Driving assistance method and driving assistance device

Abstract

To notify an occupant of a possible lane change ahead of an own vehicle to a lane in which a course planned for a target route can be changed when the own vehicle is traveling along the target route to a destination.SOLUTION: A method includes steps of: setting a lane plan indicating a lane in which an own vehicle is planned to travel based on a target route (S2); obtaining congestion information, which is information on a congestion status of each lane of a road on the target route (S6); estimating a possible lane change point in which a lane can be changed from an own vehicle lane to a planned lane before a re-routing point on the target route ahead of the own vehicle on the basis of the congestion information when the own vehicle lane on which the own vehicle runs is different from the planned lane aligned with the lane plan (S7); and notifying an occupant of the possible lane change point (S13).SELECTED DRAWING: Figure 7

Description

Technical Field

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

Background Art

[0002] In Patent Document 1 below, a technique has been proposed in which an on-vehicle computer having an automatic driving function pre-informs an occupant that the host vehicle will stop at an intersection or the like in the future.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique described in Patent Document 1, the road conditions ahead of the host vehicle cannot be grasped. For this reason, when driving the host vehicle along a target route to a destination, if the lane in which a route change planned in the target route (for example, a right or left turn at an intersection or entry into a branching lane) is possible is different from the host lane in which the host vehicle is currently traveling, it may not be possible to determine whether or not the host vehicle can change lanes to the lane in which the route change is possible until reaching the route change point. An object of the present invention is to notify an occupant that the host vehicle can change lanes ahead of the host vehicle to a lane in which a route change planned in the target route is possible when driving the host vehicle along the target route to the destination.

Means for Solving the Problems

[0005] In a driving assistance method according to one aspect of the present invention, a target route from the vehicle's current position to the destination is set, a lane plan representing the lane the vehicle is scheduled to travel in is set based on the target route, congestion information, which is information on the congestion status of each lane on the road along the target route, is acquired, and if the vehicle is traveling on a road with multiple lanes in the same direction of travel, and the lane the vehicle is traveling in is different from the planned lane, which is the lane that matches the lane plan, a point where a lane change from the vehicle's lane to the planned lane is possible is estimated based on the congestion information, before the point where a lane change is possible on the target route ahead of the vehicle's path, and the point where a lane change is possible is notified to the occupants. [Effects of the Invention]

[0006] According to the present invention, when driving a vehicle along a target route to a destination, the occupants can be notified that they can change lanes ahead of the vehicle to a lane where a lane change is possible as planned along the target route. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram of the driver assistance device according to the embodiment. [Figure 2] This is an explanatory diagram of an example of a driving assistance method according to an embodiment. [Figure 3] This diagram shows an example of a notification indicating a point where it is possible to change lanes to the planned lane. [Figure 4] Figure 1 is a block diagram showing an example of the controller's functional configuration. [Figure 5] Figures (a) to (d) show examples of lane change points and planned lanes. [Figure 6] (a) to (h) are explanatory diagrams illustrating examples of the operation of the driving assistance device of the embodiment in individual situations. [Figure 7] This is a flowchart of an example of a driving assistance method according to the embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are schematic and may differ from actual ones. Furthermore, the embodiments of the present invention described below are illustrative examples of devices and methods for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited to the structure, arrangement, etc., of the components described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims described in the patent claims.

[0009] (First Embodiment) (composition) Figure 1 is a schematic diagram of an example of a driver assistance device according to an embodiment. The vehicle 1 is equipped with a driver assistance device 10 that controls the driving of the vehicle 1. The driver assistance device 10 sets a target route from the current position of the vehicle 1 to the destination and performs driver assistance control to support driving the vehicle 1 along the target route. For example, the driver assistance control by the driver assistance device 10 may be autonomous driving control that automatically drives the vehicle 1 along a target route without driver intervention. Alternatively, the driver assistance control by the driver assistance device 10 may be navigation control that prompts the driver to change lanes at points along the target route where a lane change is required. The following explanation will illustrate the case where the driver assistance control by the driver assistance device 10 is autonomous driving control.

[0010] The driver assistance system 10 includes an object sensor 11, a vehicle sensor 12, a positioning device 13, a map database (map DB) 14, a communication device 15, a navigation device 16, a human-machine interface (HMI) 17, a controller 18, and an actuator 19. The object sensor 11 comprises multiple different types of object detection sensors that detect objects around the vehicle 1, including laser radar, millimeter-wave radar, cameras, and LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) mounted on the vehicle 1.

[0011] The vehicle sensor 12 is mounted on the vehicle 1 and detects various information (vehicle signals) obtained from the vehicle 1. The vehicle sensor 12 includes, for example, a vehicle speed sensor that detects the vehicle speed of the vehicle 1, a wheel speed sensor that detects the rotational speed of the tires of the vehicle 1, a three-axis acceleration sensor that detects the acceleration and deceleration of the vehicle 1 in three axes, a steering angle sensor that detects the steering angle of the steering wheel, a steering angle sensor that detects the turning angle of the steering wheels, a gyro sensor that detects the angular velocity of the vehicle 1, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the accelerator opening of the vehicle, and a brake sensor that detects the amount of brake operation by the driver.

