Driving assistance method and driving assistance device

Abstract

To provide a travel support method and a travel support apparatus, which are capable of preventing a distance by which an own vehicle travels on an opposite lane from increasing in a case where the own vehicle travels on the opposite lane for avoiding an obstacle on a traveling lane.SOLUTION: A method includes: adding, for each lane, to an opposite lane a node corresponding to a position of a node of an own lane including a starting point node and an end point node of a travel prohibited area where an obstacle on the own lane is positioned by using map information described by a node and a link of a travel area sectioned by the node; selecting, as a first passing node, a node of the opposite lane corresponding to the starting point node; selecting, as a second passing node, a node of the opposite lane corresponding to the end point node; finishing a lane change of the own vehicle from the own lane to the opposite lane in the first passing node; and controlling the own vehicle to travel along a travel track for starting a lane change from the opposite lane to the own lane in the second passing node.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] There is known a technique of determining a recommended lane in which a vehicle is recommended to travel among the lanes of a road including a planned travel route, using a high-precision map that describes lanes based on the connection relationship of links, and outputting candidates for the recommended lane and the priority of each candidate (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a high-precision map, nodes are set for each lane and described by the connection relationship of links defined by the nodes. Therefore, in the oncoming lane and the driving lane on a one-lane road on one side, the position of the nodes and the section of the link may be different. Therefore, in a scene where the host vehicle travels on the oncoming lane to avoid a non-drivable section by setting the section of the link where an obstacle in the driving lane is located as a non-drivable section, when the driving section on the oncoming lane is set according to the position of the nodes in the oncoming lane, Patent Document 1 has the following problems. That is, since the position of the nodes in the oncoming lane may be different from the position of the nodes corresponding to the non-drivable section in the driving lane, for example, when the length between the nodes where the driving section is set is longer than the length between the nodes defining the non-drivable section, there is a problem that the distance that the host vehicle travels on the oncoming lane becomes long.

[0005] The problem that the present invention aims to solve is to provide a driving assistance method and a driving assistance device that can prevent the distance a vehicle travels in the oncoming lane from becoming excessive when the vehicle travels in the oncoming lane to avoid an obstacle in the lane it is traveling in. [Means for solving the problem]

[0006] The present invention solves the above problem by using map information described by links of driving areas divided by nodes, where nodes are set for each lane, designating the driving area where an obstacle is located in the current lane as a no-go area, adding nodes in the opposing lane adjacent to the current lane that correspond to the positions of the nodes in the current lane, including the start and end nodes of the no-go area, selecting the node in the opposing lane corresponding to the position of the start node as the first passing node, selecting the node in the opposing lane corresponding to the position of the end node as the second passing node, calculating a driving trajectory in which the vehicle completes a lane change from the current lane to the opposing lane at the first passing node and begins a lane change from the opposing lane to the current lane at the second passing node, and controlling the vehicle's movement along the driving trajectory. [Effects of the Invention]

[0007] According to the present invention, when a vehicle travels in the oncoming lane to avoid an obstacle in the lane it is traveling in, it is possible to prevent the distance the vehicle travels in the oncoming lane from becoming excessively long. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of the configuration of the driving support system according to this embodiment. [Figure 2] This figure shows an example of a scenario in which the driving assistance method according to this embodiment is implemented. [Figure 3] This figure shows the result of a sharing process that is performed to make the nodes of the current lane and the nodes of the opposing lane share each other. [Figure 4] This figure shows the result of integrating the driving areas when an integration process is performed. [Figure 5]This flowchart shows the control flow for executing the driving assistance method according to this embodiment. [Modes for carrying out the invention]

[0009] An embodiment of the driving support device according to the present invention will be described with reference to the drawings. Figure 1 is a block diagram showing a driving support system 10 including the driving support device according to the present invention. As shown in Figure 1, the driving support system 10 includes a detection device 1, a map DB 2, a vehicle information detection device 3, a navigation device 4, a vehicle control device 5, and a driving support device 6. The detection device 1 includes an imaging device 11 and a distance measuring device 12. The vehicle information detection device 3 includes a vehicle speed detection device 31, a steering angle detection device 32, and a vehicle position detection device 33. The vehicle control device 5 includes a vehicle speed control device 51 and a steering control device 52. The devices included in the driving support system 10 are connected by CAN or other in-vehicle LAN and can exchange information with each other. The driving support system 10 according to the present invention can be applied not only to the driving of a vehicle by autonomous driving control, but also to the driving of a vehicle by manual driving by a driver.

[0010] Detection device 1 is a sensor for detecting objects around the vehicle. These objects include, for example, other vehicles, motorcycles, bicycles, pedestrians, road lane markings, zebra zone traffic guides, center lines, road markings, median strips, guardrails, curbs, highway side walls, road signs, traffic lights, pedestrian crossings, construction sites, accident sites, and traffic restrictions. These objects also include obstacles that may affect the vehicle's movement. Detection device 1 acquires the position, attitude (orientation), and speed of the moving object.

[0011] The detection device 1 detects an object, for example, using an imaging device 11 and / or a distance measuring device 12. The driving support device 6 acquires the detection results of the detection device 1 at predetermined time intervals. The imaging device 11 is a device that recognizes objects around the vehicle using images, and is such as a camera. Multiple imaging devices 11 may be installed in a single vehicle. The distance measuring device 12 is a device for calculating the relative distance and relative speed between the vehicle and an object, and is such as a laser radar. Multiple distance measuring devices 12 may be installed in a single vehicle.

[0012] Map DB2 is a memory (storage medium) that stores high-precision map information, including location information for various facilities and specific points, and is accessible from the driving support system 6. The high-precision map information stored in Map DB2 is three-dimensional map data based on road shapes detected when a data acquisition vehicle is driven on actual roads. High-precision map information is used for automatic driving control or driving support control and contains more detailed information than navigation map information. High-precision map information is map information that associates road information, lane boundary information, road attribute information, lane uphill / downhill information, lane identification information, connecting lane information, facility information, and their attribute information as three-dimensional information. Road information includes information such as road width, radius of curvature, shoulder structure, road traffic laws (speed limit, whether lane changes are permitted), road merging points, branching points, and locations where the number of lanes increases or decreases. Note that Map DB2 may also be provided in the driving support system 6.

