Steering control method and steering control device

Abstract

To reduce interference caused by driving support control with respect to steering force by an occupant in the driving support control for controlling a turning angle of one's own vehicle such that the one's own vehicle goes to a forward gazing point.SOLUTION: The steering control method includes the steps of: setting a forward gazing distance (S1); setting a predetermined lane width direction position as a first forward gazing point at a position in front of one's own vehicle by the forward gazing distance (S2); detecting a first lane width direction position which is a present lane width direction position of the one's own vehicle (S3); calculating an offset distance which is a difference between the lane width direction distance to the first forward gazing point from a first lane boundary line closer to the one's own vehicle among lane boundary lines on both sides in the lane width direction and the lane width direction distance to the first lane width direction position from the first lane boundary line (S4); calculating a second forward gazing point obtained by shifting the first forward gazing point by a correction distance equal to or less than the offset distance in the lane width direction toward the first lane boundary line side (S5, S6); and controlling a turning angle of a steering wheel such that the one's own vehicle advances toward the second forward gazing point (S7).SELECTED DRAWING: Figure 5

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, a predetermined lane width direction position at a position forward of the vehicle by the forward gaze distance is set as a first forward gaze point, the first lane width direction position, which is the current lane width direction position of the vehicle, is detected, an offset distance is calculated, which is the difference between the lane width direction distance from a first lane boundary line, which is the lane boundary line on both sides of the lane width direction that is closer to the vehicle, to the first forward gaze point and the lane width direction distance from the first lane boundary line to the first lane width direction position, a second forward gaze point is calculated by moving the first forward gaze point toward the first lane boundary line in the lane width direction by a correction distance less than the offset distance, and the steering angle of the steered wheels is controlled so that the vehicle moves toward the second 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] FIG. 10 is an explanatory diagram of an example of a method for correcting a corrected forward gaze point. [Figure 5] 4 is a flowchart of an example of a steering control method according to an 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] (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 recognition target 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 (including the turning angle), 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. FIG. 2 is an explanatory diagram of an example of a steering control method according to an embodiment.

[0020] The dashed lines L1 and L2 indicate the lane boundary lines (line marks) on the left and right sides of the lane in which the vehicle 1 is traveling. trg indicates a line that is a target for the trajectory along which the vehicle 1 is to travel under the driving assistance control of the driving assistance device 10 (hereinafter referred to as the "target driving trajectory"). For example, in the autonomous driving control, the controller 16 controls the navigation device 13 to determine the target driving trajectory T of the vehicle 1 based on the set driving route and the surrounding driving environment. trg For example, in lane departure prevention assistance, the controller 16 of the host vehicle 1 controls the steering angle δ of the host vehicle 1 based on the surrounding driving environment so that the host vehicle 1 travels at a predetermined position in the lane width direction of the driving lane. In this case, for example, a line offset inward from the lane boundary lines L1 and L2 by a predetermined distance in the lane width direction is determined as the target driving trajectory T trg For example, the target running trajectory T trg may be in the center of the lane.

[0021] The dashed line P1 indicates the current position of the vehicle 1 in the longitudinal direction along the lane, and the dashed line P2 indicates the forward gaze distance X trg_FIN Only the position ahead of the host vehicle 1 is shown. In the following description, the term "lane width direction" is defined as the lane width direction at the current position P1 of the vehicle 1. In Figures 2 and 4, the lane width direction is represented by the y-axis direction. The solid line Lt is a tangent to the lane boundary line L1 at the current position P1. The tangent line Lt is perpendicular to the lane width direction, and the x-axis direction in Figures 2 and 4 indicates the direction of the tangent line Lt. Note that the lane boundary line L1 is the lane boundary line (first lane boundary line) closer to the vehicle than the lane boundary lines L1 and L2 on both sides in the lane width direction (left and right direction).