[0012] The positioning device 13 is equipped with a Global Navigation Satellite System (GNSS) receiver and measures the current position of the vehicle 1 by receiving radio waves from multiple navigation satellites. The GNSS receiver may be, for example, a GPS receiver. The positioning device 13 may also be, for example, an inertial navigation device. The map database 14 stores road map data. For example, the map database 14 may store high-precision map data suitable for use as map information for autonomous driving (hereinafter simply referred to as "high-precision map"). The map database 14 may also store map data for navigation (hereinafter simply referred to as "navigation map"). The communication device 15 performs wireless communication with external communication devices of its own vehicle 1. The communication method used by the communication device 15 may be, for example, wireless communication via a public mobile phone network, vehicle-to-vehicle communication, vehicle-to-infrastructure communication, or satellite communication.

[0013] The navigation device 16 recognizes the vehicle's current position using the positioning device 13 and obtains map information for that current position from the map database 14. The navigation device 16 sets a target route from the vehicle's current position to the destination entered by the occupant (for example, the driver of the vehicle), and provides route guidance to the occupant according to the target route. The navigation device 16 also outputs the target route information to the controller 18. During autonomous driving control, the controller 18 automatically drives the vehicle to follow the target route set by the navigation device 16.

[0014] The HMI 17 is an interface device that exchanges information between the driving support device 10 and the vehicle occupants. The HMI 17 includes a display device visible to the vehicle occupants of the host vehicle 1 (e.g., the display screen of a navigation system), a speaker and a buzzer for outputting warning sounds, notification sounds, and voice information. The HMI 17 also includes an operator for receiving the operation input of the vehicle occupants to the driving support device 10. The operator may be a mechanical interface device such as a button, a switch, a lever, a dial, a keyboard, etc., or may be a button, a switch, a lever, a dial, a keyboard, etc. displayed on the touch panel.

[0015] The controller 18 is an electronic control unit that performs driving support control of the host vehicle 1. The controller 18 includes a processor 18a and peripheral components such as a storage device 18b. The processor 18a may be, for example, a CPU or an MPU. The storage device 18b may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The storage device 18b may include memories such as registers, cache memories, ROM and RAM used as main memories.

[0016] The functions of the controller 18 described below are realized, for example, when the processor 18a executes a computer program stored in the storage device 18b. Note that the controller 18 may be formed by dedicated hardware for executing each information process described below. For example, the controller 18 may include a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the controller 18 may have a PLD such as an FPGA.

[0017] The actuator 19 operates the steering wheel, accelerator opening, and braking device of the host vehicle according to a control signal from the controller 18 to generate the vehicle behavior of the host vehicle. The actuator 19 includes a steering actuator, an accelerator opening actuator, and a brake control actuator. The steering actuator controls the steering direction and steering amount of the steering of the host vehicle. The accelerator opening actuator controls the accelerator opening of the host vehicle. The brake control actuator controls the braking operation of the braking device of the host vehicle.

[0018] Next, an example of driving support control by the controller 18 will be described. Refer to FIG. 2. The reference sign Rd indicates the road on which the host vehicle 1 travels. As shown in the figure, the road Rd has a plurality of lanes (two lanes Lp and Le in the example of FIG. 2) in the same traffic direction. Also, the reference sign Pc indicates a route change point Pc on the target route set by the navigation device 16. FIG. 2 shows an example in which the route change on the target route is a left turn at an intersection that is the route change point Pc.

[0019] The controller 18 sets a lane plan representing the lane in which the host vehicle 1 is scheduled to travel based on the target route. The reference sign Lp indicates a planned lane that is a lane consistent with the lane plan. In the example of FIG. 2, since the route change on the target route is a left turn at the route change point Pc, the controller 18 sets a lane plan in which the left lane where a left turn can be made at the route change point Pc is the planned lane Lp. Also, the reference sign Le indicates the host lane in which the host vehicle 1 is currently traveling. Here, a case where the host lane Le is different from the planned lane Lp (for example, when the host lane Le is an adjacent lane to the planned lane Lp) is assumed.

[0020] Reference numeral 20 indicates the section around the vehicle 1 (sometimes referred to as "surrounding section 20" in the following description). For example, surrounding section 20 may be a section within the range where object detection by the object sensor 11 is possible. Reference numeral 21 indicates the section in front of the vehicle 1 that is further away than surrounding section 20 (sometimes referred to as "far section 21" in the following description). For example, far section 21 may be a section where object detection by the object sensor 11 is not possible.

[0021] Thus, when the lane in which a lane change is permitted at lane change point Pc (lane Lp in the example of Figure 2) and the lane in which vehicle 1 is traveling (lane Le in the example of Figure 2) are different, if road Rd is congested in the surrounding section 20 around vehicle 1, the occupants may not be able to determine whether or not they can change lanes to a permitted lane before reaching lane change point Pc. For example, in the example shown in Figure 2, the occupants can know that they are approaching an intersection where they should turn left (lane change point Pc) based on the route guidance screen of the navigation device 16. Alternatively, the occupants can anticipate that they are approaching an intersection where they should turn left (lane change point Pc) based on their destination displayed on the navigation device 16. In such a case, if the left lane Lp (planned lane) that allows a left turn at the lane change point Pc is congested in the surrounding section 20 around vehicle 1, it is impossible to determine whether vehicle 1 can change lanes from the right lane Le it is currently traveling in to the left lane Lp before reaching the lane change point Pc.