[0013] Furthermore, Map DB2 includes lane boundary information that indicates the boundary between the lane the vehicle is traveling in and other lanes. Lane boundaries exist on both the left and right sides relative to the direction of travel of the vehicle. Examples of lane boundaries include road markings and road structures. Road markings include, for example, lane boundary lines and center lines. Road structures include, for example, median strips, guardrails, curbs, tunnels, or highway side walls. Note that in Map DB2, a hypothetical driving boundary is pre-set as a lane boundary at points where a lane boundary cannot be identified (for example, within an intersection).

[0014] High-precision maps include information on a lane-by-lane basis. For example, a high-precision map is described by a node for each lane, and links to driving areas divided by the nodes. A node is a reference point on the lane baseline (e.g., the center line within the lane), and each lane is divided into multiple driving areas by nodes. That is, a driving area is the area between nodes. The node information includes the node's identification number, position coordinates, the number of connected lane links, and the identification numbers of the connected lane links. The driving area information includes the driving area's identification number, lane width, lane boundary line type, lane shape, lane division line shape, and lane baseline shape. Furthermore, high-precision maps may include information on areas where driving is prohibited, such as areas where construction sites are located. In addition, because high-precision maps include node and link information on a lane-by-lane basis, it is possible to identify the lane in which a vehicle is traveling along a driving route. High-precision maps have coordinates that can represent the position in the direction of lane extension and lane width.

[0015] In high-precision maps, nodes are set at points where the static road environment on the map changes, such as points where the road structure changes. Points where the road structure changes include, for example, junctions and merging points. For example, even on a road consisting of one lane in each direction, including a forward lane and an opposing lane, the location of junctions and other points may differ for each lane, so the location of nodes and the driving areas separated by nodes may differ for the forward lane and the opposing lane. Also, the distance in the direction of vehicle travel between each driving area may differ for each driving area. In other words, the distance between nodes does not need to be constant.

[0016] The vehicle information detection device 3 is a device that detects information regarding the state of the host vehicle. The state of the host vehicle includes the traveling speed, acceleration, steering angle, position, attitude, etc. of the host vehicle. The vehicle speed detection device 31 detects the traveling speed and acceleration. The steering angle detection device 32 detects the steering angle. The current position is calculated based on information obtained from the host vehicle position detection device 33. The host vehicle position detection device 33 is a positioning system including, for example, a GPS unit. The attitude is detected using an inertial measurement unit. Also, the vehicle information detection device 3 may acquire the traveling speed and steering angle of the host vehicle from the vehicle control device 5. The driving support device 6 acquires the detection results of these devices via an in-vehicle LAN as necessary.

[0017] The navigation device 4 is a device that calculates a traveling route from the current position of the host vehicle detected by the host vehicle position detection device 33 of the vehicle information detection device 3 to the destination set by the driver by referring to the map DB2. The calculated traveling route is output to the driving support device 6. The traveling route is linear with the road on which the host vehicle travels, the direction (uphill / downhill), and the lane identified. The traveling route includes information on the traveling lane.

[0018] The vehicle control device 5 is an in-vehicle computer such as an electronic control unit (ECU), and electronically controls in-vehicle devices that regulate the traveling of the vehicle. The vehicle control device 5 includes a vehicle speed control device 51 that controls the traveling speed of the host vehicle and a steering control device 52 that controls the steering operation of the host vehicle.

[0019] The vehicle speed control device 51 controls a drive device such as an electric motor and / or an internal combustion engine, which is a traveling drive source, and an automatic transmission. The vehicle speed control device 51 autonomously controls the traveling speed of the vehicle based on a control signal input from the driving support device 6. The steering control device 52 controls the steering device. The steering control device 52 controls the operation of the steering device based on a control signal input from the driving support device 6 and using at least one of the detection results of the detection device 1, the map DB2, and the host vehicle information acquired by the vehicle information detection device 3, so that the host vehicle travels while maintaining a predetermined lateral position (position in the left-right direction of the vehicle) with respect to the traveling route.

[0020] The traveling support device 6 controls the devices included in the traveling support system 10 to cooperate with each other to control the traveling of the host vehicle, and particularly supports avoidance control for avoiding obstacles on the host vehicle lane. The obstacle is a stationary object located in the traveling direction of the host vehicle and obstructing the traveling of the host vehicle. The obstacle is, for example, a parked vehicle, a construction signboard, or the like.

[0021] In the present embodiment, the traveling support device 6 realizes avoidance control support by the processor 7. The processor 7 executes the avoidance control of the host vehicle by the avoidance control function. The processor 7 acquires information including nodes in each lane of the road on which the host vehicle travels and a traveling area divided by the nodes from the high-precision map information stored in the map DB2. Based on the acquired information, the processor 7 generates a traveling trajectory for avoiding an obstacle and controls the traveling of the host vehicle along the generated traveling trajectory. For example, when it is necessary to change lanes to an adjacent lane to avoid an obstacle, the processor 7 selects a position to start the lane change from the nodes of the host vehicle lane, selects a position to end the lane change from the nodes of the adjacent lane, and controls the traveling of the host vehicle to change lanes along the traveling trajectory passing through the selected nodes. In the present embodiment, regardless of whether it is avoidance control or not, when a lane change to an adjacent lane is necessary, a node that becomes the position to end the lane change is selected from the nodes of the adjacent lane.

[0022] Here, an example of a method for generating a traveling trajectory using the lane nodes and the traveling area will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example of a scene where the method for generating a traveling trajectory using the lane nodes and the traveling area is executed. In FIG. 2, a scene is shown in which the host vehicle V1 is traveling on the host vehicle lane L1 and there is a parked vehicle V2 as an obstacle obstructing the traveling of the host vehicle V1 on the host vehicle lane L1. The road shown in FIG. 2 is a one-lane road on one side, and the adjacent lane adjacent to the host vehicle lane L1 is the oncoming lane L2. In FIG. 2, it is assumed that the vehicle traveling on the host vehicle lane L1 travels from the right side to the left side of the drawing, and the vehicle traveling on the oncoming lane L2 travels from the left side to the right side of the drawing.

