Driving assistance method and driving assistance device

Abstract

To provide a travel support method and a travel support device capable of preventing a vehicle, at a roundabout type intersection including an outer loop lane and an inner loop lane positioned inside the outer loop lane, from coming close to another vehicle positioned at an entrance to the intersection of a road connected thereto while the vehicle transfers from the inner loop lane to the outer loop lane.SOLUTION: A travel support device acquires, at a roundabout type intersection, information on a first guide route which is a guide route intersecting an approach route from a road connected to the roundabout type intersection to an inner loop lane as guide route information guiding a vehicle to transfer from the inner loop lane to an outer loop lane. When an intersection point between the first guide route and the approach route is located within the outer loop lane, the travel support device sets a travel route of the vehicle on the basis of information on a second guide route which is a guide route positioned on a far side of the first guide route in a vehicle's moving direction.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] In a circular intersection including an outer circular lane and an inner circular lane inside the outer circular lane, a technique for setting a planned driving lane of a vehicle based on information on the outer circular lane and the inner circular lane and transition guidance data for regulating a transition route from the inner circular lane to the outer circular lane is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, when the transition route from the inner circular lane to the outer circular lane is set to intersect with the second entry route, which is the entry route from the road connected to the intersection to the inner circular lane, there are the following problems. That is, in Patent Document 1, when the intersection position where the transition route and the second entry route intersect is within the outer circular lane, a vehicle traveling along the transition route approaches another vehicle that is stopped at the entrance to the intersection of the road connected to the intersection.

[0005] The problem to be solved by the present invention is to provide a driving support method and a driving support device that can prevent a vehicle moving from an inner circular lane to an outer circular lane in a circular intersection including an outer circular lane and an inner circular lane inside the outer circular lane from approaching another vehicle located at the entrance to the intersection of the road connected to the intersection.

Means for Solving the Problems

[0006] The present invention solves the above problem by acquiring information on a first guidance route, which is a guidance route that intersects with the entry route from a road connected to the ring intersection to the inner ring lane, as guidance route information for guiding vehicles to move from the inner ring lane to the outer ring lane at a ring intersection, and if the intersection point of the first guidance route and the entry route is within the outer ring lane, setting the vehicle's travel path based on information on a second guidance route, which is a guidance route located further in the direction of vehicle travel than the first guidance route. [Effects of the Invention]

[0007] According to the present invention, in a ring-shaped intersection including an outer ring lane and an inner ring lane located inside the outer ring lane, it is possible to prevent vehicles moving from the inner ring lane to the outer ring lane from approaching other vehicles located at the entrance to the intersection of roads connected to the intersection. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of the configuration of the driving support system according to this embodiment. [Figure 2] Figure 2 shows an example of a road structure at a circular intersection in which the driving assistance method according to this embodiment is implemented. [Figure 3] Figure 3 shows an example of how a driving route is set by the driving support method according to this embodiment at a circular intersection. [Figure 4] Figure 4 is a flowchart illustrating an example of the control process by which the driving assistance method according to this embodiment is implemented. [Figure 5] Figure 5 is a flowchart illustrating an example of the control process by which the driving assistance method according to this embodiment is implemented. [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. For example, the driving support system 10 assists the driving of the vehicle by displaying the driving route to the 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. Detection device 1 acquires the position, attitude (orientation), and speed of moving objects.

[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 on 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 on 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] The high-precision map includes lane information for ring-shaped intersections, including the outer ring lane and the inner ring lane located inside the outer ring lane. The lane information includes information for both the outer and inner ring lanes. The lane information includes lane-specific details such as lane width, lane boundary line type, lane shape, lane divider shape, and lane reference line shape. Furthermore, each lane in the lane information is defined by a node and described by links separated by these nodes. A node is a reference point on the lane reference line (e.g., the center line within the lane). 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. Because the high-precision map includes node and link information for each lane, it is possible to identify the lane a vehicle is traveling in on its route. The high-precision map has coordinates that can represent the position of a lane in both the lane extension direction and the lane width direction.

