Steering control method and steering control device

Abstract

To reduce interference by driving support control with steering force by an occupant in the driving support control for controlling a turning angle of an own vehicle so that the own vehicle travels toward a front gaze point.SOLUTION: A steering control method includes: determining whether there is the intention of making a lane change of an own vehicle 1 from an own lane Le to an adjacent lane Ln; when there is no intention of making the lane change, setting a prescribed lane width direction position on the own lane at a front gaze distance Xtrg_FIN in front as a first lane width direction position Ytrg; when there is the intention of making the lane change, setting the prescribed lane width direction position on the adjacent lane as the first lane width direction position Ytrg; calculating an offset distance Y0 between a present second lane width direction position Y of the own vehicle and the first lane width direction position Ytrg; calculating a front gaze point Ytrg_FIN obtained by moving the first lane width direction position to the own vehicle side by a correction distance equal to or less than the offset distance in a lane width direction; and controlling a turning angle of a steered wheel so that the own vehicle travels to the front gaze point.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a steering control method and a steering control device. [Background technology]

[0002] Patent document 1 describes a steering control device that controls the steering device of a vehicle so that the vehicle moves toward a predetermined position in the lane width direction ahead of the vehicle, a predetermined forward gaze distance, as the forward gaze point. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-312505 Summary of the Invention [Problem to be solved by the invention]

[0004] In the steering device of Patent Document 1, when a driver performs a steering operation, the steering force applied by the driver may be interfered with by the steering force applied by the steering control device, which may cause the driver to feel uncomfortable. The present invention aims to reduce interference of driving assist control with the steering force applied by a driver in driving assist control that controls the steering angle of the vehicle so that the vehicle heads toward a forward gaze point. [Means for solving the problem]

[0005] In one embodiment of the steering control method of the present invention, a forward gaze distance is set, and it is determined whether the driver of the vehicle intends to change lanes from the vehicle's own lane, which is the lane in which the vehicle is traveling, to an adjacent lane. If there is no intention to change lanes, a predetermined lane width direction position on the vehicle's own lane, which is the forward gaze distance, is set as the first lane width direction position. If there is an intention to change lanes, a predetermined lane width direction position on the adjacent lane, which is the forward gaze distance, is set as the first lane width direction position. A second lane width direction position, which is the current lane width direction position of the vehicle, is detected, an offset distance, which is the difference between the second lane width direction position and the first lane width direction position, is calculated, and a forward gaze point, which is moved in the lane width direction from the first lane width direction position toward the vehicle by a correction distance less than the offset distance, is calculated, and the steering angle of the steered wheels is controlled so that the vehicle moves toward the forward gaze point. [Effects of the Invention]

[0006] According to the present invention, in driving assistance control that controls the steering angle of the vehicle so that the vehicle heads toward a forward gaze point, interference of the driving assistance control with the steering force applied by the occupant can be reduced. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a vehicle equipped with a driving assistance device according to an embodiment. [Figure 2] FIG. 2 is an explanatory diagram of an example of a steering control method according to an embodiment. [Figure 3] 2 is a block diagram illustrating an example of a functional configuration of a controller in FIG. 1. FIG. [Figure 4] 10A is an explanatory diagram of an example of setting a corrected headway point before starting a lane change, and FIG. 10B is an explanatory diagram of an example of setting a corrected headway point after starting a lane change. [Figure 5] FIG. 10 is an explanatory diagram of an example of a method for correcting a corrected forward gaze point. [Figure 6] 4 is a flowchart of an example of a steering control method according to an embodiment. [Figure 7] FIG. 10 is an explanatory diagram of an example of setting a corrected forward gaze point in the second embodiment. [Figure 8]FIG. 11 is an explanatory diagram of an example of setting a corrected forward gaze point in the third embodiment. [Figure 9] FIG. 13 is an explanatory diagram of an example of setting a corrected forward gaze point in the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, identical or similar parts are designated by identical or similar reference numerals, and redundant explanations will be omitted. Each drawing is a schematic view, and may differ from the actual product. The embodiments shown below exemplify devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the devices and methods exemplified in the following embodiments. The technical concept of the present invention can be modified in various ways within the technical scope described in the claims.

[0009] (First embodiment) (composition) The host vehicle 1 is equipped with a driving assistance device 10 that assists in driving the host vehicle 1. The driving assistance device 10 detects the driving environment around the host vehicle 1 and automatically controls the driving of the host vehicle 1 based on the detected driving environment, thereby assisting the occupant (e.g., the driver) of the host vehicle 1 in driving the host vehicle 1. For example, driving assistance for the vehicle 1 by the driving assistance device 10 may include autonomous driving control in which the vehicle 1 is driven automatically without the involvement of an occupant. However, driving assistance by the driving assistance device 10 is not limited to such autonomous driving control. Driving assistance by the driving assistance device 10 may be any type of driving assistance that automatically controls at least the steering angle of the vehicle 1. For example, driving assistance by the driving assistance device 10 may be lane departure prevention assistance.

[0010] The driving assistance device 10 includes a positioning device 11, a map database 12, a navigation device 13, an external sensor 14, a vehicle sensor 15, a controller 16, and an actuator 17. In the drawings, the map database is referred to as a "map DB." The positioning device 11 measures the current position of the vehicle 1. The positioning device 11 may include, for example, a Global Positioning System (GNSS) receiver. The GNSS receiver is, for example, a Global Positioning System (GPS) receiver, and receives radio waves from multiple navigation satellites to measure the current position of the vehicle 1.

[0011] The map database 12 stores road map data. For example, the map database 12 may store high-precision map data (hereinafter simply referred to as "high-precision map") suitable as map information for autonomous driving. The high-precision map is map data with higher precision than map data for navigation (hereinafter simply referred to as "navigation map"). The road map data stored in the map database 12 may be a navigation map.

