Vehicle control device

Abstract

To provide a vehicle control device capable of guiding an own vehicle to a safer lane.SOLUTION: A vehicle control device includes: a storage unit (4 and 22) that stores a reference travel trajectory for each lane in a predetermined section of a road; a selection unit 34 that selects the lane in which the reference travel trajectory having the highest safety is indicated from among the reference travel trajectories of each lane in a traveling direction of a vehicle 10 when the vehicle 10 travels in the predetermined section; and a vehicle control unit 33 that causes the vehicle 10 to travel along the reference travel trajectory of the selected lane.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] In a system for controlling the automatic driving of a vehicle, a technology has been proposed in which the driving trajectory of the vehicle when actually driven manually is recorded, and when driven automatically, the vehicle is driven by referring to the recorded driving trajectory (see Patent Document 1).

[0003] The vehicle driving control device disclosed in Patent Document 1 creates a driving trajectory of the vehicle from the position history of the vehicle during manual driving, and sets the created driving trajectory as a target trajectory of the vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-22353 Summary of the Invention [Problem to be solved by the invention]

[0005] However, a manually driven vehicle does not always travel along an ideal travel path. Depending on the road section, the vehicle may travel along a travel path that deviates from the lane it is traveling in, or the travel path of each vehicle may vary. Therefore, even if a target travel path (hereinafter simply referred to as a target travel path) is set based on the travel path of a manually driven vehicle, the set target path may not be a safe path.

[0006] Therefore, an object of the present invention is to provide a vehicle control device that can guide a vehicle to a safer lane. [Means for solving the problem]

[0007] According to one embodiment, there is provided a vehicle control device that includes a storage unit that stores a reference driving trajectory for each lane in a predetermined section of a road, a selection unit that selects, when the vehicle travels along the predetermined section, a lane that exhibits the safest reference driving trajectory from among the reference driving trajectories for each lane in the vehicle's traveling direction, and a vehicle control unit that causes the vehicle to travel along the reference driving trajectory of the selected lane.

[0008] In this vehicle control device, it is preferable that the selection unit determines that the safety of a reference driving trajectory for each lane in the vehicle's direction of travel in which the position of the lane when entering a specified section is the same as the position of the lane when exiting the specified section is higher than the safety of a reference driving trajectory in which the position of the lane when entering a specified section is different from the position of the lane when exiting the specified section.

[0009] Preferably, the vehicle control device further includes a current lane detection unit that detects the current lane the vehicle is traveling in. If the current lane differs from the selected lane, the vehicle control unit preferably controls the vehicle so that the vehicle moves to the selected lane before reaching the predetermined section. [Effects of the Invention]

[0010] The vehicle control device according to the present disclosure has the effect of being able to guide the vehicle to a safer lane. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram of a vehicle control system in which a vehicle control device is implemented. [Figure 2] 1 is a hardware configuration diagram of an electronic control device that is one embodiment of a vehicle control device. [Figure 3] FIG. 2 is a functional block diagram of a processor of an electronic control unit relating to vehicle control processing according to the first embodiment. [Figure 4]10A and 10B are diagrams showing an example of the relationship between the distribution of driving trajectories in adjacent lanes and the target driving trajectory, respectively. [Figure 5] 4 is an operational flowchart of a vehicle control process according to the first embodiment. [Figure 6] FIG. 10 is a functional block diagram of a processor of an electronic control unit relating to vehicle control processing according to a second embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of the safety of a reference driving trajectory for each lane. [Figure 8] 10 is an operational flowchart of a vehicle control process according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A vehicle control device, a vehicle control method executed on the vehicle control device, and a computer program for vehicle control will be described below with reference to the drawings. The vehicle control device uses driving trajectory distribution information, which represents the distribution of driving trajectories for each lane when various vehicles actually travel along a predetermined section of a road, to set a target driving trajectory for the vehicle. The distribution of driving trajectories may include non-ideal driving trajectories for various reasons. By setting a target driving trajectory in this manner, the vehicle control device can automatically control the vehicle by taking into account the non-ideal driving trajectory information to drive the vehicle more safely. Alternatively, the vehicle control device may refer to a reference driving trajectory for each lane, select a lane that indicates the safest reference driving trajectory, and drive the vehicle along the reference driving trajectory of the selected lane.

[0013] FIG. 1 is a schematic configuration diagram of a vehicle control system in which a vehicle control device is implemented. FIG. 2 is a hardware configuration diagram of an electronic control device, which is one embodiment of the vehicle control device. In this embodiment, the vehicle control system 1 is mounted on a vehicle 10 and controls the vehicle 10. The vehicle control system 1 includes a camera 2, a GPS receiver 3, a storage device 4, and an electronic control unit (ECU) 5, which is an example of a vehicle control device. The camera 2, the GPS receiver 3, the storage device 4, and the ECU 5 are communicatively connected via an in-vehicle network conforming to a standard such as a controller area network. The vehicle control system 1 may further include a distance measurement sensor (not shown), such as a LiDAR or radar, that measures the distance from the vehicle 10 to objects present around the vehicle 10. The vehicle control system 1 may also include a wireless communication terminal (not shown) for wireless communication with devices external to the vehicle 10. The vehicle control system 1 may also include a navigation device (not shown) for searching for a planned driving route to a destination.