[0022] The controller 18 then acquires congestion information, which is information on the congestion status of each lane on the road along the target route. If the lane Le in which the vehicle 1 is traveling is different from the planned lane Lp, the controller 18 estimates a point where the vehicle 1 can change lanes from its own lane Le to the planned lane Lp, based on the congestion information, before the lane change point Pc on the target route ahead of the vehicle 1's path, and notifies the occupants of the point where the lane change is possible. For example, the controller 18 may estimate a point where the lane change is possible before the lane change point Pc in the distant section 21 and notify the occupants of the point where the lane change is possible.

[0023] Figure 3 shows an example of a notification indicating a point where it is possible to change lanes to the planned lane Lp. For example, the controller 18 may display a notification image 22 on the HMI 17's display device that indicates a point where a lane change to the planned lane Lp is possible. For example, the notification image 22 may include a string 23 indicating that a lane change to the planned lane Lp is possible ahead, and a schematic diagram 24 explaining the road conditions from the vehicle 1's current position to the lane change point Pc. The schematic diagram 24 may include a figure 24a representing the lane change point Pc, a figure 24b representing the direction of the lane change at the lane change point Pc, a figure 24c representing the lane congestion from the vehicle 1's current position to the lane change point Pc, and a display (e.g., a figure) 24d representing the point where a lane change is possible.

[0024] In this way, by notifying the vehicle 1 of the points where lane changes are possible ahead of its own path, if the occupants are unable to determine whether or not it is possible to change lanes to the planned lane Lp due to congestion in the surrounding section 20 around the vehicle 1, it becomes easier for the occupants to determine whether it is possible to change lanes to the planned lane Lp ahead of the vehicle 1 (for example, in the distant section 21). This alleviates the occupants' anxiety that they may not be able to change lanes to the planned lane Lp by the lane change point Pc. In addition to or instead of the notification image 22, the controller 18 may output an audio message from the HMI 17 informing the driver of the lane change location (for example, "You can change lanes to the left lane XX meters ahead"). Alternatively, the controller 18 may display the notification image 22 on a mobile terminal device used by the occupants of the vehicle 1 (for example, a smartphone, tablet, or mobile personal computer), or output an audio message informing the driver of the lane change location from the mobile terminal device.

[0025] Referring to Figure 4, the functions of the controller 18 will be explained in detail. The controller 18 includes a vehicle position detection unit 30, a road condition detection unit 31, a congestion information acquisition unit 32, a driving action plan setting unit 33, a driving trajectory generation unit 34, and a vehicle control unit 35. The vehicle position detection unit 30 measures the absolute position of the vehicle 1, that is, the position, attitude, and speed of the vehicle 1 relative to a predetermined reference point, based on odometry using the measurement results from the positioning device 13 and the detection results from the vehicle sensor 12.

[0026] The road condition detection unit 31 detects the road conditions of road Rd in the surrounding section 20 around the vehicle 1 based on the detection signal from the object sensor 11. For example, the road condition detection unit 31 may detect the travel speed of traffic flow in each lane in the surrounding section 20 (for example, the vehicle speed of vehicles around the vehicle 1) as a road condition. Alternatively, the road condition detection unit 31 may detect the distance between vehicles or the vehicle density in the surrounding section 20 as a road condition.

[0027] The congestion information acquisition unit 32 acquires congestion information, which is information on the congestion status of each lane on road Rd on the target route. In the example in Figure 2, congestion information for the planned lane Lp and the current lane Le is acquired. For example, the congestion information acquisition unit 32 may receive congestion information from other vehicles located in the distant section 21 via vehicle-to-vehicle communication of the communication device 15. Other vehicles located in the distant section 21 may generate congestion information by detecting the location and number of vehicles in the surrounding area using sensors they have.

[0028] Alternatively, the congestion information acquisition unit 32 may acquire congestion information for the remote section 21 from the infrastructure via road-to-vehicle communication of the communication device 15. For example, the congestion information acquisition unit 32 may receive vehicle location information on the road Rd in the remote section 21 as congestion information from the infrastructure. Alternatively, the congestion information acquisition unit 32 may acquire congestion information based on historical traffic volume data for road Rd. For example, the planned lane Lp and the current lane Le in the distant section 21 may be divided into smaller sections, and statistical values ​​of vehicle density (average, median, maximum, minimum, etc.) for each section for each time period may be acquired as congestion information. Alternatively, the driver assistance system 10 may use an external information processing device (for example, an external server device of the vehicle 1) to collect congestion information from other vehicles and infrastructure, or to acquire congestion information based on past historical data, and to obtain congestion information from the external information processing device.

[0029] The driving action plan setting unit 33 sets a general driving action plan for driving the vehicle 1 along the target route, based on the detection results from the vehicle position detection unit 30, the detection results from the road condition detection unit 31, and the congestion information acquisition unit 32. The driving actions set by the driving action plan setting unit 33 include, for example, actions such as stopping, pausing, driving speed, deceleration, acceleration, lane changes, right turns, left turns, going straight, lane changes in merging sections and on roads with multiple lanes, lane maintenance, overtaking, and responding to obstacles. Details of the driving action plan setting unit 33 will be described later.

[0030] The trajectory generation unit 34 generates a target trajectory and speed profile for the vehicle 1 based on the driving actions set by the driving action plan setting unit 33. For example, the trajectory generation unit 34 generates multiple candidate target trajectories and speed profiles, evaluates the future risk of each candidate based on a risk map that quantifies the hazard level of the driving area around the vehicle 1, and selects the optimal target trajectory and speed profile. The vehicle control unit 35 drives the actuator 19 so that the vehicle 1 travels along the target trajectory at a speed that conforms to the target vehicle speed profile generated by the trajectory generation unit 34.

