V1 when all the second objects V2 are avoidance targets. When the processor 10 sequentially determines that all of the multiple second objects V2aP, V2bP, and V2cP are avoidance targets, the processor 10 changes lanes of the host vehicle V1 from the second lane L2 to the first lane L1 and moves the host vehicle V1 to a target point TP set in front of the second object V2cP that was last determined to be an avoidance target. The second object V2cP is located furthest downstream (in the direction of travel, the Y direction in the figure) among the second objects V2aP, V2bP, and V2cP. The target point TP is set at a position where the host vehicle V1 does not pass the stop line at the intersection SE. With the above control, even if there are multiple second objects V2 in front of the first object V1P that is the object to be avoided, the host vehicle V1 can return to an appropriate position in the first lane L1 while overtaking the object to be avoided, without cutting in front of the second objects V2 that are temporarily stopped.

[0025] Control according to a vehicle queue at an intersection of the second lane L2 will be described based on Figures 5(a) and 5(b). Processor 10 evaluates the lengths E1 and E2 of the vehicle queue extending from intersection SE of the second lane L2. Vehicle V2' constituting the vehicle queue is traveling at a low speed or is stopped. Processor 10 determines whether there is a vehicle queue with a length EX that starts at intersection SE of the second lane L2 and reaches a forward position FP a predetermined distance FD ahead of the host vehicle V1. Processor 10 determines, using detection information from sensor 2, that there is a vehicle queue leading to position FP ahead of the host vehicle V1 based on the fact that the length of the vehicle queue on the second lane L2 is equal to or greater than length EX. Processor 10 determines, using detection information from sensor 2, that there is a vehicle queue leading to position FP ahead of the host vehicle V1 based on the fact that the vehicle queue on the second lane L2 extends to position FP. Processor 10 also determines, using the detection information from sensor 2, that a convoy of vehicles is present leading to a position FP ahead of vehicle V1 based on the fact that the distance between vehicle V2, the rearmost vehicle in the convoy in lane L2, and host vehicle V1 is less than or equal to a predetermined distance FD. Processor 10 determines, based on the position of vehicle V1 in lane L1, whether a convoy of vehicles is present in lane L2 of the same length as the convoy from intersection SE on lane L1 to host vehicle V1. Figure 5(a) shows an example of a convoy of vehicles with length E1 starting from intersection SE on lane L2. The length E1 of the convoy shown in Figure 5(a) is less than length EX (E1<EX). Figure 5(b) shows an example of a convoy of vehicles with length E2 starting from intersection SE on lane L2. The length E2 of the convoy shown in Figure 5(b) is greater than or equal to length EX (E2≧EX). The predetermined distance FD that defines the threshold for the length of the vehicle queue may be the distance to the position of the first object PV1 to be avoided or to a position a predetermined distance ahead of the first object PV1. If the vehicle changes lanes with the position of the first object PV1 to be avoided or a position FP ahead of the first object PV1 as the target point, the vehicle can overtake the first object PV1 and return to the first lane L1 before it. When a vehicle queue with a length EX extending from the intersection SE of the second lane L2 to a position FP a predetermined distance FD ahead of the host vehicle V1 is not formed in the second lane L2, as in the example of FIG. 5(a), the processor 10 changes the threshold for the lane change condition so that a lane change is less likely to be executed than when a vehicle queue with a length equal to or greater than EX is formed in the second lane L2, as in the example of FIG. 5(b).The threshold value of the lane change condition may be changed based on the detection of a rear vehicle V3 traveling in the second lane L2 approaching the host vehicle V1 from behind. The threshold value of the lane change condition is one or more of the following thresholds set in the lane change condition: relative speed, relative distance, relative acceleration, proximity, and the size of the host vehicle's movement area relative to other vehicles. For example, the lane change condition that requires a lane change when the relative distance is equal to or greater than a predetermined value A is changed to the lane change condition that requires a lane change when the relative distance is equal to or greater than a predetermined value B (>A). The updated lane change condition makes it more difficult to execute a lane change than the previous lane change condition. A specific processing procedure is additionally shown in FIG. 2. When the lane change condition is acquired in S16 shown in FIG. 2, the processor 10 performs a lane change condition change process (S31) if the length of the vehicle queue in the second lane L2 satisfies the requirements. The process of changing the lane change conditions may involve selecting a lane change condition with a relatively low degree of ease of execution from among pre-stored lane change conditions associated with the lane change execution ease. The processor 10 updates the current lane change conditions to the newly selected lane change conditions (S32), determines whether the updated lane change conditions are satisfied or not based on the updated lane change conditions (S17), and performs the processes from S18 onward. The processes of S31-32 are optional and can be skipped. If a line of vehicles with a length equal to or greater than EX is formed in the second lane L2, the lane change destination, the lane change is made more difficult and the timing of the lane change is delayed. Even if a vehicle approaching the second lane L2 from behind, the host vehicle V1 temporarily waits before changing lanes, and then allows the vehicle V3 to proceed toward the intersection SE before executing the lane change. Considering that the host vehicle V1 is returning from the second lane L2 to the first lane L1, as shown in Figure 5(a), if there is space ahead near the intersection SE (if there is no vehicle train reaching the forward position FP), the host vehicle V1 does not rush to change lanes, but instead prioritizes the straight-ahead driving of the rear vehicle V3 and guides the rear vehicle V3 into the space ahead. The host vehicle then changes lanes to the second lane L2 and executes a lane change from the second lane L2 back to the first lane L1. In addition, by changing the predetermined distance FD and setting the forward position FP in front of the first object PV1, the host vehicle V1 can overtake the first object PV1, which is the avoidance object, and return in front of it when returning to the first lane L1.In this way, by making it less likely that the lane change conditions for the host vehicle V1 will be met when there is no vehicle procession reaching the forward position FP on the second lane L2, even if the rear vehicle V3 is approaching the host vehicle V1, the host vehicle V1 will not obstruct the progress of the rear vehicle V3, and the host vehicle V1 can smoothly change lanes to return to an appropriate position on the first lane L1 (in front of the object to be avoided) while maintaining smooth traffic flow on the second lane L2.

