Vehicle control method and vehicle control device

Abstract

Provided is a vehicle control method in which a controller executes: processing (S1) to detect a first other vehicle traveling in a second lane adjacent to a first lane in which a host vehicle travels; processing (S2) to predict a merging point which is a point where the first other vehicle enters the first lane; processing (S3) to estimate a probability of collision between the first other vehicle and the host vehicle at the moment when the first other vehicle reaches the merging point; and processing (S4, S5) to execute, on the basis of the probability of collision, acceleration control or deceleration control of the host vehicle. Even after the probability of collision has fallen below the first threshold value, the controller continues the acceleration control or the deceleration control, which was executed in a state where, while the first other vehicle is traveling in the second lane, the probability of collision is equal to or greater than a first threshold value (S5).

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 method for controlling an autonomous vehicle traveling adjacent to a merging lane in a cooperative manner with a merging vehicle.

[0003] U.S. Patent No. 8,788,134

[0004] When a merging vehicle is entering the lane in which the host vehicle is traveling, the intentions of the host vehicle and the merging vehicle to accelerate or decelerate may mutually influence each other, resulting in frequent repeated acceleration and deceleration, which may cause the vehicle behavior to become unstable.The present invention aims to suppress the unstable vehicle behavior when a merging vehicle is entering the lane in which the host vehicle is traveling.

[0005] In one aspect of the present invention, a vehicle control method includes a controller that executes the following processes: detecting a first other vehicle traveling in a second lane adjacent to a first lane in which the host vehicle is traveling; predicting a merging point where the first other vehicle will enter the first lane; estimating a collision possibility between the first other vehicle and the host vehicle when the first other vehicle reaches the merging point; and executing one of acceleration control and deceleration control of the host vehicle based on the collision possibility. The controller continues the acceleration control or the deceleration control that was executed while the collision possibility was equal to or greater than a first threshold while the first other vehicle was traveling in the second lane, even after the collision possibility becomes less than the first threshold.

[0006] According to the present invention, it is possible to suppress disturbances in vehicle behavior when there is a merging vehicle attempting to enter the lane in which the host vehicle is traveling.

[0007] 1 is a schematic configuration diagram of an example of a vehicle control device according to an embodiment; (a) and (b) are schematic explanatory diagrams of an example of a vehicle control method according to a first embodiment; (a) and (b) are schematic diagrams of combinations of acceleration of a host vehicle and a merging vehicle that make the possibility of collision less than a predetermined threshold; (a) and (b) are schematic diagrams of an example of deceleration control for a preceding vehicle; (b) is a flowchart of an example of a vehicle control device according to a first embodiment; (a) and (b) are explanatory diagrams of an example of a method for predicting a merging point; (b) is an explanatory diagram of a method for setting a target duration; (c) is a flowchart of an example of a method for determining a target scenario; (c) is a flowchart of a first example of acceleration maintenance control; (d) is a flowchart of a second example of acceleration maintenance control; (e) is a flowchart of an example of a method for setting a target duration; (f) is a flowchart of an example of an operation of a notification generation unit.

[0008] (First embodiment) (Configuration) Fig. 1 is a schematic configuration diagram of an example of a vehicle control device according to an embodiment. A host vehicle Ce is equipped with a vehicle control device 10 that controls the traveling of the host vehicle Ce. The traveling 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 traveling 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 and braking of the host vehicle Ce. The driving assistance control may be, for example, automatic braking, preceding vehicle following control, constant speed traveling 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 communication device 15, a human-machine interface (HMI) 16, 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. 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 sensors 12 include, 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, an acceleration sensor that detects the acceleration and deceleration of the host vehicle Ce, a steering angle sensor that detects the steering angle of the steering wheel, a steering angle sensor that detects the steering 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, and a brake sensor that detects the amount of brake operation.

[0010] 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").

[0011] The communication device 15 provides a communication function between the vehicle control device 10 and an external device. The communication method used by the communication device 15 may be, for example, wireless communication via a public mobile communication network, satellite communication, etc. The HMI 16 is an interface device that exchanges information between the vehicle control device 10 and a user (e.g., a passenger such as a driver) of the vehicle Ce. For example, the HMI 16 may be provided with a display device that can be seen by the user.

[0012] 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 a register, a cache memory, and a ROM and a RAM used as a main storage device. 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 also be formed by dedicated hardware for executing each of the information processes described below.

