JP2023049571A - Steering control method and steering control device - Google Patents

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

The present invention relates to a steering control method and a steering control device.

Patent Literature 1 describes a steering control device that controls a steering device of a vehicle such that a predetermined position in the lane width direction in front of the vehicle by a predetermined forward gaze distance is set as the forward gaze point, and the own vehicle moves toward the forward gaze point. It is

Japanese Patent Application Laid-Open No. 2003-312505

In the steering system disclosed in Patent Document 1, when the passenger performs a steering operation, the steering force from the steering control device interferes with the steering force applied by the passenger, which may give the passenger a sense of discomfort.
SUMMARY OF THE INVENTION It is an object of the present invention to reduce the interference of driving support control with the steering force of a passenger in driving support control for controlling the steering angle of the own vehicle so that the own vehicle faces a point of gaze ahead.

In the steering control method of one aspect of the present invention, a forward gaze distance is set, a predetermined position in the lane width direction at a position ahead of the host vehicle by the forward gaze distance is set as the first forward gaze point, and the current host vehicle Detects the first lane width direction position, which is the lane width direction position of the lane width direction, and detects the first lane boundary line, which is the lane boundary line on the side closer to the vehicle, among the lane boundary lines on both sides in the lane width direction to the first forward note Calculate the offset distance, which is the difference between the lane width direction distance to the viewpoint and the lane width direction distance from the first lane boundary line to the first lane width direction position, and calculate the offset distance in the lane width direction from the first forward fixation point. A second forward gaze point moved toward the first lane boundary line by the following correction distance is calculated, and the turning angle of the steerable wheels is controlled so that the vehicle advances to the second forward gaze point.

Advantageous Effects of Invention According to the present invention, in driving support control for controlling the steering angle of the own vehicle so that the own vehicle faces the point of sight ahead, it is possible to reduce interference by the driving support control with the steering force of the occupant.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of schematic structure of the vehicle which mounts the driving assistance device of embodiment. FIG. 4 is an explanatory diagram of an example of a steering control method according to the embodiment; 2 is a block diagram of an example of a functional configuration of a controller in FIG. 1; FIG. FIG. 10 is an explanatory diagram of an example of a method of correcting a corrected forward gaze point; 4 is a flowchart of an example of a steering control method according to the embodiment;

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals, and overlapping descriptions are omitted. Each drawing is schematic and may differ from the actual one. The embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is specific to the devices and methods illustrated in the following embodiments. not something to do. Various modifications can be made to the technical idea of the present invention within the technical scope described in the claims.

(composition)
The host vehicle 1 includes a driving assistance device 10 that assists driving of the host vehicle 1 . The driving support device 10 detects the driving environment around the own vehicle 1 and automatically controls the driving of the own vehicle 1 based on the detected driving environment. Assist driving of own vehicle 1 .
For example, the driving support for the own vehicle 1 by the driving support device 10 may include autonomous driving control in which the own vehicle 1 is automatically driven without the involvement of the passenger. However, the driving support by the driving support device 10 is not limited to such autonomous driving control. The driving assistance by the driving assistance device 10 may at least automatically control the steering angle of the own vehicle 1 . For example, the driving assistance by the driving assistance device 10 may be lane departure prevention assistance.

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 denoted as "map DB".
The positioning device 11 measures the current position of the own vehicle 1 . The positioning device 11 may for example comprise a Global Positioning System (GNSS) receiver. The GNSS receiver is, for example, a global positioning system (GPS) receiver or the like, and measures the current position of the vehicle 1 by receiving radio waves from a plurality of navigation satellites.

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 automatic driving. A 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.

The navigation device 13 recognizes the current position of the own vehicle 1 by the positioning device 11 and acquires map information on the current position from the map database 12 . The navigation device 13 sets the travel route to the destination input by the passenger, and provides route guidance to the passenger according to the travel route.
The navigation device 13 also outputs information on the set travel route to the controller 16 . The controller 16 automatically drives the own vehicle 1 so as to travel along the travel route set by the navigation device 13 when performing autonomous travel control.

