Vehicle control method and vehicle control device

Abstract

This vehicle control method causes a controller to execute: processing (S1) for determining whether or not a host vehicle traveling in a merging lane merging with a main lane can change lanes to the main lane; processing (S2) for determining whether or not there is a preceding vehicle traveling in the merging lane in front of the host vehicle; and processing (S6) for, when it is determined that the host vehicle can change lanes to the main lane and there is a preceding vehicle, delaying a lane change of the host vehicle to the main lane until the preceding vehicle starts a lane change to the main lane.

Description

Vehicle control method and vehicle control device

[0001] The present invention relates to a vehicle control method and a vehicle control device.

[0002] The following Patent Document 1 describes a vehicle control method that determines whether or not the host vehicle can change lanes onto the main lane when the host vehicle and a preceding vehicle are traveling on the merging lane in a merging section where the merging lane merges into the main lane, and if the host vehicle can change lanes onto the main lane, immediately causes the host vehicle to change lanes onto the main lane.

[0003] Patent No. 6344695

[0004] However, if the host vehicle changes lanes onto the main lane before the preceding vehicle, it may be difficult for the preceding vehicle to change lanes onto the main lane. Furthermore, if the preceding vehicle changes lanes onto the main lane ahead of the host vehicle after the host vehicle has changed lanes onto the main lane, it may be difficult for the host vehicle to travel smoothly. The present invention aims to achieve a smooth lane change between the host vehicle and the preceding vehicle when the host vehicle and the preceding vehicle traveling on the merging lane change lanes onto the main lane in a merging section where the merging lane merges into the main lane.

[0005] In one aspect of the vehicle control method of the present invention, a controller executes the following processes: determining whether a host vehicle traveling in a merging lane that merges into a main lane can change lanes to the main lane; determining whether a preceding vehicle traveling in the merging lane is present ahead of the host vehicle; and, if it is determined that the host vehicle can change lanes to the main lane and a preceding vehicle is present, delaying the host vehicle's lane change to the main lane until the preceding vehicle starts changing lanes to the main lane.

[0006] According to the present invention, when a vehicle traveling on a merging lane and a preceding vehicle change lanes onto the main lane in a merging section where the merging lane merges into the main lane, the vehicle and the preceding vehicle can smoothly change lanes.

[0007] FIG. 1 is a schematic configuration diagram of an example of a vehicle control device of an embodiment. (a) and (b) are schematic diagrams of an example of a vehicle control method of an embodiment. FIG. 1 is a block diagram of an example of a functional configuration of a controller. FIG. 2 is an explanatory diagram of an example of processing in a target scene detection unit. FIG. 3 is an explanatory diagram of an example of processing in a merging possibility evaluation unit. FIG. 4 is an explanatory diagram of an example of processing in an obstacle possibility evaluation unit. FIG. 5 is an explanatory diagram of an example of processing in a lane change start evaluation unit. FIG. 6 is a flowchart of an example of a vehicle control method of an embodiment. FIG. 7 is a flowchart of an example of processing in a merging possibility evaluation unit. FIG. 8 is a flowchart of an example of processing in an obstacle possibility evaluation unit. FIG. 9 is a flowchart of an example of processing in a lane change start evaluation unit.

[0008] (Configuration) Fig. 1 is a schematic configuration diagram of an example of a vehicle control device according to an embodiment. The host vehicle Ce is equipped with a vehicle control device 10 that controls the driving of the host vehicle Ce. The driving control by the vehicle control device 10 includes autonomous driving control that automatically drives the host vehicle Ce without the involvement of a driver based on the driving environment around the host vehicle Ce, and driving assistance control that assists the driver in driving the host vehicle Ce by controlling at least one of driving, braking, and steering of the host vehicle Ce. The driving assistance control may be, for example, automatic steering, automatic braking, preceding vehicle following control, constant speed driving control, lane keeping control, merging assistance control, etc.

[0009] The vehicle control device 10 includes an external sensor 11, a vehicle sensor 12, a positioning device 13, a map database (map DB) 14, a human machine interface (HMI) 15, an actuator 17, and a controller 18. The external sensor 11 includes a plurality of different types of object detection sensors mounted on the host vehicle Ce, such as a laser radar, a millimeter wave radar, a camera, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), that detect objects around the host vehicle Ce.

[0010] The vehicle sensor 12 is mounted on the host vehicle Ce and detects various information (vehicle signals) obtained from the host vehicle Ce. The vehicle sensor 12 includes, for example, a vehicle speed sensor that detects the vehicle speed of the host vehicle Ce, a wheel speed sensor that detects the rotational speed of the tires of the host vehicle Ce, a three-axis acceleration sensor that detects the acceleration and deceleration in three axial directions of the host vehicle Ce, a steering angle sensor that detects the steering angle of the steering wheel, a turning angle sensor that detects the turning angle of the steered wheels, a gyro sensor that detects the angular velocity of the host vehicle Ce, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the accelerator opening of the host vehicle Ce, and a brake sensor that detects the amount of brake operation by the driver.

[0011] The positioning device 13 includes a Global Navigation System (GNSS) receiver and receives radio waves from multiple navigation satellites to measure the current position of the vehicle Ce. The GNSS receiver may be, for example, a Global Positioning System (GPS) receiver. The positioning device 13 may be, for example, an inertial navigation system. The map database 14 stores road map data. For example, the map database 14 may store high-precision map data (hereinafter simply referred to as "high-precision map") suitable as map information for autonomous driving. The map database 14 may also store map data for navigation (hereinafter simply referred to as "navigation map").