[0014] Furthermore, the lane information for a ring-shaped intersection includes information on guidance routes that guide vehicles from the inner ring lane to the outer ring lane, and information on entry routes that enter the inner or outer ring lane from connecting roads that connect to the ring-shaped intersection. In addition, the guidance route information includes information on a first guidance route, which is a guidance route that intersects with the entry route, and information on a second guidance route, which is a guidance route located further in the direction of travel than the first guidance route. The first and second guidance routes are links connecting nodes on the outer ring lane and nodes on the inner ring lane, respectively. On the inner ring lane, the starting node of the first guidance route and the starting node of the second guidance route are adjacent nodes. For example, on the inner ring lane, the starting node of the second guidance route is the node one step further in the direction of travel than the starting node of the first guidance route. Also, on the outer ring lane, the ending node of the first guidance route and the ending node of the second guidance route are adjacent nodes. For example, in the outer ring road, the end node of the second guidance route is the node adjacent to the end node of the first guidance route, in the direction of travel.

[0015] Here, the road structure of a ring-shaped intersection will be described. Figure 2 is a diagram showing an example of the road structure of a ring-shaped intersection in which the driving support method according to this embodiment is implemented. As shown in Figure 2, the ring-shaped intersection RI includes an outer ring lane OL and an inner ring lane IL. The ring-shaped intersection RI is an intersection in which vehicles travel clockwise. The outer ring lane OL and the inner ring lane IL each have lane nodes set. In addition, connecting roads Ra, Rb, Rc, and Rd are connected to the ring-shaped intersection RI. Each connecting road includes an entry lane for entering the ring-shaped intersection and an exit lane for exiting the ring-shaped intersection. As shown in Figure 2, connecting road Ra includes an entry lane L1a and an exit lane L2a. Connecting road Rb includes an entry lane L1b and an exit lane L2b. Connecting road Rc includes an entry lane L1c and an exit lane L2c. Additionally, the connecting road Rd includes the entry lane L1d and the exit lane L2d.

[0016] Furthermore, each entry lane in a ring-shaped intersection has designated entry routes for entering the inner ring lane and the outer ring lane. At ring-shaped intersection RI, there is an entry route P1a for entering the inner ring lane IL from entry lane L1a, and an entry route P2a for entering the outer ring lane OL from entry lane L1a. Additionally, there is an entry route P1b for entering the inner ring lane IL from entry lane L1b, and an entry route P2b for entering the outer ring lane OL from entry lane L1b. Furthermore, there is an entry route P1c for entering the inner ring lane IL from entry lane L1c, and an entry route P2c for entering the outer ring lane OL from entry lane L1c. Additionally, an entry route P1d is provided for entering the inner ring lane IL from the entry lane L1d, and an entry route P2d is provided for entering the outer ring lane OL from the entry lane L1d.

[0017] Furthermore, roundabouts have exit routes set up for exiting from the outer ring lane to each exit lane. Roundabout RI has exit routes P3a for exiting from the outer ring lane OL to exit lane L2a, exit route P3b for exiting from the outer ring lane OL to exit lane L2b, exit route P3c for exiting from the outer ring lane OL to exit lane L2c, and exit route P3d for exiting from the outer ring lane OL to exit lane L2d.

[0018] Furthermore, at a circular intersection, a first or second guidance route is set up to guide the vehicle's lane transition from the inner circular lane to the outer circular lane. At circular intersection RI, a first guidance route G1a intersects with entry route P1a, a first guidance route G1b intersects with entry route P1b, a first guidance route G1c intersects with entry route P1c, and a first guidance route G1d intersects with entry route P1d are set up. Additionally, at circular intersection RI, a second guidance route G2a is set up located further in the direction of travel than the first guidance route G1a, a second guidance route G2b is set up further in the direction of travel than the first guidance route G1b, a second guidance route G2c is set up further in the direction of travel than the first guidance route G1c, and a second guidance route G2d is set up further in the direction of travel than the first guidance route G1d.

