JP5213576B2 - Lane departure prevention control device - Google Patents

Description

  The present invention relates to a lane departure prevention control device that applies a steering force to a steering mechanism of a vehicle such as an automobile to prevent departure from the lane.

The lane departure prevention control device performs control to prevent departure by applying a steering force in a direction to return the host vehicle to the center of the lane according to the departure tendency of the host vehicle from the traveling lane. In the lane departure prevention control, for example, a target travel position is set at the center of the lane and the steering force is set so that the deviation of the lateral position of the host vehicle with respect to the target travel position is reduced.
In such lane departure prevention control, it is known to use integral control in which an integral term based on the integral value of the deviation is provided when calculating the target steering force. It is known that such an integral term is effective as a compensation for a lateral force disturbance caused by a side wind or a road surface inclination (cant).

For example, Patent Document 1 discloses a disturbance due to a slope of a curved road surface, etc. by calculating a steering assist torque using an integral term of a lane offset (deviation) and resetting the integral term according to a curve state of a traveling lane. A vehicle steering assist device that suppresses the influence of the above is described.
Further, as a technique for suppressing the influence of an external force acting on a vehicle, Patent Document 2 discloses a steering control torque that can be easily overcome by a driver even when a lateral acceleration such as a centrifugal force during turning is applied. Therefore, it is described that the control torque calculated based on the lateral deviation amount (deviation) is corrected based on the lateral acceleration.
JP 2005-343260 A Japanese Patent Laid-Open No. 11-147481

As a problem of control having an integral term as in Patent Document 1, there is a delay due to integration. For example, when the lateral position of the host vehicle changes in a direction deviating from the lane due to sudden disturbance, there is a concern that disturbance compensation by the integral term is not in time, and the deviation cannot be effectively prevented.
On the other hand, when the gain of the integral term is increased, the delay can be reduced, but there is a problem that the convergence of the vehicle trajectory deteriorates due to overshoot.
An object of the present invention is to provide a lane departure prevention control device capable of preventing lane departure even when sudden disturbance occurs.

The present invention solves the above-described problems by the following means.
According to a first aspect of the present invention, there is provided a lane departure prevention control device for applying a steering force to a steering mechanism so as to prevent a departure of the host vehicle from the traveling lane, and a lateral speed detecting means for detecting a lateral speed of the host vehicle with respect to the traveling lane. And a first steering force that sets a first steering force in a direction that prevents deviation from the traveling lane by integrating a deviation between a target lateral position set in the traveling lane and a lateral position of the host vehicle. Force setting means, second steering force setting means for setting a second steering force in a direction to prevent deviation from the travel lane based on the lateral speed, the first steering force and the second steering force Steering force control means for applying a steering force to the steering mechanism based on a steering force, and the steering force control means only when the vehicle detects the lateral speed in a direction deviating from the travel lane. The first steering force and the second steering force A lane departure prevention control device characterized by adding said steering force on the basis of.

According to a second aspect of the present invention, the steering force control means stops applying the steering force based on the second steering force when the host vehicle is traveling in the center of the lane, and The lane departure prevention control device according to claim 1, wherein the steering force is applied based on the steering force .
Invention 請 Motomeko 3 is provided with a turn signal operation detecting means for detecting a turn signal operation by the driver, the steering force control means, the second steering force when the turn signal operation is detected 3. The lane departure prevention control device according to claim 1, wherein the application of the steering force based on the lane departure is stopped.