[0023] In Figure 2, the positions indicated by black circles, such as point N, are the locations of lane nodes, and the area between the lane nodes is the driving area. Since the node positions are set for each lane, as shown in Figure 2, the positions of nodes and driving areas may differ between the oncoming lane and the oncoming lane, even on the same road. Node and driving area information is obtained from a high-precision map. Then, the driving area where the parked vehicle V2 is located on the oncoming lane is designated as the no-go area PA, and a driving trajectory AL is generated that avoids the no-go area PA. The no-go area PA is an area demarcated by the starting node NS and the ending node NE.

[0024] The driving trajectory AL is a trajectory that passes through nodes N1, N2, N3, and N4 in order. In this embodiment, the vehicle performs avoidance control consisting of three controls along the driving trajectory. The first control is a lane change from the vehicle's lane to the oncoming lane to avoid an obstacle, the second control is a control that drives alongside the obstacle on the oncoming lane, and the third control is a lane change from the oncoming lane back to the vehicle's lane to return to the vehicle's lane. In the first control, the driving support device 6 performs steering control that moves the lateral position, which indicates the vehicle's position in the vehicle width direction, from the center position on the vehicle's lane in the direction of avoidance, starting from a position before the obstacle in the direction of travel. Node N1 is set as the starting position for the first control. Node N2 is set as the ending position for the first control. In the second control, the driving support device 6 causes the vehicle to drive alongside the obstacle in the direction of travel. The second control starts from node N2 and ends at node N3. In the third control, the driving support device 6 performs steering control to return the lateral position of the vehicle to the center position on the lane. Node N3 is set as the starting position to initiate the third control, and node N4 is set as the ending position to terminate the third control.

[0025] In this embodiment, the start and end positions (start position of the second control) of the first control, and the start and end positions (end position of the second control) of the third control are selected from nodes in the local lane and nodes in the opposing lane, respectively. For example, the end position of the first control (start position of the second control) is the node in the opposing lane that is closest to the area corresponding to the no-travel area on the opposing lane, among the nodes in the opposing lane that are located in the opposite direction of travel of the local vehicle to the area corresponding to the no-travel area on the opposing lane. Similarly, the start position of the third control (end position of the second control) is the node in the opposing lane that is closest to the area corresponding to the no-travel area on the opposing lane, among the nodes in the opposing lane that are located in the direction of travel of the local vehicle to the area corresponding to the no-travel area on the opposing lane. That is, in Figure 2, node N2 is the end position of the first control, and node N3 is the start position of the third control.

[0026] In Figure 2, the vehicle travels along the opposing lane from node N2 to node N3, following its direction of travel, and passes to the side of the restricted area PA. In this case, as shown in Figure 2, if the positions of nodes N2 and N3 are far apart from the positions on the opposing lane corresponding to the starting node NS and ending node NE, the distance that the vehicle V1 travels along the opposing lane L2 becomes longer.

[0027] Therefore, the driving support device 6 according to this embodiment generates a driving trajectory that shortens the distance the vehicle travels on the opposing lane by sharing the nodes of the vehicle's own lane and the nodes of the opposing lane with each other. For example, an example of the case in which the nodes of the vehicle's own lane and the nodes of the opposing lane are shared with each other in a driving scene as shown in Figure 2 will be explained. Figure 3 is an example showing the result of sharing the nodes of the vehicle's own lane and the nodes of the opposing lane with each other. For example, as shown in Figure 3, the driving support device 6 sets node NE' in the opposing lane at a position corresponding to the position of node NE, based on the position of node NE in the vehicle's own lane. Similarly, the driving support device 6 sets node NS' in the opposing lane at a position corresponding to the position of node NS in the vehicle's own lane, based on the position of node NS in the vehicle's own lane. That is, nodes NE' and NS', which correspond to nodes NE and NS respectively, are nodes whose position in the direction of travel of the vehicle is the same as the position of nodes NE and NS in the direction of travel of the vehicle, and whose position in the lane width direction is on the center line of the opposing lane.

[0028] As a result, for example in Figure 3, among the nodes in the opposing lane that are located in the opposite direction of the vehicle's direction of travel to the area corresponding to the area where driving is prohibited in the opposing lane, the node in the opposing lane closest to the area is node NE'. Therefore, node NE' is set as the position where the lane change from the opposing lane L2 to the vehicle's own lane L1 begins. In other words, the vehicle can change lanes to its own lane immediately after passing the side of the area where driving is prohibited PA. As described above, in this embodiment, the driving support device 6 generates a driving trajectory that shortens the distance the vehicle travels on the opposing lane by having the nodes in the vehicle's own lane and the nodes in the opposing lane share each other. The details of the control will be described below.

[0029] The processor 7 is a computer that includes a ROM 72 in which a program is stored, a CPU 71 which is an operating circuit for functioning as a driving assistance device 6 by executing the program stored in the ROM 72, and a RAM 73 which functions as an accessible storage device. The processor 7 according to this embodiment executes each of the above functions through the cooperation of software and the hardware described above.

[0030] The processor 7 includes, as functional blocks, a self-position estimation unit 100, a driving boundary acquisition unit 101, a surrounding object acquisition unit 102, an obstacle determination unit 103, an avoidance determination unit 104, a node setting unit 105, a driving area generation unit 106, a driving trajectory generation unit 107, and a vehicle control unit 108. In this embodiment, the functions of the processor 7 are divided into nine blocks and the functions of each functional block are explained, but the functions of the processor 9 do not necessarily need to be divided into ten blocks as long as each function can be realized in that configuration.

[0031] The vehicle position estimation unit 100 estimates the position and orientation of the vehicle on the map. Based on the map information obtained from the map DB2 and the position and orientation obtained from the vehicle information detection device 3, the vehicle position estimation unit 100 estimates the current position and orientation of the vehicle on the map.

[0032] The driving boundary acquisition unit 101 acquires lane information around the vehicle. For example, the driving boundary acquisition unit 101 acquires lane information for the vehicle's own lane and for the opposing lane adjacent to the vehicle's own lane. The lane information includes the length in the width direction of the lane. Based on the vehicle's position, the driving boundary acquisition unit 101 acquires lane information around the vehicle from the map DB2 as the road structure around the vehicle.