[0019] In addition, in the present embodiment, it is also possible to set the length of the link between nodes defining the guidance path to be longer as the distance of the lane in the circular intersection connected to the target exit lane from which the vehicle exits the circular intersection is longer. For example, in the map information, the positions of the lane nodes in the circular intersection are set so that the distance between nodes becomes longer. By making the guidance path longer, it is possible to take time for the host vehicle to shift from the inner circular lane to the outer circular lane, and thus it is possible to prevent rapid steering control from being executed.

[0020] The host 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 the 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. Further, the host 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.

[0021] The navigation device 4 is a device that guides the driver on the traveling route to the destination. The navigation device 4 is a device that guides the driver on the traveling route by displaying on the in-vehicle display the traveling route from the current position of the host vehicle to the destination set by the driver, including it in the map information.

[0022] 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.

[0023] The vehicle speed control device 51 controls the drive system, such as an electric motor and / or an internal combustion engine or automatic transmission, which are the driving source. The vehicle speed control device 51 autonomously controls the vehicle's speed based on the control signals input from the driving support device 6. The steering control device 52 controls the steering system. Based on the control signals input from the driving support device 6, the steering control device 52 uses at least one of the detection results from the detection device 1, the map DB2, and the vehicle information acquired by the vehicle information detection device 3 to control the operation of the steering system so that the vehicle drives while maintaining a predetermined lateral position (the position of the vehicle in the left-right direction) relative to the driving path.

[0024] The driving support device 6 is a device that assists the driving of the vehicle by controlling and coordinating the devices included in the driving support system 10. The driving support device 6 refers to the map DB2 and calculates a driving route from the current position of the vehicle detected by the vehicle position detection device 33 of the vehicle information detection device 3 to the destination set by the driver. The driving route is a linear representation that identifies the road, direction (uphill / downhill), and lane on which the vehicle is traveling. The driving route includes information on the driving lane.

[0025] In this embodiment, the driving support device 6 calculates the vehicle's driving path in a ring intersection. The vehicle's driving in a ring intersection includes, for example, driving to transition from the vehicle's inner ring lane to the outer ring lane toward the vehicle's target exit lane. The target exit lane is the lane that vehicles traveling along the vehicle's driving path will use to exit the ring intersection. The driving path in the ring intersection is calculated to connect the lane nodes of the inner ring lane and the outer ring lane.

[0026] In this embodiment, the driving support device 6 implements driving support control via the controller 7. The controller 7 performs driving control of the vehicle in a ring-shaped intersection. The controller 7 acquires lane information of the ring-shaped intersection on which the vehicle is traveling from high-precision map information stored in the map DB2. The lane information includes information on the outer ring lane, information on the inner ring lane, and information on the guidance route that guides the vehicle to move from the inner ring lane to the outer ring lane. Based on the acquired lane information, the controller 7 sets the driving route on which the vehicle travels within the ring-shaped intersection.

[0027] The controller 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 support device 6 by executing the program stored in the ROM 72, and a RAM 73 which functions as an accessible storage device. In this embodiment, the controller 7 executes each of the above functions through the cooperation of the software and the hardware described above.

[0028] The controller 7 comprises, as functional blocks, a vehicle position estimation unit 100, a lane information acquisition unit 101, a surrounding environment acquisition unit 102, a determination unit 103, a driving route setting unit 104, and a vehicle control unit 105. In this embodiment, the functions of the controller 7 are divided into six blocks and the functions of each functional block are explained, but the functions of the controller 7 do not necessarily have to be divided into six blocks as long as each function can be realized in that configuration.

[0029] 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.