[0014] Camera 2 is an example of a sensor that generates a sensor signal representing the surroundings of vehicle 10, and includes a two-dimensional detector configured with an array of photoelectric conversion elements, such as a CCD or C-MOS, that are sensitive to visible light, and an imaging optical system that forms an image of the area to be photographed on the two-dimensional detector. Camera 2 is mounted, for example, inside the passenger compartment of vehicle 10 so as to face forward of vehicle 10. Camera 2 photographs the area in front of vehicle 10 at predetermined photographing intervals (for example, 1 / 30 to 1 / 10 seconds) and generates an image of the area in front of vehicle 10. The image obtained by camera 2 is an example of a sensor signal. Note that vehicle 10 may be provided with multiple cameras with different photographing directions or focal lengths.

[0015] Every time the camera 2 generates an image, it outputs the generated image to the ECU 5 via the in-vehicle network.

[0016] The GPS receiver 3 receives GPS signals from GPS satellites at predetermined intervals and determines the own position of the vehicle 10 based on the received GPS signals. Then, the GPS receiver 3 outputs positioning information indicating the positioning results of the own position of the vehicle 10 based on the GPS signals to the ECU 5 via the in-vehicle network at predetermined intervals. Note that the vehicle 10 may have a receiver that receives positioning signals from satellites of another satellite positioning system and determines the own position of the vehicle 10, instead of the GPS receiver.

[0017] The storage device 4 is an example of a storage unit and includes, for example, a hard disk drive, a nonvolatile semiconductor memory, or an optical recording medium and its access device. The storage device 4 stores a high-precision map used for autonomous driving control of the vehicle 10. The high-precision map includes, for example, information indicating the number of lanes and road markings such as lane markings and stop lines for each road section included in a predetermined area represented on the high-precision map. Furthermore, the high-precision map includes information for determining whether each road section corresponds to a predetermined section, such as the curvature of the road section, the presence or absence of intersections, merging points, or branching points, and vehicle entrance and exit points. Furthermore, the high-precision map includes driving trajectory distribution information for each lane of the road section for a predetermined section. The driving trajectory distribution information includes information indicating multiple driving trajectories for each lane. Furthermore, the driving trajectory distribution information may include information indicating a reference driving trajectory for each lane and a variation index value indicating the degree of variation in driving trajectories for each lane.

[0018] Note that the reference driving trajectory for each lane is the standard trajectory that a vehicle follows when traveling on that lane, unless there are special circumstances. For example, the reference driving trajectory is set as the average of multiple driving trajectories of vehicles that have actually traveled on that lane. Alternatively, the reference driving trajectory may be set to pass through the center of the lane. Furthermore, the variation index value may be the variance value in the width direction of the lane for multiple driving trajectories on a single lane. Alternatively, the variation index value may be the maximum value of the difference in position in the width direction of the lane between the multiple driving trajectories, or the distance between the reference driving trajectory and the driving trajectory that is farthest from the reference driving trajectory in the width direction of the lane among the multiple driving trajectories.

[0019] Furthermore, when the predetermined section includes an intersection, multiple exit destinations from the predetermined section may be available even if the vehicle 10 enters the predetermined section from the same side. In such cases, a reference driving trajectory and a variation index value are set for each exit destination. For example, suppose the predetermined section includes an intersection that is a crossroads, and at one end of the predetermined section, there are lanes where straight travel and left turns are possible, lanes where only straight travel is possible, and lanes where straight travel and right turns are possible. In this case, the high-precision map includes, for lanes where straight travel and left turns are possible, information representing a reference driving trajectory for vehicles traveling straight, information representing a reference driving trajectory for vehicles turning left, and corresponding variation index values. Furthermore, for lanes where only straight travel is possible, the high-precision map includes information representing a reference driving trajectory for vehicles traveling straight and a variation index value. Furthermore, for lanes where straight travel and right turns are possible, the high-precision map includes information representing a reference travel trajectory for vehicles traveling straight, information representing a reference travel trajectory for vehicles turning right, and the corresponding variation index values. Similarly, if a predetermined section includes a branch point, the high-precision map includes, for each lane, information representing a reference travel trajectory for each possible direction of travel at the branch point and a variation index value.