The external sensor 14 detects various information (driving environment information) about the driving environment around the own vehicle 1 , such as objects around the own vehicle 1 . The external sensor 14 detects the surrounding environment of the own vehicle 1, such as objects existing around the own vehicle 1, the relative position between the own vehicle 1 and the object, the distance between the own vehicle 1 and the object, and the direction in which the object exists. . The external sensor 14 outputs information about the detected 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 own vehicle 1 with respect to the own vehicle 1 . Here, the target is, for example, a traffic light provided on the road on which the vehicle 1 travels, a line on the road surface (eg, a lane boundary line such as a white line), a curb on the road shoulder, a guardrail, or the like.

The external sensor 14 may comprise a monocular camera, such as a full HD resolution color camera. The camera captures an image including recognition targets of the surrounding environment of the vehicle 1 and outputs the captured image to the controller 16 as driving environment information.
In addition, the external sensor 14 may include a distance measuring device such as a laser range finder (LRF), a radar, or a LiDAR (Light Detection and Ranging) laser radar. The range finder detects, for example, the relative position determined by the relative distance and direction to objects existing around the vehicle. The ranging device outputs the detected ranging data to the controller 16 as driving environment information.

The vehicle sensor 15 detects various information (vehicle information) obtained from the own vehicle 1 . The vehicle sensor 15 includes, for example, a vehicle speed sensor that detects the running speed (vehicle speed) of the vehicle 1, a wheel speed sensor that detects the rotation speed of each tire of the vehicle 1, acceleration in three axial directions of the vehicle 1 ( 3-axis acceleration sensor (G sensor) that detects deceleration), steering angle sensor that detects steering angle (including steering angle), steering torque sensor that detects steering torque applied to the steering wheel by the occupant, automatic A gyro sensor that detects the angular velocity generated in the vehicle 1, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the operation amount of the accelerator pedal of the own vehicle 1, and a brake sensor that detects the brake operation amount by the passenger are included.

The controller 16 is an electronic control unit (ECU) that performs driving support control of the own vehicle 1 . During driving support control of the own vehicle 1, the controller 16 automatically controls the running of the own vehicle 1 based on the surrounding running environment.
Controller 16 includes a processor 20 and peripheral components such as 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, or the like. The storage device 21 may include memories such as a register, a cache memory, a ROM (Read Only Memory) used as a main memory, and a RAM (Random Access Memory).
The functions of the controller 16 to be described below are implemented, for example, by the processor 20 executing a computer program stored in the storage device 21 .

Note that the controller 16 may be formed of dedicated hardware for executing each information processing described below.
For example, controller 16 may comprise functional logic circuitry implemented in a general purpose semiconductor integrated circuit. For example, the controller 16 may comprise a programmable logic device (PLD), such as a Field-Programmable Gate Array (FPGA), or the like.

The actuator 17 operates the accelerator opening and the brake device of the own vehicle 1 according to the control signal from the controller 16 to generate driving force for driving the own vehicle 1 or braking force for braking the own 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 vehicle 1 . The brake control actuator controls the braking operation of the brake system of the host vehicle 1 .
Further, the actuator 17 may include a steering actuator that controls the steering direction and steering amount of the steering mechanism of the vehicle 1 . The actuator 17 may operate the steering mechanism of the own vehicle 1 according to the control signal from the controller 16 .

Next, the steering control of the controller 16 during the driving support control of the own vehicle 1 will be described.
In the steering control of the own vehicle 1, the controller 16 sets the forward gaze distance, and sets the forward gaze point at a predetermined position in the lane width direction ahead of the own vehicle 1 by the forward gaze distance. The steering angle δ of the steered wheels of the vehicle 1 is controlled so that the vehicle 1 runs toward the viewpoint.
FIG. 2 is an explanatory diagram of an example of the steering control method of the embodiment.

Broken lines L1 and L2 indicate lane boundary lines (line marks) on the left and right sides of the lane in which the vehicle 1 is traveling. A solid line T _trg indicates a target trajectory along which the vehicle 1 is to travel under the driving assistance control of the driving assistance device 10 (hereinafter referred to as a “target travel trajectory”).
For example, in autonomous travel control, the controller 16 and the navigation device 13 may generate the target travel trajectory _Ttrg of the vehicle 1 based on the set travel route and the surrounding travel environment. Further, for example, in the lane departure prevention support, the own vehicle 1 controller 16 controls the steering angle δ of the own vehicle so that the own vehicle 1 travels in a predetermined position in the lane width direction of the travel lane based on the surrounding traveling environment. . In this case, for example, the target travel trajectory _Ttrg is a line that is offset inward from the lane boundary lines L1 and L2 by a predetermined distance in the lane width direction. For example, the target travel trajectory _Ttrg may be the center of the lane.

