Travel trajectory generation method and travel trajectory generation device

Abstract

According to the present invention, a controller acquires, from map information, a link line representing a road on which the host vehicle travels, and generates a travel trajectory that connects an entrance point set in a central part of the lane on which the host vehicle travels on an entry road for entering an intersection, and an exit point set on the link line representing an exit road for exiting the intersection.

Description

Travel Route Generation Method and Travel Route Generation Device

[0001] The present invention relates to a travel route generation method and a travel route generation device.

[0002] When the intersection center point is detected, a route to a right-turn waiting point set near the intersection center point is generated, and after the vehicle travels to the right-turn waiting point, an intersection exit is set based on the intersection boundary located on the road edge side in the entry direction after the right turn, and a route from the right-turn waiting point to the intersection exit is generated. This technology is known (Patent Document 1).

[0003] Japanese Patent No. 7119304

[0004] However, in the technology described in Patent Document 1, for example, at a five-way intersection or a large-scale intersection, when the detection range of the in-vehicle sensor is insufficient when the vehicle enters the intersection and the surrounding environment of the intersection exit cannot be recognized, there is a problem that a travel route to the intersection exit cannot be generated.

[0005] The problem to be solved by the present invention is to provide a travel route generation method and a travel route generation device that can generate a travel route to an intersection exit even when the surrounding environment of the intersection exit cannot be recognized using an in-vehicle sensor when the vehicle enters the intersection.

[0006] The present invention solves the above problems by acquiring a link line representing the road on which the host vehicle travels from map information, and generating a travel route connecting an entry point set at the center of the host lane on which the host vehicle travels on the entry road for entering the intersection and an exit point set on the link line representing the exit road for exiting the intersection.

[0007] According to the present invention, even when the surrounding environment of the intersection exit cannot be recognized using an in-vehicle sensor when the vehicle enters the intersection, a travel route to the intersection exit can be generated.

[0008] Figure 1 is a block diagram showing an example of an embodiment of a driving support system equipped with a driving trajectory generation device according to the present invention. Figure 2 is a schematic diagram showing an example of road information according to this embodiment. Figure 3 is a diagram showing an example of driving trajectory generation by the driving trajectory generation device according to this embodiment. Figure 4 is a diagram showing another example of driving trajectory generation by the driving trajectory generation device according to this embodiment. Figure 5 is a diagram showing another example of driving trajectory generation by the driving trajectory generation device according to this embodiment. Figure 6 is a diagram showing another example of driving trajectory generation by the driving trajectory generation device according to this embodiment. Figure 7 is a flowchart showing an example of the processing procedure of the driving trajectory generation method executed by the driving trajectory generation device according to this embodiment.

[0009] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a block diagram showing an example of an embodiment of a driving support system equipped with a driving trajectory generation device according to the present invention. The driving support system 1 is a group of devices that perform driving support for the vehicle, and driving support includes driving the vehicle by autonomous driving control and providing information to the driver of the vehicle to support the driver's driving operations. For example, the driving support system 1 generates a driving route to a destination set by the occupants and autonomously drives the vehicle along the driving route. The driving support system may be an in-vehicle system, and some of its components may be located outside the vehicle. Autonomous driving control is the autonomous control of the vehicle's driving operations, and driving operations include all driving operations such as acceleration, deceleration, starting, stopping, and steering. The autonomous control of driving operations is performed by a control device 15 mounted on the vehicle using the vehicle's devices. For driving operations that are not controlled by the control device 15, manual operation is performed by the driver. When driving by manual operation by the driver without autonomous driving control, the control device 15 does not perform autonomous control of driving operations, and the vehicle's driving operations are controlled by the driver's operation.

[0010] As shown in Figure 1, the driving support system 1 includes a driving trajectory generation device 10, a map database 11, a vehicle position acquisition device 12, a sensor group 13, a route setting device 14, a control device 15, and a drive control device 16. These devices are mounted on the vehicle and connected by a CAN or other in-vehicle LAN to exchange information with each other. In this embodiment, the driving trajectory generation device 10 is equipped with a controller 100, but it is not limited to this and may also be equipped with other devices such as a route setting device 14 and a control device 15. Note that the inclusion of a driving trajectory generation device 10 in the driving support system is just one example and is not limited to this.

[0011] The map database 11 is a storage medium in which map information is stored. The map information includes road information used for generating driving routes, navigation, and generating driving trajectories. The road information includes information on link lines (road links) that represent a single section of a road. Here, an example of road information according to this embodiment will be explained using Figure 2. Figure 2 is a schematic diagram showing an example of road information according to this embodiment. As shown in Figure 2, road information is represented as a collection of link lines (e.g., Link1, Link2, ...). A road may be one in which the upper and lower lanes of the road are represented by a single link line, or it may be one in which the upper and lower lanes of the road are represented by separate link lines. Each link line has a connection relationship with other link lines and represents the topology of the road. Each link line consists of a row of nodes (e.g., node1, 2, 3, 4, ...) and is represented as a line connecting adjacent nodes. A node has an identification number that identifies the node, a position (x, y) in the global coordinate system, an orientation (θ), and an s value which is the distance from the starting point of the link line to which it belongs. Link lines and node points represent the road shape. Nodes are placed at regular intervals (for example, about 1 meter). Nodes include points on the road where the direction of vehicle travel changes, such as intersections between link lines (intersections, junctions, etc.). Map information is output to the trajectory generation device 10 and the route setting device 14.