[0022] The controller 16 determines the forward gaze distance X trg_FIN The lane width direction position of the target in front of the vehicle 1 is set to the basic forward gaze point P f1 Set as. Here, the forward gaze distance X from the vehicle 1 trg_FIN Position P2 of lane boundary line L1 in the lane width direction just ahead of pre"Front lane boundary line position P pre ", for example, the front lane boundary line position P pre Based on the basic forward gaze point P f1 The lane width direction position may be set as follows. For example, the forward lane boundary line position P pre From the center of the lane, the target lane width distance Y trg The distance from the base forward gaze point P f1 The lane width direction position may be set as the lane width direction position.

[0023] For example, as shown in Figure 2, the target running trajectory T trg The above point is the basic forward gaze point P f1 When the target running trajectory T trg and the lane boundary line L1 is the target lane width distance Y trg In addition, for example, the basic forward gaze point P f1 When setting the lane width, the half length of the lane width is the target lane width distance Y trg is set as In addition, the forward lane boundary line position P pre Instead, the basic forward gaze point P is used as the reference point for the center of the lane. f1 That is, the forward gaze distance X trg_FIN Alternatively, the lane center position at a position P2 just ahead of the vehicle may be used as the reference.

[0024] The basic forward gaze point P f1 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 trg Or, you can drive in the center of the lane along the lane. However, there are individual differences in the preferences of the occupants as to which trajectory the vehicle should travel along within the lane. trg Basic forward gaze point P above f1If 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.

[0025] Therefore, the controller 16 calculates the lane width direction position P s1 Depending on the basic forward gaze point P f1 By correcting the corrected forward gaze point P f2 The corrected forward gaze point P f2 The steering angle δ of the steered wheels is controlled so that the vehicle moves in the direction indicated by the arrow. The lane width direction position P s1 The lane width direction position P s1 Depending on the basic forward gaze point P f1 If the corrected forward gaze point P is corrected, it is possible to reduce the discomfort felt by the occupant. f2 Therefore, it is possible to reduce interference of the driving assist control with the steering force applied by the occupant. In addition, the basic forward gaze point P f1 is an example of the "first forward gaze point" in the claims, and the corrected forward gaze point P f2 is an example of a "second forward gaze point."

[0026] For example, the controller 16 detects the lateral deviation Y between the lane boundary line L1 and the vehicle 1 at the lane width direction position, thereby determining the lane width direction position P s1 Next, the controller 16 detects the target lane width distance Y trg The difference (Y trg -Y) is calculated as the offset distance Y0. The target lane width direction position P3 at the current position P1 of the vehicle 1 is a target lane width distance Y trg Since the lane width direction position P3 is a point separated by a distance of 100 mm, the offset distance Y0 is the distance between the lane width direction position P3 and the lane width direction position P s1 It is the distance between.

[0027] The controller 16 determines the basic forward gaze point P f1 By correcting the offset distance Y0 or less, the corrected forward gaze point P f2 For example, the controller 16 multiplies the offset distance Y0 by a gain K having a value greater than 0 and less than 1, and obtains the product (K×Y0) as the correction distance. The controller 16 determines the basic forward gaze point P f1 , from the target lane width direction position P3 to the lane width direction position P s1 (i.e., in the direction toward the lane boundary line L1) by the correction distance (K × Y0), and the corrected forward gaze point P f2 Calculate the corrected forward gaze point P f2 The steering angle δ of the steered wheels is controlled so that the vehicle moves in the direction indicated by the arrow.

[0028] As a result, when the driver steers, the current lane width direction position P s1 However, if the lane is offset from the target lane width direction position P3 by an offset distance Y0, the forward gaze point is corrected in the offset direction (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.

[0029] Next, the functions of the controller 16 will be described in more detail. Figure 3 is a block diagram of an example of the functional configuration of the controller 16. The controller 16 includes a gaze point setting unit 30, a target lane width direction position setting unit 31, a lane width direction position detection unit 32, a gain setting unit 33, an adder 34, subtractors 35 and 37, a multiplier 36, a target lateral force calculation unit 38, and a conversion unit 39. The gaze point setting unit 30 determines the forward gaze distance X trg_FIN For example, the gaze point setting unit 30 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_FINFor example, the gaze point setting unit 30 may set the forward gaze distance X as the longitudinal distance (i.e., the distance along the lane) that the host vehicle 1 moves in a predetermined time (e.g., 2 seconds). trg_FIN Set as.