[0020] Furthermore, the storage device 4 may have a processor for executing processes such as updating the high precision map and processing related to a request to read out a high precision map from the ECU 5. The storage device 4 may transmit a request to acquire a high precision map together with the current position of the vehicle 10 to a map server (not shown) via a wireless communication terminal (not shown), for example, every time the vehicle 10 moves a predetermined distance. The storage device 4 may also receive a high precision map of a predetermined area around the current position of the vehicle 10 from the map server via the wireless communication terminal. Furthermore, when the storage device 4 receives a request to read out a high precision map from the ECU 5, the storage device 4 extracts an area that includes the current position of the vehicle 10 and is relatively smaller than the predetermined area from the high precision map stored therein, and outputs the extracted area to the ECU 5 via the in-vehicle network.

[0021] The ECU 5 performs automatic driving control of the vehicle 10. In this embodiment, the ECU 5 sets a target driving trajectory by referring to driving trajectory distribution information of a predetermined section in the traveling direction of the vehicle 10, and causes the vehicle 10 to travel along the set target driving trajectory.

[0022] 2, the ECU 5 includes a communication interface 21, a memory 22, and a processor 23. The communication interface 21, the memory 22, and the processor 23 may be configured as separate circuits, or may be integrated into a single integrated circuit.

[0023] The communication interface 21 has an interface circuit for connecting the ECU 5 to the in-vehicle network. Every time the communication interface 21 receives an image from the camera 2, it passes the received image to the processor 23. Every time the communication interface 21 receives positioning information from the GPS receiver 3, it passes the positioning information to the processor 23. Furthermore, the communication interface 21 passes the high-precision map read from the storage device 4 to the processor 23.

[0024] The memory 22 is another example of a storage unit and includes, for example, a volatile semiconductor memory and a non-volatile semiconductor memory. The memory 22 stores various data used in the vehicle control process executed by the processor 23. For example, the memory 22 stores parameters of the camera 2, such as the focal length, shooting direction, and installation position of the camera 2, as well as various parameters for identifying an object detection classifier used to detect features, etc. The memory 22 also stores positioning information of the vehicle 10, images of the surroundings of the vehicle 10, and high-precision maps. The memory 22 also temporarily stores various data generated during the vehicle control process.

[0025] The processor 23 includes one or more central processing units (CPUs) and their peripheral circuits. The processor 23 may further include other arithmetic circuits such as a logic operation unit, a numerical operation unit, or a graphics processing unit. The processor 23 executes vehicle control processing for the vehicle 10 at predetermined intervals.

[0026] (First embodiment) The vehicle control process according to the first embodiment will be described below. In the vehicle control process according to the first embodiment, the processor 23 sets a target driving trajectory by referring to driving trajectory distribution information of other lanes different from the own lane in which the vehicle 10 is traveling. More specifically, the processor 23 sets a target driving trajectory so as to move away from the other lanes when it is expected that other vehicles traveling in other lanes (hereinafter, may be referred to as nearby vehicles) will approach the own lane or stray into the own lane, based on the driving trajectory distribution information of the other lanes.

[0027] 3 is a functional block diagram of the processor 23 related to vehicle control processing according to the first embodiment. The processor 23 has a vehicle lane detection unit 31, a trajectory setting unit 32, and a vehicle control unit 33. Each of these units in the processor 23 is a functional module realized by, for example, a computer program running on the processor 23. Alternatively, each of these units in the processor 23 may be a dedicated arithmetic circuit provided in the processor 23.

[0028] The own lane detection unit 31 detects the own lane by comparing an image (hereinafter, sometimes simply referred to as an image) showing the surroundings of the vehicle 10, generated by the camera 2, with a high-precision map. For example, the own lane detection unit 31 assumes the position and attitude of the vehicle 10 and projects features on or around the road detected from the image onto the high-precision map, or projects features on or around the road around the vehicle 10 shown on the high-precision map onto the image. Note that features on or around the road may be, for example, road markings such as lane markings or stop lines, or curbs. The own lane detection unit 31 then estimates the position and attitude of the vehicle 10 when the features detected from the image most closely match the features shown on the high-precision map as the own position of the vehicle 10.

[0029] The own lane detection unit 31 may determine the position at which a feature is projected on a high-precision map or an image using the assumed initial values of the position and attitude of the vehicle 10 and parameters of the camera 2, such as the focal length, installation height, and shooting direction. Note that the initial values of the position and attitude of the vehicle 10 are the position of the vehicle 10 measured by the GPS receiver 3, or the position and attitude of the vehicle 10 estimated at the time of the previous own lane detection, corrected using odometry information. The own lane detection unit 31 then calculates the degree of match between features on or around the road detected from the image and corresponding features shown on the high-precision map (for example, the inverse of the sum of the squares of the distances between corresponding features).

[0030] The own lane detection unit 31 repeats the above process while changing the assumed position and attitude of the vehicle 10. Then, the own lane detection unit 31 may estimate the assumed position and attitude when the degree of match is greatest as the actual own position of the vehicle 10. Then, the own lane detection unit 31 may refer to the high-precision map and identify the lane that includes the own position of the vehicle 10 as the own lane in which the vehicle 10 is traveling.