[0030] The lane information acquisition unit 101 acquires lane information for a ring-shaped intersection. The lane information acquisition unit 101 acquires lane information from the map DB2, including information on the outer ring lane, information on the inner ring lane, and information on a guidance route that guides the vehicle to move from the inner ring lane to the outer ring lane. For example, the lane information acquisition unit 101 acquires guidance route information when its own vehicle is traveling in the inner ring lane. In this embodiment, it is not limited to acquiring lane information while driving, but lane information may also be acquired when setting the driving route before starting to drive.

[0031] The lane information acquisition unit 101 acquires information on a first guidance route, which is a guidance route that intersects with the entry route from the connecting road to the inner ring lane, when the vehicle passes in front of an exit lane located one lane before the target exit lane. The exit lane located one lane before the target exit lane is the exit lane included in the connecting road that is closest to the connecting road that includes the target exit lane, among the connecting roads located between the connecting road that includes the vehicle's entry lane to the ring intersection and the connecting road that includes the target exit lane. For example, in the ring intersection shown in Figure 2, the vehicle enters from the entry lane L1c of the connecting road Rc, with exit lane L2a included in connecting road Ra as the target exit lane. In such a case, the exit lane L2d of connecting road Rd is the connecting road closest to the connecting road Ra containing the target exit lane, among the connecting roads located between connecting road Rc, which includes the entry lane L1c into the ring intersection RI, and connecting road Ra, which includes the target exit lane L2a.

[0032] If the intersection point where the first guidance route and the entry route from the connecting road to the inner ring lane intersect is within the outer ring lane, the lane information acquisition unit 101 acquires information on the second guidance route, which is located further in the direction of vehicle travel than the first guidance route.

[0033] The surrounding environment acquisition unit 102 acquires information about the surrounding environment of the vehicle from the detection device 1. For example, the surrounding environment acquisition unit 102 acquires information about the surrounding environment at the entrance to a ring-shaped intersection of a connecting road, including the exit lane located one lane before the target exit lane. The surrounding environment information includes information about other vehicles located at the entrance to the ring-shaped intersection of the connecting road. The information about other vehicles also includes the size of the other vehicles.

[0034] First, the determination unit 103 determines whether the vehicle traveling through the roundabout enters the inner roundabout lane, based on the position of the exit lane which will be the target exit lane and the position of the entry lane for the vehicle to enter the roundabout. In this embodiment, if the connecting road including the vehicle's entry lane to the roundabout is not the connecting road located immediately before the connecting road including the target exit lane, the determination unit 103 determines that the vehicle enters the inner roundabout lane. That is, if there is another connecting road between the connecting road including the vehicle's entry lane to the roundabout and the connecting road including the target exit lane, the determination unit 103 determines that the vehicle enters the inner roundabout lane. Furthermore, the determination unit 103 determines that if the connecting road including the vehicle's entry lane into the ring-shaped intersection is located one connecting road before the connecting road including the target exit lane in the vehicle's direction of travel, the vehicle will not enter the inner ring lane, that is, the vehicle will enter the outer ring lane. In other words, the determination unit 103 determines that the vehicle will not enter the inner ring lane if there is no other connecting road between the connecting road including the vehicle's entry lane into the ring-shaped intersection and the connecting road including the target exit lane.

[0035] Furthermore, the determination unit 103 determines whether the vehicle has passed the exit lane located one lane before the target exit lane after entering the inner ring lane. For example, the determination unit 103 determines whether the vehicle has passed the exit lane located one lane before the target exit lane based on the vehicle's position and the position of a predetermined node in the inner ring lane. The predetermined node in the inner ring lane is the node where the vehicle begins to transition to the outer ring lane in order to exit from that exit lane. The determination unit 103 determines that the vehicle has passed the exit lane located one lane before the target exit lane if the vehicle has passed the predetermined node in the inner ring lane.

[0036] Furthermore, the determination unit 103 determines whether the intersection point where the first guidance route and the entry route intersect is located within the outer ring lane, based on information about the first guidance route, which is a guidance route that intersects with the entry route for entering the inner ring lane from a connecting road including the exit lane located one lane before the target exit lane. For example, the determination unit 103 obtains location information of the intersection point as information about the first guidance route from the map DB2 and determines whether the intersection point is located within the outer ring lane. The intersection point is located either within the outer ring lane or within the inner ring lane.