[0031] Next, the details of the driving action plan setting unit 33 will be explained. Here, we will explain the process when the driving action plan setting unit 33 plans a driving action of changing lanes from the current lane to an adjacent lane on a road with multiple lanes. The driving action plan setting unit 33 includes a lane plan setting unit 40, a lane change possible position acquisition unit 41, a lane change determination unit 42, and a notification processing unit 44. The lane plan setting unit 40 sets a lane plan that represents the lane in which the vehicle 1 is scheduled to travel along the target route.

[0032] For example, if the lane plan setting unit 40 has multiple lanes on the target route and there is a lane change point Pc ahead of the road Rd, it sets the lane where a lane change is possible at the lane change point Pc as the planned lane. Figures 5(a) to 5(d) show examples of lane change point Pc and planned lane Lp. In Figures 5(a) to 5(d), the dashed line Rt indicates the target path Rt. For example, a change of direction on the target path Rt may be a left or right turn at an intersection, which is the point of the change of direction Pc, as shown in Figures 5(a) and 5(b).

[0033] As shown in Figure 5(a), when turning left at lane change point Pc, one of the multiple lanes L1 and L2 included in road Rd, specifically lane L1 which allows a left turn at lane change point Pc, may be designated as the planned lane Lp. As shown in Figure 5(b), when turning right at lane change point Pc, among the multiple lanes L1 and L2 included in road Rd, lane L2 adjacent to the right-turn-only lane L3 where right turns at lane change point Pc are permitted may be set as the planned lane Lp.

[0034] Furthermore, a change of route on the target route Rt may also be, for example, an advance from the main road Rm to the branch road Rj at the branch section where the route change point Pc is, as shown in Figures 5(c) and 5(d). As shown in Figure 5(c), if there is an exit lane L6 branching off from lane L4 to branch road Rj among multiple lanes L4 and L5 on the main road Rm, the lane L4 adjacent to exit lane L6 may be designated as the planned lane Lp. As shown in Figure 5(d), if, among the multiple lanes L7 and L8 on the main road Rm, lane L7 separates from the main road Rm to become a lane on the branch road Rj, then lane L7 may be designated as the planned lane Lp. Although Figures 5(c) and 5(d) illustrate an example where the branching road Rj branches off to the left from the main road Rm, the same procedure can be used to set the planned lane Lp when the branching road Rj branches off to the right.

[0035] Refer to Figure 4. When the lane Le in which the vehicle 1 is traveling is different from the planned lane Lp, the lane change determination unit 42 determines, based on the road conditions detected by the road conditions detection unit 31, whether the traffic volume in the planned lane Lp is greater than the traffic volume in the lane Le in the surrounding section 20 around the vehicle 1. For example, the lane change determination unit 42 may determine whether the traffic volume in the planned lane Lp is greater than the traffic volume in the own lane Le, based on the vehicle speeds of the vehicles in the planned lane Lp and the vehicle speeds of the vehicles in the own lane Le in the surrounding section 20. For example, if the vehicle speed of the vehicles in the planned lane Lp is slower than the vehicle speed of the vehicles in lane Le, and the difference in vehicle speed between the vehicles in the planned lane Lp and the vehicles in lane Le is greater than or equal to a threshold, the unit may determine that the traffic volume in the planned lane Lp is greater than the traffic volume in the own lane Le in the surrounding section 20.

[0036] For example, the lane change determination unit 42 may also determine whether the traffic volume in the planned lane Lp is greater than the traffic volume in the own lane Le in the surrounding section 20, based on the distance between vehicles in the planned lane Lp and the own lane Le, and the vehicle density in the surrounding section 20. For example, if the distance between vehicles in the planned lane Lp is shorter than the distance between vehicles in the own lane Le, or if the vehicle density in the planned lane Lp is higher than the vehicle density in the own lane Le, the unit may determine whether the traffic volume in the planned lane Lp is greater than the traffic volume in the own lane Le. In other words, the unit may determine whether the planned lane Lp is more congested than the own vehicle Le.

[0037] If the lane change determination unit 42 determines that the traffic volume in the planned lane Lp is greater than the traffic volume in the current lane Le in the surrounding section 20, the lane change possible position acquisition unit 41 acquires congestion information for the planned lane Lp from the congestion information acquisition unit 32. For example, the lane change possible position acquisition unit 41 may acquire congestion information for the planned lane Lp in the distant section 21. The lane change location acquisition unit 41 estimates lane change locations where the vehicle 1 can change lanes from its own lane Le to the planned lane La, based on the acquired congestion information of the planned lane Lp. For example, the lane change locations may be estimated in the distant section 21, before the lane change location Pc.

[0038] For example, the lane change location acquisition unit 41 may estimate lane change locations based on the distance between vehicles on the planned lane Lp ahead of the vehicle 1's path. For example, a location where the distance between vehicles on the planned lane Lp is greater than or equal to a threshold may be estimated as a lane change location. The distance between vehicles on the planned lane Lp may be acquired, for example, by receiving information from cameras or radar that detect the distance between vehicles mounted on other vehicles traveling in the lane that the vehicle 1 is scheduled to travel in, via the cloud (server). For example, the lane change location acquisition unit 41 may estimate a lane change location as a point that is a first predetermined distance D1 before the lane change point Pc and where the distance between vehicles on the planned lane Lp is greater than or equal to a threshold Dth. For example, the lane change location acquisition unit 41 may estimate lane change locations based on the vehicle density on the planned lane Lp ahead of the vehicle 1's path.