According to the present invention, the following effects can be obtained.
(1) The second steering force is set in a direction to prevent deviation based on the lateral velocity, and the steering force is applied to the steering mechanism based on the second steering force, so that the rapid lateral velocity generated due to sudden disturbance is prevented. The lane departure can be prevented by exhibiting the damping effect.
(2) When the driver wants to shift the traveling position of the host vehicle in the lane by stopping the application of the steering force based on the second steering force when the host vehicle is traveling in the center of the lane. The second steering force according to the speed is set and no interference occurs, and the driver does not feel uncomfortable.
(3) By adding a steering force based on the second steering force only when the vehicle detects a lateral speed in a direction that deviates from the traveling lane, the second steering force acts only in a direction that prevents the departure. However, it does not prevent the host vehicle from returning to the lane center side.
(4) When a turn signal operation is detected, by interrupting the application of the steering force based on the second steering force, an interference occurs when the driver intentionally departs the lane due to a lane change or the like Is unlikely to occur and does not give a sense of incongruity.

The present invention aims to provide a lane departure prevention control device that can prevent lane departure even when sudden disturbance occurs, and to use a steering force obtained by multiplying a lateral speed of the vehicle with respect to the lane by a gain as a steering mechanism. Therefore, it was resolved to grant and child.

Hereinafter, a first embodiment of a lane departure prevention control apparatus to which the present invention is applied will be described.
The lane departure prevention control device according to the first embodiment is provided, for example, in a four-wheeled vehicle such as a passenger car that steers the two front wheels.
FIG. 1 is a diagram illustrating a system configuration of a vehicle including a lane departure prevention control device according to a first embodiment.
The lane departure prevention control device alerts the driver of the departure and returns the vehicle toward the center of the lane when the tendency of the vehicle to depart from the driving lane is determined. Is given.
The steering mechanism 10 performs steering by rotating the housing H that supports the front wheel FW about a predetermined steering axis (king pin).

The steering mechanism 10 includes a steering wheel 11, a steering shaft 12, a steering gear box 13, a tie rod 14, and the like.
The steering wheel 11 is an annular operation member through which a driver inputs a steering operation.
The steering shaft 12 is a rotating shaft that transmits the rotation of the steering wheel 11 to the steering gear box 13.
The steering gear box 13 includes a rack and pinion mechanism that converts the rotational movement of the steering shaft 12 into a straight movement in the vehicle width direction.
The tie rod 14 is a shaft-like member having one end connected to the rack of the steering gear box 13 and the other end connected to the knuckle arm of the housing H. The tie rod 14 pushes and pulls the knuckle arm of the housing H to rotate the housing and perform steering.

  The vehicle also includes an electric power steering (EPS) control unit 20, a steering control unit 30, an engine control unit 40, a transmission control unit 50, a vehicle integration unit 60, and the like.

The EPS control unit 20 comprehensively controls the electric power steering apparatus that generates a steering assist force in accordance with the driver's steering operation. The EPS control unit 20 is connected to an electric actuator 21, a steering angle sensor 22, a torque sensor 23, and the like.
The electric actuator 21 is, for example, an electric motor that is provided in the middle of the steering shaft 12 and applies a steering torque (steering force) to the steering mechanism 10 via a speed reduction mechanism.
The steering angle sensor 22 includes an encoder that detects the angular position of the steering shaft 12 (substantially equal to the angular position of the staying wheel 11).
The torque sensor 23 is inserted into the steering shaft 12 between the electric actuator 21 and the steering wheel 11 and detects torque acting on the steering shaft 12. Normally, the torque detected by the torque sensor 23 is substantially equal to the steering torque input to the steering wheel 11 by the driver.

The steering control unit 30 performs vehicle steering control and ABS control for individually controlling the braking force of each wheel brake. In vehicle stability control, when understeer or oversteer occurs, the braking force on the turning inner wheel side and the outer wheel side is made different to generate a yaw moment in the restoring direction. ABS control (anti-lock brake control) is for reducing and recovering the braking force of a wheel when the tendency of the wheel to lock is detected.
The steering control unit 30 is connected to a hydraulic control unit (HCU) 31, a vehicle speed sensor 32, a yaw rate sensor 33, a lateral acceleration (lateral G) sensor 34, and the like.