[0012] Each link line is associated with the road type of the corresponding road. The road type of the road includes information about whether the road to which the link line belongs is one-way or two-way. The link line information may also be associated with intersection inside / outside information, indicating whether the link line belongs inside or outside the intersection. For example, each node may be associated with intersection inside / outside information, indicating whether that node belongs inside or outside the intersection. If intersection inside / outside information indicates that either of the two node points forming the link line belongs inside the intersection, the link line may be associated with belonging inside the intersection. Similarly, if intersection inside / outside information indicates that both of the two node points forming the link line belong inside the intersection, the link line may be associated with belonging inside the intersection.

[0013] The vehicle position acquisition device 12 is a device that acquires position information indicating the current position of the vehicle on a map. The vehicle position acquisition device 12 is composed of, for example, a GNSS receiver. Note that the method for acquiring the current position of the vehicle is not limited to the method using GNSS, but may be other methods. The position information acquired by the vehicle position acquisition device 12 is output to the driving trajectory generation device 10, the route setting device 14, and the control device 15.

[0014] Sensor group 13 is a sensor mounted on the vehicle that detects the surrounding environment of the vehicle. Examples of sensor group 13 include an imaging device and a distance measuring device. The imaging device acquires an ambient image of the surrounding environment of the vehicle. The imaging device is, for example, a camera equipped with an image sensor such as a CCD, an ultrasonic camera, or an infrared camera. Multiple imaging devices can be installed on a single vehicle, for example, they can be placed in front of the vehicle, to the right, to the left, and to the rear of the vehicle. The distance measuring device is a device that calculates the relative distance and relative speed between the vehicle and surrounding objects, and is, for example, a radar device or sonar such as a laser radar, millimeter-wave radar (LRF, etc.), a LiDAR unit, or an ultrasonic radar. Multiple distance measuring devices can be installed on a single vehicle, for example, they can be placed in front of the vehicle, to the right, to the left, and to the rear of the vehicle. The detection results of sensor group 13 are output to the driving trajectory generation device 10 as ambient information of the vehicle. Sensor group 13 is an example of the "on-board sensors" described in the claims.

[0015] The objects detected by the sensor group 13 include, for example, bicycles, motorcycles, automobiles (hereinafter also referred to as other vehicles), road obstacles, traffic signals, road markings, and road structures. Road markings are lines, symbols, and letters drawn on the road surface, including lane boundaries, center lines, stop lines, and pedestrian crossings. Lane boundaries are lines drawn on the road to demarcate lanes, including solid lines, double lines, and dashed lines in white, orange, or yellow. Road structures include median strips, guardrails, curbs, and highway side walls. The sensor group 13 acquires the relative positions of objects around the vehicle with respect to the vehicle's current position. In this embodiment, the sensor group 13 acquires the detection results, including the intersection the vehicle is traveling through and the environment around the intersection, as ambient information.

[0016] The route setting device 14 searches for a route from the vehicle's current location to the destination and sets it as the driving route for the vehicle. The driving route is represented by a series of link lines included in the map information. For example, the route setting device 14 is a navigation system that presents the driving route to the occupants. The route setting device 14 acquires the vehicle's current location, which is acquired by the vehicle position acquisition device 12, and the vehicle's destination, which is entered by the occupants. Based on the acquired information and the map information acquired from the map database 11, it generates a driving route. The route information showing the driving route is output to the occupants via the in-vehicle display. The route information is also output to the driving trajectory generation device 10.

[0017] The control device 15 consists of a ROM that stores a program for controlling the vehicle's movement, a CPU that executes the program stored in the ROM, and RAM that functions as an accessible storage device. The control device 15 implements various functions for controlling the vehicle's movement by having the CPU execute the program stored in the ROM. Specifically, the control device 15 recognizes the surrounding environment of the vehicle and controls the vehicle's movement so that it travels along a designated route. In addition, when a travel trajectory is input from the travel trajectory generation device 10, the control device 15 controls the vehicle's movement so that it travels along the travel trajectory. The control device 15 calculates the control quantities (including target vehicle speed and steering angle) necessary for the vehicle to travel along the travel trajectory and outputs control signals corresponding to these control quantities to the drive control device 16.

[0018] The drive control device 16 controls the vehicle's movement. The drive control device 16 includes a brake control mechanism, an accelerator control mechanism, an engine control mechanism, and HMI (Human Interface) equipment. Control signals are input to the drive control device 16 from the control device 15. In response to the control of the control device 15, the drive control device 16 performs autonomous driving of the vehicle by controlling the operation of the drive mechanism (including the operation of the internal combustion engine in the case of an engine-powered vehicle, the operation of the electric motor in the case of an electric vehicle, and the torque distribution between the internal combustion engine and the electric motor in the case of a hybrid vehicle), the brake operation, and the operation of the steering actuator. The drive control device 16 may also control the direction of movement of the vehicle by controlling the control amount of each wheel of the vehicle in response to the control signals from the control device 15. The control of each mechanism may be performed completely automatically, or it may be performed in a manner that assists the driver's operation.