[0012] The HMI 15 is an interface device that exchanges information between the vehicle control device 10 and the occupant of the host vehicle Ce. The HMI 15 includes a display device (e.g., a display screen of a navigation system) that can be seen by the occupant of the host vehicle Ce, a speaker or buzzer for outputting warning sounds, notification sounds, and audio information, and a haptic device that presents haptic signals to the occupant. The actuator 17 operates the steering wheel, accelerator opening, and brake device of the host vehicle in response to control signals from the controller 18 to generate vehicle behavior of the host vehicle. The actuator 17 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 brake device of the host vehicle.

[0013] The controller 18 is an electronic control unit that controls the driving of the host vehicle Ce. 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, or the like. The storage device 18b may include memories such as ROM and RAM used as main storage devices, as well as registers and cache memories.

[0014] The functions of the controller 18 described below are realized, for example, by the processor 18a executing a computer program stored in the storage device 18b. Note that the controller 18 may be formed of dedicated hardware for executing the information processing described below. For example, the controller 18 may include a functional logic circuit configured in a general-purpose semiconductor integrated circuit. For example, the controller 18 may include a PLD such as an FPGA.

[0015] Next, an example of a driving control method by the controller 18 will be described. Figures 2(a) and 2(b) are schematic diagrams illustrating an example of a vehicle control method according to an embodiment. Lane Ln1 is a main lane, and lane Lnm is a merging lane (acceleration lane) that merges into the main lane Ln1. The merging lane Lnm is adjacent to the main lane Ln1 in a merging section Sm, and a vehicle traveling on the merging lane Lnm can change lanes to the main lane Ln1 in the merging section Sm. The range in which a vehicle can change lanes from the merging lane Lnm to the main lane Ln1 in the merging section Sm begins at a start position Ps and ends at an end position P (i.e., the end point of the merging lane Lnm is the end position Pe). Assume a situation in which a host vehicle Ce is traveling on the merging lane Lmn, and a leading vehicle Cp is traveling on the merging lane Lmn ahead of the host vehicle Ce.

[0016] If the host vehicle Ce determines that it can change lanes to the main lane Ln1 and changes lanes to the main lane Ln1 before the preceding vehicle Cp, as indicated by an arrow A1 in Fig. 2A, it may be difficult for the preceding vehicle Cp to change lanes to the main lane Ln1. Also, if the preceding vehicle Cp changes lanes to the main lane Ln1 ahead of the host vehicle Ce as indicated by an arrow A2 after the host vehicle Ce has changed lanes to the main lane Ln1 as indicated by an arrow A2, it may be difficult for the host vehicle Ce to travel smoothly after changing lanes to the main lane Ln1.

[0017] Therefore, the controller 18 determines whether the host vehicle Ce traveling on the merging lane Lnm can change lanes to the main lane Ln1, determines whether a preceding vehicle Cp traveling on the merging lane Lnm is present ahead of the host vehicle Ce, and if it determines that the host vehicle Ce can change lanes to the main lane Ln1 and the preceding vehicle Cp is present, delays the host vehicle Ce from changing lanes to the main lane Ln1 until the preceding vehicle Cp starts to change lanes to the main lane Ln1. This prevents the host vehicle Ce from obstructing the preceding vehicle Cp's lane change or the preceding vehicle Cp from changing lanes to the main lane Ln1 ahead of the host vehicle Ce after the host vehicle Ce has changed lanes to the main lane Ln1, thereby realizing a smooth lane change between the host vehicle Ce and the preceding vehicle Cp.

[0018] The controller 18 will be described in detail with reference to Fig. 3. The controller 18 includes an object detection unit 30, a vehicle position estimation unit 31, a map acquisition unit 32, a detection integration unit 33, an object tracking unit 34, an in-map position calculation unit 35, a lane change control unit 36, and a vehicle control unit 37. The object detection unit 30 detects the positions, postures, sizes, speeds, etc. of objects around the vehicle Ce, such as vehicles, motorcycles, pedestrians, and obstacles, based on detection signals from the external sensors 11. The object detection unit 30 may acquire information about objects around the vehicle Ce from other vehicles or infrastructure via vehicle-to-vehicle communication or road-to-vehicle communication.

[0019] The host vehicle position estimation unit 31 measures the absolute position of the host vehicle Ce, i.e., the position, attitude, and speed of the host vehicle Ce relative to a predetermined reference point, based on odometry using measurement results from the positioning device 13 and detection results from the vehicle sensor 12. The map acquisition unit 32 acquires map information about roads around the host vehicle Ce from the map database 14. The map acquisition unit 32 may acquire map information about the structure of roads around the current position of the host vehicle Ce (e.g., map information about merging lanes Lnm). For example, the map acquisition unit 32 may acquire information about the end position Pe of the merging lane Lm (i.e., the end position Pe of the merging section Sm) as the map information about the merging lane Lnm. The map acquisition unit 32 may also acquire map information from an external map data server.

[0020] The detection integration unit 33 integrates the multiple detection results obtained by the object detection unit 30 from each of the multiple object detection sensors and outputs a single detection result for each object. Specifically, the detection integration unit 33 calculates the most reasonable object behavior that minimizes error from the object behavior obtained from each object detection sensor, taking into account the error characteristics of each object detection sensor. For example, sensor fusion technology is used to comprehensively evaluate the detection results from multiple types of sensors to obtain more accurate detection results.