[0014] Next, an example of a vehicle control method by the controller 18 will be described. FIG. 2A is a schematic explanatory diagram of an example of the vehicle control method of the first embodiment. The first lane Ln1 is a lane on the main road, and the second lane Ln2 is a merging lane that merges into the first lane Ln1 of the main road at a merging section Sm. The merging section Sm starts merging at a start position Ps and ends merging at an end position Pe. Assume a scenario in which the host vehicle Ce is traveling on the first lane Ln1 adjacent to the second lane Ln2, and a merging vehicle Cm on the second lane Ln2 attempts to enter (merge) from the second lane Ln2 into the first lane Ln1, as indicated by the dashed line 20. The merging vehicle Cm is an example of a "first other vehicle" as defined in the claims. The present invention is applicable not only to the merging section Sm but also to a wide range of situations in which a vehicle traveling in the second lane Ln2 is unable to continue traveling in the second lane Ln2 and enters the first lane Ln1. For example, as shown in Figure 2(b), the present invention is applicable to a case in which a merging vehicle Cm on the main lane, the second lane Ln2, is unable to continue traveling in the second lane Ln2 due to an obstacle 21 (e.g., road construction) in front of the vehicle, and therefore enters the first lane Ln1 as shown by the dashed line 20.

[0015] In such a scenario, the intentions of the host vehicle Ce traveling in the first lane Ln1 and the merging vehicle Cm attempting to enter the first lane Ln1 to accelerate or decelerate may mutually influence each other, causing the host vehicle Ce to frequently accelerate and decelerate, resulting in unstable vehicle behavior. For example, at the same time that the host vehicle Ce begins to decelerate to make it easier for the merging vehicle Cm to enter ahead of the host vehicle Ce, the merging vehicle Cm may decelerate in an attempt to enter behind the host vehicle Ce. In this case, the host vehicle Ce may stop deceleration and start accelerating to avoid interference with the merging vehicle Cm that has begun decelerating. Meanwhile, the merging vehicle Cm may also stop deceleration and start accelerating to avoid interference with the host vehicle Ce. In turn, both the host vehicle Ce and the merging vehicle Cm may stop acceleration and start deceleration to avoid interference with each other. Continuing this interaction may cause the host vehicle Ce to frequently accelerate and decelerate, resulting in unstable vehicle behavior.

[0016] Therefore, the controller 18 of the embodiment predicts a merging point Pm, which is the point where the merging vehicle Cm enters the first lane Ln1, and estimates a collision probability Pc between the merging vehicle Cm and the host vehicle Ce when the merging vehicle Cm reaches the merging point Pm. The controller 18 then predicts whether the collision probability Pc is equal to or greater than a predetermined threshold Th1. For example, the controller 18 may predict at least one of the time headway (THW) or time to collision (TTC) between the merging vehicle Cm and the host vehicle Ce as the collision probability Pc. The collision probability Pc being less than the first threshold means that the merging vehicle Cm can enter the first lane Ln1 at the merging point Pm after achieving the minimum allowable time headway THW or time to collision TTC between the merging vehicle Cm and the host vehicle Ce. The predetermined threshold Th1 is an example of a "first threshold" as defined in the claims.

[0017] 3A and 3B are schematic diagrams illustrating combinations of accelerations of the host vehicle Ce and the merging vehicle Cm that result in a collision probability Pc equal to or greater than a predetermined threshold Th1 when the merging vehicle Cm entering ahead of the host vehicle Ce reaches the merging point Pm. In this specification, the term "acceleration" is used to include not only positive values ​​but also negative values ​​(i.e., deceleration). The range R1 indicated by diagonal hatching indicates the range in which the collision probability Pc is equal to or greater than the predetermined threshold Th1. On the other hand, the range R2 indicated by sand-grain hatching indicates the range in which the collision probability Pc is less than the predetermined threshold Th1. In other words, this shows the range in which the merging vehicle Cm can enter the first lane Ln1 while achieving the minimum allowable time headway THW and time to collision TTC between the host vehicle Ce and the merging vehicle Cm. The value Ammax indicates the maximum acceleration capability of the merging vehicle Cm, and the value (-Aemin) indicates the maximum deceleration capability of the host vehicle Ce.

[0018] For example, the controller 18 may determine whether the merging vehicle Cm can set its acceleration so that the collision probability Pc is less than the predetermined threshold value Th1 when the host vehicle Ce sets its acceleration according to a speed plan that is set regardless of the merging vehicle Cm, or when the current acceleration and vehicle speed are maintained. In the case of FIG. 3A , regardless of whether the host vehicle Ce's negative acceleration (i.e., deceleration) is between the maximum deceleration (−Aemin) and zero, the merging vehicle Cm can make the collision probability Pc at the merging point Pm less than the predetermined threshold value Th1 by accelerating at or below the maximum acceleration capability Ammax. The controller 18 may estimate the maximum acceleration capability and maximum deceleration capability of the merging vehicle Cm based on the merging vehicle Cm detected by the external sensor 11. For example, the controller 18 may estimate the model (e.g., passenger car, truck, etc.) and type of the merging vehicle Cm based on the results of photographing the merging vehicle Cm by the camera of the external sensor 11, and then estimate the model maximum acceleration capability and maximum deceleration capability of the merging vehicle Cm based on the estimated model and type. For example, the controller 18 may acquire information about the maximum acceleration and deceleration capabilities of the merging vehicle Cm through vehicle-to-vehicle communication with the merging vehicle Cm. On the other hand, in the case of FIG. 3B , if the acceleration of the host vehicle Ce is greater than the negative value (−Ae1), the collision probability Pc at the merging point Pm cannot be reduced to less than the predetermined threshold Th1 even if the merging vehicle Cm accelerates at its maximum acceleration capability Ammax. In other words, the collision probability Pc at the merging point Pm cannot be reduced to less than the predetermined threshold Th1 solely through the capability of the merging vehicle Cm. In such a situation, if the host vehicle Ce accelerates or decelerates to cooperate with the merging vehicle Cm, as described above, the intentions of the host vehicle Ce and the merging vehicle Cm to accelerate and decelerate may influence each other, causing frequent repeated acceleration and deceleration by the host vehicle Ce and the merging vehicle Cm, which may disrupt the vehicle behavior.