[0019] The trajectory generation device 10 generates a trajectory for the vehicle to make right and left turns at intersections. The trajectory generation device 10 is, for example, an electronic control unit (ECU) and includes a controller 100. The controller 100 is a device that controls and coordinates the devices that constitute the driving support system 1 to generate a trajectory. The controller 100 is, for example, a computer and consists of a ROM that stores a program for generating a trajectory, a CPU that executes the program stored in the ROM, and RAM that functions as an accessible storage device. The trajectory generation device 10 realizes each function for generating a trajectory by having the CPU execute the program stored in the ROM. The controller 100 includes, as functional blocks, a link acquisition unit 101, a surrounding information acquisition unit 102, a trajectory generation unit 103, a surrounding environment recognition unit 104, and a trajectory correction unit 105.

[0020] The link acquisition unit 101 executes a link acquisition process to acquire link lines representing the roads the vehicle is traveling on from the map information stored in the map database 11. In the link acquisition process, the link acquisition unit 101 acquires link lines of roads around an intersection, for example, when the vehicle approaches an intersection. The acquired link lines are link lines of roads connected to the intersection, and include link lines representing entry roads for the vehicle to enter the intersection, link lines representing exit roads for the vehicle to exit the intersection, and other link lines at the intersection. Other link lines at the intersection include, for example, link lines that have an intersection with a link line representing an entry road within the intersection, and link lines that have an intersection with a link line representing an exit road within the intersection. The information of the acquired link lines includes information of nodes belonging to the link line. The link line information may also include information about whether the link line is inside or outside the intersection.

[0021] For example, the link acquisition unit 101 identifies the current position of the vehicle on the map and the road the vehicle is traveling on, based on the current position of the vehicle acquired from the vehicle position acquisition device 12 and the map information stored in the map database 11. If the identified road is an access road, the link acquisition unit 101 acquires the road link lines around the intersection connected to the access road from the map information. For example, the link acquisition unit 101 may determine whether the vehicle is approaching an intersection based on the recognition result using the sensor group 13, and if the vehicle is approaching an intersection, it may acquire the road link lines around the intersection.

[0022] The surrounding information acquisition unit 102 performs surrounding information acquisition processing to acquire surrounding information, including the environment around the vehicle, from the sensor group 13. Surrounding information includes objects located around the vehicle, such as road markings and road structures. For example, surrounding information is an surrounding image captured around the vehicle. The surrounding information acquisition unit 102 acquires the relative positions of objects around the vehicle with respect to the vehicle itself. The surrounding information acquisition processing is performed at regular intervals.

[0023] The trajectory generation unit 103 performs a trajectory generation process to generate a trajectory for the vehicle to make right or left turns at an intersection. The trajectory is the path (route) of the vehicle and is a trajectory having a predetermined curvature. Specifically, the trajectory generation unit 103 sets an entrance point and an exit point of the intersection on the travel route and generates a curve that smoothly connects the entrance point and the exit point to generate the trajectory. For example, the trajectory is generated as a curve defined by control points that include the entrance point and the exit point. Bezier curves and spline curves are used to generate the trajectory. The vehicle's movement is controlled so that it travels along the generated trajectory. For example, the vehicle travels so that its center of gravity moves along the trajectory. The generated trajectory may be displayed on an in-vehicle display.

[0024] In this embodiment, the trajectory generation unit 103 generates a trajectory connecting an entry point set in the center of the vehicle's lane on the entry road and an exit point set on the link line of the exit road. Alternatively, the trajectory generation unit 103 may use the intersection points of the link line representing the entry road and other link lines at the intersection, and / or the intersection points of the link line representing the exit road and other link lines at the intersection, as control points to generate a curve that smoothly connects the entry point and the exit point as the trajectory. This makes it possible to generate a trajectory that matches the actual road shape at an intersection, even if the intersection is large in scale. For example, the trajectory is generated as a curve defined by control points including a central point. The central point is the intersection of the link line representing the entry road and the link line representing the exit road.

[0025] Here, an example of trajectory generation by the trajectory generation device according to this embodiment will be explained using Figure 3. Figure 3 is a diagram showing an example of trajectory generation by the trajectory generation device according to this embodiment. Figure 3 shows an intersection through which the vehicle V passes. The intersection is connected to an entry road R1 for entering the intersection and an exit road R2 for exiting the intersection. The road is a two-lane road with one lane in each direction, divided into up and down lanes, and one link line is associated with the uphill road and the downhill road, respectively. The entry road R1 is associated with link line L1. The exit road R2 is associated with link line L3. In the example in Figure 3, the trajectory generation unit 103 sets an entry point P1 on link line L1 and on the stop line SL before the intersection, and sets an exit point P2 on link line L3. The trajectory generation unit 103 sets a center point P3 at the intersection of link line L1 and link line L3. The track generation unit 103 generates a track T connecting the entrance point P1 and the exit point P2, including the central point P3 as a control point. In the example in Figure 3, the link lines L1 and L3 are set in the center of the corresponding entrance and exit roads, but the position of the link lines is not limited to the center of the road.

[0026] Furthermore, another example of trajectory generation by the trajectory generation device 10 will be explained using Figure 4. Figure 4 is a diagram showing another example of trajectory generation by the trajectory generation device according to this embodiment. Figure 4 shows an intersection through which the vehicle V passes. The intersection is connected to an entry road R1 for entering the intersection and an exit road R2 for exiting the intersection. Each road is one lane in each direction, and the up and down lanes are associated with a single link line. Link lines L1 and L2 are associated with the entry road R1 and the exit road R2, respectively. A central point P3 is set at the intersection of link line L1 and link line L2. For example, in the example in Figure 4, the trajectory T' is a trajectory generated as a trajectory connecting the entry point and the exit point without including the central point P3 as a control point. As shown in Figure 4, if the intersection is large in scale, simply connecting the entry point and the exit point may result in a large discrepancy from the actual road shape. In contrast, in this embodiment, the trajectory generation unit 103 may generate the trajectory T as a curve defined by control points including the central point P3. This makes it possible to generate a trajectory that conforms to the actual road shape at the intersection.