[0012] The navigation device 13 recognizes the current position of the vehicle 1 using the positioning device 11, and acquires map information for the current position from the map database 12. The navigation device 13 sets a driving route to the destination input by the occupant, and provides route guidance to the occupant along this driving route. Furthermore, the navigation device 13 outputs information about the set travel route to the controller 16. When performing autonomous travel control, the controller 16 automatically drives the vehicle 1 so that the vehicle travels along the travel route set by the navigation device 13.

[0013] The external sensor 14 detects various information (driving environment information) about the driving environment around the vehicle 1, for example, objects around the vehicle 1. The external sensor 14 detects the environment around the vehicle 1, such as objects present around the vehicle 1, the relative positions between the vehicle 1 and the objects, the distance between the vehicle 1 and the objects, and the direction in which the objects exist. The external sensor 14 outputs the detected information about the driving environment to the controller 16 as driving environment information. For example, the external sensor 14 detects the relative positions of other vehicles and targets around the vehicle 1 relative to the vehicle 1. Here, targets include, for example, traffic lights provided on the road on which the vehicle 1 is traveling, lines on the road surface (e.g., lane boundary lines such as white lines), curbs on the shoulders of the road, guardrails, etc.

[0014] The external sensor 14 may include a monocular camera such as a full HD color camera. The camera captures an image including a target to be recognized in the environment surrounding the vehicle 1, and outputs the captured image to the controller 16 as driving environment information. The external sensor 14 may also include a distance measuring device such as a laser range finder (LRF), radar, or a laser radar such as LiDAR (Light Detection and Ranging). The distance measuring device detects the relative position of the vehicle, which is determined by the relative distance and direction to an object present around the vehicle. The distance measuring device outputs the detected distance data to the controller 16 as driving environment information.

[0015] The vehicle sensor 15 detects various information (vehicle information) obtained from the host vehicle 1. The vehicle sensor 15 includes, for example, a vehicle speed sensor that detects the traveling speed (vehicle speed) of the host vehicle 1, a wheel speed sensor that detects the rotational speed of each tire equipped on the host vehicle 1, a three-axis acceleration sensor (G sensor) that detects the acceleration (including deceleration) in three axial directions of the host vehicle 1, 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 steering torque sensor that detects the steering torque applied to the steering wheel by the occupant, a gyro sensor that detects the angular velocity generated in the host vehicle 1, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the amount of operation of the accelerator pedal of the host vehicle 1, and a brake sensor that detects the amount of brake operation by the occupant.

[0016] The controller 16 is an electronic control unit (ECU) that performs driving assistance control of the host vehicle 1. When performing driving assistance control of the host vehicle 1, the controller 16 automatically controls the driving of the host vehicle 1 based on the surrounding driving environment. The controller 16 includes a processor 20 and peripheral components such as a storage device 21. The processor 20 may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The storage device 21 may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The storage device 21 may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main memory device, and a RAM (Random Access Memory). The functions of the controller 16 described below are realized by, for example, the processor 20 executing a computer program stored in the storage device 21 .

[0017] The controller 16 may be formed by dedicated hardware for executing each of the information processes described below. For example, the controller 16 may include a functional logic circuit configured in a general-purpose semiconductor integrated circuit, such as a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

[0018] The actuator 17 operates the accelerator opening and braking device of the host vehicle 1 in response to a control signal from the controller 16 to generate a driving force for driving the host vehicle 1 or a braking force for braking the host vehicle 1. The actuator 17 includes an accelerator opening actuator and a brake control actuator. The accelerator opening actuator controls the accelerator opening of the host vehicle 1. The brake control actuator controls the braking operation of the braking device of the host vehicle 1. The actuator 17 may also include a steering actuator that controls the steering direction and steering amount of the steering mechanism of the host vehicle 1. The actuator 17 may operate the steering mechanism of the host vehicle 1 in response to a control signal from the controller 16.

[0019] Next, the steering control of the controller 16 during driving assistance control of the host vehicle 1 will be described. In steering control of the host vehicle 1, the controller 16 sets a forward gaze distance, sets a forward gaze point at a predetermined position in the lane width direction, the forward gaze distance ahead of the host vehicle 1, and controls the steering angle δ of the steering wheels of the host vehicle 1 so that the host vehicle 1 travels toward the forward gaze point.

[0020] FIG. 2 is an explanatory diagram of an example of a steering control method according to an embodiment. e indicates the lane in which the vehicle is traveling, and reference symbol L n is the current lane L e The dashed line 30 indicates the adjacent lane of the vehicle. e and adjacent lane L n The solid line 31 indicates the lane boundary (line mark) between the e The adjacent lane L n The solid line 32 indicates the lane boundary line far from the adjacent lane L. n Between the lane boundaries on both sides of the lane L e The dashed line T indicates the lane boundary line far from the lane. trge The driving assistance control of the driving assistance device 10 e The dashed line T trgn indicates that vehicle 1 is in the adjacent lane L n This shows the target driving trajectory when traveling within the

[0021] For example, in autonomous driving control, the controller 16 may generate a target driving trajectory for the host vehicle 1 based on the driving route set by the navigation device 13 and the surrounding driving environment. Also, for example, in lane departure prevention assistance, the host vehicle 1 controller 16 may generate a target driving trajectory based on the surrounding driving environment so that the host vehicle 1 drives at a predetermined position in the lane width direction of the driving lane. For example, of the lane boundary lines on both the left and right sides of the lane in which the host vehicle 1 drives, a line offset inward in the lane width direction by a predetermined distance from the lane boundary line closest to the host vehicle 1 is set as the target driving trajectory. The target driving trajectory may be, for example, a trajectory extending along the center of the lane.