[0021] The object tracking unit 34 tracks the object detected by the object detection unit 30. Specifically, based on the detection results integrated by the detection integration unit 33, the object tracking unit 34 verifies (corresponds) the identity of the object between different times from the behavior of the object output at different times, and predicts the behavior of the object, such as its speed, based on the correspondence. The intra-map position calculation unit 35 estimates the position and attitude of the host vehicle Ce on the map from the absolute position of the host vehicle Ce obtained by the host vehicle position estimation unit 31 and the map information acquired by the map acquisition unit 32. The intra-map position calculation unit 35 also identifies the road on which the host vehicle Ce is traveling. Furthermore, it identifies the lane on which the host vehicle Ce is traveling.

[0022] The lane change control unit 36 ​​executes a lane change operation to automatically change the host vehicle Ce from the current driving lane to an adjacent lane. For example, the lane change operation may be a driving operation that moves the host vehicle Ce laterally to the adjacent lane and starts the execution of a lane keeping function in the adjacent lane once the movement to the adjacent lane is complete. For example, the lane change control unit 36 ​​may execute a lane change operation when the occupant operates a turn signal. Furthermore, for example, when a target driving route from the current position to the destination is set, the lane change control unit 36 ​​may execute a lane change operation by determining whether a lane change is necessary to travel along the target driving route. Below, an example will be described in which the host vehicle Ce changes lanes from the merging lane Lnm to the main lane Ln1.

[0023] The lane change control unit 36 ​​includes a lane change possibility determination unit 40, a target scene detection unit 41, a merging possibility evaluation unit 42, an obstacle possibility evaluation unit 43, and a lane change start evaluation unit 44. The lane change possibility determination unit 40 determines whether the host vehicle Ce can change lanes from the merging lane Lnm to the main lane Ln1 (i.e., the possibility of the host vehicle Ce changing lanes from the merging lane Lnm to the main lane Ln1). At this time, the lane change possibility determination unit 40 may determine the possibility of the host vehicle Ce changing lanes regardless of the presence or absence of a preceding vehicle, the position of the preceding vehicle Cp, or the vehicle speed vp of the preceding vehicle Cp. For example, the lane change possibility determination unit 40 may determine that the vehicle Ce can change lanes if certain lane change conditions are met (e.g., there is space in the main lane Ln1 where a lane change is possible, the speed of the preceding vehicle in the main lane Ln1 meets certain conditions, the radius of curvature of the road is greater than or equal to a threshold, etc.).

[0024] The target scene detection unit 41 determines whether the current driving scene of the host vehicle Ce is a specific target scene that should delay a lane change from the merging lane Lnm to the main lane Ln1. See FIG. 4 . For example, the target scene detection unit 41 may determine whether a preceding vehicle Cp traveling on the merging lane Lnm is present ahead of the host vehicle Ce. The target scene detection unit 41 may determine that the current driving scene is a target scene if the preceding vehicle Cp is present, and may determine that the current driving scene is not a target scene if the preceding vehicle Cp is not present. Note that reference characters C1 and C2 indicate other vehicles on the main lane. For example, the target scene detection unit 41 may also determine whether another vehicle traveling on the main lane Ln1 is present within a range R in the longitudinal direction from the position of the host vehicle Ce to a position P1 that is a predetermined distance D1 (e.g., 10 m when the preceding vehicle Cp is traveling at 60 km / h) ahead of the position of the preceding vehicle Cp. This determines whether the preceding vehicle Cp will merge in front of the host vehicle Ce or in front of another vehicle traveling on the main lane Ln1. The target scene detection unit 41 may determine that the current driving scene is a target scene when the preceding vehicle Cp is present and no other vehicle is present within the range R, and may determine that the current driving scene is not a target scene when the preceding vehicle Cp is not present or another vehicle is present within the range R. Here, if the preceding vehicle Cp is approaching the rear of another vehicle traveling on the main lane Ln1 (for example, Time Headway is less than 0.5 seconds), it is determined that the preceding vehicle Cp will not merge between the other vehicle and the host vehicle Ce.

[0025] See FIG. 3 . The merging possibility evaluation unit 42 determines whether there is a merging possibility (being-merged possibility or being-merged risk) when the current driving scene is a target scene. The merging possibility is the possibility that, when the host vehicle Ce changes lanes to the main lane Ln1, the preceding vehicle Cp will change lanes to the main lane Ln1 in front of the host vehicle Ce after the host vehicle Ce has changed lanes to the main lane Ln1. See FIG. 5 . For example, the merging possibility evaluation unit 42 may determine whether the planned driving route Tr of the host vehicle Ce includes a route that passes through the main lane Ln1. Alternatively, for example, the merging possibility evaluation unit 42 may determine whether a distance D2 from the preceding vehicle Cp to the end position Pe of the merging lane Lnm is longer than a predetermined first distance threshold Thd1.