[0027] Next, the method for setting the entrance and exit points will be described. For example, the trajectory generation unit 103 sets the entrance and / or exit points based on the intersection inside / outside information of the link lines around the intersection. In this embodiment, each node point stored in the map information stores intersection inside / outside information regarding whether it belongs to the inside or outside of the intersection. Based on the intersection inside / outside information of each node, the trajectory generation unit 103 sets the entrance and exit points, respectively, at positions that are the boundaries between the inside and outside of the intersection on the entry road and the exit road. For example, the trajectory generation device 10 identifies a node belonging to the inside of the intersection and a node belonging to the outside of the intersection adjacent to that node on the entry road, and sets the entrance point on the link line between the two identified nodes. The trajectory generation device 10 identifies a node belonging to the inside of the intersection and a node belonging to the outside of the intersection adjacent to that node on the exit road, and sets the exit point on the link line between the two identified nodes. It should be noted that the inclusion of intersection-specific information in the map data, and the setting of entrance and exit points based on intersection-specific information, are not essential components of the present invention and may be included in the configuration as needed.

[0028] The trajectory generation unit 103 may set the entrance point using the intersection of the link line representing the entrance road and other link lines at the intersection. The trajectory generation unit 103 obtains the intersection of the link line representing the entrance road and other link lines at the intersection from map information and identifies the nearest intersection on the entrance road side, which is the closest intersection on the entrance road side among the intersections of the link line representing the entrance road and other link lines at the intersection. That is, the nearest intersection on the entrance road side is the first intersection when the travel route is traced from the entrance road side in the exit direction among the intersections of the link line representing the entrance road and the link line representing other roads at the intersection. The trajectory generation unit 103 sets the entrance point at a predetermined distance away from the identified nearest intersection on the entrance road side along the travel route. The predetermined distance may be a distance set in advance, or it may be the same distance as the distance from the nearest intersection on the entrance road side to the stop line before the intersection on the entrance road.

[0029] The trajectory generation unit 103 may set the exit point using the intersection of the link line representing the exit road and other link lines at the intersection. The trajectory generation unit 103 obtains the intersection of the link line representing the exit road and other link lines at the intersection from the map information and identifies the nearest intersection on the exit road side that is closest to the exit road side. That is, the nearest intersection on the exit road side is the first intersection of the link line representing the exit road and the link line representing other roads at the intersection when the driving route is traced from the exit road side in the direction of entry. The trajectory generation unit 103 sets the exit point at a predetermined distance away from the identified nearest intersection on the exit road side along the driving route. The predetermined distance used to set the exit point may be the same distance as the predetermined distance used to set the entrance point. As described above, even if the map information does not contain information about inside or outside of intersections, the entrance point and exit point can be set based on the intersection of the link lines.

[0030] Here, an example of trajectory generation by the trajectory generation device 10 will be explained using Figure 5. Figure 5 is a diagram showing another example of trajectory generation by the trajectory generation device according to this embodiment. Figure 5 shows an intersection through which the vehicle V passes. The intersection is connected to an entry road R1 for entering the intersection and an exit road R2 for exiting the intersection. Each road is one lane in each direction, and the up and down lanes are associated with a single link line. The entry road R1 and the exit road R2 are associated with link lines L1 and L2, respectively. Link line L1 has an intersection P4 with another link line L3. Link line L2 has an intersection P5 with another link line L4. In the example in Figure 5, intersection P4 is a nearby intersection on the entry road side. Intersection P5 is a nearby intersection on the exit road side. The trajectory generation unit 103 sets an entrance point P1 on a link line L1 at a predetermined distance D from intersection P4 toward the entrance road, and sets an exit point P2 on a link line L2 at a predetermined distance D from intersection P5 toward the exit road. The predetermined distance D used to set the entrance point and the exit point is the same. As described above, in this embodiment, even in cases such as a five-way intersection or a large intersection where the detection range of the sensor group 13 is insufficient to recognize the surrounding environment of the intersection exit when a vehicle enters the intersection, the exit point of the intersection can be set based on the link line, and a trajectory to the intersection exit can be generated. In this embodiment, when setting the entrance point, if the surrounding environment recognition unit 104 recognizes the center of the vehicle's lane on the entrance road, the entrance point may be set at the center of the vehicle's lane instead of on the link line.

[0031] The surrounding environment recognition unit 104 recognizes the surrounding environment of the vehicle based on detection information detected by the sensor group 13. The surrounding environment includes objects such as road markings and road structures on the road. In this embodiment, the surrounding environment recognition unit 104 recognizes the surrounding environment at regular intervals based on surrounding information acquired by the surrounding information acquisition unit 102, and for example, when the vehicle approaches an intersection, it recognizes the surrounding environment of the intersection. The recognized surrounding environment of the intersection includes the entrance road and exit road of the intersection. For example, the surrounding environment recognition unit 104 recognizes the road markings and road structures of the entrance road of the intersection even before entering the intersection. Furthermore, if the exit road of the intersection comes into the detection range of the sensor group 13 while the vehicle is traveling through the intersection, the surrounding environment recognition unit 104 recognizes the road markings and road structures of the exit road.