[0022] Now, vehicle 1 is at position 1 eVehicle 1 is in lane L e The controller 16 determines the forward gaze distance X trg_FIN Only the lane L in front of the vehicle 1 e A given lane width direction position Y above trg The position of the forward gaze distance X trg_FIN The basic forward gaze point in front of the vehicle 1 is simply referred to as the "basic forward gaze point Y trg ". Also, in the drawings, the reference symbol "Y trg " indicates the basic forward gaze point. For example, the controller 16 may be configured to trg_FIN From the position on the lane boundary line 30 just ahead to the position on the own lane L e The position at a predetermined distance in the lane width direction toward the lane center is called the lane width direction position Y trg For example, the lane width direction position Y trg is the target driving trajectory T trge You can set it above.

[0023] The basic forward gaze point Y set in this way trg By controlling the steering angle δ of the steering wheels of the vehicle 1 so that the vehicle 1 travels toward the target travel trajectory T trge It can be run along the However, there are individual differences in the preferences of passengers as to which trajectory the vehicle should follow within the lane. trge Top basic forward gaze point Y trg If the steering angle is uniformly controlled so as to move in the opposite direction, it may not suit the occupant's preference. Therefore, if the occupant applies corrective steering, the steering force applied by the driver assistance device 10 may interfere with the steering force applied by the occupant, causing the occupant to feel uncomfortable.

[0024] Therefore, the controller 16 calculates the basic forward gaze point Y according to the current lane width direction position Y of the vehicle 1. trg By correcting the corrected forward gaze point Y trg_FIN Calculate. The current lane width direction position Y of the vehicle 1 reflects the preference of the driver of the vehicle 1 as to the trajectory along which the vehicle should travel. trg If the corrected forward gaze point Y is corrected, it is possible to reduce the discomfort felt by the occupant. trg_FIN Therefore, it is possible to reduce interference of the driving assist control with the steering force applied by the occupant.

[0025] For example, the lane width direction position Y and the basic forward gaze point Y trg The difference between the lane width direction position and trg -Y) is calculated as the offset amount Y0, and the correction amount less than the offset amount Y0 is used to calculate the basic forward gaze point Y trg For example, the controller 16 multiplies the offset amount Y0 by a gain K that is greater than 0 and equal to or less than 1, and calculates the product (K×Y0) as the correction distance. The controller 16 determines the basic forward gaze point Y trg The lane width direction position of the vehicle is shifted (moved) by a correction distance (K × Y0) in the direction toward the lane width direction position Y (i.e., toward the vehicle 1 side), and the corrected forward gaze point Y trg_FIN The controller 16 calculates the corrected forward gaze point Y trg_FIN The steering angle δ of the steered wheels is controlled so that the vehicle moves in the direction indicated by the arrow.

[0026] As a result, the current lane width direction position Y of the vehicle 1 is shifted to the target driving trajectory T trge When the lane width direction position Y is offset by the offset amount Y0 from the lane width direction position Y, the forward gaze point is corrected in the direction in which the lane width direction position Y is offset (to the left in the example of Figure 2), and the steering force to move in the opposite direction (to the right in the example of Figure 2) is reduced. This reduces interference of the driving assist control with the steering force applied by the driver in the driving assist control that controls the steering angle δ of the vehicle 1 so that the vehicle 1 heads toward the forward gaze point.

[0027] Next, it is assumed that the vehicle 1 changes lanes. e From adjacent lane L nFor example, the controller 16 may determine whether the driver of the vehicle 1 intends to change lanes based on the operation of a turn signal by the driver. n When the vehicle reaches the lane L e From adjacent lane L n Assume that it is determined that the driver intends to change lanes.

[0028] At this time, the controller 16 determines the forward gaze distance X trg_FIN Only the adjacent lane L in front of the vehicle 1 n A given lane width direction position Y above trg is set as the basic forward gaze point. For example, the controller 16 sets the forward gaze distance X trg_FIN From the position on the lane boundary line 30 just ahead to the adjacent lane L n The position at a predetermined distance in the lane width direction toward the lane center is called the lane width direction position Y trg For example, when it is determined that the driver intends to change lanes, the controller 16 may set the vehicle position in the adjacent lane L n Target trajectory T above trgn and the lane width direction position Y trg The target running trajectory T trgn You can set it above.

[0029] The controller 16 determines the basic forward gaze point Y when the host vehicle 1 does not change lanes. trg Similarly, the basic forward gaze point Y is calculated according to the current lane width direction position Y of the vehicle 1. trg By correcting the corrected forward gaze point Y trg_FIN The corrected forward gaze point Y trg_FIN The steering angle δ of the steered wheels is controlled so that the vehicle moves in the direction indicated by the arrow. As a result, even when the vehicle 1 changes lanes, the corrected forward gaze point Y trg_FIN can be set.

[0030] In addition, when changing lanes, the basic forward gaze point Y trg is the adjacent lane L nTherefore, until the vehicle 1 crosses the lane boundary line 30, the basic forward gaze point Y trg In this case, the distance in the lane width direction between the vehicle 1 and the vehicle 2 may become larger than when the vehicle does not change lanes. As a result, if the driving assistance device 10 generates a strong steering force against the driver's will, the driver may feel uncomfortable. trg Move it to the side of the vehicle 1 and correct the forward gaze point Y trg_FIN is calculated, the steering force due to the steering control of the driving support device 10 is suppressed. This makes it possible to make the steering force of the driving support device 10 less likely to give an uncomfortable feeling to the occupant. In addition, the basic forward gaze point Y trg is an example of the "first lane width direction position" in the claims, the lane width direction position Y is an example of the "second lane width direction position", and the corrected forward gaze point Y trg_FIN is an example of a "forward gaze point."

[0031] Next, a detailed description will be given of the functions of the controller 16. Fig. 3 is a block diagram showing an example of the functional configuration of the controller 16. The controller 16 includes a target white line selection unit 40, a gaze point setting unit 41, a gain setting unit 43, an adder 44, subtractors 45 and 47, a multiplier 46, a target lateral force calculation unit 48, and a conversion unit 49. The target white line selection unit 40 detects lane boundaries around the vehicle 1 by recognizing lane boundaries from an image of the vehicle 1 captured by the camera of the external sensor 14. The target white line selection unit 40 may detect lane boundaries using a distance measurement device such as LiDAR. The target white line selection unit 40 selects the lane boundary line that is the shortest distance between the host vehicle 1 and the lane boundary line in the lane width direction from the detected lane boundary line, based on the lane width direction position Y of the host vehicle 1 and the basic forward gaze point Y. trg The lane boundary line to be used as the reference lane boundary line is selected (hereinafter, sometimes referred to as the "reference lane boundary line").