The dashed-dotted line P1 indicates the current position of the vehicle 1 in the longitudinal direction along the lane, and the dashed-dotted line P2 indicates the position ahead of the vehicle 1 by the forward gaze distance _{Xtrg_FIN} .
In the following description, the term “lane width direction” is defined as the lane width direction of the vehicle 1 at the current position P1. 2 and 4, the lane width direction is represented by the y-axis direction.
A solid line Lt is a tangent to the lane boundary line L1 at the current position P1. The tangent line Lt is orthogonal to the lane width direction, and the x-axis direction indicates the direction of the tangent line Lt in FIGS. Note that the lane boundary line L1 is the lane boundary line (first lane boundary line) closer to the host vehicle among the lane boundary lines L1 and L2 on both sides in the lane width direction (horizontal direction).

The controller 16 sets a target lane width direction position ahead of the vehicle 1 by the forward gaze distance X _{trg_FIN} as a basic forward gaze point P _f1 .
Here, if the position P _pre of the lane boundary line L1 in the lane width direction at the position P2 ahead of the host vehicle 1 by the forward viewing distance X _{trg_FIN} is defined as the "front lane boundary line position P _pre ", for example, the front lane boundary line The lane width direction position of the basic forward gaze point P _f1 may be set with the position P _pre as a reference.
For example, a position at a target lane width distance Y _trg in the lane width direction toward the lane center from the forward lane boundary position P _pre may be set as the lane width direction position of the basic forward gaze point P _f1 .

For example, when a point on the target travel trajectory T _trg is set as the basic forward gaze point P _{f1 as} shown in FIG _. is set as Further, for example, when the basic forward gaze point _Pf1 is set at the center of the lane, the half length of the lane width is set as the target lane width distance _Ytrg .
Note that the basic forward gaze point P _f1 may be set based on the lane center position instead of the forward lane boundary position P _pre . That is, the lane center position at the position P2 ahead of the host vehicle 1 by the forward gaze distance X _{trg_FIN} may be used as a reference.

By controlling the steering angle δ of the steered wheels of the vehicle 1 so that the vehicle 1 travels toward the basic forward gaze point _Pf1 set in this way, the controller 16 causes the vehicle 1 to travel toward the target travel point. It can run along the trajectory T _trg . Alternatively, it can be driven in the center of the lane along the lane.
However, there are individual differences in occupant's preferences as to what kind of track the vehicle should run in the lane. Therefore, if the steering angle is uniformly controlled so as to direct the vehicle toward the basic forward gaze point _Pf1 on the target travel trajectory _Ttrg , it may not suit the occupant's taste. For this reason, when the passenger applies corrective steering, the steering force applied by the driving support device 10 interferes with the steering force applied by the passenger, which may give the passenger a sense of discomfort.

Therefore, the controller 16 calculates a corrected forward gaze point Pf2 by correcting the basic forward gaze point _Pf1 according to the lane width direction position _Ps1 at the current position P1 of the own vehicle 1, and calculates the corrected forward gaze point _Pf2 . The steering angle δ of the steerable wheels is controlled so as to proceed to the forward fixation point _Pf2 .
The lane width direction position P _s1 of the vehicle 1 at the current position P1 reflects the preferences of the occupant of the vehicle 1 as to what kind of track the vehicle should travel along. Therefore, by correcting the basic forward gaze point _Pf1 according to the lane width direction position _Ps1 , it is possible to set a corrected forward gaze point _Pf2 that does not give the passenger a sense of discomfort. Therefore, it is possible to reduce the interference of the driving support control with the steering force by the passenger.
The basic forward gaze point _Pf1 is an example of a "first forward gaze point", and the corrected forward gaze point _Pf2 is an example of a "second forward gaze point".