The HCU 31 is a device that individually controls the brake fluid hydraulic pressure applied to the hydraulic service brake of each wheel. The HCU 31 includes a motor pump that pressurizes the brake fluid, a solenoid valve that adjusts the pressure applied to the caliper cylinder of each wheel, and the like.
The vehicle speed sensor 32 is provided in a housing that holds the hub bearing of each wheel, and outputs a vehicle speed pulse signal corresponding to the wheel speed. The vehicle speed pulse signal is subjected to predetermined processing, whereby the traveling speed of the vehicle can be obtained.
The yaw rate sensor 33 and the lateral G sensor 34 include a MEMS sensor that detects a rotational speed around the vertical axis of the vehicle body and a lateral acceleration, respectively.

The engine control unit 40 controls the engine, which is a driving power source for the vehicle, and its auxiliary equipment.
The transmission control unit 50 controls the automatic transmission that shifts the output of the engine and transmits it to the front and rear differentials.
The vehicle integration unit 60 controls the electrical components of the vehicle other than those related to each unit.
A turn signal switch 61 is connected to the vehicle integration unit 60. The turn signal switch 61 is for the driver to turn on and off a turn signal lamp (not shown).

Further, the lane departure prevention apparatus of the first embodiment includes a lane departure prevention control unit 100 described below.
The lane departure prevention control unit 100 is a main body part of the lane departure prevention control device according to the present invention, and the EPS control unit 20, the operation control unit 30, the engine control unit 40, the transmission control unit 50, the vehicle integrated unit described above. 60, for example, via a vehicle-mounted LAN such as a CAN communication system, and various information and signals can be acquired.

  The lane departure prevention control unit 100 includes an environment recognition unit 110, a host vehicle traveling path estimation unit 120, a deviation control steering force calculation unit 130, a lateral speed detection unit 140, a lateral speed control steering force calculation unit 150, and a target steering force setting. Means 160, steering force control means 170, etc. are provided. Each of these means may be configured as independent hardware, or a part or all of them may be configured as common hardware.

The environment recognition unit 110 recognizes the environment ahead of the host vehicle based on image information obtained by imaging the front of the host vehicle, and sets the traveling lane of the host vehicle.
The environment recognition unit 110 is connected to a stereo camera 111, an image processing unit 112, and the like.

The stereo camera 111 includes, for example, a pair of main cameras and sub-cameras provided near the room mirror base at the upper end of the front window of the vehicle. Each of the main camera and the sub camera has a CCD camera. The main camera and the sub camera are installed apart from each other in the vehicle width direction. The main camera and the sub camera capture a reference image and a comparative image, respectively, and output image data related to these images to the image processing unit 112.
The image processing unit 112 performs A / D conversion on the image data of the reference image and the comparison image output from the stereo camera 111, performs predetermined image processing, and outputs the result to the environment recognition unit 110. This image processing includes, for example, correction of an attachment position error of each camera, noise removal, gradation optimization, and the like. The digitized image has, for example, a plurality of pixels arranged in a matrix in the vertical direction and the horizontal direction. Each of these pixels has a luminance value corresponding to the brightness of the subject.

  The environment recognition unit 110 detects the parallax of a pixel group that is a block composed of an arbitrary pixel or a plurality of pixels on the reference image based on the data of the reference image and the comparison image. This parallax is the amount of deviation between the position on the reference image and the position on the comparison image of a certain pixel or pixel group. Using this parallax, the distance from the vehicle to the subject corresponding to the pixel can be calculated based on the principle of triangulation.

The environment recognizing means 110 sets the traveling lane of the host vehicle by recognizing the shape of the white line arranged at both ends of the lane ahead of the host vehicle. In this specification, claims, etc., a white line means a continuous line or a broken line drawn at the end in the width direction of the lane, and the actual color is other than white (for example, amber) Includes lines.
FIG. 2 is a diagram illustrating an example of a planar arrangement of the host vehicle and the travel lane.
The environment recognizing means 110 detects the white line WL portion from the reference image data based on the luminance data of each pixel corresponding to the location on the road surface. The orientation of the pixel group of the white line WL portion with respect to the host vehicle is detected based on the pixel position on the image data. Specifically, an area corresponding to a pixel position in the vertical direction on the road surface is scanned in the horizontal direction, and a portion where the luminance value changes suddenly is recognized as a lane outline. And the position of a white line is detected by calculating the distance of the pixel group of the said white line part using the parallax mentioned above.