[0026] Further, for example, the merging possibility evaluation unit 42 may determine whether the degree of proximity between the host vehicle Ce and the preceding vehicle Cp is lower than a predetermined first threshold. For example, when the vehicle speed vp of the preceding vehicle Cp is equal to or higher than the vehicle speed of the host vehicle Ce, the degree of proximity between the host vehicle Ce and the preceding vehicle Cp may be the inter-vehicle distance D3 between the host vehicle Ce and the preceding vehicle Cp. When the vehicle speed vp of the preceding vehicle Cp is lower than the vehicle speed of the host vehicle Ce, the degree of proximity between the host vehicle Ce and the preceding vehicle Cp may be the time to collision TTC1 from the host vehicle Ce to the preceding vehicle Cp. The shorter the inter-vehicle distance D3 and the time to collision TTC1, the higher the degree of proximity between the host vehicle Ce and the preceding vehicle Cp, and the longer the inter-vehicle distance D3 and the time to collision TTC1, the lower the degree of proximity between the host vehicle Ce and the preceding vehicle Cp. The merging possibility evaluation unit 42 may determine that the degree of proximity is lower than a predetermined first threshold value when the inter-vehicle distance D3 is longer than the threshold value Th1a or the time to collision TTC1 is longer than the threshold value Th1b, and may determine that the degree of proximity is greater than or equal to the predetermined first threshold value when the inter-vehicle distance D3 is equal to or less than the threshold value Th1a or the time to collision TTC1 is equal to or less than the threshold value Th1b.

[0027] For example, the merging possibility evaluation unit 42 may determine that there is a possibility of merging when the planned traveling route Tr of the host vehicle includes a route that passes through the main lane Ln1, and the distance D2 from the preceding vehicle Cp to the end position Pe of the merging lane Lnm is equal to or less than the first distance threshold Thd1, and the proximity between the host vehicle Ce and the preceding vehicle Cp is equal to or greater than the first threshold. Conversely, the merging possibility evaluation unit 42 may determine that there is no possibility of merging when the planned traveling route Tr of the host vehicle does not include a route that passes through the main lane Ln1, or the distance D2 is longer than the first distance threshold Thd1, and the proximity between the host vehicle Ce and the preceding vehicle Cp is less than the first threshold.

[0028] See FIG. 3 . When the current driving scene is a target scene (or when the merging possibility evaluation unit 42 determines that there is a possibility of being blocked), the obstruction possibility evaluation unit 43 determines whether there is a possibility of being blocked (being-blocked possibility or being-blocked risk). The obstruction possibility refers to the possibility that if the host vehicle Ce delays changing lanes to the main lane Ln1 until the preceding vehicle Cp starts changing lanes to the main lane Ln1, the host vehicle Ce's lane change to the main lane Ln1 will be obstructed by another vehicle on the main lane Ln1 or another vehicle on an adjacent lane adjacent to the main lane Ln1 on the opposite side of the merging lane Lnm. See FIG. 6 . For example, the obstruction possibility evaluation unit 43 may detect, as a target vehicle, an approaching vehicle C1 traveling behind the host vehicle Ce on the main lane Ln1 in the same direction as the host vehicle Ce. For example, the interference possibility assessment unit 43 may detect an approaching vehicle C3 as a target vehicle when the approaching vehicle C3 is traveling in the same direction as the vehicle Ce on the main lane Ln2, which is an adjacent lane to the main lane Ln1 adjacent to the merging lane Lnm on the opposite side of the vehicle Ce, and has its turn signal turned on in the direction of the main lane L1.

[0029] The interference possibility evaluation unit 43 may determine whether the degree of proximity between the subject vehicle Ce and the target vehicles C1, C3 is higher than a predetermined second threshold. For example, when the vehicle speed of the target vehicles C1, C3 is equal to or lower than the vehicle speed of the subject vehicle Ce, the degree of proximity between the subject vehicle Ce and the target vehicles C1, C3 may be the inter-vehicle distance D4 between the subject vehicle Ce and the target vehicles C1, C3. Note that in this specification, the "inter-vehicle distance D4 between the subject vehicle Ce and the target vehicles C1, C3" refers to the distance in the front-to-rear direction between the rear end position of the subject vehicle Ce and the front end position of the target vehicles C1, C3. When the vehicle speed of the target vehicles C1, C3 is higher than the vehicle speed of the subject vehicle Ce, the degree of proximity between the subject vehicle Ce and the target vehicles C1, C3 may be the time to collision TTC2 from the target vehicles C1, C3 to the subject vehicle Ce. In this specification, the term "time to collision TTC2" refers to the time required for the front end of the target vehicles C1 and C3 to reach the rear end of the subject vehicle Ce in the longitudinal direction. The shorter the inter-vehicle distance D4 and the time to collision TTC2, the higher the degree of proximity between the subject vehicle Ce and the target vehicles C1 and C3. The longer the inter-vehicle distance D4 and the time to collision TTC2, the lower the degree of proximity between the subject vehicle Ce and the target vehicles C1 and C3. The interference possibility assessment unit 43 may determine that the degree of proximity is equal to or lower than the second threshold value when the inter-vehicle distance D4 is equal to or greater than the threshold value Th2a or the time to collision TTC2 is equal to or greater than the threshold value Th2b, and may determine that the degree of proximity is higher than the second threshold value when the inter-vehicle distance D4 is less than the threshold value Th2a or the time to collision TTC2 is less than the threshold value Th2b. For example, the obstruction possibility assessment unit 43 may determine that there is a possibility of obstruction when the degree of proximity between the subject vehicle Ce and the target vehicles C1 and C3 is higher than a second threshold value, and may determine that there is no possibility of obstruction when the degree of proximity between the subject vehicle Ce and the target vehicles C1 and C3 is equal to or lower than the second threshold value.