[0032] For example, the surrounding environment recognition unit 104 recognizes road markings on the road. These markings include white lines such as stop lines and lane boundaries, as well as pedestrian crossings. The surrounding environment recognition unit 104 performs image recognition processing on the surrounding image, including the road surface around the vehicle, which is acquired by the surrounding information acquisition unit 102. For example, the surrounding environment recognition unit 104 applies semantic segmentation to the surrounding image and acquires feature points of road markings such as white lines, stop lines, and pedestrian crossings in the image coordinate system. The surrounding environment recognition unit 104 then converts the acquired feature points of road markings into the three-dimensional relative position of the vehicle in real space. The method of semantic segmentation is not particularly limited, and known techniques may be used as appropriate.

[0033] The surrounding environment recognition unit 104 may recognize road structures on the road. Road structures include curbs on the left and right sides of the road. The surrounding environment recognition unit 104 performs image recognition processing on the surrounding image, including the road surface around the vehicle, acquired by the surrounding information acquisition unit 102. For example, semantic segmentation is used for the image recognition processing. Through image recognition processing, the surrounding environment recognition unit 104 recognizes the road edges of the road located around the intersection and identifies the central point between the left and right road edges. For example, the surrounding environment recognition unit 104 identifies a position that is an intermediate point equidistant from each of the left and right road edges as the central point between the road edges.

[0034] The trajectory correction unit 105 performs a trajectory correction process to correct the trajectory generated by the trajectory generation unit 103 based on the recognition results using the sensor group 13. In the trajectory correction process, the trajectory correction unit 105 corrects the positions of the entrance point, exit point, and center point based on the recognition results using the sensor group 13. The trajectory correction unit 105 generates a new trajectory using the corrected entrance point, exit point, and center point as control points, and corrects the trajectory to the newly generated trajectory. The recognition results include road markings and road structures recognized by the surrounding environment recognition unit 104. In this embodiment, the entrance point, exit point, and center point are corrected, but it is not necessary to correct all of them; it is sufficient if at least one of them is corrected.

[0035] First, in order to align the link line with the surrounding environment based on the recognition results, the trajectory correction unit 105 offsets the link line so that the center point between the left and right road edges and the center point of the link line corresponding to the road overlap when the surrounding environment recognition unit 104 recognizes the road edges of roads located around the intersection. The center point between the left and right road edges is the midpoint, equidistant from each of the recognized left and right road edges. The center point of the link line is the midpoint, equidistant from each of the two link lines, if there are two link lines corresponding to the road (up and down lines). The offset of the link line is performed by parallel and / or rotational movement of the link line. The road that serves as the reference for the offset is the entry road or the exit road. Furthermore, the road that serves as the reference for the offset is not limited to the entry road and the exit road, but may also be a road whose road edge has been recognized by the surrounding environment recognition unit 104. If there is only one link line corresponding to each road, the position of the link line may be the center point of the link line. In this case, the trajectory correction unit 105 offsets the link lines so that the central part between the edges of the roads and the link lines corresponding to the roads located around the intersection overlap.

[0036] Next, the trajectory correction unit 105 corrects the trajectory generated by the trajectory generation unit 103 based on the recognition results from the surrounding environment recognition unit 104. Since the link lines only represent the shape at the road level, the trajectory generated based on the link lines may deviate from the actual road shape. By correcting the trajectory using the recognition results from the surrounding environment recognition unit 104, the trajectory can be adjusted at the lane level. The following describes the correction of the entry and exit points based on the recognition results from the surrounding environment recognition unit 104. Note that the correction of the entry and exit points is performed as needed based on the recognition results of the surrounding environment. In other words, the trajectory is updated in accordance with the changes in the recognized surrounding environment as the vehicle moves. This makes it possible to obtain a faster and more accurate trajectory.

[0037] First, the correction of the entrance and exit points based on the recognition results of road markings will be explained. The trajectory correction unit 105 corrects the position of the entrance point when the surrounding environment recognition unit 104 recognizes road markings related to entering an intersection, such as stop lines and pedestrian crossings on the entrance road. For example, if the surrounding environment recognition unit 104 recognizes a stop line or pedestrian crossing before an intersection on the entrance road, the trajectory correction unit 105 corrects the position of the entrance point to be on the stop line or on the side of the pedestrian crossing in the direction of travel. At this time, the position of the entrance point is corrected along a direction parallel to the link line representing the entrance road. The trajectory correction unit 105 corrects the position of the exit point to correspond to the positional relationship between the position of the entrance point before correction and the position of the entrance point after correction. Specifically, the trajectory correction unit 105 corrects the position of the exit point so that the distance from the corrected entrance point to the nearby intersection on the entrance road side is the same as the distance from the exit point to the nearby intersection on the exit road side. At this time, the position of the exit point is corrected along a direction parallel to the link line representing the exit road. This improves the accuracy of the longitudinal position (in the direction of vehicle travel) of the entrance and exit points of intersections.