[0031] The own lane detection unit 31 may detect a feature by inputting an image to a classifier that has been trained in advance to detect the feature from the image. The own lane detection unit 31 may use, as such a classifier, a deep neural network (DNN) having a convolutional neural network (CNN)-type architecture, such as a Single Shot MultiBox Detector or Faster R-CNN. Alternatively, the own lane detection unit 31 may use, as such a classifier, a DNN having a self attention network (SAN)-type architecture, such as a Vision Transformer.

[0032] The current lane detection unit 31 notifies the trajectory setting unit 32 of information indicating the detected current lane.

[0033] The trajectory setting unit 32 sets a target traveling trajectory by referring to the traveling trajectory distribution information for a predetermined section that exists between the current position of the vehicle 10 and a point a predetermined distance (for example, several hundred meters to several kilometers) away in the traveling direction of the vehicle 10.

[0034] The predetermined section may be, for example, a curved section having a curvature equal to or greater than a predetermined value, or a road section including an intersection. Alternatively, the predetermined section may be a road section including a junction where the road merges with another road, or a road section facing a vehicle entrance / exit, such as an entrance / exit to a parking lot. Note that the predetermined section is not limited to these road sections, and may be a simple straight road section. Alternatively, the predetermined section may be a road section for which driving trajectory distribution information is included in the high-precision map.

[0035] The trajectory setting unit 32 refers to a high-precision map to identify a predetermined section that exists between the current position of the vehicle 10 and a point a predetermined distance away along the traveling direction of the vehicle 10. The trajectory setting unit 32 then refers to the traveling trajectory distribution information of lanes other than the own lane, particularly, the traveling trajectory distribution information of an adjacent lane adjacent to the own lane, from the traveling trajectory distribution information of the predetermined section included in the high-precision map. Note that the adjacent lane is not limited to a parallel lane through which surrounding vehicles traveling in the same direction as the traveling direction of the vehicle 10 can pass, but may also be an oncoming lane. The trajectory setting unit 32 then sets the target traveling trajectory so that it is separated by at least a predetermined distance from any of the multiple traveling trajectories for the other lanes included in the traveling trajectory distribution information. Furthermore, the trajectory setting unit 32 sets the target traveling trajectory so that the deviation from the center of the own lane or the reference traveling trajectory is minimized as long as it is separated by at least the predetermined distance from any of the multiple traveling trajectories for the other lanes.

[0036] If the driving trajectory distribution information for other lanes includes abnormal driving trajectories that approach the own lane or stray into the own lane, it is assumed that there is a possibility that a surrounding vehicle traveling in another lane may approach the own lane or stray into the own lane. Therefore, by setting the target driving trajectory as described above, it becomes possible to maintain a certain distance from vehicle 10 even if such a surrounding vehicle exists.

[0037] 4(a) and 4(b) are diagrams showing an example of the relationship between the distribution of driving trajectories in adjacent lanes and the target driving trajectory. In the example shown in FIGS. 4(a) and 4(b), vehicle 10 is traveling in the right lane 402 of two lanes 401 and 402 on road 400. In other words, lane 402 is the vehicle's own lane. Therefore, to set the target driving trajectory, the driving trajectory distribution information for the left lane 401 is referenced.

[0038] 4(a), there is relatively little variation among the multiple driving trajectories 410 included in the driving trajectory distribution information for the lane 401, and all of the driving trajectories pass near the center of the lane 401. Therefore, the target driving trajectory 420, which is set to be at least a predetermined distance away from each driving trajectory, is also set to pass near the center of the own lane 402.

[0039] 4(b), of the multiple driving trajectories 410 included in the driving trajectory distribution information of the lane 401, the driving trajectory 410a passes through a position close to the boundary between the own lane 402 and the lane 401. Therefore, as the driving trajectory 410a approaches the own lane 402, the target driving trajectory 430 is set to pass through a position farther away from the lane 401 than the center of the own lane 402.

[0040] As described above, the driving trajectory distribution information may include, for each lane, a reference driving trajectory for that lane and a variation index value indicating the degree of variation in the driving trajectory. In this case, the trajectory setting unit 32 may set the target driving trajectory so that the greater the variation index value for the other lane, the greater the deviation from the reference driving trajectory of the other lane. For example, when the variation index value of an adjacent lane is equal to or less than a predetermined variation threshold, the trajectory setting unit 32 sets the reference driving trajectory of the own lane as the target trajectory. Furthermore, when the variation index value of the adjacent lane is greater than a predetermined variation index value, the trajectory setting unit 32 sets the target driving trajectory so that the target driving trajectory passes through a position shifted from the reference driving trajectory of the own lane by an offset distance corresponding to the variation index value of the adjacent lane in a direction away from the adjacent lane. In this way, the target driving trajectory is set so as to deviate from the reference driving trajectory of the adjacent lane with a larger variation index value. In this case, as in the above example, the trajectory setting unit 32 can set a target driving trajectory that allows a certain degree of distance to be maintained from the vehicle 10 even when a nearby vehicle traveling in another lane approaches the vehicle's own lane or extends into the vehicle's own lane.