[0030] The gaze point setting unit 30 also determines the forward lane boundary line position P pre For example, the gaze point setting unit 30 calculates the forward lane boundary line position P based on the curvature ρ of the lane boundary line L1, the curvature change ρ', the yaw angle deviation Ψ between the vehicle 1 and the lane boundary line L1, and the lateral deviation Y. pre Calculate. The curvature ρ, curvature change ρ', yaw angle deviation Ψ, and lateral deviation Y may be calculated based on, for example, an image of the surroundings of the host vehicle 1 captured by a camera of the external sensor 14. Alternatively, the current position and attitude of the host vehicle 1 may be calculated by odometry or dead reckoning using the vehicle sensor 15, or map matching using the detection signal of the external sensor 14, and the calculations may be performed based on the position information of the lane boundary line L1 and the lane shape stored in the map database 12.

[0031] For example, the gaze point setting unit 30 calculates the distance P from the tangent line Lt to the front lane boundary line position P based on the following equation (1). pre Lane boundary deviation Y, which is the distance to pre By calculating the tangent line Lt, the forward lane boundary line position P pre The lane width direction position of the vehicle may be calculated.

number

[0032] The target lane width direction position setting unit 31 sets the target lane width distance Y trg Set the target lane width distance Y trg By setting the target lane width direction position P f1 , P3 are set as lane width direction positions. For example, a target driving trajectory T trg If generated, the target driving trajectory T trg and the lane boundary line L1 is set as the target lane width distance Y trgFor example, when the vehicle is traveling in the center of the lane during lane departure prevention support, half the length of the lane width may be set as the target lane width distance Y trg It may be set as

[0033] The lane width direction position detection unit 32 detects a lateral deviation Y between the lane boundary line L1 and the vehicle 1 at a position in the lane width direction. The gain setting unit 33 sets the basic forward gaze point P f1 The gain setting unit 33 sets the gain K to a value greater than 0 and equal to or less than 1.

[0034] If the gain K is small, even if the occupant's steering causes an offset distance Y0 of the current position of the vehicle 1 from the target lane width direction position P3, the correction distance (K x Y0) will be small. Therefore, the occupant's steering will be less likely to be reflected in the setting of the forward gaze point. Conversely, if the gain K is large, the occupant's steering will be more likely to be reflected in the setting of the forward gaze point, thereby further reducing interference by the driving assist control with the occupant's steering force.

[0035] For example, the gain setting unit 33 may set a smaller gain K when the lateral deviation Y between the lane boundary line L1 and the host vehicle 1 is short compared to when the lateral deviation Y is long. For example, the shorter the lateral deviation Y, the smaller the gain K that may be set. This allows the steering force by the driving assist control to be increased in the range close to the lane boundary line L1 so as not to deviate from the lane.

[0036] Also, for example, a larger gain K may be set when the curvature ρ of the lane within a predetermined distance ahead of the current position P1 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, a larger gain K may be set when the curvature ρ is large, thereby further reducing interference by the driving assist control with the steering force applied by the occupant, thereby making it possible to prioritize the occupant's preferences.

[0037] 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.

[0038] Further, for example, it may be possible to determine whether the host vehicle 1 is facing toward the center of the lane based on the yaw angle deviation Ψ between the host vehicle 1 and the lane boundary line L1, and to reduce the gain K when the host vehicle 1 is facing toward the outside of the lane compared to when the host vehicle 1 is facing toward the center of the lane. This allows the steering force provided by the driving assist control to be increased so as not to deviate from the lane. Further, for example, the gain setting unit 33 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.

[0039] The adder 34 calculates the lane boundary deviation Y pre and target lane width distance Y trg The sum of (Y pre +Y trg ) is calculated from the tangent Lt to the basic forward gaze point P f1 The distance in the lane width direction to the tangent line Lt is calculated. f1 The lane width direction position of the vehicle is calculated. The subtractor 35 calculates the target lane width distance Y trg Subtract the lateral deviation Y from the offset distance Y0 = Y trg Calculate -Y. A multiplier 36 multiplies the offset distance Y0 by a gain K to calculate a correction distance (K×Y0).