[0032] Figure 4(a) shows the corrected forward gaze point Y before the lane change. trg_FIN 4(b) is an explanatory diagram of a setting example of the corrected forward gaze point Y after the start of the lane change. trg_FINFIG. In the example of Figure 4(a), the vehicle is in the lane L e The vehicle 1 is traveling slightly to the left of the lane L. e Of the lane boundary lines 30, 31 on both the left and right sides of the lane boundary line, the left lane boundary line 30 is selected as the reference lane boundary line. In addition, adjacent lane L n The vehicle 1 that is changing lanes to the lane L is in the lane L as shown in FIG. e and adjacent lane L n To approach the lane boundary line 30 between

[0033] 3, the target lane line selection unit 40 calculates the curvature ρ of the reference lane boundary line, the curvature change ρ', and the yaw angle deviation Ψ between the yaw angle of the vehicle 1 and the extension direction of the reference lane boundary line. The target lane line selection unit 40 outputs the curvature ρ, the curvature change ρ', and the yaw angle deviation Ψ to the gaze point setting unit 41. The target lane line selection unit 40 also detects the lane width direction position Y of the vehicle 1 based on the reference lane boundary line. For example, the target white line selection unit 40 may calculate the lane width direction position of the reference lane boundary line in a relative coordinate system with the center of gravity of the vehicle 1 as the coordinate origin as the lane width direction position Y. The target white line selection unit 40 outputs the lane width direction position Y to the gaze point setting unit 41 and the subtractor 45.

[0034] The target white line selection unit 40 also selects the lane L e From adjacent lane L n For example, the target white line selection unit 40 may determine whether the driver of the vehicle 1 intends to change lanes based on the operation of a turn signal by the driver. e When a preceding vehicle slower than the host vehicle 1 is present ahead of the host vehicle 1, the driver may be suggested to overtake the preceding vehicle. Whether or not the driver intends to change lanes may be determined based on whether or not the driver accepts the suggestion to overtake. Also, for example, if there is a point where the direction of travel changes, such as a branch point, a junction point, an exit, or a toll gate, on the travel route set by the navigation device 13, and the vehicle 1 approaches the point where the direction of travel changes, the navigation device 13 may suggest a lane change to the point where the direction of travel changes. Whether the driver intends to change lanes may be determined based on whether the driver accepts the suggestion to change lanes.

[0035] 4(a), when there is no intention to change lanes, the target white line selection unit 40 selects the lane L e The predetermined lane width direction position above is the basic forward gaze point Y trg Specifically, the basic forward gaze point Y trg deviation of lane width direction position d trg For example, the target lane line selection unit 40 calculates the target driving trajectory T trge The deviation of d trg This can be considered. 4(b), when there is no intention to change lanes, the target white line selection unit 40 selects the adjacent lane L n The predetermined lane width direction position above is the basic forward gaze point Y trg Specifically, the basic forward gaze point Y trg Lane width direction position deviation d trg For example, the target lane line selection unit 40 calculates the target driving trajectory T trgn The deviation of d trg The target white line selection unit 40 may be set as the deviation d trg is output to the adder 44.

[0036] Referring to FIG. 3, the gaze point setting unit 41 determines the forward gaze distance X trg_FIN For example, the gaze point setting unit 41 sets the forward gaze distance X based on the vehicle speed of the host vehicle 1 detected by the vehicle speed sensor of the vehicle sensor 15. trg_FIN For example, the gaze point setting unit 41 may set the longitudinal distance (i.e., the distance along the lane) that the host vehicle 1 moves in a predetermined time (e.g., 2 seconds) as the forward gaze distance X trg_FIN Set as. The gaze point setting unit 41 also sets the forward gaze distance Xtrg_FIN The position of the reference lane boundary line in the lane width direction at a position just ahead of the vehicle is defined as the forward lane boundary line position Y pre For example, the gaze point setting unit 41 calculates the forward lane boundary line position P based on the curvature ρ of the reference lane boundary line, the curvature change ρ', the yaw angle deviation Ψ, and the lane width direction position Y, using the following formula (1): pre Calculate.

[0037]

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[0038] The gain setting unit 43 sets the basic forward gaze point Y trg The gain setting unit 43 sets the gain K to a value greater than 0 and equal to or less than 1. When the gain K is small, the offset amount Y0 (i.e., the lane width direction position Y and the basic forward gaze point Y) is changed by the steering of the occupant. trg The difference between the lane width direction position and trg Even if a steering error (-Y) occurs, the correction distance (K x Y0) becomes small. Therefore, the occupant's steering is less likely to be reflected in the setting of the forward gaze point. Conversely, when the gain K is large, the occupant's steering is more likely to be reflected in the setting of the forward gaze point, so interference by the driving assist control with the occupant's steering force can be further reduced.

[0039] For example, the gain setting unit 43 may set a larger gain K when there is an intention to change lanes compared to when there is no intention to change lanes. Also, for example, a larger gain K may be set when the offset amount Y0 is large compared to when the offset amount Y0 is small. For example, the larger the offset amount Y0, the larger the gain K may be set. For example, the current lane L e and adjacent lane L n A larger gain K may be set when the distance between the lane boundary line 30 and the vehicle 1 is large compared to when the distance is small. For example, the larger the distance, the larger the gain K may be set. Since the driving trajectory preferences during lane changes vary greatly from driver to driver, the occupant's preferences can be prioritized by setting a large gain K and further reducing the interference of the driving assistance control with the steering force applied by the occupant.