[0041] In some cases, such as when an intersection is included in the predetermined section, there may be multiple possible travel directions for the current lane and the other lanes. In such cases, the trajectory setting unit 32 may execute the above process by referring to the reference travel trajectory and the variation index value set for the other lanes, the reference travel trajectory and the variation index value for the same direction (in the case of parallel lanes) or the opposite direction (in the case of an oncoming lane) as the direction in which the vehicle 10 is traveling in the current lane. In addition, the trajectory setting unit 32 may identify the direction in which the vehicle 10 is traveling in the predetermined section by referring to the planned travel route of the vehicle 10 received from a navigation device (not shown).

[0042] After setting the target travel locus, the locus setting unit 32 notifies the vehicle control unit 33 of the set target travel locus.

[0043] The vehicle control unit 33 controls each unit of the vehicle 10 so that the vehicle 10 travels along the target travel trajectory received from the trajectory setting unit 32. To this end, the vehicle control unit 33 measures the position of the vehicle 10 at predetermined intervals and compares the measured position of the vehicle 10 with the target travel trajectory. As described for the own lane detection unit 31, the vehicle control unit 33 may measure the accurate position of the vehicle 10 by comparing an image acquired by the camera 2 with a high-precision map. If the measured position of the vehicle 10 is on the target travel trajectory, the vehicle control unit 33 determines a steering angle of the vehicle 10 so that the vehicle 10 travels along the target travel trajectory, and controls the steering of the vehicle 10 to achieve the determined steering angle. If the measured position of the vehicle 10 is away from the target travel trajectory, the vehicle control unit 33 determines a steering angle of the vehicle 10 so that the vehicle 10 approaches the target travel trajectory, and controls the steering of the vehicle 10 to achieve the determined steering angle.

[0044] The vehicle control unit 33 also sets the acceleration / deceleration of the vehicle 10 so that the inter-vehicle distance between the vehicle 10 and another vehicle traveling ahead is maintained at or above a certain distance. To this end, the vehicle control unit 33 detects the other vehicle by inputting an image obtained by the camera 2 or a distance measurement signal obtained by a distance measurement sensor (not shown) into a classifier that has been trained in advance to detect other vehicles. The vehicle control unit 33 then estimates the distance between the vehicle 10 and the other vehicle based on the size of the other vehicle in the image, the position of the bottom edge of the area in which the other vehicle is represented, or the distance indicated in the distance measurement signal in the direction to the detected other vehicle. When the inter-vehicle distance between the vehicle 10 and the other vehicle falls below a predetermined distance threshold, the vehicle control unit 33 sets the acceleration / deceleration of the vehicle 10 to decelerate the vehicle 10. On the other hand, when the inter-vehicle distance between the vehicle 10 and the other vehicle is equal to or greater than the predetermined distance threshold, the vehicle control unit 33 sets the acceleration / deceleration of the vehicle 10 to maintain a constant speed of the vehicle 10 or to approach the speed limit of the road on which the vehicle 10 is traveling or a target speed set by the driver. The vehicle control unit 33 then sets the accelerator opening or braking amount according to the set acceleration / deceleration. The vehicle control unit 33 calculates the fuel injection amount according to the set accelerator opening, and outputs a control signal corresponding to the fuel injection amount to a fuel injection device of the engine of the vehicle 10. Alternatively, the vehicle control unit 33 calculates the amount of power to be supplied to the motor according to the set accelerator opening, and controls the motor drive circuit so that the amount of power is supplied to the motor. Alternatively, the vehicle control unit 33 outputs a control signal corresponding to the set braking amount to the brake of the vehicle 10.

[0045] 5 is an operational flowchart of the vehicle control process according to the first embodiment, which is executed by the processor 23. The processor 23 may execute the vehicle control process in accordance with the following operational flowchart at predetermined intervals.

[0046] The current lane detection unit 31 of the processor 23 detects the current lane in which the vehicle 10 is traveling (step S101).

[0047] Furthermore, the trajectory setting unit 32 of the processor 23 refers to the driving trajectory distribution information of lanes other than the own lane for a predetermined section that exists up to a point a predetermined distance ahead in the traveling direction of the vehicle 10, and sets a target driving trajectory in the own lane so that the target driving trajectory is separated from any driving trajectory of the other lanes by a predetermined distance or more (step S102). Note that the trajectory setting unit 32 may set the target driving trajectory so that the larger the variation index value in the other lanes, the more the target driving trajectory is separated from the reference driving trajectory of the other lanes, as described above.