[0030] See FIG. 3 . When the merging possibility evaluation unit 42 determines that there is no possibility of being merged or when the obstruction possibility evaluation unit 43 determines that there is a possibility of being obstructed, the lane change control unit 36 ​​starts a lane change of the host vehicle Ce to the main lane Ln1 (for example, before the preceding vehicle Cp starts to change lanes to the main lane Ln1). The lane change control unit 36 ​​sets a target driving path for laterally moving the host vehicle Ce from the merging lane Lnm to the main lane Ln1 and a vehicle speed plan (hereinafter sometimes referred to as a “target vehicle speed profile”) that is a target speed of the host vehicle Ce at each point on the target driving path. The vehicle control unit 37 drives the actuator 17 so that the host vehicle 1 travels along the target driving trajectory at a speed that conforms to the target vehicle speed profile generated by the lane change control unit 36.

[0031] On the other hand, if the merging possibility evaluation unit 42 determines that there is a possibility of being merged and the obstruction possibility evaluation unit 43 determines that there is no possibility of obstruction, the lane change control unit 36 ​​delays the start of the lane change of the host vehicle Ce to the main lane Ln1. After the start of the lane change of the host vehicle Ce to the main lane Ln1 has been delayed, if the preceding vehicle Cp starts changing to the main lane Ln1, the lane change control unit 36 ​​starts the lane change of the host vehicle Ce to the main lane Ln1. In other words, the lane change control unit 36 ​​delays the lane change of the host vehicle Ce to the main lane Ln1 until the preceding vehicle Cp starts changing to the main lane Ln1. For example, the lane change control unit 36 ​​may determine whether the preceding vehicle Cp has started a driving operation to change lanes to the main lane Ln1. For example, the lane change control unit 36 ​​may determine that the preceding vehicle Cp has started a driving operation to change lanes to the main lane Ln1 when the preceding vehicle Cp turns on a turn signal toward the main lane Ln1 or when the preceding vehicle Cp starts moving laterally toward the main lane Ln1. When the lane change control unit 36 ​​detects the start of a lane change operation by the preceding vehicle Cp toward the main lane Ln1, it may start a lane change of the host vehicle Ce to the main lane Ln1.

[0032] After the host vehicle Ce starts to delay changing lanes to the main lane Ln1, the lane change start evaluation unit 44 determines whether to stop the delay or continue the delay. See FIG. 7 . For example, the lane change start evaluation unit 44 may determine whether the distance D2 from the preceding vehicle Cp to the end position Pe of the merging lane Lnm is less than a predetermined second distance threshold Thd2. Alternatively, for example, the lane change start evaluation unit 44 may determine whether the vehicle speed vp of the preceding vehicle Cp is less than a predetermined speed threshold Thv. Alternatively, for example, the lane change start evaluation unit 44 may determine whether the degree of proximity between the host vehicle Ce and a following vehicle Cf traveling behind the host vehicle Ce on the merging lane Lnm is greater than a predetermined third threshold.

[0033] For example, when the vehicle speed of the following vehicle Cf is equal to or lower than the vehicle speed of the host vehicle Ce, the degree of proximity between the host vehicle Ce and the following vehicle Cf may be the inter-vehicle distance D5 between the host vehicle Ce and the following vehicle Cf. When the vehicle speed of the following vehicle Cf is higher than the vehicle speed of the host vehicle Ce, the degree of proximity between the host vehicle Ce and the following vehicle Cf may be the time to collision TTC3 from the following vehicle Cf to the host vehicle Ce. The shorter the inter-vehicle distance D5 and the time to collision TTC3, the higher the degree of proximity between the host vehicle Ce and the following vehicle Cf, and the longer the inter-vehicle distance D5 and the time to collision TTC3, the lower the degree of proximity between the host vehicle Ce and the following vehicle Cf. The lane change start evaluation unit 44 may determine that the degree of proximity is less than or equal to the third threshold value when the inter-vehicle distance D5 is greater than or equal to the threshold value Th3a or the time to collision TTC3 is greater than or equal to the threshold value Th3b, and may determine that the degree of proximity is greater than the third threshold value when the inter-vehicle distance D5 is less than the threshold value Th3a or the time to collision TTC3 is less than the threshold value Th3b.

[0034] For example, the lane change start evaluation unit 44 may determine to stop the delay of the lane change when the distance D2 from the preceding vehicle Cp to the end position Pe of the merging lane Lnm becomes less than the second distance threshold Thd2, when the vehicle speed vp of the preceding vehicle Cp becomes less than the speed threshold Thv, or when the degree of proximity between the host vehicle Ce and the following vehicle Cf becomes higher than a third threshold, and may determine to continue the delay of the lane change when the distance D2 is not less than the predetermined second distance threshold Thd2, the vehicle speed vp is not less than the speed threshold Thv, and the degree of proximity is not higher than the third threshold. When the lane change start evaluation unit 44 determines to stop the delay of the lane change, the lane change control unit 36 ​​may start the lane change of the host vehicle Ce into the main lane Ln1. When the lane change start evaluation unit 44 determines that the delay in the lane change should be continued, the lane change control unit 36 ​​continues to delay the lane change without starting the lane change of the host vehicle Ce to the main lane Ln1.

[0035] (Operation) FIG. 8 is a flowchart of an example of a vehicle control method according to an embodiment. In step S1, the lane change possibility determination unit 40 determines whether the host vehicle Ce can change lanes from the merging lane Lnm to the main lane Ln1. If the host vehicle Ce cannot change lanes (step S1: N), the process ends. If the host vehicle Ce can change lanes (step S1: Y), the process proceeds to step S2. In step S2, the target scene detection unit 41 determines whether a preceding vehicle Cp traveling on the merging lane Lnm is present ahead of the host vehicle Ce. If a preceding vehicle Cp is not present (step S2: N), the process proceeds to step S9. If a preceding vehicle Cp is present (step S2: Y), the process proceeds to step S3.