[0040] The subtractor 37 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) trg_FIN =Y pre +Y trg Calculate -(K×Y0). This difference Y trg_FIN is the basic forward gaze point P f1 The lane width direction position (i.e., the corrected forward gaze point P f2 ) and the tangent line Lt. trg_FIN By calculating the corrected forward gaze point P based on the tangent line Lt, f2 The lane width direction position is determined. trg_FIN "Target lane width direction distance trg_FIN " is sometimes written as ".

[0041] The target lateral force calculation unit 38 calculates the target lateral force based on the mass m of the host vehicle 1, the vehicle speed V, and the forward gaze distance X trg_FIN and the target lane width direction distance trg_FIN Based on the lateral deviation Y, the host vehicle 1 is adjusted to the corrected forward gaze point P f2 Target lateral force F directed towards y Calculate. Here, if the turning radius of the host vehicle 1 is represented as R, the target lateral force F y can be calculated using the following formula (2).

number

[0042] Therefore, the target lateral force calculation unit 38 calculates the target lateral force F based on, for example, the following equation (3): y may be calculated.

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[0043] The conversion unit 39 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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[0044] If the above correction distance (K × Y0) becomes too large, the corrected forward gaze point P f2 It is possible that the vehicle will be steering too far away from the center of the lane, causing the driver to feel uncomfortable. This situation will be explained with reference to Figure 4. Now, based on the current steering angle δ and vehicle speed V, the forward gaze distance X trg_FIN The lane width direction position of the vehicle 1 at the forward position P2 is P s2 Let us consider the case where it is estimated that: In such a case, the corrected forward gaze point P f2 The lane width direction position P s2 If it is set outside of this, the steering control will be performed in a direction that deviates from the lane center Lc, which may cause the driver to feel uncomfortable.

[0045] 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 P of the vehicle 1 at the forward position P2 s2 and the corrected forward gaze point P f2 is the lane width direction position P s2 Whether it is outside of the lane width direction position P s2 is the corrected forward gaze point P f2 and the lane center Lc), and f2 is the lane width direction position P s2 If it is outside the corrected forward gaze point P f2may be corrected to approach the lane center Lc. As a result, the correction distance (K × Y0) becomes too large and the corrected forward gaze point P f2 This can prevent the vehicle from moving too far away from the center of the lane, causing discomfort to the driver.

[0046] (operation) FIG. 5 is a flowchart of an example of a steering control method according to an embodiment. In step S1, the gaze point setting unit 30 calculates a forward gaze distance X trg_FIN Set. In step S2, the target lane width direction position setting unit 31 and the adder 34 calculate the basic forward gaze point P f1 Set. In step S3, the lane width direction position detection unit 32 detects the lane width direction position P s1 Detect. In step S4, the subtractor 35 calculates the offset distance Y0.

[0047] In step S5, the gain setting unit 33 sets the basic forward gaze point P f1 Set the gain K to adjust the correction distance (K × Y0) that corrects the above. In step S6, the multiplier 36 and the subtractor 37 calculate the basic forward gaze point P using the correction distance (K×Y0). f1 Correct the corrected forward gaze point P f2 Calculate. In step S7, the target lateral force calculation unit 38 and the conversion unit 39 calculate the corrected forward gaze point P f2 The steering angle δ of the steered wheels is controlled so that the vehicle moves to the target position. Then, the process ends.

[0048] (Effects of the embodiment) (1) The controller 16 sets a forward gaze distance, sets a lane width direction position at a position forward of the vehicle 1 by the forward gaze distance as the first forward gaze point, detects the first 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 lane width direction distance from the first lane boundary line, which is the lane width direction lane boundary line on both sides of the lane width direction that is closer to the vehicle, to the first forward gaze point and the lane width direction distance from the first lane boundary line to the first lane width direction position, calculates a second forward gaze point by moving the first forward gaze point toward the first lane boundary line in the lane width direction by a correction distance less than the offset distance, and controls the steering angle of the steered wheels so that the vehicle 1 moves toward the second 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.