[0040] For example, if the vehicle 1 is in the lane L e While driving in the lane L e Lane boundary lines 30 and 31 of the adjacent lane L n When the distance between the lane boundary line 31 farthest from the host vehicle 1 is small, a smaller gain K may be set than when the distance is large. For example, the smaller the distance, the smaller the gain K may be set. In addition, vehicle 1 is in the adjacent lane L n While driving in the adjacent lane L n Among the lane boundaries 30 and 32, the lane L e When the distance between the lane boundary line 32 farthest from the host vehicle 1 is small, a smaller gain K may be set than when the distance is large. For example, the smaller the distance, the smaller the gain K may be set. This allows the steering force provided by the driving assistance control to be increased in the range close to the lane boundary line so as not to deviate from the lane.

[0041] Also, for example, a larger gain K may be set when the curvature ρ of the lane within a predetermined distance ahead from the current position of the vehicle 1 is large compared to when it is small. For example, the larger the curvature ρ, the larger the gain K may be set. Since occupants have significant differences in preferences for the trajectory the vehicle should follow when traveling on a curved road, setting a larger gain K when the curvature ρ is large can further reduce interference by the driving assist control with the steering force applied by the occupant, thereby making it possible to prioritize the occupant's preferences.

[0042] Also, for example, a larger gain K may be set when the steering torque applied by the occupant to the steering wheel is large compared to when the steering torque is small. For example, the larger the steering torque, the larger the gain K may be set. This allows the occupant's steering to be given priority when the occupant has a strong intention to steer. Further, for example, the gain K may be set to be larger when the vehicle speed of the host vehicle 1 is low than when the vehicle speed is high. For example, the lower the vehicle speed, the larger the gain K may be set. When the vehicle speed is low, the forward gaze distance X trg_FIN Therefore, by setting a large gain K when the vehicle speed is low, the interference of the driving assist control with the steering force applied by the occupant can be further reduced, thereby reducing the discomfort felt by the occupant. Further, for example, the gain setting unit 43 may increase or decrease the gain K based on a switch operation by the occupant, thereby realizing a steering feel that suits the occupant's preference.

[0043] The adder 44 calculates the front lane boundary line position Y pre deviation d trg The sum (Y pre +d trg ) to calculate the basic forward gaze point Y trg The subtractor 45 calculates the lane width direction position of the basic forward gaze point Y trg The offset amount Y0 is calculated by subtracting the lane width direction position Y from the lane width direction position Y. trg Calculate -Y. A multiplier 46 multiplies the offset amount Y0 by a gain K to calculate a corrected distance (K×Y0).

[0044] The subtractor 47 subtracts the basic forward gaze point P from the tangent line Lt. f1 Lane width direction distance (Y pre +Y trg ) minus the correction distance (K × Y0) (Y pre +Y trg -(K×Y0)) is the corrected forward gaze point Y trg_FIN The lane width direction position is calculated as the lane width direction position. The target lateral force calculation unit 48 calculates the target lateral force based on the mass m of the vehicle 1, the vehicle speed V, and the forward gaze distance X trg_FIN and the corrected forward gaze point Y trg_FIN Based on the lane width direction position of the vehicle 1, the corrected forward gaze point Y trg_FIN Target lateral force F directed towards y Calculate. Now, if the turning radius of the host vehicle 1 is denoted as R, the target lateral force Fy can be calculated using the following formula (2).

number

[0045] Therefore, the corrected forward gaze point Y in the relative coordinate system with the center of gravity of the vehicle 1 as the coordinate origin is trg_FIN The lane width direction position of trg_FIN ", the target lateral force F y can be calculated based on the following formula (3):

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[0046] The conversion unit 49 converts the target lateral force F y The target steering angle δ of the steered wheels is calculated based on the following equation (4): tar Convert to.

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[0047] If the above correction distance (K × Y0) becomes too large, the corrected forward gaze point Y trg_FIN is the target running trajectory T trge , T trgn It is possible that steering control will be performed such that the vehicle is too far away from the target and the driver feels uncomfortable. Such a situation will be explained with reference to Figure 5. Now, based on the current steering angle δ and vehicle speed V, the forward gaze distance X trg_FIN Consider a case where the position of the vehicle 1 ahead in the lane width direction is estimated to be Y3. In such a case, the corrected forward gaze point Y trg_FINHowever, if the position is set outside the lane width direction position Y3, the steering control will be performed in a direction that deviates from the center of the lane, which may cause the driver to feel uncomfortable.

[0048] Therefore, the controller 16 calculates the forward gaze distance X based on the current steering angle δ and vehicle speed V of the vehicle 1. trg_FIN The lane width direction position Y3 of the vehicle 1 ahead is estimated, and the corrected forward gaze point Y trg_FIN is outside the lane width direction position Y3 (i.e., whether the lane width direction position Y3 is outside the corrected forward gaze point Y trg_FIN and the center of the lane), and trg_FIN is outside the lane width direction position Y3, the corrected forward gaze point Y trg_FIN may be corrected to move closer to the center of the lane. As a result, the correction distance (K × Y0) becomes too large and the corrected forward gaze point Y trg_FIN is the center of the lane (for example, the target driving trajectory T trgn ) and thus prevent the driver from feeling uncomfortable.

[0049] (operation) FIG. 6 is a flowchart of an example of a steering control method according to an embodiment. In step S1, the gaze point setting unit 41 determines the forward gaze distance X trg_FIN Set. In step S2, the target lane line selection unit 40 detects the lane width direction position Y of the vehicle 1 based on the reference lane boundary line. In step S3, the target white line selection unit 40 selects the lane L e From adjacent lane L n It is determined whether the driver of the vehicle 1 intends to change lanes. If there is an intention to change lanes (step S3: Y), the process proceeds to step S4. If there is no intention to change lanes (step S3: N), the process proceeds to step S5.