[0033] The surrounding object acquisition unit 102 acquires surrounding object information about objects around the vehicle based on the detection information detected by the detection device 1. The surrounding object information includes the position, orientation, and speed of the surrounding objects. For example, the surrounding object acquisition unit 102 acquires surrounding object information about objects located in the direction of travel of the vehicle's lane. The surrounding object acquisition unit 102 also acquires position information of the surrounding objects based on the vehicle's current position information and the relative position (distance and direction) between the vehicle and the surrounding objects.

[0034] The obstacle detection unit 103 determines whether or not there is an obstacle in its own lane that would obstruct the vehicle's movement, based on lane information and surrounding object information. For example, the obstacle detection unit 103 determines whether or not there is an object on its own lane that satisfies the conditions described below, based on the position of the left and right boundaries of its own lane, the length of its own lane in the width direction, which are included in the lane information of its own lane, and the position of surrounding objects and the state of surrounding objects, which are included in the surrounding object information. If there is an object on its own lane that satisfies the conditions described below, the obstacle detection unit 103 identifies the object as an obstacle and determines that there is an obstacle in its own lane. Also, if there is no object that satisfies the conditions described below, the obstacle detection unit 103 determines that there is no obstacle in its own lane.

[0035] The criteria for determining the presence or absence of an obstacle are, for example, whether the following three conditions are met. The first condition is that an object exists in the direction of travel of the vehicle's lane and that the object is stationary; the second condition is that when the vehicle passes alongside the obstacle along the set travel path, the vehicle makes contact with the obstacle, or the distance between the vehicle and the obstacle becomes less than a predetermined distance; and the third condition is that the object is located at or above a predetermined distance to either the left or right of the center of the vehicle's lane. Even if a stationary object exists in the direction of travel of the vehicle's lane and the vehicle cannot travel in its lane, the object may be a vehicle waiting at a traffic light. By setting the condition that a stationary object is located at or above the left or right of the vehicle's lane, the obstacle determination unit 103 determines that there is an obstacle in the vehicle's lane if the object is a parked vehicle.

[0036] Furthermore, in this embodiment, the obstacle determination unit 103 may acquire information on the driving area in the direction of travel of the vehicle on its own lane from the map DB2, and determine that there is an obstacle on the vehicle's lane if there is a no-travel area where a construction site or the like is located in the direction of travel of the vehicle.

[0037] The avoidance determination unit 104 identifies the driving area where the obstacle is located as a no-go area and determines whether or not to avoid the no-go area based on lane information. If the obstacle determination unit 103 determines that there is an obstacle, the avoidance determination unit 104 uses map information to identify the start and end nodes of the no-go area and determines whether or not the vehicle should avoid the no-go area depending on whether or not it is passable between the vehicle's lane and the oncoming lane. The avoidance determination unit 104 determines whether or not it is passable between the vehicle's lane and the oncoming lane. For example, if the lane boundary between the vehicle's lane and the oncoming lane is a road marking that is physically passable, the avoidance determination unit 104 determines that it is passable between the vehicle's lane and the oncoming lane. The lane boundary by road marking is, for example, a solid white line, a dashed line, or a solid yellow line. Furthermore, the avoidance determination unit 104 determines that it is not possible to pass between the vehicle's lane and the oncoming lane if the lane boundary between the vehicle's lane and the oncoming lane is a road structure that makes it physically impossible to pass. Examples of lane boundaries made by road structures include median strips and lane dividers such as rubber poles.

[0038] Furthermore, the avoidance determination unit 104 may determine whether or not to avoid an obstacle based on lane information and detection information. For example, if it is possible to pass between the own lane and the oncoming lane, the avoidance determination unit 104 will determine, based on detection information, whether or not there is an obstacle on the oncoming lane that would hinder avoidance control. Obstacles include, for example, parked vehicles and oncoming vehicles. The avoidance determination unit 104 will determine whether or not there is an obstacle in the driving area of ​​the oncoming lane located within the avoidance section. The avoidance section is, for example, a section of distance necessary to perform avoidance control to avoid an area where driving is not permitted. If there is no obstacle on the oncoming lane, the avoidance determination unit 104 will determine to avoid the obstacle on the own lane. If there is an obstacle on the oncoming lane, the avoidance determination unit 104 will determine not to avoid the obstacle on the own lane.

[0039] The node setting unit 105 obtains node information for the direction of travel of the vehicle from the map DB2, which is included in the map information. The node information includes node information for the vehicle's own lane and node information for the opposing lane. At this time, since the position of each node included in the map information is set for each lane, the position of the node for the vehicle's own lane and the position of the node for the opposing lane may differ in the direction of travel of the vehicle.

[0040] Furthermore, the node setting unit 105 performs a sharing process that allows the nodes of the current lane and the opposing lane to share with each other. The node setting unit 105 uses map information to add nodes to the current lane that correspond to the positions of nodes set in the opposing lane on the map. The position of the node in the current lane that corresponds to the node in the opposing lane in the direction of travel of the current vehicle is set to be the same as the position of the corresponding node in the opposing lane in the direction of travel of the current vehicle. In addition, the position of the node in the current lane that corresponds to the node in the opposing lane in the direction of travel of the current lane is set to be on the center line of the current lane.

[0041] Furthermore, the node setting unit 105 uses map information to add nodes to the opposing lane that correspond to the positions of nodes set in the local lane on the map. The position of the node in the opposing lane corresponding to the node in the local lane in the direction of travel of the local vehicle is set to the same position as the corresponding node in the local lane in the direction of travel of the local vehicle. Also, the position of the node in the opposing lane corresponding to the node in the local lane in the lane width direction is set to lie on the centerline of the opposing lane. At this time, the node in the local lane added to the opposing lane includes the start and end points of the no-travel area on the local lane. In this way, by sharing nodes between the local lane and the opposing lane, the positions of the nodes in the local lane and the opposing lane can be aligned. Note that in this embodiment, it is not limited to sharing nodes between the local lane and the opposing lane; nodes from one lane may be added to the other lane.