[0036] In step S3, the target scene detection unit 41 determines whether or not there is another vehicle traveling on the main lane Ln1 within a range R in the longitudinal direction from the position of the host vehicle Ce to a position P1 a predetermined distance D1 ahead of the position of the preceding vehicle Cp. If there is another vehicle within the range R (step S3: Y), the process proceeds to step S9. If there is no other vehicle within the range R (step S3: N), the process proceeds to step S4. In step S4, the merging possibility evaluation unit 42 determines whether or not there is a possibility of being merged. FIG. 9 is a flowchart of an example of the process in the merging possibility evaluation unit 42. In step S10, the merging possibility evaluation unit 42 determines whether or not the planned driving route Tr of the host vehicle Ce includes a route that passes through the main lane Ln1. If the planned driving route Tr does not include a route that passes through the main lane Ln1 (step S10: N), the process proceeds to step S14. If the planned travel route Tr includes a route that passes through the main lane Ln1 (step S10: Y), the process proceeds to step S11.

[0037] In step S11, the merging possibility evaluation unit 42 determines whether the distance D2 from the preceding vehicle Cp to the end position Pe of the merging lane Lnm is equal to or less than the first distance threshold Thd1. If the distance D2 is not equal to or less than the first distance threshold Thd1 (step S11: N), the process proceeds to step S14. If the distance D2 is equal to or less than the first distance threshold Thd1 (step S11: Y), the process proceeds to step S12. In step S12, the merging possibility evaluation unit 42 determines whether the vehicle speed vp of the preceding vehicle Cp is equal to or greater than the vehicle speed of the host vehicle Ce. If the vehicle speed vp of the preceding vehicle Cp is not equal to or greater than the vehicle speed of the host vehicle Ce (step S12: N), the process proceeds to step S16. If the vehicle speed vp of the preceding vehicle Cp is equal to or greater than the vehicle speed of the host vehicle Ce (step S12: Y), the process proceeds to step S13.

[0038] In step S13, the merging possibility evaluation unit 42 determines whether the inter-vehicle distance D3 between the host vehicle Ce and the preceding vehicle Cf is longer than the threshold value Th1a. If the inter-vehicle distance D3 is not longer than the threshold value Th1a (step S13: N), the process proceeds to step S15. If the inter-vehicle distance D3 is longer than the threshold value Th1a (step S13: Y), the process proceeds to step S14. In step S14, the merging possibility evaluation unit 42 determines that there is no possibility of being merged. The process then ends. In step S15, the merging possibility evaluation unit 42 determines that there is a possibility of being merged. The process then ends. In step S16, the merging possibility evaluation unit 42 determines whether the time to collision TTC1 from the host vehicle Ce to the preceding vehicle Cp is longer than the threshold value Th1b. If the time to collision TTC1 is not longer than the threshold value Th1b (step S16: N), the process proceeds to step S15. If the time to collision TTC1 is longer than the threshold value Th1b (step S16: Y), the process proceeds to step S17. In step S17, the merge possibility evaluation unit 42 determines that there is no possibility of being merged. Then, the process ends.

[0039] See FIG. 8. If there is no possibility of being merged (step S4: N), the process proceeds to step S9. If there is a possibility of being merged (step S4: Y), the process proceeds to step S5. In step S5, the interference possibility evaluation unit 43 determines whether there is a possibility of interference. FIG. 10 is a flowchart of an example of the process in the interference possibility evaluation unit 43. In step S20, the interference possibility evaluation unit 43 determines whether there is an approaching vehicle C1 traveling on the main lane Ln1 behind the host vehicle Ce. If there is an approaching vehicle C1 (step S20: Y), the interference possibility evaluation unit 43 detects the approaching vehicle C1 as a target vehicle. Thereafter, the process proceeds to step S23. If there is no approaching vehicle C1 (step S20: N), the process proceeds to step S21.

[0040] In step S21, the interference possibility evaluation unit 43 determines whether or not there is an approaching vehicle C3 traveling on the main lane Ln2, which is an adjacent lane to the main lane Ln1 adjacent to the merging lane Lnm on the opposite side. If there is no approaching vehicle C3 (step S21: N), the process proceeds to step S25. If there is an approaching vehicle C3 (step S21: Y), the process proceeds to step S22. In step S22, the interference possibility evaluation unit 43 determines whether or not the approaching vehicle C3 is illuminating its turn signal toward the main lane L1. If the approaching vehicle C3 is not illuminating its turn signal (step S22: N), the process proceeds to step S25. If the approaching vehicle C3 is illuminating its turn signal (step S22: Y), the interference possibility evaluation unit 43 detects the approaching vehicle C3 as a target vehicle. Then, the process proceeds to step S23.

[0041] In step S23, the interference possibility evaluation unit 43 determines whether the target vehicle is faster than the subject vehicle Ce. If the target vehicle is faster than the subject vehicle Ce (step S23: Y), the process proceeds to step S27. If the target vehicle is not faster than the subject vehicle Ce (step S23: N), the process proceeds to step S24. In step S24, the interference possibility evaluation unit 43 determines whether the inter-vehicle distance D4 between the subject vehicle Ce and the target vehicle is equal to or greater than the threshold value Th2a. If the inter-vehicle distance D4 is not equal to or greater than the threshold value Th2a (step S24: N), the process proceeds to step S26. If the inter-vehicle distance D4 is equal to or greater than the threshold value Th2a (step S24: Y), the process proceeds to step S25. In step S25, the interference possibility evaluation unit 43 determines that there is no interference possibility. Then, the process ends. In step S26, the interference possibility evaluation unit 43 determines that there is an interference possibility. Then, the process ends.