[0050] In step S4, the target white line selection unit 40, the gaze point setting unit 41, and the adder 44 calculate the basic forward gaze point Y trg After that, the process proceeds to step S6. In step S5, the target white line selection unit 40, the gaze point setting unit 41, and the adder 44 calculate the basic forward gaze point Y trg After that, the process proceeds to step S6. In step S6, the subtractor 45 calculates the offset amount Y0. In step S7, the multiplier 46 and the subtractor 47 calculate the basic forward gaze point Y by the correction distance (K×Y0). trg Correct the corrected forward gaze point Y trg_FIN Calculate. In step S8, the target lateral force calculation unit 48 and the conversion unit 49 calculate the corrected forward gaze point Y trg_FIN The steering angle δ of the steered wheels is controlled so that the vehicle moves to the target position. Then, the process ends.

[0051] (Second embodiment) 7(a) and 7(b), when the vehicle starts to change lanes, the vehicle is in the same lane as the vehicle in the same lane L. e and adjacent lane L n If the distance |Y| between the lane boundary line 30 between the adjacent lanes L and the vehicle 1 is large, n Target trajectory T above trgn The distance in the lane width direction to the intersection becomes larger. In such a case, the basic forward gaze point Y trg The target running trajectory T trgn If set to above, the base forward gaze point Y trg Corrected forward gaze point Y trg_FIN Even if the correction is made to the corrected forward gaze point Y trg_FIN The difference between the lane width direction position of the vehicle 1 and the lane width direction position Y of the vehicle 1 may become large. As a result, the driving assistance device 10 may generate a strong steering force against the intention of the occupant, which may cause the occupant to feel uncomfortable.

[0052] Therefore, the target white line selection unit 40 of the second embodiment determines whether the lane width direction distance |Y| between the lane boundary line 30 and the vehicle 1 is equal to or greater than a first threshold value when the vehicle starts to change lanes. If the lane width direction distance |Y| is equal to or greater than the first threshold value, the target white line selection unit 40 determines the forward gaze distance X trg_FINThe basic forward gaze point Y is located in front of the vehicle 1 and on the lane boundary line 30. trg At this time, for example, the target white line selection unit 40 sets the deviation d trg Set to 0.

[0053] Basic forward gaze point Y on lane boundary line 30 trg After setting the second threshold value, the target white line selection unit 40 determines whether the distance between the lane boundary line 30 and the host vehicle 1 is equal to or less than a second threshold value. The second threshold value is set to a value smaller than the first threshold value. For example, the target white line selection unit 40 may determine whether the host vehicle 1 has passed over the lane boundary line 30. In this case, the second threshold value is set to 0. When the distance between the lane boundary line 30 and the vehicle 1 becomes equal to or less than the second threshold, the target white line selection unit 40, the gaze point setting unit 41, and the adder 44 determine the forward gaze distance X trg_FIN Only in front of the vehicle 1 and in the adjacent lane L n A predetermined lane width direction position (for example, target driving trajectory T trgn (top position) Basic forward gaze point Y trg Set.

[0054] (Third embodiment) 8, the target white line selection unit 40 of the third embodiment selects the target white line of the own lane L when the lane width direction distance |Y| is equal to or greater than the first threshold value when the vehicle starts to change lanes. e Target trajectory T above trge and adjacent lane L n Target trajectory T above trgn Calculate the midpoint C1 between trg_FIN The basic forward gaze point Y is located in front of the vehicle 1 and at the intermediate point C1. trg Set. Target driving trajectory T relative to lane boundary line 30 trge , T trgn If the deviations are d1 and d2, the target white line selection unit 40 selects the deviation d trg may be set to (d1-d2) / 2. Basic forward gaze point Y at intermediate point C1 trgAfter setting the distance, if the distance between the lane boundary line 30 and the vehicle 1 becomes equal to or less than the second threshold, the target white line selection unit 40, the gaze point setting unit 41, and the adder 44 set the forward gaze distance X trg_FIN Only in front of the vehicle 1 and in the adjacent lane L n A predetermined lane width direction position (for example, target driving trajectory T trgn (top position) Basic forward gaze point Y trg Set.

[0055] (Fourth embodiment) 9, the target white line selection unit 40 of the fourth embodiment calculates the midpoint C2 between the lane boundary line 31 and the lane boundary line 32 when the lane width direction distance |Y| is equal to or greater than the first threshold value when the vehicle starts to change lanes, and calculates the forward gaze distance X trg_FIN The basic forward gaze point Y is located in front of the vehicle 1 and at the intermediate point C2. trg Set. Own lane L e and adjacent lane L n When the lane widths are w1 and w2, the target white line selection unit 40 calculates the deviation d trg may be set to (W1-W2) / 4. Basic forward gaze point Y at intermediate point C2 trg After setting the distance, if the distance between the lane boundary line 30 and the vehicle 1 becomes equal to or less than the second threshold, the target white line selection unit 40, the gaze point setting unit 41, and the adder 44 set the forward gaze distance X trg_FIN Only in front of the vehicle 1 and in the adjacent lane L n A predetermined lane width direction position (for example, target driving trajectory T trgn (top position) Basic forward gaze point Y trg Set.

[0056] (Effects of the embodiment) (1) The controller 16 sets a forward gaze distance and determines whether the driver of the vehicle 1 intends to change lanes from the vehicle's own lane, which is the lane in which the vehicle 1 is traveling, to an adjacent lane. If there is no intention to change lanes, the controller 16 sets a predetermined lane width direction position on the vehicle's own lane in front of the vehicle 1 by the forward gaze distance as the first lane width direction position. If there is an intention to change lanes, the controller 16 sets a predetermined lane width direction position on the adjacent lane in front of the vehicle 1 by the forward gaze distance as the first lane width direction position. The controller 16 detects the second lane width direction position, which is the current lane width direction position of the vehicle 1, calculates an offset distance, which is the difference between the second lane width direction position and the first lane width direction position, calculates a forward gaze point by moving the first lane width direction position toward the vehicle 1 in the lane width direction by a correction distance less than or equal to the offset distance, and controls the steering angle of the steered wheels so that the vehicle 1 moves toward the forward gaze point. This reduces interference of the driving assist control with the steering force applied by the occupant in the driving assist control that controls the steering angle of the vehicle so that the vehicle heads toward the forward gaze point. Also, when changing lanes to an adjacent lane using driving assist control that controls the steering angle of the vehicle so that the vehicle heads toward the forward gaze point, it is possible to prevent the occupant from feeling uncomfortable due to the generation of a strong steering force against the occupant's intention.