[0048] The vehicle control unit 33 of the processor 23 controls each part of the vehicle 10 so that the vehicle 10 travels along the target travel path (step S103). Then, the processor 23 ends the vehicle control process.

[0049] As described above, this vehicle control device uses the driving trajectory distribution information of other lanes to set the target driving trajectory of the vehicle. Therefore, this vehicle control device can set a highly safe target driving trajectory that takes into account the possible trajectories of surrounding vehicles traveling in other lanes.

[0050] In addition, in a section where the travel trajectory distribution information indicates that the degree of variation in the travel trajectories of other lanes is large, it is assumed that nearby vehicles traveling in other lanes may inadvertently approach the vehicle 10's lane. Therefore, according to a modified example, in a section where the variation index value in lanes other than the vehicle's lane is equal to or greater than a predetermined threshold, the vehicle control unit 33 may notify the driver via a display device (not shown) or a speaker (not shown) provided in the vehicle cabin that nearby vehicles may approach the vehicle 10.

[0051] Furthermore, for sections where the travel trajectory distribution information indicates a large degree of variation in the travel trajectories for the own lane, it is assumed that there is a possibility that some kind of disturbance may be applied while the vehicle 10 is traveling. Therefore, the vehicle control unit 33 may also notify the driver via a display device or speaker provided in the vehicle cabin of a warning to call attention to the driving of the vehicle 10 for sections where the variation index value for the own lane is equal to or greater than a predetermined threshold.

[0052] According to another modification, the trajectory setting unit 32 may set the target driving trajectory such that, among the lanes in the traveling direction of the vehicle 10 in the predetermined section, lanes with smaller variation index values are prioritized. For example, the trajectory setting unit 32 identifies the lane with the smallest variation index value among the lanes that the vehicle 10 can travel before reaching the predetermined section. The trajectory setting unit 32 then sets a target driving trajectory from the current position of the vehicle 10 represented by the latest positioning information to the predetermined section so that the vehicle 10 will move to the identified lane before reaching the predetermined section. The trajectory setting unit 32 may set the target driving trajectory for the predetermined section according to the above embodiment or modification. Note that the distance required for one lane change (hereinafter referred to as the lane change distance) may be stored in advance in the memory 22. The trajectory setting unit 32 then refers to the high-precision map to determine the distance from the current position of the vehicle 10 to the predetermined section, and sets the resulting number, obtained by dividing the distance by the lane change distance, as the maximum number of lane changes that the vehicle 10 can make before reaching the predetermined section. The trajectory setting unit 32 may set each of the lanes that the vehicle 10 can move from the current lane with no more than the maximum number of lane changes as lanes that the vehicle 10 can move before reaching the predetermined section. According to this modification, the trajectory setting unit 32 can set a target driving trajectory so that the vehicle 10 can travel while avoiding lanes where external disturbances are likely to occur.

[0053] (Second embodiment) Next, a vehicle control process according to the second embodiment will be described. In the vehicle control process according to the second embodiment, processor 23 refers to the reference driving trajectory for each lane and selects the lane that indicates the safest reference driving trajectory as the target lane. Then, processor 23 causes vehicle 10 to travel along the reference driving trajectory of the selected target lane.

[0054] The vehicle control process according to the second embodiment differs from the vehicle control process according to the first embodiment in part of the process executed by the processor 23. Therefore, the following will describe the differences from the first embodiment.

[0055] In the second embodiment, the high precision map includes information representing the reference driving trajectory for each lane for a predetermined section. Note that the predetermined section in the second embodiment may be the same road section as the predetermined section in the first embodiment. Also, in the second embodiment, the road section itself in which the high precision map includes information representing the reference driving trajectory for each lane may be the predetermined section.

[0056] 6 is a functional block diagram of the processor 23 relating to vehicle control processing according to the second embodiment. The processor 23 includes a vehicle lane detection unit 31, a selection unit 34, and a vehicle control unit 33. Each of these units included in the processor 23 is a functional module implemented by a computer program running on the processor 23. Alternatively, each of these units included in the processor 23 may be a dedicated arithmetic circuit provided in the processor 23.

[0057] As in the first embodiment, the current lane detection unit 31 detects the current lane in which the vehicle 10 is traveling. Then, the current lane detection unit 31 notifies the selection unit 34 of the detected current lane.

[0058] The selection unit 34 refers to the high-precision map to identify a predetermined section that exists between the current position of the vehicle 10 and a point a predetermined distance away along the traveling direction of the vehicle 10. The selection unit 34 then sets a target traveling trajectory based on the reference traveling trajectory of each lane for the predetermined section. In this embodiment, when the vehicle 10 travels through the predetermined section, the selection unit 34 selects, as the target lane, a lane that indicates the safest reference traveling trajectory among the reference traveling trajectories of each lane in the traveling direction of the vehicle 10. In this case, as in the above-described modified example, the selection unit 34 may set, as the lane to be selected, a lane that the vehicle 10 can travel before reaching the predetermined section. Alternatively, if the predetermined section includes an intersection or a branch point, the selection unit 34 may refer to the planned traveling route of the vehicle 10 received from a navigation device (not shown) and set, as the lane to be selected, a lane that can lead the vehicle 10 to its destination from among multiple lanes in the predetermined section.