[0037] Furthermore, the determination unit 103 determines whether or not there is another vehicle at the entrance to the roundabout, based on information about the surrounding environment at the entrance to the roundabout, which includes the exit lane located one lane before the target exit lane. If the determination unit 103 determines that there is another vehicle at the entrance, it obtains the size of the other vehicle based on the information about the surrounding environment and determines whether or not the size of the other vehicle is greater than or equal to a predetermined size. The predetermined size is the size of a vehicle that would cause the driver of the vehicle to feel a sense of pressure when approaching the other vehicle, and is determined, for example, experimentally.

[0038] The route setting unit 104 sets the route the vehicle will take within the ring-shaped intersection. Based on lane information including information on the inner ring lane, the outer ring lane, and the guidance route, the route setting unit 104 identifies the locations of the nodes the vehicle will pass through and sets the route to connect the identified nodes. Furthermore, if the intersection point where the first guidance route and the entry route intersect is within the inner ring lane, the route setting unit 104 sets the guidance route based on lane information including information on the first guidance route. In other words, the route setting unit 104 sets a route in which the vehicle transitions from the inner ring lane to the outer ring lane along the first guidance route.

[0039] Furthermore, if the intersection point where the first guidance path and the entry path intersect is within the outer ring lane, the driving path setting unit 104 sets the driving path as the guidance path based on lane information including information about the second guidance path. In other words, the driving path setting unit 104 sets a driving path in which the vehicle moves from the inner ring lane to the outer ring lane along the second guidance path, which is located further in the direction of travel than the first guidance path.

[0040] Furthermore, if the determination unit 103 determines that there are no other vehicles at the entrance to the connecting road, the route setting unit 104 sets a route based on lane information including information on the first guided route, even if the intersection is within the outer ring lane. Also, if there are other vehicles at the entrance to the connecting road and the size of the other vehicles is greater than or equal to a predetermined size, the route setting unit 104 sets a route based on lane information including information on the second guided route.

[0041] Next, we will describe an example of a driving route set in a roundabout. Figure 3 is a diagram showing an example of a driving route set in a roundabout. In Figure 3, vehicle V1 enters the roundabout RI by traveling in the entry lane L1c of connecting road Rc, and exits the roundabout RI from the target exit lane L2a of connecting road Ra, which is the target exit lane. In Figure 3, another connecting road Rd is located between connecting road Rc, which vehicle V1 uses to enter the roundabout R1, and connecting road Ra, which vehicle V1 uses to exit the roundabout R1. In the scenario shown in Figure 3, since the vehicle needs to pass in front of connecting road Rd via the inner ring lane IL, the entry route from connecting road Rc is set to entry route P1c.

[0042] Furthermore, on the connecting road Rd, which includes the exit lane just before the target exit lane, the first guidance route G1d intersects with the entry route P1d for entering the inner ring lane IL from the connecting road Rd within the outer ring lane OL. That is, the intersection point CP is within the outer ring lane OL. In this case, the guidance route from the inner ring lane IL to the outer ring lane OL is set to the second guidance route G2d, which is located further in the direction of travel of the vehicle than the first guidance route G1d. Then, after the vehicle V1 moves to the outer ring lane OL, the exit route for the vehicle V1 to exit from the outer ring lane OL to the connecting road is set to the exit route P3a which connects to the target exit lane L2a. As described above, the driving route TP is set to pass through the entry route Plc, the lane node of the inner ring lane IL, the second guidance route G2d, the lane node of the outer ring lane, and the exit route P3a.

[0043] In this embodiment, even if the intersection point CP is within the outer ring lane OL as shown in Figure 3, if no other vehicle V2 is present on the entry lane L1d, the travel path TP is set to a path that passes through the first guidance path G1d and transitions from the inner ring lane IL to the outer ring lane OL.