[0049] (2) The controller 16 may calculate the correction distance by multiplying the offset distance by a gain having a value greater than 0 and less than 1. This makes it possible to calculate a correction distance that is equal to or less than the offset distance. (3) The controller 16 may detect the distance between the first lane boundary line and the host vehicle 1, and may reduce the gain when the distance is short compared to when the distance is long. 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 to prevent the host vehicle 1 from deviating from the lane.

[0050] (4) 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. (5) 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_FIN Therefore, 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.

[0051] (6) The controller 16 may detect the yaw angle of the vehicle 1 relative to the lane boundary line, and may reduce the gain when the vehicle 1 is facing toward the outside of the lane compared to when the vehicle 1 is facing toward the center of the lane. This allows the steering force provided by the driving assistance control to be increased so as not to deviate from the lane. (7) The controller 16 may estimate a second lane width direction position, which is the lane width direction position of the vehicle 1 at a point the forward gaze distance ahead, and if the second lane width direction position is between the second forward gaze point and the center of the lane, may correct the second forward gaze point to move closer to the center of the lane. This prevents the correction distance from becoming too large, causing the second forward fixation point to be too far away from the center of the lane, which can cause the driver to feel uncomfortable. [Explanation of symbols]

[0052] 1...Own vehicle, 10...Driver 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, 30...Gaze point setting unit, 31...Target lane width direction position setting unit, 32...Lane width direction position detection unit, 33...Gain setting unit, 34...Adder, 35, 37...Subtractor, 36...Multiplier, 38...Target lateral force calculation unit, 39...Conversion unit

Claims

1. Set the forward gaze distance, setting a predetermined position in a lane width direction at a position forward of the host vehicle by the forward gaze distance as a first forward gaze point; Detecting a first 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 a lane width direction distance from a first lane boundary line, which is a lane boundary line on both sides of the lane width direction that is closer to the vehicle, to the first forward gaze point and a lane width direction distance from the first lane boundary line to the first lane width direction position; calculating a correction distance by multiplying the offset distance by a gain having a value greater than 0 and less than 1; calculating a second headway point by moving the first headway point in the lane width direction toward the first lane boundary line by the correction distance; controlling the steering angle of the steered wheels so that the host vehicle moves toward the second forward gaze point; A steering control method comprising:

2. Detecting a distance between the first lane boundary line and the host vehicle; The gain is made smaller when the separation distance is short than when the separation distance is long.

2. The steering control method according to claim 1.

3. 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.

3. The steering control method according to claim 1 or 2.

4. Detecting the speed of the vehicle; The gain is increased when the vehicle speed is low compared to when the vehicle speed is high.

4. The steering control method according to claim 1, wherein the steering control method is a steering control method for steering a vehicle.

5. Detecting a yaw angle of the host vehicle relative to a lane boundary line; The gain is made smaller when the host vehicle is facing toward the outside of the lane than when the host vehicle is facing toward the center of the lane.

5. A steering control method according to claim 1, wherein the steering control method is a steering control method for steering a vehicle.

6. Estimating a second 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 second lane width direction position is between the second forward gaze point and a center of the lane, the second forward gaze point is corrected to approach the center of the lane.

6. A steering control method according to claim 1, wherein the steering control method is a steering control method for steering a vehicle.

7. a controller that sets a forward gaze distance, sets a predetermined lane width direction position at a position forward of the host vehicle by the forward gaze distance as a first forward gaze point, detects a first 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 lane width direction distance from a first lane boundary line that is the lane width direction lane boundary line on both sides of the lane width direction and the first forward gaze point and the lane width direction distance from the first lane boundary line to the first lane width direction position, calculates a correction distance by multiplying the offset distance by a gain having a value greater than 0 and less than 1, calculates a second forward gaze point that is obtained by moving the first forward gaze point by the correction distance in the lane width direction toward the first lane boundary line, and sets a target steering angle of steered wheels so that the host vehicle moves toward the second forward gaze 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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