[0059] For example, the selection unit 34 may determine that the smaller the deviation of each lane from the center of the lane to the reference driving trajectory, the safer the lane is. Alternatively, the selection unit 34 may determine that the smaller the maximum value of the angle change in the traveling direction per unit distance on the reference driving trajectory, the safer the lane is.

[0060] Furthermore, if a specified section includes an intersection, the relative position of a lane relative to the road edge for the reference driving trajectory at the intersection may differ when entering the intersection and when exiting the intersection. For example, when entering an intersection with three or more lanes on each side, the reference driving trajectory for the second lane from the center may move to the leftmost lane when turning right at the intersection and exiting the intersection. In such a case, a vehicle turning right at the intersection along the reference driving trajectory for the second lane from the center and another vehicle entering the intersection from the oncoming lane and turning left at the intersection may end up traveling in the same lane when exiting the intersection. On the other hand, if the reference driving trajectory for the centermost lane remains in the rightmost lane even after turning right, it is assumed that the above-mentioned situation is unlikely to occur. Furthermore, if there are multiple lanes into which a left turn can be made at an intersection, and the reference driving trajectory of one of those lanes indicates a shift to the right lane when exiting the intersection, it is assumed that vehicle 10 traveling along that lane will need to shift to the right lane after making a left turn. On the other hand, if the reference driving trajectory of the rightmost lane among those lanes into which a left turn can be made maintains the rightmost lane even after exiting the intersection, it is assumed that vehicle 10 traveling along that rightmost lane will not need to change lanes after making a left turn. Therefore, the selection unit 34 determines that the safety of a reference driving trajectory in which the position of the lane including the entry point of a specified section and the position of the lane including the exit point of the specified section are the same is higher than the safety of a reference driving trajectory in which the position of the lane including the entry point of a specified section and the position of the lane including the exit point of the specified section are different. This gives priority to lanes indicated by reference driving trajectories that maintain the lane, allowing the selection unit 34 to select a target lane that prevents inadvertent lane changes.

[0061] The selection unit 34 may select a target lane based on one or more of the lane selection criteria described above. When multiple selection criteria are used, the selection unit 34 may, for example, prioritize a lane that indicates a reference driving trajectory that maintains the lane within a specified section. When multiple such lanes exist, the selection unit 34 selects a target lane by evaluating, for the multiple lanes, either the deviation of the reference driving trajectory from the center of the lane or the maximum angle change in the direction of travel per unit distance as a second priority, and the other as a third priority. Alternatively, when multiple lanes are prioritized based on any of the above selection criteria, the selection unit 34 may select the lane closest to the vehicle's own lane from the multiple lanes as the target lane.

[0062] The selection unit 34 sets the reference driving trajectory of the target lane that is determined to be the safest for the predetermined section as the target driving trajectory. Furthermore, if the target lane and the own lane are different, the selection unit 34 sets the target driving trajectory for the section from the current position of the vehicle 10 to the predetermined section so that the vehicle 10 moves from the own lane to the target lane before reaching the predetermined section.

[0063] Fig. 7 is a diagram showing an example of the safety of each lane in the reference driving trajectory. In the example shown in Fig. 7, an intersection 700 is included in the predetermined section. Of the multiple lanes included in road 710, which is one of the roads entering the intersection 700, two lanes 711 and 712 allow left turns at the intersection 700. Furthermore, road 720, located to the left of road 710, has three lanes 721, 722, and 723 that exit the intersection 700.

[0064] Here, the reference driving trajectory 711a for turning left from the lane 711 located at the leftmost side of the road 710 indicates that the vehicle will pass through the leftmost lane 721 even when exiting the intersection 700. In other words, for the reference driving trajectory 711a, the position of the lane relative to the road edge does not change when entering and exiting a predetermined section. In contrast, the reference driving trajectory 712a for turning left from the lane 712 located second from the left on the road 710 indicates that the vehicle will pass through the centralmost lane 723 on the road 720 when exiting the intersection 700. In other words, for the reference driving trajectory 712a, the relative position of the lane relative to the road edge changes when entering and exiting a predetermined section. Therefore, the reference driving trajectory 711a for the lane 711 is determined to be safer than the reference driving trajectory 712a for the lane 712. Therefore, when the vehicle 10 enters the intersection 700 from the road 710 and makes a left turn at the intersection 700, the lane 711 is selected as the target lane.