[0039] For example, the planned lane Lp ahead of the vehicle 1 is divided into small sections, and the vehicle density for each section is calculated. Any point within a section where the vehicle density is below a threshold (for example, the center of the section) may be estimated as a point where lane changes are possible. For example, if the vehicle density on the planned lane Lp is high, the first predetermined distance D1 may be set to a larger value than when the vehicle density is low. Also, for example, if the vehicle density on the planned lane Lp is high, the threshold Dth may be set to a smaller value than when the vehicle density is low. Furthermore, some or all of the processing performed by the lane change position acquisition unit 41 may be executed by an information processing device external to the driver assistance device 10 (for example, a server device external to the vehicle 1).

[0040] When the lane change determination unit 42 obtains the lane change location acquisition unit 41's estimated lane change location, it determines whether there are multiple estimated lane change locations. If there are multiple estimated points where a lane change is possible, the lane change determination unit 42 obtains congestion information for its own lane Le from the congestion information acquisition unit 32. The lane change determination unit 42 estimates the time required to reach the destination when changing lanes from the current lane Le to the planned lane Lp at a point where a lane change is possible, based on the congestion information of the planned lane Lp and the congestion information of the current lane Le, for each of the multiple points where a lane change is possible.

[0041] For example, the lane change determination unit 42 estimates the vehicle speed of the planned lane Lp and the vehicle in its own lane Le in the surrounding section 20 and the distant section 21 based on the detection results by the road condition detection unit 31 and the congestion information acquisition unit 32. The lane change determination unit 42 calculates the time required from the current position to the point where a lane change is possible, based on the distance from the current position to the point where a lane change is possible and the vehicle speed in the current lane Le. It also calculates the time required from the point where a lane change is possible to the destination, based on the distance from the point where a lane change is possible to the destination and the vehicle speed in the planned lane Lp. In this case, the lane change determination unit 42 assumes that the vehicle 1 will travel from the point where a lane change is possible to the destination according to the lane plan (that is, it assumes that the vehicle will travel in the lane planned in the lane plan for the section from the point where a lane change is possible to the destination).

[0042] The lane change determination unit 42 selects the lane change location that requires the shortest time from among the multiple lane change locations estimated by the lane change location acquisition unit 41. The lane change determination unit 42 decides that the vehicle 1 will change lanes at the selected lane change point as a driving action. On the other hand, if there is only one estimated lane change point, the lane change determination unit 42 decides that the vehicle 1 should change lanes at the lane change point estimated by the lane change point acquisition unit 41 as a driving action.

[0043] When the driver of vehicle 1 decides to change lanes at a point where lane changes are permitted, the driving trajectory generation unit 34 generates a target driving trajectory that changes lanes from the current lane Le to the planned lane Lp at the point where lane changes are permitted. On the other hand, if the lane change determination unit 42 does not determine that the traffic volume in the planned lane Lp is greater than the traffic volume in the vehicle's lane Le in the surrounding section 20 around the vehicle 1, the vehicle change determination unit 42 decides that the vehicle 1 should immediately change lanes from its lane Le to the planned lane Lp as a driving action. In this case, the driving trajectory generation unit 34 generates a target driving trajectory that immediately changes lanes from its lane Le to the planned lane Lp. The vehicle control unit 35 drives the actuator 19 based on the target travel trajectory generated by the travel trajectory generation unit 34, thereby performing an automatic lane change for the vehicle 1.

[0044] When the lane change determination unit 42 decides to change lanes at a point where lane changes are permitted, the notification processing unit 44 determines whether or not the notification timing for notifying the point where lane changes are permitted has arrived. For example, the notification processing unit 44 may determine that the notification timing has arrived when the distance between the vehicle 1 and the lane change point Pc falls below a threshold distance. Furthermore, the notification processing unit 44 may inform the occupants to change lanes at lane change point Pc when the distance between the vehicle 1 and lane change point Pc becomes the second predetermined distance D2. The notification processing unit 44 may determine that the notification timing for notifying the lane change point has arrived when informing the occupants to change lanes at lane change point Pc.

[0045] Alternatively, for example, the system may determine whether the notification timing has arrived in response to a decrease in the vehicle speed of a vehicle in its own lane Le or a decrease in the vehicle speed of a vehicle in the planned lane Lp in the vicinity of its own vehicle 1 (for example, the surrounding section 20). For example, the system may determine that the notification timing has arrived when it detects a decrease in the vehicle speed of a vehicle in its own lane Le or a vehicle in the planned lane Lp based on the road conditions of the surrounding section 20 detected by the road condition detection unit 31.

[0046] Alternatively, for example, the notification timing may be determined to have arrived when the road condition detection unit 31 detects that the following distance on the planned lane Lp in the vicinity of the vehicle 1 (for example, the surrounding section 20) exceeds a threshold value, based on the road conditions of the surrounding section 20 detected by the road condition detection unit 31. When the notification timing is determined to have arrived, the notification processing unit 44 notifies the occupants of the lane change point where it is possible to change lanes to the planned lane Lp. For example, the notification processing unit 44 may display a notification image 22 (see Figure 3) representing the lane change point on the display device of the HMI 17.