[0019] Therefore, when the controller 18 determines that the collision possibility Pc at the merging point Pm is equal to or greater than the predetermined threshold Th1, the controller 18 continues one of the acceleration control and the deceleration control that was being performed when the collision possibility Pc was equal to or greater than the predetermined threshold Th1, even after the collision possibility Pc subsequently falls below the predetermined threshold Th1. In the following description, the acceleration control or the deceleration control that is continued when the collision possibility Pc is determined to be equal to or greater than the predetermined threshold Th1 may be referred to as "acceleration maintenance control." This makes the merging vehicle less susceptible to the influence of the host vehicle, thereby suppressing mutual influence between the host vehicle's and the merging vehicle's intentions to accelerate or decelerate. As a result, it is possible to suppress frequent repeated acceleration and deceleration of the host vehicle, which would cause erratic vehicle behavior.

[0020] 4 . The duration Td for continuing the acceleration maintenance control when it is determined that the collision possibility Pc is equal to or greater than the predetermined threshold Th1 may be longer than, for example, the operation time of deceleration control for maintaining a distance Dist between the host vehicle Ce and a preceding vehicle Cf traveling in front of the host vehicle Ce on the first lane Ln1. The duration Td may be longer than, for example, the operation time of a forward emergency brake to prevent a collision with the preceding vehicle Cf or the operation time of continuous deceleration control in adaptive cruise control for maintaining a vehicle-to-vehicle distance from the preceding vehicle Cf. Furthermore, for example, the controller 18 may continue the acceleration maintenance control until the merging vehicle Cm has traveled a predetermined distance or a predetermined time on the first lane Ln1 since entering the first lane Ln1.

[0021] 3A and 3B show an example of the collision possibility Pc when a merging vehicle Cm entering ahead of the host vehicle Ce reaches the merging point Pm, but the present invention is also applicable to a case where the merging vehicle Cm enters behind the host vehicle Ce. In this case, when determining whether the collision possibility Pc at the merging point Pm is equal to or greater than the predetermined threshold value Th1, it may be determined whether the collision possibility Pc at the merging point Pm can be made less than the predetermined threshold value Th1 even if the merging vehicle Cm decelerates at its maximum deceleration capacity.

[0022] FIG. 5 is a flowchart of an example of the vehicle control device of the first embodiment. In step S1, the controller 18 determines whether or not a merging vehicle Cm traveling in the second lane Ln2 adjacent to the first lane Ln1 is present. If a merging vehicle Cm is not present (step S1: N), the process ends. If a merging vehicle Cm is present (step S1: Y), the process proceeds to step S2. In step S2, the controller 18 predicts a merging point Pm. In step S3, the controller 18 estimates a collision probability Pc. In step S4, the controller 18 determines whether or not the collision probability Pc is equal to or greater than a predetermined threshold value Th1. If the collision probability Pc is not equal to or greater than the predetermined threshold value Th1 (step S4: N), the process ends. If the collision probability Pc is equal to or greater than the predetermined threshold value Th1 (step S4: Y), the process proceeds to step S5. In step S5, the controller 18 continues the acceleration maintenance control until a predetermined termination condition is satisfied. Thereafter, the process ends.

[0023] Second Embodiment Fig. 6 is a block diagram showing an example of the functional configuration of the controller 18. 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, an acceleration / deceleration 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.

[0024] 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 the road on which the host vehicle Ce is traveling, as well as map information about merging lanes Lm and merging sections Sm that merge onto the road on which the host vehicle Ce is traveling.

[0025] For example, the map acquisition unit 32 may acquire information regarding the start position Ps and end position Pe of the merging section Sm as map information regarding the merging section Sm. The map acquisition unit 32 may acquire map information from an external map data server. The detection integration unit 33 integrates multiple detection results obtained by the object detection unit 30 from 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 of multiple types of sensors to obtain more accurate detection results.

[0026] 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.