For example, the controller 16 detects the lane width direction position _Ps1 of the vehicle 1 by detecting the lateral deviation Y between the lane boundary line L1 and the vehicle 1 at the lane width direction position. Next, the controller 16 calculates the difference (Y _trg −Y) obtained by subtracting the lateral deviation Y from the target lane width distance Y _trg as the offset distance Y ₀ .
The target lane width direction position P3 at the current position P1 of _the host vehicle 1 is a point away from the lane boundary line L1 by the target lane width distance Y _trg . It becomes the distance between the direction position _Ps1 .

The controller 16 calculates a corrected forward gaze point _Pf2 by correcting the basic forward gaze point _Pf1 by a correction distance equal to or less than the offset distance _Y0 . For example, the controller 16 obtains the product (K×Y ₀ ) obtained by multiplying the offset distance Y ₀ by a gain K having a value greater than 0 and less than 1 as the correction distance.
The controller 16 shifts the basic forward gaze point P _f1 from the target lane width direction position P3 toward the lane width direction position P _s1 (that is, the direction toward the lane boundary line L1) by the correction distance (K×Y ₀ ). (move) to calculate the corrected forward gaze point _Pf2 , and control the turning angle δ of the steered wheels so as to advance to the corrected forward gaze point _Pf2 .

As a result, when the current position _Ps1 of the vehicle in the lane width direction is offset by the offset distance _Y0 from the target position P3 in the lane width direction due to steering by the occupant, the offset direction ( The forward gaze point is corrected in the left direction in the example), and the steering force for going in the opposite direction (the right direction in the example of FIG. 2) is reduced.
As a result, in the driving support control for controlling the steering angle δ of the own vehicle 1 so that the own vehicle 1 faces the point of sight ahead, it is possible to reduce the interference of the driving support control with the steering force of the occupant.

Next, functions of the controller 16 will be described in more detail. FIG. 3 is a block diagram of an example of the functional configuration of the controller 16. As shown in FIG. 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, and a multiplier. 36 , a target lateral force calculator 38 , and a converter 39 .
The gaze point setting unit 30 sets the forward gaze distance X _{trg_FIN} . For example, the gaze point setting unit 30 may set the forward gaze distance X _{trg_FIN} based on the vehicle speed of the own vehicle 1 detected by the vehicle speed sensor of the vehicle sensor 15 . For example, the point-of-regard setting unit 30 sets the longitudinal distance (that is, the distance along the lane) that the vehicle 1 moves in a predetermined time (for example, two seconds) as the forward gaze distance X _{trg_FIN} .

The point-of-regard setting unit 30 also calculates the front lane boundary line position P _pre . For example, the point-of-regard setting unit 30 determines the front lane boundary line position 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. Calculate P _pre .
The curvature ρ, the curvature change ρ′, the yaw angle deviation ψ, and the lateral deviation Y may be calculated, for example, based on the surrounding image of the vehicle 1 captured by the camera of the external sensor 14 . Alternatively, the current position and attitude of the vehicle 1 are calculated by odometry and dead reckoning using the vehicle sensor 15 and map matching using the detection signal of the external sensor 14, and the lane boundary line L1 stored in the map database 12 is calculated. It may be calculated based on the position information and the shape of the lane.

For example, the point-of-regard setting unit 30 calculates the lane boundary line deviation Y _pre , which is the distance from the tangent line Lt to the forward lane boundary line position P _pre , based on the following equation (1). The lane width direction position of the forward lane boundary line position P _pre may be calculated.

The target lane width direction position setting unit 31 sets the target lane width distance _Ytrg . By setting the target lane width distance Y _trg , the lane width direction positions of the target lane width direction positions P _f1 and P3 with reference to the lane boundary line L1 are set.
For example, when the target travel trajectory T _trg is generated by autonomous travel control or the like, the distance between the target travel trajectory T _trg and the lane boundary line L1 may be set as the target lane width distance Y _trg . Further, for example, when traveling in the center of the lane during lane departure prevention assistance, the target lane width distance Y _trg may be set to half the width of the lane.

The lane width direction position detector 32 detects a lateral deviation Y between the lane boundary line L1 and the host vehicle 1 at the lane width direction position.
The gain setting unit 33 sets a gain K for adjusting a correction distance (K×Y ₀ ) for correcting 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.