[0026] The process of changing the driving plan for lane change control executed in this driving control will be described with reference to FIG. 5(c). As shown in FIG. 5(c), when a first object PV1 and one or more second objects V2 are detected in the target scene and a traffic light SE is recognized as displaying a stop signal (STOP), the processor 10 executes a lane change to the second lane L2 to avoid the first object PV1 and obtain detection information for the second object V2. In this process, the standard first lane change control C1 is changed to a second lane change control C2 that is modified for application to avoidance control. First, when the processor 10 detects the first object PV1 and the second object V2 in the target scene and determines that a traffic light SG is displaying a stop signal (STOP), the processor 10 changes the standard set vehicle speed in the first lane change control C1 to a lower value in the lane change control to be executed. The set vehicle speed includes an upper limit vehicle speed and an applicable vehicle speed. The executed lane changes include a lane change from the first lane L1 to the second lane L2 and a lane change from the second lane L2 to the first lane L1. The changed set vehicle speed is applied to both lane changes. As a result, whether a lane change from the first lane L1 to the second lane L2 or a lane change from the second lane L2 back to the first lane L1, the host vehicle V1 can be accurately moved to the target point, and driving control can be executed to move the host vehicle V1 to or return it to a limited area in front of an object to be avoided and behind an object that is not to be avoided.

[0027] Second, when the processor 10 detects the first object PV1 and the second object V2 in the target scene and determines that the traffic light SG is displaying a stop signal, it plans to determine whether the lane change condition is met and to execute lane change control. Before executing lane change control, the processor 10 changes the target trajectory used in lane change control. As shown in FIG. 5(c), the processor 10 calculates a second target trajectory including a second lateral position P2 that is shifted toward the second lane L2 from the first lateral position P1 of the first target trajectory calculated in the normally applied first lane change control C1. The processor 10 then causes the host vehicle to execute a lane change using the second target trajectory including the second lateral position P2. The second target trajectory in this embodiment is longer than the first target trajectory. The second target trajectory can move the host vehicle V1 further away from the second object V2 in the first lane L1 than the first target trajectory. The calculated second target trajectory is applied to a lane change from the first lane L1 to the second lane L2. In this way, by executing the second lane change control C2 using the second target trajectory, the amount of lateral movement of the host vehicle V1 toward the second lane L2 can be increased, thereby increasing the change in the positional relationship between the first object PV1 and the second object V2 relative to the host vehicle V1. Therefore, the sensor 2 can obtain sufficient detection information on the shoulder side of the second object V2. As a result, the distance W1 between the second object V2 and the shoulder can be accurately measured, allowing for highly accurate determination of whether the second object V2 is an object to be avoided. A specific processing procedure is additionally shown in FIG. 2. This change in the lane change control driving plan is performed in the lane change driving plan calculation process (S18). Before starting lane change control execution (S19), the processor 10 performs the above-mentioned process of changing the set vehicle speed and / or the target trajectory (S41). The lane change control change process may be a process of selecting a driving plan with a relatively low set vehicle speed from among lane change control driving plans previously stored in association with set vehicle speeds. The change process for the lane change control may be a process of selecting a driving plan for a target trajectory in which the lateral position is relatively shifted toward the second lane L2 from among driving plans for the lane change control that have been stored in advance and associated with each target trajectory with a different lateral position. The processor 10 updates the driving plan for the lane change (S42), starts the lane change control based on the updated driving plan (S19), and performs the processes from S20 onwards.The processing of S41-42 is optional and can be skipped.