[0047] The notification processing unit 44 may output an audio message from the HMI 17 informing the driver of the lane change location, in addition to or instead of the notification image 22. Alternatively, the notification image 22 may be displayed on a mobile terminal device used by the occupants of the vehicle 1, or an audio message informing the driver of the lane change location may be output from the mobile terminal device. The lane change determination unit 42 may also acquire information on the distance between vehicles in the planned lane Lp at the lane change point. The notification processing unit 44 may notify the occupants, along with the lane change point, that the probability of a successful lane change is lower when the distance between vehicles in the planned lane Lp at the lane change point is short compared to when the distance is long. For example, a message in red indicating that the probability of a successful lane change is low may be displayed on the display device of the HMI 17. Alternatively, the notification image 22 displayed on the display device of the HMI 17 may be made red to indirectly indicate that the probability of a successful lane change is low. Furthermore, if the distance between vehicles in the planned lane Lp at a point where a lane change is possible is less than the third predetermined distance D3, which is shorter than the first predetermined distance D1, the notification processing unit 44 may notify the occupants, along with the point where a lane change is possible, that the navigation device 16 may reset the target route.

[0048] (action) Figures 6(a) to 6(h) are explanatory diagrams illustrating examples of the operation of the driving assistance device 10 in specific situations. As shown in Figures 6(a) and 6(b), if the planned lane Lp is congested in the surrounding section 20 and this condition continues to the distant section 21, it is desirable to start changing lanes early in order to reliably move to the planned lane Lp at the lane change point Pc. For this reason, start changing lanes from the current lane Le to the planned lane Lp immediately. Furthermore, as shown in Figure 6(b), if the driver starts changing lanes from their own lane Le to the planned lane Lp even though the lane Le is not congested in the surrounding section 20, it may cause discomfort to the occupants. For this reason, the notification processing unit 44 may notify the occupants that it is starting to change lanes from their own lane Le to the planned lane Lp and the reason for starting the lane change. For example, it may notify the occupants that the lane change should be started early because the congested condition of the planned lane Lp continues to the distant section 21 (or the heavy traffic on the planned lane Lp continues to the lane change point Pc).

[0049] As shown in Figures 6(c) and 6(d), if the planned lane Lp is congested in the surrounding section 20, but the planned lane Lp is not congested in the distant section 21 and there are points where lane changes are possible, the driver will change lanes from their current lane Le to the planned lane Lp at a point where lane changes are possible. In this case, because the planned lane Lp is congested in the surrounding section 20, the occupants may feel anxious about whether they will be able to change lanes to the planned lane Lp by the point where the route change is possible Pc. Therefore, the notification processing unit 44 notifies the occupants of a point where lane changes to the planned lane Lp are possible.

[0050] As shown in Figures 6(e) and 6(g), if the traffic volume in the planned lane Lp in the surrounding section 20 is less than the traffic volume in the current lane Le, the vehicle will immediately change lanes from the current lane Le to the planned lane Lp. As shown in Figures 6(f) and 6(h), if both the planned lane Lp and the vehicle's own lane Le are empty in the surrounding section 20, and it is not determined that the traffic volume in the planned lane Lp is greater than the traffic volume in the vehicle's own lane Le, the vehicle will immediately change lanes from the vehicle's own lane Le to the planned lane Lp.

[0051] (operation) Figure 7 is a flowchart of an example of a driving assistance method according to the embodiment. In step S1, the navigation device 16 sets a target route from the current location of the vehicle 1 to the destination. In step S2, the lane plan setting unit 40 sets a lane plan that represents the lane in which the vehicle 1 is scheduled to travel along the target route. In step S3, the road condition detection unit 31 detects the road conditions of road Rd in the surrounding section 20 around the vehicle 1.

[0052] In step S4, the lane change determination unit 42 determines whether the traffic volume in the planned lane Lp is greater than the traffic volume in the current lane Le in the surrounding section 20. If the traffic volume in the planned lane Lp is greater than the traffic volume in the current lane Le (step S4:Y), the process proceeds to step S6. If the traffic volume in the planned lane Lp is not greater than the traffic volume in the current lane Le (step S4:N), the process proceeds to step S5. In step S5, the lane change determination unit 42 decides that the vehicle 1 should immediately change lanes from its own lane Le to the planned lane Lp as a driving action. The driving trajectory generation unit 34 and the vehicle control unit 35 change the vehicle 1's lane from its own lane Le to the planned lane Lp by an automatic lane change. The process then ends.

[0053] In step S6, the congestion information acquisition unit 32 acquires congestion information for the planned lane Lp. In step S7, the lane change location acquisition unit 41 estimates a lane change location before the lane change point Pc where it is possible to change lanes from the current lane Le to the planned lane La, based on congestion information of the planned lane Lp. In step S8, the lane change determination unit 42 determines whether there are multiple estimated lane change locations. If there are multiple lane change locations (step S8:Y), the process proceeds to step S9. If there are no multiple lane change locations (step S8:N), the process proceeds to step S12.

[0054] In step S9, the congestion information acquisition unit 32 acquires congestion information for its own lane Le. In step S10, the lane change determination unit 42 estimates the time required to reach the destination when changing lanes from the current lane Le to the planned lane Lp at a lane change point, based on the congestion information of the planned lane Lp and the congestion information of the current lane Le, for each of the multiple lane change points. In step S11, the lane change determination unit 42 selects the lane change point that requires the shortest time from among multiple possible lane change points. The lane change determination unit 42 decides that the driving action of the vehicle 1 is to change lanes from the current lane Le to the planned lane Lp at the selected lane change point.