If the gain K is small, the corrected distance (K×Y ₀ ) becomes small even if the offset distance Y ₀ of the current position of the vehicle 1 from the target position P 3 in the lane width direction is generated by steering by the occupant. Therefore, it becomes difficult for the driver's steering to be reflected in the setting of the forward gaze point. On the contrary, when the gain K is large, the driver's steering is more likely to be reflected in the setting of the forward gaze point, so that the interference of the driver's steering force by the driving support control can be further reduced.

For example, the gain setting unit 33 may set a small gain K when the lateral deviation Y between the lane boundary line L1 and the vehicle 1 is short compared to when the lateral deviation Y is long. For example, a smaller gain K may be set as the lateral deviation Y becomes shorter. As a result, in a range close to the lane boundary line L1, the steering force by the driving support control can be increased so as not to deviate from the lane.

Further, for example, a large 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. When the vehicle is traveling on a curved road, the trajectory on which the vehicle is to travel depends greatly on the preference of the occupant. Therefore, when the curvature ρ is large, a large gain K is set to control driving support for the steering force by the occupant. By further reducing the interference caused by the vehicle, it is possible to give priority to the occupant's preference.

Further, for example, a large gain K may be set when the steering torque applied to the steering wheel by the occupant 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. As a result, when the passenger has a strong steering intention, priority can be given to steering by the passenger.
Further, for example, the gain K may be increased when the vehicle speed of the own vehicle 1 is low compared to 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} becomes short, so the steering by driving support control tends to be steep. Therefore, when the vehicle speed is low, a large gain K is set to further reduce the interference of the driving support control with the steering force of the occupant, thereby reducing the discomfort of the occupant.

Further, for example, based on the yaw angle deviation Ψ between the own vehicle 1 and the lane boundary line L1, it is determined whether or not the own vehicle 1 is facing the center of the lane. The gain K may be made smaller when the host vehicle 1 is facing the outside of the lane compared to the case. Thereby, the steering force by the driving support control can 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 passenger. As a result, it is possible to realize a steering feeling that suits the occupant's taste.

The adder 34 calculates the sum (Y _pre +Y _trg ) obtained by adding the lane boundary line deviation Y _pre and the target lane width distance Y _trg to obtain the lane width direction distance from the tangent line Lt to the basic forward gaze point P _f1 . Calculate As a result, the lane width direction position of the basic forward gaze point _Pf1 with reference to the tangent line Lt is calculated.
A subtractor 35 subtracts the lateral deviation Y from the target lane width distance Y _trg to calculate an offset distance Y ₀ =Y _trg -Y.
The multiplier 36 multiplies the offset distance Y ₀ by the gain K to calculate the correction distance (K×Y ₀ ).

_A subtractor 37 calculates a difference Y _{trg_FIN} = _{Y pre +} Y _trg − ₍ K _× Y ₀ ) is calculated.
This difference Y _{trg_FIN} is the distance between the lane width direction position (that is, the corrected forward gaze point P _f2 ) obtained by shifting the basic forward gaze point P _f1 by the correction distance (K×Y ₀ ) and the tangent line Lt. By calculating the difference Y _{trg_FIN} , the lane width direction position of the corrected forward gaze point P _f2 with reference to the tangent line Lt is determined. Hereinafter, the difference Y _{trg_FIN} may be referred to as "target lane width direction distance _{trg_FIN} ".

Based on the mass m of the vehicle 1, the vehicle speed V, the forward gaze distance X _{trg_FIN} , the target lane width direction distance _{trg_FIN} , and the lateral deviation Y, the target lateral force calculation unit 38 calculates the corrected forward force of the vehicle 1. A target lateral force _Fy directed toward the gaze point _Pf2 is calculated.
Here, if the turning radius of the host vehicle 1 is denoted by R, the target lateral force _Fy can be calculated by the following equation (2).

Therefore, the target lateral force calculator 38 may calculate the target lateral force _Fy based on the following equation (3), for example.

上式（４）において、Ｃは操向輪の転舵角δとステアリングホイールの操舵角との変換係数であり、ｌ_ｘはホイールベース長であり、Ａはステアビリティファクタである。
変換部３９は、アクチュエータ１７のステアリングアクチュエータを駆動することにより、目標転舵角δ_ｔａｒとなるように操向輪の転舵角δを制御する。 The conversion unit 39 converts the target lateral force F _y into a target steering angle δ _tar of the steerable wheels based on the following equation (4).