The environment recognizing means 110 continuously detects the position of the white line, sets a plurality of lane candidate points P _L in the traveling direction of the vehicle, ignores the lane candidate points P _L that cannot be matched, A lane shape in front of the host vehicle is recognized by performing a complementary process using least square approximation.
Here, the white line WL is approximated by Equation 1 below.

y = ax ² + bx + c (Expression 1)
a, b, c: constants

Here, c represents the distance from the center of gravity of the vehicle to the left and right lane edges, and the sum of c (C_right) on the right white line and c (C_left) on the left white line represents the lateral deviation from the center of the lane of the vehicle, These differences indicate the lane width.
The environment recognition unit 110 also functions as a target travel position setting unit that sets the target travel position Xc at the center of the white line WL on the left and right lanes.

Ｘｅ［ｍ］：注視距離における自車両重心の推定横位置
α［ｒａｄ］：ハンドル角度
Ａ：スタビリティファクタ
Ｖ［ｋｍ／ｈ］：車速
ｌ_ｗ［ｍ］：ホイールベース
ｎ_ｓｇｒ：ステアリングギアレシオ
The own vehicle traveling path estimation means 120 is based on information from the environment recognition means 110, the running state of the vehicle detected by the rudder angle sensor 21, the vehicle speed sensor 32, the yaw rate sensor 33, and the known vehicle specifications. The traveling path of the host vehicle is estimated.
The vehicle traveling path is estimated by, for example, calculating the lateral position of the center of gravity of the vehicle at a gaze distance Z that is a predetermined distance ahead of the vehicle. The gaze distance Z is a predetermined distance in front of the host vehicle, and is set, for example, at a position where the host vehicle reaches several seconds later (for example, about 2 seconds).
The following description will be made using a coordinate system having the center of gravity of the host vehicle as the origin, the X axis extending in the vehicle width direction, and the Z axis extending forward of the vehicle body.
The lateral position Xe of the own vehicle traveling path at the gaze distance Z is obtained by the following formula 2.

Xe [m]: Estimated lateral position of the center of gravity of the vehicle at the gaze distance α [rad]: Steering angle A: Stability factor V [km / h]: _Vehicle speed l _w [m]: Wheel base n _sgr : Steering gear ratio

The deviation control steering force calculation means 130 is a deviation control based on a deviation ΔX which is a difference between the target travel position Xc set by the environment recognition means 110 and the lateral position Xe of the own vehicle OV calculated by the own vehicle traveling path estimation means 120. The steering torque τ1 is calculated. The deviation control steering force calculation means 130 is, for example, a third-order control term obtained by multiplying a value obtained by squaring the deviation ΔX by a predetermined gain Gx, an integral term obtained by multiplying a value obtained by integrating the deviation ΔX by a predetermined gain Gi, and the like. Is added to calculate the steering torque τ1.
This deviation control steering force calculation means 130 functions as the first steering force setting means according to the present invention.

  The lateral speed detection means 140 detects the lateral speed V_lat with respect to the lane of the host vehicle OV. The lateral speed detecting means 140 performs the time differentiation of the deviation ΔX between the target travel position Xc set by the environment recognizing means 110 and the lateral position Xe of the own vehicle OV calculated by the own vehicle traveling path estimating means 120, thereby obtaining the lateral speed V_lat. Is detected.