[0038] The trajectory correction unit 105 corrects the entry point based on the boundary line of the vehicle's lane when the surrounding environment recognition unit 104 recognizes the boundary line of the vehicle's lane. The vehicle's lane is determined according to whether the vehicle is passing through the intersection to the left or right. When the vehicle is traveling on a two-lane road and turns right at an intersection, the entry point is corrected based on the boundary line of the right lane, and when the vehicle is turning left at an intersection, the entry point is corrected based on the boundary line of the left lane. When the trajectory correction unit 105 recognizes the lane boundary line of the vehicle's lane on the approaching road, it corrects the position of the entry point in the lane width direction so that it is located in the center of the vehicle's lane. The center of the vehicle's lane is the midpoint between the left and right lane boundary lines, and is a position on the centerline that is equidistant from each of the left and right lane boundary lines. The trajectory correction unit 105 corrects the position of the center point in conjunction with the correction of the entry point. The center point is set at the intersection of a straight line passing through the modified entrance point, which is parallel to the link line representing the entrance road, and a straight line passing through the exit point, which is parallel to the link line representing the exit road.

[0039] In this embodiment, as the vehicle travels, if the surrounding environment recognition unit 104 recognizes the edge of the exit road (e.g., the left and right curbs) or a pedestrian crossing, the position of the exit point is corrected. For example, the driving trajectory correction unit 105 identifies the central part of the exit road (the central part between the left and right road edges or the central part of the pedestrian crossing area) and corrects the position of the exit point in the lane width direction of the vehicle's lane so that it is located in the central part of the exit road. The central part between the road edges is the midpoint position equidistant from each of the left and right road edges. The road edges include, for example, the curbs located on the left and right sides of the road, and the left and right edges of a pedestrian crossing. Furthermore, as the vehicle approaches the exit of the intersection, if the surrounding environment recognition unit 104 recognizes the boundary line of the vehicle's lane on the exit road, the driving trajectory correction unit 105 corrects the exit point of the intersection based on the boundary line. For example, the driving trajectory correction unit 105 corrects the position of the exit point in the lane width direction so that it is located in the central part between the boundary lines of the vehicle's lane. The midpoint between the lane boundary lines is located on the centerline, at an equal distance from both the left and right lane boundary lines. If the exit point is modified, the midpoint is modified to the intersection of a straight line passing through the modified entrance point, parallel to the link line representing the entry road, and a straight line passing through the modified exit point, parallel to the link line representing the exit road.

[0040] Here, an example of track generation by the track generation device according to this embodiment will be explained using Figure 6. Figure 6 is a diagram showing an example of track generation by the track generation device according to this embodiment. In Figure 6, an intersection into which the vehicle V enters is shown. First, the track generation unit 103 sets an entrance point P11 on link line L1 representing the entrance road, an exit point P21 on link line L2 representing the exit road, and a center point P31 at the intersection of link line L1 and link line L2. The method for setting the entrance point P11, exit point P21 and center point P31 is as described in the explanation of the track generation unit 103.

[0041] Next, the trajectory correction unit 105 corrects the positions of the entrance point and the exit point based on the recognition results of the surrounding environment using the sensor group 13. For example, if the surrounding environment recognition unit 104 recognizes a stop line SL located on the entrance road, the trajectory correction unit 105 corrects the position of the entrance point along the link line L1 so that the entrance point is located at position P12 on the stop line SL. Furthermore, the trajectory correction unit 105 corrects the position of the exit point to correspond to the positional relationship between the entrance point position before correction and the entrance point position after correction. Specifically, the trajectory correction unit 105 corrects the position of the exit point to position P22 on the link line L2, which is a predetermined distance from the exit point P21 before correction. The predetermined distance is the same as the distance between the entrance point position before correction and the entrance point position after correction (the distance between position P11 and position P12). The trajectory correction unit 105 may also correct the position of the center point in conjunction with the correction of the entrance point and the exit point positions.

[0042] Furthermore, when the surrounding environment recognition unit 104 recognizes the lane boundaries B1 and B2 on the approach road, the driving trajectory correction unit 105 corrects the position of the entrance point along the lane width direction so that the entrance point is located at the central position P13 between the lane boundaries B1 and B2. The driving trajectory correction unit 105 corrects the position of the central point in accordance with the correction of the entrance point position. For example, the driving trajectory correction unit 105 corrects the position of the central point to the intersection point P32 of a straight line passing through the entrance point P13 and parallel to the link line L1, and a straight line passing through the exit point P22 and parallel to the link line L2. The driving trajectory correction unit 105 corrects the position of the exit point to correspond to the positional relationship between the entrance point position before correction and the entrance point position after correction. Specifically, the driving trajectory correction unit 105 corrects the position of the exit point to a position P23, which is a predetermined distance away from the exit point P22 before correction along the lane width direction. The predetermined distance is the same as the distance between the position of the entrance point before correction and the position of the entrance point after correction (the distance between position P12 and position P13). The track correction unit 105 corrects the position of the center point in conjunction with the correction of the exit point. For example, the track correction unit 105 corrects the position of the center point to the intersection point P33 of a straight line passing through the entrance point P13 and parallel to the link line L1, and a straight line passing through the exit point P23 and parallel to the link line L2.

[0043] As described above, after the travel trajectory is generated by the travel trajectory generation unit 103, while the host vehicle is traveling within the intersection along the generated travel trajectory, the surrounding environment is recognized at a fixed cycle. Then, based on the recognition result, the travel trajectory correction unit 105 repeatedly corrects the positions of the entry point, the exit point, and the center point to correct the travel trajectory. Thereby, the accuracy of the travel trajectory can be gradually improved. After the host vehicle has passed the entry point, the travel trajectory correction unit 105 may correct the travel trajectory in a fixed state without correcting the position of the entry point. For example, when the host vehicle passes the entry point, the travel trajectory correction unit 105 stores the position of the passed entry point. When the surrounding environment is newly recognized, the travel trajectory correction unit 105 corrects the position of the exit point based on the recognition result. Then, the travel trajectory correction unit 105 generates a travel trajectory connecting the stored entry point and the corrected exit point.