In the above equation (4), C is a conversion coefficient between the steering angle δ of the steered wheels and the steering angle of the steering wheel, _lx is the length of the wheel base, and A is the steering factor.
The conversion unit 39 drives the steering actuator of the actuator 17 to control the steering angle δ of the steered wheels so as to achieve the target steering angle _δtar .

If the corrected distance (K×Y ₀ ) becomes excessively large, the corrected forward gaze point P _f2 may be too far from the center of the lane, causing steering control that gives the driver a sense of discomfort.
This situation is explained with reference to FIG. Consider a case where the lane width direction position of the vehicle 1 at a position P2 ahead of the forward gaze distance _{Xtrg_FIN} is estimated to be _Ps2 based on the current steering angle δ and vehicle speed V. FIG.
In such a case, if the corrected forward gaze point P _f2 is set outside the lane width direction position P _s2 , the steering control is performed in the direction of deviating from the lane center Lc. may cause discomfort.

Therefore, the controller 16 estimates the lane width direction position _Ps2 of the vehicle 1 at the position P2 ahead of the forward gaze distance X _{trg_FIN} based on the current steering angle δ and the vehicle speed V of the vehicle 1, and calculates the corrected forward position P2. Whether or not the gaze point P _f2 is outside the lane width direction position P _s2 (that is, whether or not the lane width direction position P _s2 is between the corrected forward gaze point P _f2 and the lane center Lc) is determined. If the corrected forward gaze point _Pf2 is outside the lane width direction position _Ps2 , the corrected forward gaze point _Pf2 may be corrected so as to approach the lane center Lc.
As a result, it is possible to prevent the corrected distance (K×Y ₀ ) from being excessively large and the corrected forward gaze point P _f2 to be too far from the center of the lane, thereby giving the driver a sense of discomfort.

(motion)
FIG. 5 is a flowchart of an example of the steering control method of the embodiment.
In step S1, the gaze point setting unit 30 sets a forward gaze distance X _{trg_FIN} .
In step S2, the target lane width direction position setting unit 31 and the adder 34 set the basic forward gaze point _Pf1 .
In step S3, the lane width direction position detector 32 detects the lane width direction position _Ps1 of the vehicle 1 at the current position P1.
In step S4, the subtractor 35 calculates the offset distance _Y0 .

In step S5, the gain setting unit 33 sets a gain K for adjusting a correction distance (K×Y ₀ ) for correcting the basic forward gaze point _Pf1 .
In step S6, the multiplier 36 and the subtractor 37 correct the basic forward gaze point _Pf1 using the correction distance (K× _Y0 ) to calculate a corrected forward gaze point _Pf2 .
In step S7, the target lateral force calculation unit 38 and the conversion unit 39 control the steering angle δ of the steered wheels so that the vehicle advances to the corrected forward gaze point _Pf2 . Processing then ends.

(Effect of Embodiment)
(1) The controller 16 sets the forward gaze distance, sets the position in the lane width direction at a position ahead of the vehicle 1 by the forward gaze distance as the first forward gaze point, and sets the current lane width direction of the vehicle 1. The first lane width direction position is detected, and the lane from the first lane boundary line, which is the lane boundary line on the side closer to the vehicle among the lane boundary lines on both sides in the lane width direction, to the first forward gaze point. An offset distance, which is the difference between the width direction distance and the lane width direction distance from the first lane boundary line to the first lane width direction position, is calculated, and the first forward fixation point in the lane width direction is corrected to be less than or equal to the offset distance. A second forward gaze point moved to the first lane boundary line side by an amount is calculated, and the turning angle of the steerable wheels is controlled so that the vehicle 1 advances to the second forward gaze point.
As a result, in the driving support control that controls the steering angle of the own vehicle so that the own vehicle faces the point of sight ahead, it is possible to reduce the interference of the driving support control with the steering force of the occupant.

(2) The controller 16 may calculate the correction distance by multiplying the offset distance by a gain having a value greater than zero and less than one. Thereby, a correction distance equal to or less than the offset distance can be calculated.
(3) The controller 16 may detect the separation distance from the first lane boundary line to the vehicle 1, and reduce the gain when the separation distance is short compared to when the separation distance is long. As a result, in a range close to the lane boundary line, the steering force by the driving support control can be increased so as not to deviate from the lane.