[0042] Furthermore, in this embodiment, for example, when the vehicle starts traveling to its destination, the nodes of the vehicle's own lane and the nodes of the opposing lane may be shared with each other over the entire travel route to the destination, or the nodes of the vehicle's own lane and the nodes of the opposing lane may be shared only in specific sections. By limiting the sections in which the nodes of the vehicle's own lane and the nodes of the opposing lane are shared with each other, an increase in the amount of data can be prevented. In other words, by sharing the nodes of the vehicle's own lane and the nodes of the opposing lane with each other, each lane can be subdivided, but this will increase the amount of data. Therefore, unnecessary subdivision can be suppressed to reduce the increase in the amount of data.

[0043] The node setting unit 105 adds nodes to the local lane that correspond to the positions of nodes set in the opposing lane, and adds nodes to the opposing lane that correspond to the positions of nodes set in the local lane, in sections where it is possible to pass between the local lane and the opposing lane. For example, if the section between the local lane and the opposing lane in a detour section to avoid an area where it is impossible to drive in the local lane is a section where it is possible to pass between the local lane and the opposing lane, the node setting unit 105 makes the nodes of the local lane and the nodes of the opposing lane share each other in that section.

[0044] Furthermore, the node setting unit 105 may add nodes in its own lane that correspond to the positions of nodes set in the opposing lane, and add nodes in the opposing lane that correspond to the positions of nodes set in its own lane, in the section of the opposing lane driving area adjacent to the no-driving area. For example, in the driving scene shown in Figure 2, the two driving areas located between nodes N2 and N3 in the opposing lane are the driving areas in the opposing lane adjacent to the no-driving area PA. The node setting unit 105 makes the nodes in its own lane and the nodes in the opposing lane share each other in the section between nodes N2 and N3.

[0045] Furthermore, the node setting unit 105 adds nodes to the vehicle's lane that correspond to the positions of nodes set in the opposing lane, and adds nodes to the opposing lane that correspond to the positions of nodes set in the vehicle's lane, when the vehicle's lane in the direction of travel is a single lane. For example, the node setting unit 105 acquires lane information for the vehicle's direction of travel, and when the vehicle's lane in the direction of travel is a single lane, such as on a road with one lane in each direction, it makes the nodes in the vehicle's lane and the nodes in the opposing lane share each other in the section where the vehicle's lane in the direction of travel is a single lane.

[0046] The driving area generation unit 106 divides the lanes into driving areas based on the nodes for each lane, including the newly added nodes, after the nodes for the local lane and the opposing lane have been shared by the node setting unit 105. In other words, the node setting unit 105 newly generates driving areas for each lane based on the nodes set for each lane after node sharing. For example, as shown in Figure 3, the driving area generation unit 106 divides the opposing lane by the newly added nodes NE' and N3, and generates a new driving area in the section between the opposing lane's node NE' and node N3. In Figure 3, the vehicle changes lanes within the driving areas of the local and opposing lanes in the section between node NE' and node N3.

[0047] Furthermore, the driving area generation unit 106 merges two driving areas separated by a node to be deleted into a single driving area by deleting a node that meets predetermined conditions. For example, the conditions for a node to be deleted are that it is located within a no-drive area and within the driving area of ​​the opposing lane corresponding to the no-drive area. After nodes are added to the local lane and the opposing lane through the sharing process, the driving area generation unit 106 determines whether there are any nodes to be deleted located within a no-drive area and within the driving area of ​​the opposing lane corresponding to the no-drive area. If there are nodes to be deleted located within a no-drive area and within the driving area of ​​the opposing lane corresponding to the no-drive area, the driving area generation unit 106 deletes the nodes to be deleted. Then, the driving area generation unit 106 divides the lanes into driving areas based on the nodes in each lane after the deletion of the nodes to be deleted. As a result, the no-drive area is merged into a single driving area, and the driving area of ​​the opposing lane corresponding to the no-drive area is also merged into a single driving area.

[0048] For example, as shown in Figure 3, the no-drive area PA is divided into multiple driving areas by the addition of node N5' corresponding to node N5. Also, the driving area PA' of the opposite lane corresponding to the no-drive area PA is divided into multiple driving areas by node N5. Therefore, the driving area generation unit 106 integrates the multiple driving areas included in the no-drive area into one driving area, and integrates the multiple driving areas included in the driving area of ​​the opposite lane corresponding to the no-drive area into one driving area. That is, the driving area generation unit 106 deletes node N5' which divides the no-drive area PA and node N5 which divides the driving area PA' of the opposite lane corresponding to the no-drive area, and divides each lane into driving areas using the nodes for each lane after deleting each node. Nodes within the no-drive area do not become the end or start positions of lane changes, so there is no need to set nodes within the no-drive area. Therefore, by deleting unnecessary nodes and generating driving areas, the amount of data can be reduced.

[0049] Furthermore, the condition for a node to be deleted is that it is located within a predetermined distance in the opposite direction of the vehicle's travel from the starting node of the no-travel area and the starting node of the travel area of ​​the opposing lane corresponding to the no-travel area. After nodes are added to the own lane and the opposing lane through shared processing, the travel area generation unit 106 determines whether there are any nodes to be deleted that are located within a predetermined distance in the opposite direction of the vehicle's travel from the starting node of the no-travel area and the starting node of the travel area of ​​the opposing lane corresponding to the no-travel area. If there are any nodes to be deleted that are located within a predetermined distance in the opposite direction of the vehicle's travel from the starting node of the no-travel area and the starting node of the travel area of ​​the opposing lane corresponding to the no-travel area, the travel area generation unit 106 deletes the nodes to be deleted. Then, the travel area generation unit 106 divides the lanes into travel areas based on the nodes in each lane after the deletion of the nodes to be deleted.