[0027] The acceleration / deceleration control unit 36 ​​controls the acceleration or deceleration of the host vehicle Ce. The acceleration / deceleration control unit 36 ​​includes a scenario detection unit 40, a cooperation level evaluation unit 41, a driving behavior determination unit 42, a continuation control unit 43, and a notification generation unit 44. The scenario detection unit 40 detects a target scenario for which continuation of acceleration maintenance control is to be executed. That is, the scenario detection unit 40 determines whether the driving scene of the host vehicle Ce is the target scenario. In determining the target scenario, the scenario detection unit 40 first determines whether another vehicle traveling in the second lane Ln2 adjacent to the first lane Ln1 can continue traveling in the second lane Ln2. For example, the scenario detection unit 40 determines whether the second lane Ln2 is a merging lane ( FIG. 2( a) ) and whether an obstacle 21 exists ahead on the second lane Ln2 ( FIG. 2( b) ).

[0028] The scenario detection unit 40 also determines whether a merging vehicle Cm traveling in the second lane Ln2 is detected. Furthermore, the scenario detection unit 40 predicts the merging point Pm. See FIG. 7( a). The scenario detection unit 40 may predict the merging point Pm based on the remaining length Lr of the second lane Ln2 through which the merging vehicle Cm can travel. For example, the scenario detection unit 40 may calculate a travel distance L1 for a predetermined time T1 (e.g., 3 seconds) based on the speed limit VL of the first lane Ln1 on the main road, and estimate the merging point Pm as a point that is the distance L1 before the end position Pe of the second lane Ln2 (i.e., the point at which the merging vehicle Cm reaches the end position Pe within the predetermined time T1). Alternatively, for example, the scenario detection unit 40 may estimate the merging point Pm at which the merging vehicle Cm enters the first lane Ln1 early to avoid the merging vehicle Cm hastily merging near the merging point Pm. See FIG. 7( b). 7A, the scenario detection unit 40 may estimate a point a distance L2 before the end position Pe that is longer than the distance L1 as the merging point Pm. For example, the predetermined time T1 may be a parameter that can be arbitrarily set by the user of the host vehicle Ce, and the controller 18 may receive a setting input of the predetermined time T1 from the user via the HMI 16.

[0029] The scenario detection unit 40 may determine that a target scenario has been detected if all of the following target scenario detection conditions (A1) to (A3) are satisfied. It may also determine that a target scenario has not been detected if any of the conditions (A1) to (A3) are not satisfied. (A1) Another vehicle traveling in the second lane Ln2 adjacent to the first lane Ln1 is unable to continue traveling in the second lane Ln2. For example, the second lane Ln2 is a merging lane ( FIG. 2(a) ). Also, for example, an obstacle 21 exists ahead on the second lane Ln2 ( FIG. 2(b) ). The following description will discuss an example in which the second lane Ln2 is a merging lane. (A2) A merging vehicle Cm traveling in the second lane Ln2 is detected. (A3) Acceleration or deceleration of the merging vehicle Cm alone is not enough to reduce the collision probability Pc at the merging point Pm below the predetermined threshold Th1.

[0030] The cooperation level evaluation unit 41 determines whether the above condition (A3) is satisfied. Based on the positions of the host vehicle Ce, the merging vehicle Cm, and the merging point Pm and the vehicle speeds of the host vehicle Ce and the merging vehicle Cm, the cooperation level evaluation unit 41 calculates a combination of accelerations of the host vehicle Ce and the merging vehicle Cm that will make the collision probability Pc equal to or greater than a predetermined threshold value Th1 when the merging vehicle Cm reaches the merging point Pm, as shown in the examples of FIGS. 3( a) and 3(b). Based on the calculated combination of accelerations, the cooperation level evaluation unit 41 estimates, as a required control amount Ra, the acceleration required of the merging vehicle Cm to make the collision probability Pc less than the predetermined threshold value Th1.

[0031] For example, when the host vehicle Ce sets its acceleration according to a speed plan that is set regardless of the merging vehicle Cm, the cooperation level evaluation unit 41 may estimate, as the required control amount Ra, the acceleration of the merging vehicle Cm that is necessary for the collision possibility Pc to be less than the predetermined threshold value Th1. For example, when the host vehicle Ce maintains its current acceleration or vehicle speed, the cooperation level evaluation unit 41 may estimate, as the required control amount Ra, the acceleration of the merging vehicle Cm that is necessary for the collision possibility Pc to be less than the predetermined threshold value Th1. When the required control amount Ra exceeds the maximum acceleration capability or maximum deceleration capability of the merging vehicle Cm, the cooperation level evaluation unit 41 determines that the collision possibility Pc cannot be reduced to less than the predetermined threshold value Th1 simply by accelerating or decelerating the merging vehicle Cm. In other words, the cooperation level evaluation unit 41 determines that the merging vehicle Cm cannot resolve interference with the host vehicle Ce and enter (merge) into the first lane Ln1 simply by accelerating or decelerating the merging vehicle Cm.