[0044] The vehicle control unit 105 controls the vehicle to travel along the designated route. For example, the vehicle control unit 105 calculates the target vehicle speed and target steering angle for traveling along the set route, 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. In addition, the vehicle control unit 105 activates the vehicle's turn signals when the vehicle reaches the starting node of the first guided route, regardless of whether the vehicle is traveling along the first guided route or the second guided route. Furthermore, the vehicle control unit 105 may also activate the vehicle's turn signals when the vehicle reaches a node located before the node in the direction of travel where the vehicle begins to transition from the inner ring lane to the outer ring lane along the guided route.

[0045] Next, an example of the procedure of the driving support method according to this embodiment will be explained using Figure 4. Figure 4 is a flowchart showing an example of the procedure of the driving support method according to this embodiment. In this embodiment, when the vehicle approaches a ring road, the control flow starts from step S1. For example, when the vehicle enters a connecting road that leads to a ring road, the controller 7 starts the control flow. In this embodiment, the control flow may also start from step S1 when setting the driving route to the destination before the vehicle starts driving.

[0046] In step S1, the controller 7 determines the entry route for entering the ring intersection from the entry lane of the connecting road. In this embodiment, the entry route is either an entry route for entering the inner ring lane or an entry route for entering the outer ring lane of the ring intersection. If the vehicle is to exit the ring intersection with the exit lane of a connecting road adjacent to the connecting road it is traveling on to enter the ring intersection as the target exit lane, the controller 7 determines the entry route to be an entry route for entering the outer ring lane. Also, if there is another connecting road between the connecting road the vehicle is traveling on to enter the ring intersection and the connecting road including the target exit lane, the controller 7 determines the entry route to be an entry route for entering the inner ring lane.

[0047] In step S2, the controller 7 determines whether the vehicle will enter the inner ring lane of the ring intersection along the entry route determined in step S1. If it determines that the vehicle will enter the inner ring lane, the controller 7 proceeds to step S3. If it determines that the vehicle will not enter the inner ring lane, i.e., will enter the outer ring lane, the controller 7 proceeds to step S11.

[0048] In step S3, the controller 7 controls the vehicle to enter the inner ring lane. In step S11, the controller 7 controls the vehicle to enter the outer ring lane. If the vehicle enters the outer ring lane, the controller 7 controls the vehicle to travel along the outer ring lane and exit the ring intersection via the target exit lane.

[0049] In step S4, the controller 7 determines whether the vehicle has passed the exit lane located one lane before the target exit lane. If it determines that the vehicle has passed the exit lane located one lane before the target exit lane, the controller 7 proceeds to step S5. If it determines that the vehicle has not passed the exit lane located one lane before the target exit lane, the controller 7 returns to step S4 and repeats the following flow.

[0050] In step S5, the controller 7 obtains information on the first guidance route from the map DB2. In step S6, the controller 7 determines whether the intersection of the first guidance route and the entry route, which enters the inner ring lane from an entry lane located one lane before the target exit lane, is within the outer ring lane. If it is determined that the intersection of the first guidance route and the entry route is within the outer ring lane, the controller 7 proceeds to step S7. If it is determined that the intersection of the first guidance route and the entry route is not within the outer ring lane, i.e., is within the inner ring lane, the controller 7 proceeds to step S9. In step S7, the controller 7 obtains information on the second guidance route. In step S8, the controller 7 sets the driving route based on the second guidance route. In step S9, the controller 7 sets the driving route based on the first guidance route. In step S10, the controller 7 controls the vehicle's movement within the ring intersection along the set driving route.

[0051] In this embodiment, the vehicle is autonomously driven along the route after it has been generated, but it is not limited to this, and the route may also be presented to the driver of the vehicle. Furthermore, in this embodiment, the route within the roundabout may be generated while the vehicle is driving, for example, while the vehicle is entering the roundabout, but it is not limited to this, and the route may also be generated based on lane information obtained from the map DB2 when the route is generated before the vehicle starts driving.