[0057] (2) When there is an intention to change lanes and the distance between the lane boundary line between the vehicle's lane and an adjacent lane is equal to or greater than a first threshold, the controller 16 may set a first lane width direction position on the lane boundary line and ahead of the vehicle 1 by a forward gaze distance, and when the distance between the lane boundary line and the vehicle's lane becomes equal to or less than a second threshold after setting the first lane width direction position on the lane boundary line, the controller 16 may set the first lane width direction position at a predetermined lane width direction position on the adjacent lane. This prevents the generation of strong steering force against the occupants' intentions, which causes discomfort to the occupants, when changing lanes to an adjacent lane by driving assistance control that controls the steering angle of the vehicle so that the vehicle 1 moves toward the forward gaze point, because the vehicle 1 is away from the lane boundary line between the vehicle 1 and the adjacent lane.

[0058] (3) The controller 16 generates a first target driving trajectory for the host vehicle 1 to drive in the host lane, and if there is an intention to change lanes, generates a second target driving trajectory for the host vehicle 1 to drive in an adjacent lane, and if there is an intention to change lanes and the distance between the lane boundary line between the host lane and the adjacent lane and the host lane is equal to or greater than a first threshold, sets a first lane width direction position a forward gaze distance ahead of the host vehicle 1 and at a midpoint between the first target driving trajectory and the second target driving trajectory, and after setting the first lane width direction position at the midpoint, if the distance between the lane boundary line and the host lane becomes equal to or less than a second threshold, sets the first lane width direction position at a predetermined lane width direction position on the adjacent lane. This prevents the generation of strong steering force against the occupants' intentions, which causes discomfort to the occupants, when changing lanes to an adjacent lane by driving assistance control that controls the steering angle of the vehicle so that the vehicle 1 moves toward the forward gaze point, because the vehicle 1 is away from the lane boundary line between the vehicle 1 and the adjacent lane.

[0059] (4) When there is an intention to change lanes and the distance between the lane boundary line between the own lane and the adjacent lane and the own lane is equal to or greater than a first threshold, the controller 16 may set a first lane width direction position at a midpoint between the lane boundary line of the own lane that is farther from the adjacent lane and the lane boundary line of the adjacent lane that is farther from the own lane, and after setting the first lane width direction position at the midpoint, when the distance between the lane boundary line between the own lane and the adjacent lane and the own lane becomes equal to or less than a second threshold, the controller 16 may set the first lane width direction position at a predetermined lane width direction position on the adjacent lane. This prevents the generation of strong steering force against the occupants' intentions, which causes discomfort to the occupants, when changing lanes to an adjacent lane by driving assistance control that controls the steering angle of the vehicle so that the vehicle 1 moves toward the forward gaze point, because the vehicle 1 is away from the lane boundary line between the vehicle 1 and the adjacent lane.

[0060] (5) The controller 16 may calculate the correction distance by multiplying the offset distance by a gain having a value greater than 0 and equal to or less than 1. This allows the calculation of a correction distance equal to or less than the offset distance. (6) The controller 16 may set a larger gain when the vehicle intends to change lanes compared to when the vehicle does not intend to change lanes. The controller 16 may set a larger gain when the offset distance is large compared to when the offset distance is small. The controller 16 may set a larger gain when the first distance between the vehicle 1 and the lane boundary line between the vehicle's lane and the adjacent lane is large compared to when the first distance is small. Since the driving trajectory preferences during lane changes vary greatly from driver to driver, the occupant's preferences can be prioritized by setting a large gain K and further reducing the interference of the driving assistance control with the steering force applied by the occupant.

[0061] (7) While the host vehicle 1 is traveling in the host lane, the controller 16 may set a smaller gain when the second distance between the host vehicle 1 and a lane boundary line of the host lane that is far from the adjacent lane and the second distance is small, or may set a smaller gain when the third distance between the host vehicle 1 and a lane boundary line of the adjacent lane that is far from the host lane and the third distance is small while the host vehicle 1 is traveling in the adjacent lane. This allows the steering force by the driving assist control to be increased in the range close to the lane boundary line so as not to deviate from the lane. (8) The controller 16 may detect the curvature of the lane from the current position of the vehicle 1 to a predetermined distance ahead, and may increase the gain when the curvature is large compared to when the curvature is small. The trajectory that a vehicle should follow when traveling on a curved road varies greatly depending on the driver's preference. Therefore, by setting a large gain when the curvature ρ is large and reducing the interference of the driving assist control with the steering force applied by the driver, the driver's preference can be prioritized.