[0032] Furthermore, the cooperation level evaluation unit 41 evaluates a requested cooperation level Cr, which is an index of the strength (magnitude) of cooperation required between the merging vehicle Cm and the host vehicle Ce so that the collision probability Pc becomes less than the predetermined threshold Th1 when the merging vehicle Cm reaches the merging point Pm. For example, when the collision probability Pc does not become less than the predetermined threshold Th1 even when the merging vehicle Cm accelerates at its maximum acceleration capacity or decelerates at its maximum deceleration capacity, the cooperation level evaluation unit 41 may calculate, as the requested cooperation level Cr, the acceleration of the host vehicle Ce required to make the collision probability Pc less than the predetermined threshold Th1. For example, the cooperation level evaluation unit 41 may calculate the requested cooperation level Cr based on the requested control amount Ra. For example, when the merging vehicle Cm enters ahead of the host vehicle Ce, the absolute value (i.e., the magnitude of the deceleration) of the deceleration obtained by subtracting the requested control amount Ra, calculated as a positive acceleration value, from the maximum acceleration capacity of the merging vehicle Cm may be calculated as the requested cooperation level Cr of the host vehicle Ce. When a merging vehicle Cm enters behind the host vehicle Ce, the absolute value (i.e., magnitude of acceleration) of the acceleration (maximum deceleration capacity - required control amount Ra) obtained by subtracting the required control amount Ra calculated as a negative acceleration (deceleration) from the maximum deceleration capacity of the merging vehicle Cm may be calculated as the required cooperation level Cr of the host vehicle Ce.

[0033] The driving behavior determination unit 42 generates driving behaviors (e.g., a target driving trajectory and a speed plan for the host vehicle Ce) for driving the host vehicle 1 based on the objects around the host vehicle Ce detected by the object detection unit 30 and the object tracking unit 34 and the position of the host vehicle Ce on the map calculated by the intra-map position calculation unit 35. The driving behavior determination unit 42 sets a target acceleration based on the speed plan.

[0034] When the scenario detection unit 40 detects a target scenario, the continuation control unit 43 starts maintaining acceleration control using the target acceleration set by the driving behavior determination unit 42. That is, it starts continuing the above-mentioned "acceleration maintenance control." The continuation control unit 43 sets a target duration Tdt, which is a target value for the time period for which acceleration maintenance control is to be continued. For example, the scenario detection unit 40 sets the target duration Tdt according to the requested cooperation level Cr evaluated by the cooperation level evaluation unit 41. For example, when the requested cooperation level Cr is high, the scenario detection unit 40 sets a longer target duration Tdt than when the requested cooperation level Cr is low. For example, the higher the requested cooperation level Cr, the longer the target duration Tdt may be set.

[0035] FIG. 8 is an explanatory diagram of a method for setting the target duration Tdt. The continuation control unit 43 sets a maximum value Tdmax and a minimum value Tdmin of the target duration Tdt. For example, the maximum value Tdmax may be set to a predetermined value (e.g., 10 seconds). For example, the maximum value Tdmax may be set so that the vehicle speed does not deviate from a predetermined allowable vehicle speed range even when the acceleration maintenance control continues for a time period reaching the maximum value Tdmax. For example, the maximum value Tdmax may be set so that the acceleration time of the host vehicle Ce at a positive target acceleration does not exceed the speed limit even when the acceleration time reaches the maximum value Tdmax. For example, the minimum value Tdmin may be set so that the vehicle speed does not fall below a predetermined minimum allowable speed even when the deceleration time of the host vehicle Ce at a negative target acceleration reaches the maximum value Tdmax. For example, the minimum value Tdmin may be set to a length (e.g., 1.2 seconds) long enough for the merging vehicle Cm to confirm the host vehicle Ce's intention to accelerate (when the target acceleration is a positive value) or decelerate (when the target acceleration is a negative value).

[0036] When the requested cooperation level Cr is equal to or less than the minimum value Crmin, the continuation control unit 43 sets the target duration Tdt to the minimum value Tdmin. Furthermore, when the requested cooperation level Cr is equal to or greater than the maximum value Cmax, the continuation control unit 43 sets the target duration Tdt to the maximum value Tdmax. When the requested cooperation level Cr is in the range from the minimum value Crmin to the maximum value Cmax, the target duration Tdt is set to increase from the minimum value Tdmin to the maximum value Tdmax. For example, the target duration Tdt may be set to increase monotonically as the requested cooperation level Cr increases. For example, as shown in FIG. 8 , the target duration Tdt may be set to increase in proportion to the requested cooperation level Cr, or may be set to increase nonlinearly. The minimum value Crmin and the maximum value Cmax of the requested cooperation level Cr may be set to any appropriate value. For example, if the requested cooperation level Cr represents the magnitude of deceleration required of the host vehicle Ce, the deceleration when the accelerator pedal is released may be set as the minimum value Crmin. Also, the deceleration during relatively strong braking in normal driving (for example, 0.3 G) may be set as the maximum value Crmax.