[0044] Next, an example of a travel trajectory generation method executed by the travel trajectory generation device 10 will be described using FIG. 7. FIG. 7 is a flowchart showing an example of the processing procedure of the travel trajectory generation method executed by the travel trajectory generation device according to the present embodiment. When the host vehicle is approaching the intersection, the travel trajectory generation device 10 starts the control flow from step S1. In step S1, the controller 100 acquires a link line representing the road on which the host vehicle travels from the map information stored in the map database 11. The acquired link line includes link lines of roads located around the intersection, such as the approach road and the exit road. In step S2, the controller 100 recognizes the surrounding environment of the intersection using the sensor group 13. The surrounding environment of the intersection includes, for example, the center of the host vehicle lane in which the host vehicle travels on the approach road. In step S3, based on the link line acquired in step S1 and the surrounding environment of the intersection recognized in S2, the controller 100 generates a travel trajectory for the host vehicle to turn right or left and travel at the intersection. Specifically, the controller 100 sets an entry point at the center of the host vehicle lane in which the host vehicle travels on the approach road, sets an exit point on the link line representing the exit road, and generates a travel trajectory connecting the entry point and the exit point.

[0045] In this embodiment, the flowchart shown in Figure 7 does not need to include all of steps S1 to S3; some steps may be omitted, or additional steps may be added as appropriate. For example, step S2 may be omitted, and a trajectory may be generated based on the link lines, or a step may be added to modify the trajectory based on the surrounding environment of the intersection after generating the trajectory based on the link lines. The step of generating the trajectory may also include a step of setting the entry point and the exit point. A step of controlling the vehicle based on the generated or modified trajectory may be added. Furthermore, the processing order of each step in the control flow may be changed as appropriate.

[0046] As described above, in the driving trajectory generation method and driving trajectory generation device according to this embodiment, the controller that generates a driving trajectory for the vehicle to turn right or left at an intersection acquires a link line representing the road on which the vehicle will travel from map information, and generates a driving trajectory connecting an entrance point set in the center of the vehicle's lane on the entrance road for entering the intersection, and an exit point set on the link line representing the exit road for exiting the intersection. This makes it possible to generate a driving trajectory to the exit of the intersection even when the surrounding environment of the intersection exit cannot be recognized using on-board sensors when the vehicle enters the intersection.

[0047] Furthermore, in this embodiment, the link lines include information indicating whether the link lines belong to the inside or outside of the intersection, and the controller sets the entrance and / or exit points based on the information about the link lines around the intersection. This allows the entrance and / or exit points of the intersection to be appropriately set using the link line information included in the map information.

[0048] In addition, in the present embodiment, the controller sets an entry point based on the entry-road-side near intersection, which is the intersection closest to the entry road side among the intersections of the link line representing the entry road and the other link lines at the intersection, and / or sets an exit point based on the exit-road-side near intersection, which is the intersection closest to the exit road side among the intersections of the link line representing the exit road and the other link lines at the intersection. Thereby, even when there is no information in the map information regarding whether the link line belongs to the inside or outside of the intersection, the entry point and / or the exit point of the intersection can be appropriately set.

[0049] In addition, in the present embodiment, the controller sets an exit point at a position that is a predetermined distance away from the exit-road-side near intersection toward the exit road side, and the predetermined distance is the same as the distance from the entry-road-side near intersection to the stop line in front of the intersection on the entry road. Thereby, even when the surrounding environment of the intersection exit cannot be recognized using the in-vehicle sensor, the exit point of the intersection can be appropriately set.

[0050] In addition, in the present embodiment, the controller generates a curve defined by a control point including a central point, which is the intersection of the link line representing the entry road and the link line representing the exit road, as a travel trajectory. Thereby, even when the intersection is a large-scale intersection, a travel trajectory corresponding to the actual road shape can be generated.

[0051] In addition, in the present embodiment, the controller uses the in-vehicle sensor of the host vehicle to identify the central part between the road edges of the roads located around the intersection, and offsets the link line so that the central part between the road edges overlaps with the link line corresponding to the road located around the intersection. Thereby, the position of the link line included in the map information can be matched with the recognition result.

[0052] In addition, in the present embodiment, the controller uses the in-vehicle sensor of the host vehicle to recognize the surrounding environment of the intersection, corrects the positions of the entry point, the exit point, and the central point based on the recognition result by the in-vehicle sensor, and generates a travel trajectory using the corrected entry point, exit point, and central point as control points. Thereby, the position of the travel trajectory can be adjusted at the lane level.

[0053] Furthermore, in this embodiment, when the controller uses an on-board sensor to recognize a stop line before an intersection on the entry road, it corrects the position of the entry point on the stop line and corrects the position of the exit point along a link line representing the exit road so as to correspond to the positional relationship between the position of the entry point before correction and the position of the entry point after correction. This improves the accuracy of the longitudinal position of the entry and exit points of the intersection.