[0028] 100... driving control system, 1... driving control 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... object information acquisition device, 5... map information, 51... lane information, 6... navigation device, 7... signal recognition device, 200... vehicle controller, 210... steering control device, 220... drive control device

Claims

1. A driving control method used in a processor to control autonomous driving of a host vehicle, wherein the processor: determines, based on detection information from the host vehicle's sensors and map information including lane information, that the host vehicle is traveling in a first lane adjacent to the shoulder of a road among multiple lanes that belong to a road entering an intersection equipped with traffic lights and have a common direction of travel; and, if it determines, based on the detection information, that a first object stationary in front of the host vehicle within a predetermined range from the intersection is an object to be avoided by the host vehicle, and that a second object is present within a predetermined distance ahead of the first object, the processor stops the host vehicle behind the first object if it recognizes that the traffic light is displaying a go signal; and, if it recognizes that the traffic light is displaying a stop signal, determines whether a lane change condition is met or not based on the detection information, and, when the lane change condition is met, causes the host vehicle to change lanes to a second lane adjacent to the first lane.

2. The driving control method of claim 1, wherein the processor measures the lateral position of the second object relative to the first lane based on the detection information while executing the lane change from the first lane to the second lane, and determines whether the second object is the object to be avoided based on the measured lateral position, and if it is determined that the second object is the object to be avoided, causes the host vehicle, which has moved to the second lane, to change lanes from the second lane to the first lane and move in front of the second object, and if it is determined that the second object is not the object to be avoided, causes the host vehicle, which has moved to the second lane, to change lanes from the second lane to the first lane and move behind the second object.

3. A driving control method according to claim 1 or 2, wherein the processor, when detecting a plurality of second objects lined up in front of the first object, measures the lateral positions of the second objects in order starting from the second object closest to the host vehicle while the lane change is being performed, and sequentially determines whether or not the second objects are the object to be avoided based on the measured lateral positions; when an initial determination is made that the second object is not the object to be avoided, causes the host vehicle to change lanes from the second lane to the first lane, and moves the host vehicle behind the second object that was initially determined not to be the object to be avoided; when all of the plurality of second objects are determined to be the object to be avoided, causes the host vehicle to change lanes from the second lane to the first lane, and finally moves the host vehicle in front of the second object that was determined to be the object to be avoided.

4. A driving control method as claimed in any one of claims 1 to 3, wherein when the processor recognizes that the traffic light is displaying the stop signal and detects a rear vehicle approaching the vehicle from behind the second lane, the processor determines whether the lane change condition is met or not based on the relative distance and relative speed of the rear vehicle to the vehicle.

5. A driving control method as described in any one of claims 1 to 4, wherein the processor changes the threshold value of the lane change condition so that, when a line of vehicles of a length extending from the intersection to a predetermined distance ahead of the vehicle is not formed in the second lane, the execution of the lane change becomes more unlikely than when a line of vehicles of at least that length is formed in the second lane.

6. A driving control method as claimed in any one of claims 1 to 5, wherein the processor changes the standard set vehicle speed to a lower value in controlling the planned lane change when it is recognized that the traffic light is presenting the stop signal.

7. A driving control method as described in any one of claims 1 to 6, wherein the processor, in controlling the lane change planned when it is recognized that the traffic light is presenting the stop signal, executes control of the lane change from the first lane to the second lane using a second target trajectory that includes a second lateral position that is shifted toward the second lane from a first lateral position of a first target trajectory that is calculated in a standard manner.

8. A driving control device having a processor that controls autonomous driving of a vehicle, wherein the processor determines, based on detection information from the vehicle's sensors and map information including lane information, that the vehicle is traveling in a first lane adjacent to the shoulder of a road among multiple lanes with a common direction of travel that belong to a road entering an intersection equipped with traffic lights; and, if it determines, based on the detection information, that a first object stationary in front of the vehicle within a predetermined range from the intersection is an object to be avoided by the vehicle, and that a second object is present within a predetermined distance ahead of the first object, the processor stops the vehicle behind the first object if it recognizes that the traffic light is displaying a go signal; and, if it recognizes that the traffic light is displaying a stop signal, determines, based on the detection information, whether a lane change condition is met, and, when the lane change condition is met, causes the vehicle to change lanes to a second lane adjacent to the first lane.

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