[0062] (9) The controller 16 may detect the speed of the vehicle 1 and increase the gain when the vehicle speed is low compared to when the vehicle speed is high. trg_FINTherefore, by setting a large gain when the vehicle speed is low, the interference of the driving assist control with the steering force applied by the occupant can be further reduced, thereby reducing the discomfort felt by the occupant. (10) The controller 16 may estimate a third lane width direction position, which is the lane width direction position of the vehicle 1 at a point the look-ahead distance ahead, and correct the look-ahead point to move closer to the lane center when the third lane width direction position is between the center of the lane for which the look-ahead point is set and the look-ahead point. This prevents the correction distance from becoming too large and the look-ahead point from being too far from the lane center, which can cause the driver to feel uncomfortable. [Explanation of symbols]

[0063] 1...Own vehicle, 10...driving assistance device, 11...positioning device, 12...map database, 13...navigation device, 14...external sensor, 15...vehicle sensor, 16...controller, 17...actuator, 20...processor, 21...storage device, 40...target white line selection unit, 41...gain setting unit, 43...gain setting unit, 44...adder, 45, 47...subtractor, 46...multiplier, 48...target lateral force calculation unit, 49...conversion unit

Claims

1. Set the forward gaze distance, determining whether or not the driver of the vehicle intends to change lanes from the own lane in which the vehicle is traveling to an adjacent lane; When there is no intention to change lanes, a predetermined lane width direction position on the own vehicle that is the forward gaze distance ahead of the own vehicle is set as a first lane width direction position; When there is an intention to change lanes, the predetermined lane width direction position on the adjacent lane ahead of the host vehicle by the forward gaze distance is set as the first lane width direction position; Detecting a second lane width direction position, which is the current lane width direction position of the host vehicle; Calculating an offset distance that is a difference between the second lane width direction position and the first lane width direction position; Calculating a forward gaze point obtained by moving the first lane width direction position in the lane width direction toward the host vehicle by a correction distance that is equal to or less than the offset distance; controlling the steering angle of the steered wheels so that the host vehicle moves toward the forward gaze point; A steering control method comprising:

2. When there is an intention to change lanes and the distance between the lane boundary line between the own vehicle lane and the adjacent lane is equal to or greater than a first threshold, the first lane width direction position is set at a position forward of the own vehicle by the forward gaze distance and on the lane boundary line; and after the first lane width direction position is set on the lane boundary line, when the distance between the lane boundary line and the own lane becomes equal to or less than a second threshold, the first lane width direction position is set at the predetermined lane width direction position on the adjacent lane.

2. The steering control method according to claim 1.

3. generating a first target driving trajectory for the host vehicle to travel in the host lane; generating a second target driving trajectory for the host vehicle to drive in the adjacent lane when the host vehicle intends to change lanes; When there is an intention to change lanes and the distance between the lane boundary line between the own vehicle lane and the adjacent lane is equal to or greater than a first threshold, the first lane width direction position is set to a point forward of the own vehicle by the forward gaze distance and at a midpoint between the first target driving trajectory and the second target driving trajectory; and after setting the first lane width direction position at the midpoint, when the distance between the lane boundary line and the own lane becomes equal to or less than a second threshold, setting the first lane width direction position at the predetermined lane width direction position on the adjacent lane.

2. The steering control method according to claim 1.

4. When there is an intention to change lanes and the distance between the lane boundary line between the own lane and the adjacent lane and the own lane is equal to or greater than a first threshold, the first lane width direction position is set to a midpoint that is the look-ahead distance ahead of the own vehicle and between a lane boundary line of the own lane that is farther from the adjacent lane and a lane boundary line of the adjacent lane that is farther from the own lane, and after setting the first lane width direction position at the midpoint, when a distance between the lane boundary line between the own lane and the adjacent lane and the own lane becomes equal to or less than a second threshold, the first lane width direction position is set at the predetermined lane width direction position on the adjacent lane.

2. The steering control method according to claim 1.

5. 5. The steering control method according to claim 1, wherein the correction distance is calculated by multiplying the offset distance by a gain having a value greater than 0 and equal to or less than 1.

6. 6. The steering control method according to claim 5, wherein the gain is set to be larger when there is an intention to change lanes than when there is no intention to change lanes.

7. 7. The steering control method according to claim 5, wherein the gain is set to be larger when the offset distance is large than when the offset distance is small.

8. The steering control method according to any one of claims 5 to 7, characterized in that the gain is set to be larger when the first distance between the lane boundary line between the own lane and the adjacent lane and the own vehicle is large compared to when the first distance is small.

9. The steering control method according to any one of claims 5 to 8, characterized in that, while the host vehicle is traveling in the host lane, the gain is set to be smaller when a second distance between the host vehicle and a lane boundary line of the host lane that is farther from the adjacent lane and the second distance is small, or, while the host vehicle is traveling in the adjacent lane, the gain is set to be smaller when a third distance between the host vehicle and a lane boundary line of the adjacent lane that is farther from the host lane and the third distance is small.

10. Detecting the curvature of the lane from the current position of the vehicle to a predetermined distance ahead; The gain is increased when the curvature is large compared to when the curvature is small.

10. The steering control method according to claim 5, wherein the steering control method is a steering control method for steering a vehicle.

11. Detecting the speed of the host vehicle; The gain is increased when the vehicle speed is low compared to when the vehicle speed is high. A steering control method according to any one of claims 5 to 10.

12. Estimating a third lane width direction position, which is the lane width direction position of the host vehicle at a point forward by the forward gaze distance; When the third lane width direction position is between a center of a lane in which the headway point is set and the headway point, the headway point is corrected to approach the center of the lane. A steering control method according to any one of claims 1 to 11.

13. a controller that sets a look-ahead distance, determines whether or not a driver of the host vehicle intends to change lanes from the host lane, which is the lane in which the host vehicle is traveling, to an adjacent lane, and if the driver does not intend to change lanes, sets a predetermined lane width direction position on the host lane by the look-ahead distance as a first lane width direction position, and if the driver intends to change lanes, sets the predetermined lane width direction position on the adjacent lane, which is the forward gaze distance as the first lane width direction position, detects a second lane width direction position that is the current lane width direction position of the host vehicle, calculates an offset distance that is the difference between the second lane width direction position and the first lane width direction position, calculates a look-ahead point that is moved in the lane width direction from the first lane width direction position toward the host vehicle by a correction distance that is equal to or less than the offset distance, and sets a target steering angle of steered wheels so that the host vehicle moves toward the look-ahead point; an actuator for controlling the steering angle of the steered wheels in accordance with the target steering angle; A steering control device comprising:

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