The lateral speed control steering force calculation means 150 calculates a steering torque τ2 by lateral speed control (hereinafter referred to as lateral position damping control) based on the lateral speed V_lat of the host vehicle OV detected by the lateral speed detection means 140. For example, the lateral speed control steering force calculation unit 150 calculates the steering torque τ2 by multiplying the lateral speed V_lat by a predetermined gain Gv.
The lateral speed control steering force calculation means 150 is such that the lateral position Xe of the host vehicle OV is outside the predetermined dead zone lateral position, the lateral speed V_lat is in the lane departure direction, and driver intervention and other control operations are performed. The steering torque τ2 is set only when there is not. This point will be described in detail later.
FIG. 3 is a schematic plan view showing the effect of the lateral position damping control. As shown in FIG. 3, when the host vehicle OV has a tendency to deviate with a lateral speed V_lat approaching the white line WL, the steering torque τ2 corresponding to the lateral speed V_lat by the lateral position damping control It exhibits an effect similar to the virtual damper it has and acts as a drag against lane departure.
The lateral speed control steering force calculation means 150 functions as a second steering force setting means according to the present invention.

  The target steering force setting unit 160 adds the steering torques τ1 and τ2 calculated by the deviation control steering force calculation unit 130 and the lateral speed control steering force calculation unit 150, respectively, and performs necessary corrections to obtain the target steering torque τ. It is to set.

The steering force control means 170 drives the electric actuator 21 via the EPS control unit 20 based on the target steering torque τ set by the target steering force setting means 160, and gives the steering mechanism 10 steering torque. .
The target steering force setting means 160 and the steering force control means 170 cooperate to function as the steering force control means according to the present invention.

Next, the lateral position damping control in the lane departure prevention control apparatus according to the first embodiment will be described.
FIG. 4 is a flowchart showing lateral position damping control. Hereinafter, the steps will be described step by step.
<Step S01: Environmental recognition>
The environment recognition unit 110 measures the deviation ΔX = Xc−Xe as the lateral position in the lane of the host vehicle OV.
Thereafter, the process proceeds to step S02.

<Step S02: White line lateral velocity calculation>
The lateral speed detecting means 140 calculates the lateral speed V_lat with respect to the lane of the host vehicle OV based on the differential value of the deviation ΔX.
Thereafter, the process proceeds to step S03.

<Step S03: Dead zone determination>
When the deviation ΔX of the lateral position Xe of the host vehicle OV with respect to the target travel position Xc is greater than or equal to the dead zone lateral position, which is a predetermined threshold, the lateral speed control steering force calculation means 150 assumes that the host vehicle is outside the dead zone region. Proceeding to step S04, otherwise, assuming that it is in the dead zone region, the process returns to step S01 and the subsequent processing is repeated. Here, the dead zone region is a region in which the steering torque by the lateral position damping control is not set when the host vehicle is set in the center of the traveling lane.

<Step S04: Lane lateral speed direction determination>
The lateral speed control steering force calculation means 150 determines the direction of the lateral speed V_lat with respect to the lane of the host vehicle OV. Specifically, the signs of the lateral position in the lane and the lateral speed direction are discriminated. If they are the same sign, it is assumed that the host vehicle OV has a lateral speed V_lat in the direction deviating from the lane, and the process proceeds to step S05. In the case of an opposite sign, it is assumed that the host vehicle OV has a lateral speed V_lat in a direction to return to the lane center side, and the process returns to step S01 and the subsequent processing is repeated.

<Step S05: Driver Intervention Determination>
The lateral speed control steering force calculation means 150 determines whether or not the driver is intentionally intervening to depart from the lane. Specifically, if the turn signal switch 61 is OFF and the output of the torque sensor 23 is equal to or lower than a predetermined threshold value, the process proceeds to step S06 assuming that there is no intervention by the driver, and otherwise the intervention by the driver. Returning to step S01, the subsequent processing is repeated.

<Step S06: Other control operation status determination>
The lateral speed control steering force calculating means 150 assumes that the host vehicle OV is in an emergency situation in which emergency avoidance is necessary when the steering control unit 30 is executing the vehicle steering control or ABS control described above. The steering assist is not performed, the process returns to step S01, and the subsequent processing is repeated. Otherwise, the process proceeds to step S07.