[0052] Next, an example of the procedure of the driving assistance method according to this embodiment will be explained using Figure 5. Figure 5 is a flowchart showing an example of the procedure of the driving assistance method according to this embodiment. The processing in steps S21 to S26 and 33 is the same as the processing in steps S1 to S6 and 11 in Figure 4, so the explanation will be omitted. As shown in Figure 5, if the controller 7 determines in step S26 that the intersection is within the outer ring lane, it proceeds to step S27. If the controller 7 determines in step S26 that the intersection is not within the outer ring lane, that is, that it is within the inner ring lane, it proceeds to step S31.

[0053] In step S27, the controller 7 acquires information about the surrounding environment. In step S28, the controller 7 determines whether or not there are other vehicles at the entrance to the connecting road. If it determines that there are other vehicles at the entrance to the connecting road, the controller 7 proceeds to step S29. If it determines that there are no other vehicles at the entrance to the connecting road, the controller 7 proceeds to step S31.

[0054] In step S29, the controller 7 acquires information on the second guidance path. In step S30, the controller 7 sets the driving path based on the second guidance path. In step S31, the controller 7 sets the driving path based on the first guidance path. In step S32, the controller 7 controls the vehicle's movement within the circular intersection along the driving path. Note that the driving support method according to this embodiment is not limited to autonomously controlling the vehicle's movement after generating the driving path, but may also display the driving path to the vehicle's driver.

[0055] As described above, in this embodiment, the controller acquires lane information including information on the outer ring lane within the ring-shaped intersection, information on the inner ring lane located inside the outer ring lane, and information on a guidance route that guides a vehicle to move from the inner ring lane to the outer ring lane. As guidance route information, the controller acquires information on a first guidance route, which is a guidance route that intersects with the entry route from the connecting road to the ring-shaped intersection to the inner ring lane. If the intersection point where the first guidance route and the entry route intersect is within the outer ring lane, the controller acquires information on a second guidance route, which is a guidance route located further in the direction of travel of the vehicle than the first guidance route. Based on the lane information including the information on the second guidance route, the controller sets the driving route that the vehicle will travel within the ring-shaped intersection. This makes it possible to prevent a vehicle moving from the inner ring lane to the outer ring lane in a ring-shaped intersection that includes the outer ring lane and the inner ring lane located inside the outer ring lane from approaching other vehicles located at the entrance to the intersection of the roads connecting to the intersection.

[0056] Furthermore, in this embodiment, the controller acquires information about the surrounding environment at the entrance to the ring-shaped intersection of the connecting road, determines whether or not there are other vehicles at the entrance based on the surrounding environment information, and if it is determined that there are no other vehicles, it sets a driving path based on lane information including information about the first guidance path, even if the intersection is within the outer ring lane. As a result, if there are no other vehicles at the entrance to the ring-shaped intersection of the connecting road, the vehicle can move to the outer ring lane with more time to spare before reaching the target exit lane.

[0057] Furthermore, in this embodiment, if the controller determines that another vehicle is present, it determines whether the size of the other vehicle is greater than or equal to a predetermined size. If the size of the other vehicle is greater than or equal to the predetermined size, it sets a driving path based on lane information including information on a second guidance path. This prevents the occupants of the vehicle from feeling pressured when approaching a large vehicle.

[0058] Furthermore, in this embodiment, the first guidance path and the second guidance path are links connecting a node on the outer ring lane and a node on the inner ring lane, respectively. On the outer ring lane, the nodes of the first guidance path and the nodes of the second guidance path are adjacent nodes, and on the inner ring lane, the nodes of the first guidance path and the nodes of the second guidance path are adjacent nodes. This allows the vehicle to move to the outer ring lane in accordance with the driving rules without getting too close to the target exit lane.