(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 increase the gain when the curvature is large compared to when the curvature is small.
What kind of track the vehicle is to run on when traveling on a curved road is greatly different from the preference of the occupants. Therefore, by setting a large gain when the curvature ρ is large to reduce the interference of the driver's steering force by the driving support control, it is possible to give priority to the preference of the passenger.
(5) The controller 16 may detect the vehicle speed of the own vehicle 1 and increase the gain when the vehicle speed is low compared to when the vehicle speed is high. When the vehicle speed is low, the forward gaze distance X _{trg_FIN} becomes short, so the steering by driving support control tends to be steep. Therefore, by setting a large gain when the vehicle speed is low to further reduce the interference of the driving support control with the steering force of the passenger, the discomfort of the passenger can be reduced.

(6) The controller 16 detects the yaw angle of the vehicle 1 with respect to the lane boundary line, and adjusts the gain when the vehicle 1 faces the outside of the lane compared to when the vehicle 1 faces the center of the lane. You can make it smaller.
Thereby, the steering force by the driving support control can be increased so as not to deviate from the lane.
(7) The controller 16 estimates a second lane width direction position, which is the lane width direction position of the vehicle 1 at a point ahead by the forward gaze point, and the second lane width direction position is the second forward gaze point and the lane line. If it is between and the center, the second forward gaze point may be modified to be closer to the center of the lane.
As a result, it is possible to prevent the driver from feeling uncomfortable due to the correction distance being excessively large and the second forward gaze point being too far from the center of the lane.

Reference Signs List 1 own vehicle 10 driving support 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: point-of-regard 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: multiplication device, 38 ... target lateral force calculation unit, 39 ... conversion unit

Claims (8)

Set the forward gaze distance,
setting a predetermined position in the lane width direction at a position ahead of the own 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 own vehicle;
Distance in the lane width direction from the first lane boundary line, which is the lane boundary line closer to the vehicle, to the first forward gaze point, and from the first lane boundary line. calculating an offset distance that is a difference from the lane width direction distance to the first lane width direction position;
calculating a second forward gaze point by moving the first forward gaze point in the lane width direction toward the first lane boundary line by a correction distance equal to or less than the offset distance;
controlling the turning angle of the steerable wheels so that the own vehicle advances to the second forward gaze point;
A steering control method characterized by: 2. 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 less than 1. detecting a separation distance from the first lane boundary line to the own vehicle;
reducing the gain when the separation distance is short compared to when the separation distance is long;
The steering control method according to claim 2, characterized in that: Detecting the curvature of the lane from the current position of the vehicle to a predetermined distance ahead,
increasing the gain when the curvature is large compared to when the curvature is small;
The steering control method according to claim 2 or 3, characterized in that: detecting the vehicle speed of the own vehicle;
increasing the gain when the vehicle speed is low compared to when the vehicle speed is high;
The steering control method according to any one of claims 2 to 4, characterized in that: detecting the yaw angle of the own vehicle with respect to the lane boundary;
reducing the gain when the vehicle is facing the outside of the lane compared to when the vehicle is facing the center of the lane;
The steering control method according to any one of claims 2 to 5, characterized in that: estimating a second lane width direction position, which is the lane width direction position of the own vehicle at a point ahead of the forward gaze distance,
when the second lane width direction position is between the second forward gaze point and the lane center, correcting the second forward gaze point to approach the lane center;
The steering control method according to any one of claims 1 to 6, characterized in that: A forward gaze distance is set, a predetermined lane width direction position at a position ahead of the own vehicle by the forward gaze distance is set as a first forward gaze point, and the current lane width direction position of the own vehicle is set as the first forward gaze point. a lane width direction distance from a first lane boundary line, which is a lane boundary line on the side closer to the vehicle among lane boundary lines on both sides in the lane width direction, to the first forward gaze point; calculating an offset distance that is a difference from the lane width direction distance from the first lane boundary line to the first lane width direction position; a controller that calculates a second forward gaze point moved to the first lane boundary side by a distance, and sets a steering angle of a steerable wheel so that the host vehicle proceeds to the second forward gaze point;
an actuator that controls the steering angle of the steerable wheels according to the target steering angle;
A steering control device comprising:

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