[0050] Furthermore, the condition for a node to be deleted is that there is a node to be deleted located within a predetermined distance in the direction of travel of the vehicle from the endpoint node of the no-drive area and the endpoint node of the driving area of ​​the opposing lane corresponding to the no-drive area. After nodes are added to the vehicle's lane and the opposing lane through shared processing, the driving area generation unit 106 determines whether there is a node to be deleted located within a predetermined distance in the direction of travel of the vehicle from the endpoint node of the no-drive area and the endpoint node of the driving area of ​​the opposing lane corresponding to the no-drive area. If there is a node to be deleted located within a predetermined distance in the direction of travel of the vehicle from the endpoint node of the no-drive area and the endpoint node of the driving area of ​​the opposing lane corresponding to the no-drive area, the driving area generation unit 106 deletes the node to be deleted. Then, the driving area generation unit 106 divides the lanes into driving areas based on the nodes in each lane after the deletion of the node to be deleted.

[0051] This merges the two driving areas, which were separated by the node to be deleted, into a single driving area. The predetermined distance is the distance necessary to properly execute steering control for lane changes, for example, 15m. In other words, the predetermined distance is the distance necessary so that the steering control for lane changes does not result in sudden steering that would impair the comfort of the occupants. In this embodiment, since the lane change is performed between one node, if the distance between nodes is less than or equal to the predetermined distance, the steering control for lane changes cannot be properly executed. Therefore, if there is a distance of more than the predetermined distance between nodes before a distance of less than or equal to the predetermined distance between nodes, the section between the preceding nodes may be designated as the section for performing the lane change.

[0052] For example, in Figure 3, if the distance in the direction of travel of the vehicle in section D1 between node NS' and the adjacent node N2 in the opposing lane is less than or equal to a predetermined distance, a lane change cannot be properly performed in section D1. Therefore, at the node positions shown in Figure 3, node NS' cannot be set as the end position of the lane change, and the lane change may be performed in section D2 between node N1 and node N2', which is before section D1. In this case, the vehicle will travel along section D1 in the opposing lane in the direction of travel, and the distance the vehicle travels along the opposing lane in the direction of travel becomes longer.

[0053] Therefore, the driving area generation unit 106 deletes node N2' located within a predetermined distance from the starting node NS in the opposite direction of the vehicle's travel, and node N2 located within a predetermined distance from node NS' of the opposing lane corresponding to the starting node NS in the opposite direction of the vehicle's travel. Then, the driving area generation unit 106 divides each lane into driving areas based on the nodes of each lane after deletion. In this way, the areas that were divided into two driving areas by nodes N2 and N2' are integrated into a single driving area.

[0054] Here, we will explain an example of the integrated result of combining the driving areas using Figure 4. Figure 4 shows the integrated result after performing the driving area integration process on the driving areas that were divided after node sharing as shown in Figure 3. In Figure 4, compared to Figure 3, nodes N5, N5', N2, and N2' have been deleted, and the driving areas that were divided by each node have been integrated.

[0055] In this embodiment, if the section of the driving area adjacent to the restricted area does not have the distance necessary to properly execute steering control for lane changes, as shown in Figure 4, the distance necessary to properly execute steering control for lane changes can be secured in the section of the driving area adjacent to the restricted area. Furthermore, since nodes set within the restricted area or the driving area of ​​the opposing lane corresponding to the restricted area are not set as the start or end positions for lane changes, integrating the restricted area and the driving area of ​​the opposing lane corresponding to the restricted area into a single driving area allows for the removal of nodes unnecessary for avoidance control, thereby reducing the amount of data.

[0056] The driving trajectory generation unit 107 generates a driving trajectory in which the vehicle completes a lane change from its own lane to the oncoming lane at the first passing node and begins a lane change from the oncoming lane to its own lane at the second passing node. The first passing node is a node on the oncoming lane and is the position where the vehicle completes a lane change from its own lane to the oncoming lane to avoid the no-travel area (first control). In other words, the vehicle completes the lane change at the first passing node and begins driving on the oncoming lane in line with the direction of travel of the vehicle (second control). The second passing node is a node on the oncoming lane and is the position where the vehicle begins a lane change from the oncoming lane to its own lane after avoiding the no-travel area (third control). In other words, the vehicle completes the second control at the second passing node and begins a lane change from the oncoming lane to its own lane (third control).

[0057] The trajectory generation unit 107 selects the node in the opposing lane that is closest to the area corresponding to the no-go area on the opposing lane, from among the nodes in the opposing lane that are located in the opposite direction of the vehicle's direction of travel to the area corresponding to the no-go area on the opposing lane, as the first passing node. The trajectory generation unit 107 also selects the node in the opposing lane that is closest to the area corresponding to the no-go area on the opposing lane, from among the nodes in the opposing lane that are located in the direction of the vehicle's direction of travel to the area corresponding to the area corresponding to the no-go area on the opposing lane, as the second passing node. As shown in Figure 4, when selecting the first and second passing nodes after the nodes in the vehicle's lane and the nodes in the opposing lane are shared, the trajectory generation unit 107 selects the node NS' in the opposing lane corresponding to the position of the starting node NS as the first passing node, and selects the node NE' in the opposing lane corresponding to the position of the ending node NE as the second passing node.

[0058] Next, the driving trajectory generation unit 107 identifies the avoidance start node and the avoidance end node. The avoidance start node is a node in the vehicle's own lane and is the starting position for a lane change from the vehicle's own lane to the oncoming lane (first control) to avoid the impassable area, and the avoidance end node is a node in the vehicle's own lane and is the ending position for a lane change from the oncoming lane to the vehicle's own lane (third control) after avoiding the impassable area. The driving trajectory generation unit 107 selects the node in the vehicle's own lane that is closest to the first pass node from among the nodes in the vehicle's own lane that are a predetermined distance away in the direction opposite to the vehicle's direction of travel, starting from the first pass node, as the avoidance start node. The driving trajectory generation unit 107 also selects the node in the lane that is closest to the second pass node from among the nodes in the vehicle's own lane that are a predetermined distance away in the direction of travel, starting from the second pass node, as the avoidance end node. The predetermined distance is the distance necessary to appropriately execute steering control for lane changes.

[0059] In this embodiment, because the integration by the driving area generation unit 106 results in a distance of more than a predetermined distance between the driving area and the section of the driving area adjacent to the section of the no-driving area, the driving trajectory generation unit 107 selects the starting node of the driving area located in front of the no-driving area as the avoidance start node, and selects the ending node of the driving area located behind the no-driving area as the avoidance end node. In the driving scene shown in Figure 4, the driving area generation unit 106 selects node N1 as the avoidance start node and node N3' as the avoidance end node.