<Step S07: Implementation of lateral position damping control>
The lateral speed control steering force calculation means 150 sets the steering torque τ2 by the lateral position damping control described above. This steering torque τ 2 is reflected in the target steering torque τ set by the target steering force setting means 160 and is applied to the steering mechanism 10 by the electric actuator 21.
Thereafter, the series of processing is terminated (returned).

According to the first embodiment described above, the following effects can be obtained.
(1) Based on the lateral speed V_lat, the steering torque τ2 is set in a direction to prevent deviation, and the steering torque τ is applied to the steering mechanism 10 based on the steering torque τ2, thereby causing a high lateral speed V_lat generated by sudden disturbance. On the other hand, a lane departure can be prevented by exhibiting a damping effect.
(2) When the driver wants to shift the traveling position of the own vehicle OV in the lane by canceling the lateral position damping control when the own vehicle OV is traveling in the dead zone set in the center of the lane. The steering torque τ2 corresponding to the lateral speed V_lat is set so that no interference occurs and the driver does not feel uncomfortable.
(3) By adding the steering force τ2 based on the lateral position damping control only when the vehicle OV detects the lateral velocity V_lat in the direction deviating from the traveling lane, the vehicle OV is prevented from returning to the lane center side. Absent.
(4) When a turn signal operation is detected by the turn signal switch 61, the lateral position damping control is stopped, so that when the driver deliberately departs from the lane, interference does not easily occur and a sense of incongruity is given. There is no.

Next, a reference example of a lane departure prevention control apparatus to which the present invention is applied will be described. In addition, about the location substantially the same as Example 1 mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted and a difference is mainly demonstrated.
The lane departure prevention control device of the reference example includes a lane departure prevention control unit 200 described below instead of the lane departure prevention control unit 100 of the first embodiment.
The lane departure prevention control unit 200 includes, in place of the lateral speed control steering force calculation means 150 in the lane departure prevention control unit 100 of the first embodiment, a gain correction means 210, a departure determination means 220, a threshold value correction means 230, and the like described below. I have.

The gain correction unit 210 corrects the gain of the tertiary control of the deviation control steering force calculation unit 130 according to the in-lane lateral speed V_lat of the host vehicle OV detected by the lateral speed detection unit 140.
FIG. 6 is a graph showing a change in the steering torque τ with respect to the deviation ΔX when the gain is corrected by the gain correction unit 210.
The gain correction unit 210 increases the gain of the tertiary control from G0 to G1, and further from G1 to G2 in accordance with the increase in the lateral speed V_lat. As a result, as shown in FIG. 6, the steering torque τ also increases, and the increase in the steering torque τ becomes remarkable particularly in the region where the deviation ΔX is large.

  The departure determination unit 220 determines the departure of the host vehicle when the deviation ΔX between the target travel position Xc and the lateral position Xe of the host vehicle exceeds a predetermined threshold. When the departure determination is established, the target steering force setting means 160 causes the driver to vibrate the steering wheel 11 by including, for example, a pulsed component τp that is periodically turned on and off in the target steering torque τ. Perform alarm control to notify deviation.

The threshold correction unit 230 corrects the threshold used in the departure determination unit 220 according to the lateral speed V_lat of the host vehicle OV detected by the lateral speed detection unit 140. The threshold correction unit 230 performs correction to change the threshold from ΔX0 to ΔX1 and further from ΔX1 to ΔX2 in accordance with the increase in the lateral velocity V_lat.
FIG. 7 is a schematic plan view showing the relationship between the vehicle lateral position and the deviation determination threshold value. The threshold value is shifted to the lane center side (target travel position Xc side) according to the increase in the lateral speed, and as a result, the timing at which the departure determination is established is advanced.