[0059] Furthermore, in this embodiment, the controller sets the length of the links between nodes defining the guidance path to be longer the longer the distance between lanes within the ring intersection that connect to the target exit lane from which the vehicle exits the ring intersection. This helps to suppress sudden vehicle behavior when the vehicle transitions to the outer ring lane.

[0060] Furthermore, in this embodiment, the controller activates the vehicle's turn signals when the vehicle reaches the starting node of the first guidance path. This activates the vehicle's turn signals earlier than the timing when the vehicle moves into the outer ring lane, thereby preventing it from approaching following vehicles in the outer ring lane.

[0061] 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]

[0062] 10…Driving assistance systems 6… Driving assistance system 7…Controller 100... Vehicle position estimation unit 101... Lane information acquisition unit 102... Surrounding Environment Acquisition Unit 103...Judgment section 104... Route setting unit 105... Vehicle Control Unit

Claims

1. A driving assistance method, executed by a controller, which acquires lane information including information on the outer ring lane within a ring-shaped intersection, information on the inner ring lane inside the outer ring lane, and information on a guidance route that guides a vehicle from the inner ring lane to the outer ring lane, and sets a driving route for the vehicle to travel within the ring-shaped intersection based on the lane information, The aforementioned controller, As information on the aforementioned guidance route, information on the first guidance route, which is the guidance route that intersects with the access route from the connecting road to the ring-shaped intersection to the inner ring lane, is obtained. If the intersection point where the first guidance path and the entry path intersect is within the outer ring lane, information on the second guidance path, which is located further in the direction of travel of the vehicle than the first guidance path, is acquired. A driving assistance method for setting the driving route based on the lane information, which includes information on the second guidance route.

2. The aforementioned controller, Information on the surrounding environment at the entrance to the ring road of the aforementioned connecting road is acquired. Based on the information about the surrounding environment, it is determined whether or not there is another vehicle at the entrance. If it is determined that there are no other vehicles, the driving assistance method according to claim 1, which sets the driving route based on the lane information including the information of the first guidance route, even if the intersection is within the outer ring lane.

3. The aforementioned controller, If it is determined that the aforementioned other vehicle is present, it is determined whether the size of the aforementioned other vehicle is greater than or equal to a predetermined size. The driving assistance method according to claim 2, wherein the driving route is set based on the lane information including the information of the second guidance route when the size of the other vehicle is greater than or equal to the predetermined size.

4. The first guidance path and the second guidance path are links connecting a node on the outer ring lane and a node on the inner ring lane, The driving assistance method according to claim 1 or 2, wherein on the outer ring lane, the node of the first guidance route and the node of the second guidance route are adjacent nodes, and on the inner ring lane, the node of the first guidance route and the node of the second guidance route are adjacent nodes.

5. The aforementioned controller, The driving assistance method according to claim 1 or 2, wherein the longer the distance of the lanes within the ring intersection that connect to the target exit lane from which the vehicle exits the ring intersection, the longer the length of the links between nodes defining the guidance route is set.

6. The aforementioned controller, The driving assistance method according to claim 1 or 2, wherein the vehicle's turn signal is activated when the vehicle reaches the starting node of the first guidance path.

7. A driving support device comprising a controller that acquires lane information including information on the outer ring lane within a ring-shaped intersection, information on the inner ring lane inside the outer ring lane, and information on a guidance route that guides a vehicle from the inner ring lane to the outer ring lane, and sets a driving route for the vehicle to travel within the ring-shaped intersection based on the lane information, The aforementioned controller, As information on the aforementioned guidance route, information on the first guidance route, which is the guidance route that intersects with the access route from the connecting road to the ring-shaped intersection to the inner ring lane, is obtained. If the intersection point where the first guidance path and the entry path intersect is within the outer ring lane, information on the second guidance path, which is located further in the direction of travel of the vehicle than the first guidance path, is acquired. A driving support device that sets the driving route based on the lane information, which includes information on the second guidance route.

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