[0042] In step S27, the interference possibility evaluation unit 43 determines whether the time to collision TTC2 from the target vehicle to the host vehicle Ce is equal to or greater than the threshold value Th2b. If the time to collision TTC2 is not equal to or greater than the threshold value Th2b (step S27: N), the process proceeds to step S26. If the time to collision TTC2 is equal to or greater than the threshold value Th2b (step S27: Y), the process proceeds to step S28. In step S28, the interference possibility evaluation unit 43 determines that there is no interference possibility. The process then ends. See FIG. 8. If there is interference possibility (step S5: Y), the process proceeds to step S9. If there is no interference possibility (step S5: N), the process proceeds to step S6.

[0043] In step S6, the lane change control unit 36 ​​delays the start of the lane change of the host vehicle Ce to the main lane Ln1. In subsequent step S7, the lane change start evaluation unit 44 determines whether to stop the delay of the lane change or continue the delay. FIG. 11 is a flowchart of an example of processing in the lane change start evaluation unit 44. In step S30, the lane change start evaluation unit 44 determines whether the distance D2 from the preceding vehicle Cp to the end position Pe of the merging lane Lmn is less than the second distance threshold Thd2. If the distance D2 is less than the second distance threshold Thd2 (step S30: Y), the processing proceeds to step S32. If the distance D2 is not less than the second distance threshold Thd2 (step S30: N), the processing proceeds to step S31. In step S31, the lane change start evaluation unit 44 determines whether the vehicle speed vp of the preceding vehicle Cp is less than the speed threshold Thv. If the vehicle speed vp is less than the speed threshold Thv (step S31: Y), the process proceeds to step S32. If the vehicle speed vp is not less than the speed threshold Thv (step S31: N), the process proceeds to step S33. In step S32, the lane change start evaluation unit 44 determines to stop the lane change delay. Then, the process ends.

[0044] In step S33, the lane change start evaluation unit 44 determines whether or not a following vehicle Cf traveling on the merging lane Lnm is present behind the host vehicle Ce. If the following vehicle Cf is not present (step S33: N), the process proceeds to step S36. If the following vehicle Cf is present (step S33: Y), the process proceeds to step S34. In step S34, the lane change start evaluation unit 44 determines whether or not the following vehicle Cf is faster than the host vehicle Ce. If the following vehicle Cf is faster than the host vehicle Ce (step S34: Y), the process proceeds to step S38. If the following vehicle Cf is not faster than the host vehicle Ce (step S34: N), the process proceeds to step S35.

[0045] In step S35, the lane change start evaluation unit 44 determines whether the inter-vehicle distance D5 between the subject vehicle Ce and the following vehicle Cf is equal to or greater than the threshold value Th3a. If the inter-vehicle distance D5 is not equal to or greater than the threshold value Th3a (step S35: N), the process proceeds to step S37. If the inter-vehicle distance D5 is equal to or greater than the threshold value Th3a (step S35: Y), the process proceeds to step S36. In step S36, the lane change start evaluation unit 44 determines to continue the delay in the lane change. The process then ends. In step S37, the lane change start evaluation unit 44 determines to stop the delay in the lane change. The process then ends. In step S38, the lane change start evaluation unit 44 determines whether the time to collision TTC3 from the following vehicle Cf to the subject vehicle Ce is equal to or greater than the threshold value Th3b. If the time to collision TTC3 is not equal to or greater than the threshold value Th3b (step S38: N), the process proceeds to step S37. If the time to collision TTC3 is equal to or greater than the threshold value Th3b (step S38: Y), the process proceeds to step S39. In step S39, the lane change initiation evaluation unit 44 determines to continue the lane change delay. The process then ends.

[0046] See Figure 8. If the delay in the lane change is to be stopped (step S7: Y), the process proceeds to step S9. If the delay in the lane change is to be continued (step S7: N), the process proceeds to step S8. In step S8, the lane change control unit 36 ​​determines whether the preceding vehicle Cp has started to change lanes into the main lane Ln1. If the lane change has not started (step S8: N), the process returns to step S4. If the lane change has started (step S8: Y), the process proceeds to step S9. In step S9, the lane change control unit 36 ​​starts the lane change of the host vehicle Ce into the main lane Ln1. The process then ends.

[0047] (Effects of the Embodiments) (1) In the vehicle control method, a controller executes the following processes: determining whether a host vehicle traveling in a merging lane merging into a main lane can change lanes to the main lane; determining whether a preceding vehicle traveling in the merging lane is present ahead of the host vehicle; and, if it is determined that the host vehicle can change lanes to the main lane and a preceding vehicle is present, delaying the host vehicle's lane change to the main lane until the preceding vehicle starts to change lanes to the main lane. This enables smooth lane changes between the host vehicle traveling in the merging lane and the preceding vehicle when they change lanes to the main lane.

[0048] (2) When there is another vehicle traveling on the main lane within a range in the longitudinal direction from the position of the host vehicle to a position a predetermined distance ahead of the position of the leading vehicle, the controller may start a lane change of the host vehicle without waiting for the leading vehicle to start changing lanes. When the distance from the leading vehicle to an end point of the merging lane is longer than a predetermined first distance threshold, the controller may start a lane change of the host vehicle without waiting for the leading vehicle to start changing lanes. When the degree of proximity between the host vehicle and the leading vehicle is lower than a predetermined first threshold, the controller may start a lane change of the host vehicle without waiting for the leading vehicle to start changing lanes. This allows the host vehicle to start a lane change without waiting for the leading vehicle in a situation where the leading vehicle is delayed in changing lanes.