[0054] Furthermore, in this embodiment, when the controller uses an on-board sensor to recognize the lane boundary line of the vehicle's lane on the entry road, it corrects the position of the entry point in the lane width direction so that it lies on the center line between the lane boundary lines. When the controller uses an on-board sensor to recognize the lane boundary line of the vehicle's lane on the exit road, it corrects the position of the exit point in the lane width direction so that it lies on the center line between the lane boundary lines. The controller then corrects the position of the center point to the intersection of a straight line passing through the corrected entry point that is parallel to the link line representing the entry road and a straight line passing through the corrected exit point that is parallel to the link line representing the exit road. This improves the accuracy of the lateral positions of the entry and exit points.

[0055] Furthermore, in this embodiment, if the controller uses an on-board sensor to recognize the edge of the exit road, it corrects the position of the exit point based on the position of the road edge. This makes it possible to improve the accuracy of the driving trajectory based on the recognition results from the on-board sensor, even when the boundary line on the road is not recognized.

[0056] Furthermore, in this embodiment, the controller controls the vehicle to travel along the trajectory, and after the vehicle passes the entrance point, it generates the trajectory with the position of the entrance point fixed without correction. This allows for the appropriate generation of the trajectory even when the trajectory needs to be corrected after the vehicle enters the intersection.

[0057] 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.

[0058] 1... Driving support system, 10... Driving trajectory generation device, 11... Map database, 12... Vehicle position acquisition device, 13... Sensor group, 100... Controller, 101... Link acquisition unit, 102... Surrounding information acquisition unit, 103... Driving trajectory generation unit, 104... Surrounding environment recognition unit, 105... Driving trajectory correction unit

Claims

1. A method for generating a driving path, which is performed by a controller that generates a driving path for a vehicle to make a right or left turn at an intersection, wherein the controller obtains a link line representing the road on which the vehicle will travel from map information, and generates the driving path connecting an entrance point set in the center of the vehicle's lane on an entrance road for entering the intersection, and an exit point set on a link line representing an exit road for exiting the intersection.

2. A method for generating a driving trajectory according to claim 1, wherein the link line includes intersection inside / outside information relating to whether the link line belongs inside or outside the intersection, and the controller sets the entrance point and / or the exit point based on the intersection inside / outside information of the link line around the intersection.

3. A method for generating a driving trajectory according to claim 1, wherein the controller sets the entrance point based on the nearest intersection point on the entrance road side, which is the closest intersection point on the entrance road side, among the intersection points of the link line representing the entrance road and the other link line at the intersection, and / or sets the exit point based on the nearest intersection point on the exit road side, which is the closest intersection point on the exit road side, among the intersection points of the link line representing the exit road and the other link line at the intersection.

4. A method for generating a driving trajectory according to claim 3, wherein the controller sets the exit point at a predetermined distance away from the intersection near the exit road, and the predetermined distance is the same as the distance from the intersection near the entrance road to the stop line before the intersection on the entrance road.

5. A method for generating a driving track according to any one of claims 1 to 4, wherein the controller generates a curve as the driving track, which is defined by control points including a central point that is the intersection of a link line representing the entry road and a link line representing the exit road.

6. A method for generating a driving trajectory according to any one of claims 1 to 5, wherein the controller uses an on-board sensor of the vehicle to identify the central part between the road edges of roads located around the intersection, and offsets the link line so that the central part between the road edges and the link line corresponding to the roads located around the intersection overlap.

7. A method for generating a driving trajectory according to claim 5, wherein the controller recognizes the surrounding environment of the intersection using the on-board sensors of the vehicle, corrects the positions of the entrance point, the exit point and the center point based on the recognition results from the on-board sensors, and generates the driving trajectory using the corrected entrance point, exit point and center point as the control points.

8. A method for generating a driving trajectory according to claim 7, wherein the controller, using the on-board sensor, recognizes a stop line before the intersection on the entry road, corrects the position of the entry point on the stop line, and corrects the position of the exit point along a link line representing the exit road so as to correspond to the positional relationship between the position of the entry point before correction and the position of the entry point after correction.

9. A method for generating a driving trajectory according to claim 7 or 8, wherein the controller, using the on-board sensor, recognizes the lane boundary line of the vehicle's lane on the entry road, and modifies the position of the entry point in the lane width direction of the vehicle's lane so that it lies on the center line between the lane boundary lines; uses the on-board sensor to recognize the lane boundary line of the vehicle's lane on the exit road, and modifies the position of the exit point in the lane width direction so that it lies on the center line between the lane boundary lines; and modifies the position of the center point to the intersection of a straight line passing through the modified entry point and parallel to the link line representing the entry road, and a straight line passing through the modified exit point and parallel to the link line representing the exit road.

10. A method for generating a driving trajectory according to any one of claims 7 to 9, wherein the controller, using the on-board sensor, recognizes the edge of the exit road and corrects the position of the exit point based on the position of the edge of the road.

11. A method for generating a driving trajectory according to any one of claims 7 to 10, wherein the controller controls the vehicle so that it travels along the driving trajectory, and after the vehicle has passed the entrance point, generates the driving trajectory while keeping the position of the entrance point fixed without correcting it.

12. A driving trajectory generating device comprising a controller that generates a driving trajectory for a vehicle to make a right or left turn at an intersection, wherein the controller obtains a link line representing the road on which the vehicle will travel from map information, and generates the driving trajectory connecting an entrance point set in the center of the vehicle's lane on an entrance road for entering the intersection, and an exit point set on a link line representing an exit road for exiting the intersection.

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