[0060] The driving trajectory generation unit 107 selects a first passing node, a second passing node, an avoidance start node, and an avoidance end node, and then generates a driving trajectory in which the vehicle changes lanes from the avoidance start node to the first passing node, travels on the opposing lane from the first passing node to the second passing node, and changes lanes again from the second passing node to the avoidance end node. As shown in Figure 4, the driving trajectory AL is a driving trajectory that passes through node N1, node NS', node NE', and node N3'.

[0061] The vehicle control unit 108 controls the vehicle so that it performs avoidance control along the driving trajectory. Specifically, the vehicle control unit 108 controls the vehicle's movement so that a lane change from the vehicle's own lane to the oncoming lane to avoid the no-go area begins at the avoidance start node and ends at the first passing node. Furthermore, the vehicle control unit 108 controls the vehicle's movement so that a lane change from the oncoming lane back to the vehicle's own lane to return to the vehicle's own lane after avoiding the no-go area begins at the second passing node and ends at the avoidance end node. The vehicle control unit 108 calculates the target vehicle speed and target steering angle for driving along the set driving trajectory, and generates a control signal to drive the vehicle based on the calculated target vehicle speed and target steering angle. The generated control signal is output to the vehicle control device 5.

[0062] Next, the process related to avoidance support control performed by the driving support device 6 will be explained. Figure 3 is a flowchart showing the control flow for performing avoidance support control in the driving support device 6. When the vehicle starts moving, the processor 7 starts the control flow from step S1.

[0063] In step S1, the processor 7 acquires map information. The map information includes lane information and node information for the direction of travel of the vehicle. The lane information includes lane information for the current lane and the oncoming lane. The node information includes node information for the current lane and the oncoming lane. In step S2, the processor 7 acquires surrounding object information. The surrounding object information includes information on objects located in the direction of travel of the vehicle. In step S3, the processor 7 determines whether or not there is an obstacle in the current lane based on the lane information and surrounding object information. If it is determined that there is an obstacle in the current lane, the processor 7 proceeds to step S4. If it is determined that there is no obstacle in the current lane, the processor 7 returns to step S1 and repeats the control flow as follows.

[0064] In step S4, the processor 7 determines whether the vehicle will avoid the obstacle. For example, the processor 7 determines that the vehicle will avoid the obstacle if it is possible to pass between its own lane and the oncoming lane. If the processor 7 determines that the vehicle will avoid the obstacle, it proceeds to step S5. If the processor 7 determines that the vehicle will not avoid the obstacle, it terminates the avoidance support control. In this embodiment, if avoidance control cannot be started and the avoidance support control flow terminates, the driving control switches to manual driving by the driver.

[0065] In step S5, the processor 7 identifies the driving area where the obstacle is located as a no-go area. The processor 7 identifies the locations of the start and end nodes of the no-go area. In step S6, the processor 7 adds nodes to the current lane corresponding to the locations of nodes in the opposing lane included in the map information. In step S7, the processor 7 adds nodes to the opposing lane corresponding to the locations of nodes in the current lane included in the map information. In step S8, the processor 7 selects the nodes to pass through. The processor 7 selects the node in the opposing lane that is closest to the area corresponding to the no-go area on the opposing lane, from among the nodes in the opposing lane that are located in the opposite direction of the vehicle's travel from the area corresponding to the no-go area on the opposing lane, as the first node to pass through. The processor 7 also selects the node in the opposing lane that is closest to the area corresponding to the no-go area on the opposing lane, from among the nodes in the opposing lane that are located in the direction of the vehicle's travel from the area corresponding to the no-go area on the opposing lane, as the second node to pass through.

[0066] In step S9, the processor 7 selects the avoidance start node and the avoidance end node. In step S10, the processor 7 generates a driving trajectory. The processor 7 generates a driving trajectory in which the vehicle changes lanes from its own lane to the oncoming lane from the avoidance start node to the first passing node, and changes lanes from the oncoming lane back to its own lane from the second passing node to the avoidance end node. In step S11, the processor 7 controls the vehicle's movement. The processor 7 generates a control signal to cause the vehicle to follow the driving trajectory and outputs the control signal to the vehicle control device 5. When the vehicle control device 5 receives the control signal, it controls the vehicle's movement based on the control signal.

[0067] As described above, in this embodiment, a driving assistance method is performed by a processor, in which, for each lane, nodes are set and map information described by links of driving areas divided by nodes is used, and a driving area where an obstacle that obstructs the vehicle's movement is located on the vehicle's own lane is defined as a no-go area, and nodes corresponding to the positions of the nodes in the vehicle's own lane, including the start and end nodes of the no-go area, are added to the opposing lane adjacent to the vehicle's own lane. If it is possible to pass between the vehicle's own lane and the opposing lane, the node in the opposing lane corresponding to the position of the start node is selected as the first passing node, and the node in the opposing lane corresponding to the position of the end node is selected as the second passing node, and the driving trajectory is calculated in which the vehicle completes a lane change from its own lane to the opposing lane at the first passing node and begins a lane change from the opposing lane to its own lane at the second passing node, and the driving of the vehicle is controlled along the driving trajectory. This prevents the distance the vehicle travels on the opposing lane from becoming too long when the vehicle travels on the opposing lane to avoid an obstacle in the lane it is traveling in.

[0068] Furthermore, in this embodiment, the processor adds nodes to the local lane corresponding to the positions of nodes set in the opposing lane, and adds nodes to the opposing lane corresponding to the positions of nodes set in the local lane, in sections where it is possible to pass between the local lane and the opposing lane. This limits node sharing to sections where it is possible to pass between the local lane and the opposing lane, thereby suppressing the increase in data volume associated with node sharing.

[0069] Furthermore, in this embodiment, the processor adds nodes to its own lane corresponding to the positions of nodes set in the opposing lane in the section of the opposing lane's driving area adjacent to the area where driving is prohibited, and adds nodes to the opposing lane corresponding to the positions of nodes set in its own lane. This limits node sharing to the section of the opposing lane's driving area adjacent to the area where driving is prohibited, thereby suppressing the increase in data volume associated with node sharing.