[0055] In step S12, the notification processing unit 44 determines whether the notification timing for notifying a lane change point has arrived. If the notification timing has arrived (step S12:Y), the process proceeds to step S13. If the notification timing has not arrived (step S12:N), the process returns to step S12. In step S13, the notification processing unit 44 notifies the occupants of a point where a lane change to the planned lane Lp is possible. In step S14, when the vehicle 1 reaches a point where a lane change is possible, the trajectory generation unit 34 and the vehicle control unit 35 change the vehicle 1 from its own lane Le to the planned lane Lp by an automatic lane change.

[0056] (Effects of the embodiment) (1) In the driving assistance method, a target route from the current position of the vehicle 1 to the destination is set, a lane plan representing the lane that the vehicle 1 is scheduled to travel in is set based on the target route, congestion information which is information on the congestion status of each lane on the road on the target route is acquired, and if the vehicle 1 is traveling on a road with multiple lanes in the same direction of travel and the lane that the vehicle 1 is traveling in is different from the planned lane which is the lane that matches the lane plan, the system estimates a point where the vehicle 1 can change lanes from its current lane to the planned lane before the point where the vehicle 1 will change lanes on the target route ahead of its path, based on the congestion information, and notifies the occupants of the point where the lane can change lanes. For example, the system may detect road conditions around its own vehicle 1 and estimate points where lane changes are possible if the planned lane is congested. Alternatively, it may determine whether the planned lane is more congested than the current lane based on road conditions and estimate points where lane changes are possible if the planned lane is more congested than the current lane.

[0057] This system notifies the occupants of the point ahead in the vehicle's path where a lane change is possible. This makes it easier for occupants to determine whether a lane change to the planned lane is possible ahead in the vehicle's path, even if they are unsure whether it is possible due to congestion in the planned lane around the vehicle. This alleviates the occupants' anxiety that they may not be able to change lanes to the planned lane by the point of lane change.

[0058] (2) The planned lane may be determined to be more congested than the current lane based on at least one of the vehicle speeds of vehicles around the current vehicle 1, or the distance between vehicles around the current vehicle 1. Furthermore, road conditions may be detected by detecting vehicles in the vicinity of vehicle 1 using the vehicle's sensors, or by obtaining location information of vehicles in the vicinity of vehicle 1 from the infrastructure. This allows us to determine whether the planned lane is more congested than the current lane in the vicinity of our vehicle 1.

[0059] (3) Alternatively, congestion information may be obtained by receiving detection results from other vehicles that have been detected by sensors of other vehicles traveling on the road along the target route, which indicate the presence of vehicles in the vicinity of those vehicles. Alternatively, congestion information may be obtained by acquiring location information of vehicles traveling on roads along the target route from the infrastructure. Congestion information may be obtained based on historical traffic volume data for roads along the target route. This makes it possible to acquire congestion information in the distant section 21, which is beyond the detection range of the vehicle sensor 12 of the vehicle 1.

[0060] (4) When the distance between the vehicle 1 and the point where the lane change is possible falls below a threshold, the occupants may be notified of the point where the lane change is possible. This allows the system to notify occupants of the point where a lane change is permitted at the same time as instructing them to change lanes at a lane change point. (5) The occupants may be notified of a point where a lane change is possible in response to a decrease in the speed of a vehicle traveling in the same lane around the vehicle 1 or a decrease in the speed of a vehicle traveling in the planned lane around the vehicle 1. This allows for the occupants to be notified of the presence of a lane change point ahead when the area around their vehicle 1 becomes congested and the vehicle speed decreases, thereby alleviating their anxiety. (6) When the distance between vehicles in the planned lane around the vehicle 1 exceeds a threshold, the occupants may be notified of a point where a lane change is possible. If the vehicle does not change lanes into the planned lane despite the distance between vehicles in the planned lane around the vehicle increasing, the occupants' discomfort can be alleviated by notifying them that there is a point where a lane change is possible ahead. (7) As points where lane changes are possible, points that are a distance before the point where the lane change is to be made and where the distance between vehicles in the planned lane is greater than or equal to a threshold may be estimated. This makes it possible to estimate points where it is possible to change lanes into the planned lane before the point where the lane change is to be made. If the vehicle density on the planned lane is high, the predetermined distance may be set to a larger value than when the vehicle density is low. When the vehicle density is high and congestion is occurring, preparing to change lanes in advance will ensure that the lane change is successful. When the vehicle density on the planned lane is high, the threshold can be set to a smaller value than when the vehicle density is low. When the vehicle density is high and congestion is occurring, speeds are expected to be low, so allowing lane changes with short following distances makes it easier to estimate points where lane changes are possible. (8) When the distance between vehicles in the planned lane at a point where a lane change is possible is short, the occupants may be notified that the probability of a successful lane change is lower than when the distance is long. This can prevent a decrease in the occupants' confidence in the driver assistance control when they are actually unable to change lanes. The driver may also notify the occupants of the location where a lane change is possible, along with the location itself, that if the distance between vehicles in the planned lane at a lane change point is less than a predetermined distance, the target route may be reset. This allows the occupants to be informed in advance that the driving route will be changed if a lane change is not actually possible. (9) Points where lane changes are permitted may be displayed on a display device inside the vehicle or on a terminal device used by the occupants. This allows the driver to notify occupants of points where lane changes are permitted. [Explanation of Symbols]