[0037] The continuation control unit 43 determines whether the duration Td of the acceleration maintenance control (i.e., the elapsed time since the start of the acceleration maintenance control) has reached the target duration Tdt. If the duration Td has not reached the target duration Tdt, the acceleration maintenance control is continued. If the duration Td has reached the target duration Tdt, the acceleration maintenance control is terminated.

[0038] The notification generation unit 44 generates a notification regarding the acceleration maintenance control and outputs it to the user of the host vehicle Ce from the HMI 16. For example, the notification generation unit 44 may determine whether an event such as the start or end of the acceleration maintenance control has been detected. When an event such as the start or end of the acceleration maintenance control is detected, the notification generation unit 44 may generate a notification notifying the event and output it from the HMI 16 to the user of the host vehicle Ce. Furthermore, for example, the notification generation unit 44 may generate a notification of information on the progress status of the acceleration maintenance control (hereinafter referred to as "progress information") and output it from the HMI 16 to the user of the host vehicle Ce. The progress information may include, for example, information on a predicted time until the acceleration maintenance control ends and information on a change in the requested cooperation level Cr over time. Even after the continuation control unit 43 sets the target duration time Tdt, the cooperation level evaluation unit 41 may continuously repeat evaluation of the requested cooperation level Cr until the merging vehicle Cm has completed entering (merging into) the first lane Ln. The controller 18 may be configured so that the user of the vehicle Ce can set whether to enable or disable notification of progress information (i.e., whether to allow or prohibit output of progress information from the HMI 16).

[0039] The vehicle control unit 37 drives the actuator 17 so that the host vehicle Ce accelerates or decelerates in accordance with the acceleration set by the driving behavior determination unit 42. While the continuation control unit 43 continues the acceleration maintenance control, the vehicle control unit 37 drives the actuator 17 so that the host vehicle Ce accelerates or decelerates in accordance with the acceleration maintained by the continuation control unit 43.

[0040] 9 is a flowchart of an example of a method for determining a target scenario by the scenario detection unit 40 and the cooperation level evaluation unit 41. In step S10, the scenario detection unit 40 determines whether the host vehicle Ce is traveling in a lane adjacent to the merging lane. If the host vehicle Ce is not traveling in a lane adjacent to the merging lane (step S10: N), the process proceeds to step S17. If the host vehicle Ce is traveling in a lane adjacent to the merging lane (step S10: Y), the process proceeds to step S11. In step S11, the scenario detection unit 40 determines whether a merging vehicle Cm has been detected. If a merging vehicle Cm has not been detected (step S11: N), the process proceeds to step S16. If a merging vehicle Cm has been detected (step S11: Y), the process proceeds to step S12. In step S12, the scenario detection unit 40 predicts the merging point Pm.

[0041] In step S13, the cooperation level evaluation unit 41 estimates the required control amount Ra. In step S14, the cooperation level evaluation unit 41 determines, based on the required control amount Ra, whether or not interference with the host vehicle Ce can be resolved by simply accelerating or decelerating the merging vehicle Cm. If interference with the host vehicle Ce can be resolved (step S14: Y), the process proceeds to step S17. If interference with the host vehicle Ce cannot be resolved (step S14: N), the process proceeds to step S15. In step S15, the scenario detection unit 40 determines that a target scenario has been detected. The process then ends. In step S16, the scenario detection unit 40 determines whether or not the host vehicle Ce has passed through the merging section Sm. If the host vehicle Ce has not passed through the merging section Sm (step S16: N), the process returns to step S11. If the host vehicle Ce has passed through the merging section Sm (step S16: Y), the process proceeds to step S17. In step S17, the scenario detection unit 40 determines that the target scenario has not been detected, and then the process ends.

[0042] FIG. 10 is a flowchart of a first example of acceleration maintenance control by the continuation control unit 43. In step S20, the driving behavior determination unit 42 sets a target acceleration. In step S21, the continuation control unit 43 sets a target duration Tdt. In step S22, the continuation control unit 43 outputs an acceleration instruction signal indicating the target acceleration determined by the driving behavior determination unit 42 to the vehicle control unit 37. In step S23, the controller 18 determines whether an emergency has occurred in the driving environment around the host vehicle Ce. For example, it determines whether there is a risk of excessive approach to a merging vehicle Cm, another vehicle, an obstacle, or the like. If an emergency has not occurred (step S23: N), the process proceeds to step S24. If an emergency has occurred (step S23: Y), the process proceeds to step S27. In step S27, the controller 18 executes a predetermined emergency control (e.g., emergency stop control or emergency avoidance control). The process then ends.