[0070] Furthermore, in this embodiment, when the vehicle's direction of travel has only one lane, the processor adds a node to its own lane corresponding to the position of a node set in the opposing lane, and adds a node to the opposing lane corresponding to the position of a node set in its own lane. This limits node sharing to sections where crossing into the opposing lane is necessary, thereby suppressing the increase in data volume associated with node sharing.

[0071] Furthermore, in this embodiment, the processor adds nodes to the local lane corresponding to the locations of nodes set in the opposing lane. After nodes are added to both the local and opposing lanes, if there are nodes to be deleted located within the no-drive area and within the driving area of ​​the opposing lane corresponding to the no-drive area, the processor deletes these nodes. The lanes are then divided into driving areas based on the nodes remaining in each lane after the deletion of the nodes to be deleted. This suppresses the increase in data volume and simplifies processing.

[0072] Furthermore, in this embodiment, the processor adds a node to the local lane corresponding to the position of a node set in the opposing lane. After nodes are added to both the local and opposing lanes, if there are nodes to be deleted located within a predetermined distance in the opposite direction of travel from the starting node of the no-travel area and the starting node of the driving area of ​​the opposing lane corresponding to the no-travel area, the processor deletes the nodes to be deleted. After nodes are added to both the local and opposing lanes, if there are nodes to be deleted located within a predetermined distance in the direction of travel from the ending node of the no-travel area and the ending node of the driving area of ​​the opposing lane corresponding to the no-travel area, the processor deletes the nodes to be deleted. The lanes are then divided into driving areas based on the nodes in each lane after the nodes to be deleted are removed. This allows the starting point of crossing into the opposing lane to be brought closer to the no-travel area.

[0073] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0074] 6… Driving assistance system 7…Processor 100... Vehicle position estimation unit 101...Travel boundary acquisition unit 102... Surrounding object acquisition unit 103... Obstacle detection unit 104...Avoidance judgment section 105...Node configuration section 106... Driving area generation unit 107...Trajectory generation unit 108... Vehicle Control Unit

Claims

1. A driving assistance method performed by a processor, The aforementioned processor, For each lane, a node is set, and using map information described by links of driving areas divided by the nodes, a driving area where an obstacle is located that obstructs the vehicle's movement on the vehicle's lane is defined as a no-go area, a node corresponding to the location of the node set in the adjacent opposing lane is added to the vehicle's lane, and a node corresponding to the location of the node in the vehicle's lane, including the start and end nodes of the no-go area, is added to the opposing lane. If it is possible to pass between the current lane and the opposing lane, the node in the opposing lane corresponding to the position of the starting node is selected as the first passing node, and the node in the opposing lane corresponding to the position of the ending node is selected as the second passing node. The system calculates the driving trajectory of the vehicle, which completes a lane change from its own lane to the oncoming lane at the first passing node and begins a lane change from the oncoming lane back to its own lane at the second passing node. A driving support method for controlling the movement of the vehicle along the aforementioned driving trajectory.

2. The driving assistance method according to claim 1, wherein the processor adds a node to the own lane corresponding to the position of the node set in the opposing lane in a section where it is possible to pass between the own lane and the opposing lane, and adds a node to the opposing lane corresponding to the position of the node set in the own lane.

3. The driving assistance method according to claim 1 or 2, wherein the processor adds a node to the own lane corresponding to the position of the node set in the opposing lane in a section of the driving area of ​​the opposing lane adjacent to the area where driving is not permitted, and adds a node to the opposing lane corresponding to the position of the node set in the own lane.

4. The driving assistance method according to claim 1 or 2, wherein the processor adds a node to the own lane corresponding to the position of the node set in the opposing lane when the lane in the direction of travel of the own vehicle is one lane, and adds a node to the opposing lane corresponding to the position of the node set in the own lane.

5. The aforementioned processor, A node corresponding to the position of the node set in the opposing lane is added to the own lane, including the area where driving is prohibited. After the nodes have been added to the current lane and the opposing lane, if there are any nodes to be deleted located within the no-travel area and within the travel area of ​​the opposing lane corresponding to the no-travel area, the nodes to be deleted are deleted. The driving assistance method according to claim 1 or 2, wherein the lanes are divided into driving areas based on the nodes for each lane after the nodes to be deleted have been removed.

6. The aforementioned processor, After the nodes have been added to the local lane and the opposing lane, if there are any nodes to be deleted located within a predetermined distance in the opposite direction of travel from the starting node of the no-travel area and the starting node of the travel area of ​​the opposing lane corresponding to the no-travel area, then the nodes to be deleted are deleted. After the nodes have been added to the local lane and the opposing lane, if there are any nodes to be deleted located within a predetermined distance in the direction of travel of the local vehicle from the endpoint node of the no-travel area and the endpoint node of the travel area of ​​the opposing lane corresponding to the no-travel area, then the nodes to be deleted are deleted. The driving assistance method according to claim 1 or 2, wherein the lanes are divided into driving areas based on the nodes for each lane after the nodes to be deleted have been removed.

7. A driving assistance system equipped with a processor that controls the driving of the vehicle, The aforementioned processor, For each lane, a node is set, and using map information described by links of driving areas divided by the nodes, a driving area where an obstacle is located that obstructs the vehicle's movement on the vehicle's lane is defined as a no-go area, a node corresponding to the location of the node set in the adjacent opposing lane is added to the vehicle's lane, and a node corresponding to the location of the node in the vehicle's lane, including the start and end nodes of the no-go area, is added to the opposing lane. If it is possible to pass between the current lane and the opposing lane, the node in the opposing lane corresponding to the position of the starting node is selected as the first passing node, and the node in the opposing lane corresponding to the position of the ending node is selected as the second passing node. The system calculates the driving trajectory of the vehicle, which completes a lane change from its own lane to the oncoming lane at the first passing node and begins a lane change from the oncoming lane back to its own lane at the second passing node. A driving support device that controls the movement of the vehicle along the aforementioned driving trajectory.

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