[0065] When the selection unit 34 sets the target travel path from the current position of the vehicle 10 to passing through the predetermined section, the selection unit 34 notifies the vehicle control unit 33 of the set target travel path.

[0066] Similar to the vehicle control unit 33 according to the first embodiment, the vehicle control unit 33 controls each part of the vehicle 10 so that the vehicle 10 travels along the target travel trajectory. When the target lane and the own lane are different, the vehicle control unit 33 controls each part of the vehicle 10 so that the vehicle 10 moves from the own lane to the target lane along the target travel trajectory before reaching a predetermined section.

[0067] 8 is an operational flowchart of the vehicle control process according to the second embodiment. The processor 23 may execute the vehicle control process in accordance with the following operational flowchart at predetermined intervals.

[0068] The current lane detection unit 31 of the processor 23 detects the current lane in which the vehicle 10 is traveling (step S201).

[0069] Furthermore, the selection unit 34 of the processor 23 selects, as a target lane, the lane that indicates the safest reference driving trajectory from among the reference driving trajectories of each lane in a predetermined section ahead of the vehicle 10 (step S202).The selection unit 34 then sets a target driving trajectory so that the vehicle 10 moves from the own lane to the target lane in the section from the current position of the vehicle 10 to the predetermined section (step S203).Furthermore, the selection unit 34 sets the reference driving trajectory of the target lane as the target driving trajectory for the predetermined section (step S204).

[0070] The vehicle control unit 33 of the processor 23 controls each part of the vehicle 10 so that the vehicle 10 travels along the target travel path (step S205). Then, the processor 23 ends the vehicle control process.

[0071] As described above, the vehicle control device according to the second embodiment refers to the reference driving trajectory for each lane for a predetermined section ahead of the vehicle, and selects the lane that indicates the safest reference driving trajectory as the target lane. Then, this vehicle control device causes the vehicle to travel along the reference driving trajectory of the selected lane. Therefore, this vehicle control device can guide the host vehicle to a safer lane.

[0072] According to a modified example, the vehicle control unit 33 may execute following control to control the vehicle 10 so that the vehicle 10 follows a preceding vehicle traveling ahead of the vehicle 10. In this case, if the predetermined section includes an intersection and the reference traveling trajectory of the vehicle's own lane is a trajectory that moves to an adjacent lane after turning right or left at the intersection, the preceding vehicle is likely to move to the adjacent lane after turning right or left at the intersection. Therefore, when following control is applied to the vehicle 10 in such a predetermined section including an intersection, the vehicle control unit 33 may lower the priority of the following control. For example, the vehicle control unit 33 may control each unit of the vehicle 10 so that the vehicle 10 does not follow the preceding vehicle but maintains traveling in the present lane even if the preceding vehicle moves to an adjacent lane.

[0073] Furthermore, the processor 23 may be configured to be able to execute both the vehicle control according to the first embodiment and the vehicle control according to the second embodiment. For example, the processor 23 may execute the vehicle control process according to the second embodiment to select a target lane in a predetermined section and set a target driving trajectory from the current position of the vehicle 10 to the predetermined section. The processor 23 may then execute the vehicle control process according to the first embodiment for the predetermined section to set the target driving trajectory for the predetermined section.

[0074] A computer program that realizes the functions of the processor 23 of the ECU 5 according to the above embodiment or variant may be provided in a form recorded on a computer-readable portable recording medium such as a semiconductor memory, a magnetic recording medium or an optical recording medium.

[0075] As described above, those skilled in the art can make various modifications to the embodiments within the scope of the present invention. [Explanation of symbols]

[0076] 1. Vehicle control system 10 vehicles 2 Cameras 3 GPS receivers 4. Storage devices 5 Electronic Control Unit (ECU) 21 Communication Interface 22 Memory 23 processors 31 Lane detection unit 32 Trajectory setting section 33 Vehicle control unit 34 Selection section

Claims

1. a storage unit that stores a reference driving trajectory for each lane in a predetermined section of a road; a selection unit that selects, when the vehicle travels in the predetermined section, a lane that indicates a reference travel trajectory with the highest safety from among the reference travel trajectories of each lane in the traveling direction of the vehicle; a vehicle control unit that causes the vehicle to travel along the reference travel path of the selected lane; A vehicle control device having the above.

2. 2. The vehicle control device according to claim 1, wherein the selection unit determines that the safety of a reference driving trajectory in which the position of the lane when entering the specified section is the same as the position of the lane when exiting the specified section is higher than the safety of a reference driving trajectory in which the position of the lane when entering the specified section is different from the position of the lane when exiting the specified section.

3. a lane detection unit for detecting a lane in which the vehicle is traveling; 3. The vehicle control device according to claim 1, wherein, when the vehicle's own lane and the selected lane are different, the vehicle control unit controls the vehicle so that the vehicle moves to the selected lane before the vehicle reaches the predetermined section.

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