[0043] On the other hand, in step S24, the continuation control unit 43 determines whether the target duration Tdt has elapsed. If the target duration Tdt has not elapsed (step S24: N), the process returns to step S22. If the target duration Tdt has elapsed (step S24: Y), the process proceeds to step S25. In step S25, the continuation control unit 43 determines whether the merging vehicle Cm has completed entering (merging) into the first lane Ln1. If the merging vehicle Cm has not completed entering (merging) into the first lane Ln1 (step S25: N), the process returns to step S20. If the merging vehicle Cm has completed entering (merging) into the first lane Ln1 (step S25: Y), the process proceeds to step S26. In step S26, the controller 18 resumes normal acceleration / deceleration control, and then the process ends.

[0044] FIG. 11 is a flowchart of a second example of acceleration maintenance control by the continuation control unit 43. The processes of steps S30 and S31 are similar to the processes of steps S20 and S21 in FIG. 10. In step S32, a requested coordination level threshold Th2 is set. The requested coordination level threshold Th2 is a threshold for determining whether to continue acceleration maintenance control based on the requested coordination level Cr. For example, the requested coordination level threshold Th2 may be set to an appropriate predetermined value. The requested coordination level threshold Th2 is an example of the "second threshold" described in the claims. The processes of steps S33 to S35 are similar to the processes of steps S22 to S24 in FIG. 10. In step S36, the continuation control unit 43 determines whether the requested coordination level Cr is less than the requested coordination level threshold Th2. If the requested coordination level Cr is not less than the requested coordination level threshold Th2 (step S36: N), the process returns to step S33. If the requested cooperation level Cr is less than the requested cooperation level threshold Th2 (step S36: Y), the process proceeds to step S37. The processes of steps S37 to S39 are the same as the processes of steps S25 to S27 in FIG.

[0045] FIG. 12 is a flowchart illustrating an example of a method for setting the target duration Tdt by the continuation control unit 43. In step S40, the continuation control unit 43 sets a minimum value Tdmin of the target duration Tdt. In step S41, the continuation control unit 43 sets a maximum value Tdmax of the target duration Tdt. In step S42, the continuation control unit 43 sets the target duration Tdt according to the required cooperation level Cr. FIG. 13 is a flowchart illustrating an example of the operation of the notification generation unit 44. In step S50, the notification generation unit 44 determines whether an event, such as the start or end of acceleration maintenance control, has been detected. If an event has not been detected (step S50: N), the process proceeds to step S52. If an event has been detected (step S50: Y), the process proceeds to step S51. In step S51, the notification generation unit 44 notifies the user of the event. The process then ends. In step S52, the notification generation unit 44 determines whether notification of progress information is enabled. If the notification of the progress information is not valid (step S52: N), the process ends. If the notification of the progress information is valid (step S52: Y), the process proceeds to step S53. In step S53, the notification generation unit 44 notifies the user of the progress information. Then, the process ends.

[0046] Effects of the embodiment (1) The controller executes the following processes: detects a first other vehicle traveling in a second lane adjacent to a first lane in which the host vehicle is traveling; predicts a merging point where the first other vehicle will enter the first lane; estimates a collision possibility between the first other vehicle and the host vehicle when the first other vehicle reaches the merging point; and performs one of acceleration control and deceleration control of the host vehicle based on the collision possibility; and continues the acceleration control or deceleration control that was executed when the collision possibility was equal to or greater than a first threshold while the first other vehicle was traveling in the second lane, even after the collision possibility becomes less than the first threshold. This reduces the influence of the first other vehicle on the host vehicle, thereby suppressing mutual influence between the host vehicle and the first other vehicle's intentions to accelerate or decelerate. As a result, it is possible to suppress erratic vehicle behavior caused by frequent acceleration and deceleration of the host vehicle.

[0047] (2) The duration of the acceleration control or the deceleration control after the collision possibility becomes less than the first threshold may be longer than the duration of the deceleration control for maintaining a distance between the host vehicle and the second other vehicle traveling in the first lane ahead of the host vehicle. This makes it easier for the first other vehicle to understand the host vehicle's intention to maintain the acceleration control or the deceleration control. (3) The controller may continue the acceleration control or the deceleration control until the first other vehicle has traveled a predetermined distance or a predetermined time in the first lane. This makes it possible to end the continuation of the acceleration control or the deceleration control when the first other vehicle is less susceptible to the behavior of the host vehicle.

[0048] (4) The controller may set a duration of control for continuing either the acceleration control or the deceleration control in accordance with a required acceleration or deceleration of the first other vehicle that is required for the likelihood of collision at the time the first other vehicle reaches the merging point to be less than a first threshold. This allows the duration of control to be appropriately set in accordance with the driving situation.