[0049] (3) When the degree of proximity between the host vehicle and another vehicle traveling in the main lane behind the host vehicle is higher than a predetermined second threshold, the controller may start the lane change of the host vehicle without waiting for the preceding vehicle to start changing lanes. This delays the host vehicle's lane change to the main lane, thereby preventing the host vehicle's lane change from being blocked by another vehicle on the main lane. (4) When the controller detects the start of a lane change operation by the preceding vehicle to the main lane after delaying the host vehicle's lane change to the main lane, the controller may start the lane change of the host vehicle. This delays the host vehicle's lane change to the main lane until the preceding vehicle changes lanes to the main lane.

[0050] (5) The controller may initiate a lane change of the host vehicle when the vehicle speed of the preceding vehicle becomes less than a predetermined speed threshold after delaying the lane change of the host vehicle to the main lane. The controller may initiate a lane change of the host vehicle when the distance from the preceding vehicle to the end point of the merging lane becomes less than a predetermined second distance threshold after delaying the lane change of the host vehicle to the main lane. This prevents the host vehicle from being unable to initiate a lane change due to waiting for the preceding vehicle to change lanes when the preceding vehicle does not change lanes. (6) The controller may initiate a lane change of the host vehicle when the degree of proximity between the host vehicle and another vehicle traveling in the merging lane behind the host vehicle becomes greater than a predetermined third threshold after delaying the lane change of the host vehicle to the main lane. This prevents the smooth travel of a following vehicle traveling in the merging lane from being hindered by a delay in the lane change of the host vehicle to the main lane.

[0051] 10...vehicle control device, 11...external sensor, 12...vehicle sensor, 13...positioning device, 14...map database, 15...human-machine interface, 17...actuator, 18...controller, 18a...processor, 18b...storage device, 30...object detection unit, 31...own vehicle position estimation unit, 32...map acquisition unit, 33...detection integration unit, 34...object tracking unit, 35...in-map position calculation unit, 36...lane change control unit, 37...vehicle control unit, 40...lane change possibility determination unit, 41...target scene detection unit, 42...merging possibility evaluation unit, 43...obstacle possibility evaluation unit, 44...lane change start evaluation unit

Claims

1. A vehicle control method comprising having a controller execute the following processes: determining whether a host vehicle traveling in a merging lane merging into a main lane can change lanes to the main lane; determining whether a preceding vehicle traveling in the merging lane is present ahead of the host vehicle; and, if it is determined that the host vehicle can change lanes to the main lane and a preceding vehicle is present, delaying the host vehicle's lane change to the main lane until the preceding vehicle starts to change lanes to the main lane.

2. The vehicle control method described in claim 1, characterized in that the controller starts a lane change of the host vehicle without waiting for the preceding vehicle to start changing lanes when there is another vehicle traveling on the main lane within a range from the position of the host vehicle to a position a predetermined distance ahead of the position of the preceding vehicle in the forward / backward direction.

3. A vehicle control method as described in claim 1 or 2, characterized in that the controller starts changing lanes of the vehicle without waiting for the preceding vehicle to start changing lanes when the distance from the preceding vehicle to the end point of the merging lane is longer than a predetermined first distance threshold.

4. A vehicle control method as described in any one of claims 1 to 3, characterized in that the controller starts changing lanes of the vehicle without waiting for the preceding vehicle to start changing lanes when the degree of proximity between the vehicle and the preceding vehicle is lower than a predetermined first threshold.

5. A vehicle control method as described in any one of claims 1 to 4, characterized in that the controller starts a lane change of the host vehicle without waiting for the preceding vehicle to start changing lanes when the degree of proximity between the host vehicle and another vehicle traveling in the main lane behind the host vehicle is higher than a predetermined second threshold.

6. A vehicle control method as described in any one of claims 1 to 5, characterized in that the controller starts the lane change of the vehicle when it detects that the preceding vehicle has started a lane change operation to the main lane after delaying the lane change of the vehicle to the main lane.

7. A vehicle control method as described in any one of claims 1 to 6, characterized in that the controller starts the lane change of the host vehicle when the vehicle speed of the preceding vehicle becomes less than a predetermined speed threshold after delaying the lane change of the host vehicle to the main lane.

8. A vehicle control method as described in any one of claims 1 to 7, characterized in that the controller starts the lane change of the vehicle when, after delaying the lane change of the vehicle to the main lane, the distance from the preceding vehicle to the end point of the merging lane becomes less than a predetermined second distance threshold.

9. A vehicle control method as described in any one of claims 1 to 8, characterized in that the controller initiates a lane change of the host vehicle when, after delaying the lane change of the host vehicle to the main lane, the degree of proximity between the host vehicle and another vehicle traveling in the merging lane behind the host vehicle becomes higher than a predetermined third threshold.

10. A vehicle control device comprising a controller that executes the following processes: determining whether a host vehicle traveling in a merging lane merging into a main lane can change lanes to the main lane; determining whether a preceding vehicle traveling in the merging lane is present ahead of the host vehicle; and, if it is determined that the host vehicle can change lanes to the main lane and a preceding vehicle is present, delaying the host vehicle's lane change to the main lane until the preceding vehicle starts to change lanes to the main lane.

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