[0061] 1...Own vehicle, 10...Driving assistance system, 11...Object sensor, 12...Vehicle sensor, 13...Positioning device, 14...Map database, 15...Communication device, 16...Navigation device, 17...Human-machine interface, 18...Controller, 18a...Processor, 18b...Storage device, 19...Actuator, 30...Own vehicle position detection unit, 31...Road condition detection unit, 32...Congestion information acquisition unit, 33...Driving action plan setting unit, 34...Travel trajectory generation unit, 35...Vehicle control unit, 40...Lane plan setting unit, 41...Lane change possible position acquisition unit, 42...Lane change judgment unit, 44...Notification processing unit

Claims

1. The controller Set the target route from your vehicle's current location to the destination. Based on the aforementioned target route, a lane plan is set representing the lane in which the vehicle is scheduled to travel. Congestion information, which is information on the congestion status of each lane on the road along the aforementioned target route, is obtained. When the vehicle is traveling on a road with multiple lanes in the same direction of travel, and the lane the vehicle is traveling in is different from the planned lane which is consistent with the lane plan, the system estimates, based on the congestion information, the point at which the vehicle can change lanes from its current lane to the planned lane, before the point at which it can change lanes on the target route ahead of its path. The occupants are notified of the aforementioned point where lane changes are permitted. As the lane change point, a point is estimated that is a predetermined distance before the lane change point and where the distance between vehicles in the planned lane is greater than or equal to a threshold. If the vehicle density on the planned lane is high, the threshold is set to a smaller value than when the vehicle density is low. A driving assistance method characterized by the following features.

2. The driving assistance method according to Claim 1, characterized in that the controller detects road conditions around the vehicle and estimates a point where a lane change is possible when the planned lane is congested.

3. The controller is Based on the aforementioned road conditions, it is determined whether the planned lane is more congested than the current lane. If the planned lane is more congested than the current lane, the point at which a lane change is possible is estimated. The driving assistance method according to feature 2.

4. The driving assistance method according to claim 3, characterized in that the controller determines whether the planned lane is more congested than the own lane based on at least one of the vehicle speeds of vehicles around the own vehicle or the distance between vehicles around the own vehicle.

5. The driving assistance method according to claim 2, characterized in that the controller detects the road conditions by detecting vehicles present in the vicinity of the vehicle using the vehicle's sensors, or by obtaining location information of vehicles present in the vicinity of the vehicle from the infrastructure.

6. The driving assistance method according to Claim 1, characterized in that the controller acquires the congestion information by receiving from the other vehicle the detection result of vehicles present in the vicinity of the other vehicle detected by the sensor of the other vehicle traveling on the road on the target route.

7. The driver assistance method according to Claim 1, characterized in that the controller obtains the congestion information by obtaining location information of vehicles traveling on the road along the target route from the infrastructure.

8. The driving assistance method according to claim 1, characterized in that the controller acquires the congestion information based on historical data of past traffic volume on the roads along the target route.

9. The driving assistance method according to Claim 1, characterized in that the controller notifies the occupant of the lane change point when the distance between the vehicle and the lane change point falls below a threshold.

10. The driving assistance method according to Claim 1, characterized in that the controller notifies the occupants of the lane change point in response to a decrease in the vehicle speed of a vehicle traveling in the lane around the vehicle or a decrease in the vehicle speed of a vehicle traveling in the planned lane around the vehicle.

11. The driving assistance method according to claim 1, characterized in that the controller notifies the occupants of the lane change point when the distance between vehicles in the planned lane around the vehicle exceeds a threshold.

12. The driving assistance method according to claim 1, characterized in that the controller sets the predetermined distance to a larger value when the vehicle density on the planned lane is high than when the vehicle density is low.

13. The driving assistance method according to Claim 1, characterized in that the controller notifies the occupant, along with the lane change location, that the probability of a successful lane change is lower when the distance between vehicles in the planned lane at the lane change location is short than when the distance between vehicles is long.

14. The driving assistance method according to claim 1, characterized in that the controller notifies the occupants, along with the lane change location, that it may reset the target route if the distance between vehicles in the planned lane at the lane change location is less than a predetermined distance.

15. The driving assistance method according to any one of claims 1 to 14, characterized in that the controller displays the lane change point on a display device in the vehicle or on a terminal device used by the occupant.

16. The system includes a controller that performs the following processes: setting a lane plan representing the lane the vehicle is scheduled to travel in based on a set target route from the vehicle's current location to its destination; acquiring congestion information, which is information on the congestion status of each lane on the road along the target route; and, if the vehicle is traveling on a road with multiple lanes in the same direction of travel and the lane the vehicle is traveling in is different from the planned lane, which is a lane consistent with the lane plan, estimating a point where the vehicle can change lanes from its current lane to the planned lane, based on the congestion information, before a point on the target route ahead of the vehicle's path where it can change lanes; and notifying the occupants of the point where the vehicle can change lanes. The aforementioned controller, As the lane change point, a point is estimated that is a predetermined distance before the lane change point and where the distance between vehicles in the planned lane is greater than or equal to a threshold. If the vehicle density on the planned lane is high, the threshold is set to a smaller value than when the vehicle density is low. A driving assistance device characterized by the following features.

Images