[0049] (5) The controller may terminate the continuation of one of the acceleration control and the deceleration control when a predetermined time has elapsed since the start of the continuation of one of the acceleration control and the deceleration control, and an index value corresponding to the acceleration or deceleration of the host vehicle required for the collision probability at the time the first other vehicle reaches the merging point to be less than a first threshold is less than a second threshold. This allows the continuation of one of the acceleration control and the deceleration control to be terminated at an appropriate time. (6) The controller may estimate the required acceleration or deceleration based on the remaining length of the second lane in which the first other vehicle can travel and the acceleration or deceleration capability of the first other vehicle. The controller may adjust the distance from the end of the section in which the vehicle can travel on the second lane to the predicted merging point in accordance with parameters set by an occupant of the host vehicle, and estimate the required acceleration or deceleration based on the predicted merging point and the acceleration or deceleration capability of the first other vehicle. This allows the required acceleration or deceleration to be appropriately estimated based on the time until the first other vehicle reaches the merging point and the acceleration or deceleration capability of the first other vehicle.

[0050] (7) The controller may notify the occupant of at least one of the start and end of acceleration control or deceleration control. The controller may execute processing to notify the occupant of at least one of a predicted time until the end of acceleration control or deceleration control, or a change in an index value corresponding to the acceleration or deceleration of the host vehicle required for the collision probability at the time the first other vehicle reaches the merging point to be less than a first threshold. This can improve the occupant's confidence in the behavior of the host vehicle.

[0051] Ce...own vehicle, Cm...merging vehicle, 10...vehicle control device, 11...external sensor, 12...vehicle sensor, 13...positioning device, 14...map database, 15...communication device, 16...human-machine interface, 17...actuator, 18...controller, 18a...processor, 18b...storage device

Claims

1. A process of detecting a first other vehicle traveling ahead in a second lane adjacent to a first lane in which the host vehicle is traveling; A process of predicting a merging point where the first other vehicle will enter the first lane; a process of estimating a possibility of a collision between the first other vehicle and the host vehicle at a time when the first other vehicle reaches the merging point; a process of executing one of acceleration control and deceleration control of the host vehicle based on the collision possibility; A vehicle control method for causing a controller to execute The vehicle control method is characterized in that the controller continues one of the acceleration control or the deceleration control that was being executed when the possibility of collision was equal to or greater than a first threshold while the first other vehicle was traveling in the second lane, even after the possibility of collision becomes less than the first threshold, until the first other vehicle completes merging.

2. The vehicle control method described in claim 1, characterized in that the control duration for continuing one of the acceleration control or the deceleration control after the collision possibility becomes less than the first threshold is longer than the operation time of the deceleration control for maintaining a distance between the host vehicle and a second other vehicle traveling on the first lane in front of the host vehicle.

3. 3. The vehicle control method according to claim 1, wherein the controller continues the one control until the first other vehicle has traveled a predetermined distance or a predetermined time in the first lane.

4. The vehicle control method described in claim 1, characterized in that the controller sets the length of control duration for continuing one of the acceleration control or the deceleration control in accordance with a required acceleration or deceleration, which is the acceleration or deceleration of the first other vehicle required for the collision possibility at the time the first other vehicle reaches the merging point to be less than the first threshold value.

5. The vehicle control method according to claim 1, characterized in that the controller completes the continuation of one of the acceleration control and the deceleration control when a predetermined length of time has elapsed since the continuation of one of the acceleration control and the deceleration control began, and an index value corresponding to the acceleration or deceleration of the host vehicle required for the collision probability at the time the first other vehicle reaches the merging point to be less than the first threshold is less than a second threshold.

6. 5. The vehicle control method according to claim 4, wherein the controller estimates the required acceleration / deceleration based on the remaining length of the second lane in which the first other vehicle can travel and the acceleration or deceleration capability of the first other vehicle.

7. The controller adjusting a distance from an end of a section in which the vehicle can travel on the second lane to a predicted point of the merging point in accordance with a parameter set by an occupant of the vehicle; estimating the required acceleration / deceleration based on the predicted merging point and the acceleration or deceleration capability of the first other vehicle; 5. The vehicle control method according to claim 4.

8. 3. The vehicle control method according to claim 1, wherein the controller executes a process of notifying an occupant of at least one of the start and end of continuation of one of the acceleration control and the deceleration control.

9. The vehicle control method according to any one of claims 4 to 7, characterized in that the controller executes a process of notifying an occupant of at least one of a predicted time until one of the acceleration control or the deceleration control ends, or a change in an index value corresponding to the acceleration or deceleration of the host vehicle required for the collision probability at the time the first other vehicle reaches the merging point to be less than the first threshold value.

10. A process of detecting a first other vehicle traveling ahead in a second lane adjacent to a first lane in which the host vehicle is traveling; A process of predicting a merging point where the first other vehicle will enter the first lane; a process of estimating a possibility of a collision between the first other vehicle and the host vehicle at a time when the first other vehicle reaches the merging point; a process of executing one of acceleration control and deceleration control of the host vehicle based on the collision possibility; A vehicle control device comprising a controller that executes The vehicle control device is characterized in that the controller continues to perform one of the acceleration control or the deceleration control, which was performed when the possibility of collision was greater than or equal to a first threshold while the first other vehicle was traveling in the second lane, even after the possibility of collision becomes less than the first threshold, until the first other vehicle completes merging.