Next, the departure prevention threshold value and gain change control in the lane departure prevention control device of the reference example will be described.
FIG. 8 is a flowchart showing deviation prevention threshold value and gain change control. Hereinafter, the steps will be described step by step.
<Step S11: Environmental recognition>
The environment recognition unit 110 measures the deviation ΔX = Xc−Xe as the lateral position in the lane of the host vehicle OV.
Thereafter, the process proceeds to step S12.

<Step S12: Calculation of lateral speed in white line>
The lateral speed detecting means 140 calculates the lateral speed V_lat with respect to the lane of the host vehicle OV based on the differential value of the deviation ΔX.
Thereafter, the process proceeds to step S13.
<Step S13: Deviation determination lateral position setting>
The departure determination means 220 sets the departure determination lateral position, which is a threshold for departure determination, to ΔX0.
Thereafter, the process proceeds to step S14.

<Step S14: Driver Intervention Determination>
The gain correction unit 210 and the threshold correction unit 230 determine whether or not the driver is intentionally intervening to depart from the lane. Specifically, if the turn signal switch 61 is OFF and the output of the torque sensor 23 is equal to or lower than a predetermined threshold value, the process proceeds to step S15 assuming that there is no intervention by the driver, and otherwise the intervention by the driver. It returns to step S11 as there is, and the subsequent processing is repeated.

<Step S15: Vehicle lateral speed determination (1)>
The gain correction unit 210 and the threshold correction unit 230 determine whether or not the lateral speed V_lat is equal to or greater than a predetermined lateral speed threshold value 1. If the lateral speed threshold value is equal to or greater than 1, the process proceeds to step S16, and otherwise returns to step S11. Repeat the subsequent processing.
<Step S16: Vehicle lateral speed determination (2)>
The gain correction unit 210 and the threshold correction unit 230 determine whether or not the lateral speed V_lat is equal to or greater than the predetermined lateral speed threshold 2. If the lateral speed V_lat is greater than or equal to the lateral speed threshold 2, the process proceeds to step S17. . Here, the lateral speed threshold 2 is set larger than the lateral speed threshold 1 described above.

<Step S17: Set white line horizontal position shift ΔX2>
The threshold value correction means 230 sets a threshold value ΔX2 that is offset to the lane center side from the initial value ΔX0 as the threshold value for departure determination used in the departure determination means 220. This threshold value ΔX2 is offset toward the lane center side with respect to the threshold value ΔX1.
The departure determination means 220 performs departure determination using this threshold value ΔX2.
Thereafter, the process proceeds to step S18.
<Step S18: Set gain G2 for tertiary control>
The gain correction unit 210 sets a gain G2 larger than the gain G0, which is an initial value, as the gain of the tertiary control used in the deviation control steering force calculation unit 130. The gain G2 is set larger than the gain G1.
The deviation control steering force calculation means 130 calculates the steering torque τ1 using this gain G2.
Thereafter, the series of processing is terminated (returned).

<Step S19: Set white line horizontal position shift ΔX1>
The threshold correction unit 230 sets a threshold value ΔX1 that is offset toward the lane center side from the initial value ΔX0 as the threshold value for departure determination used in the departure determination unit 220.
The departure determination means 220 performs departure determination using this threshold value ΔX1.
Thereafter, the process proceeds to step S20.
<Step S20: Set the third control gain G1>
The gain correction unit 210 sets a gain G1 larger than the gain G0 that is an initial value as a gain of the tertiary control used in the deviation control steering force calculation unit 130.
The deviation control steering force calculation means 130 calculates the steering torque τ1 using this gain G1.
Thereafter, the series of processing is terminated (returned).

According to the reference example described above, the following effects can be obtained.
(1) By shifting the threshold value in the departure determination means 220 to the center side of the traveling lane according to the increase in the lateral speed V_lat, when the lateral speed V_lat is large and the margin time until the departure is short, the lane center side is relatively Even when the vehicle is running, by establishing departure judgment, the timing at which departure judgment is established can be advanced, the steering wheel can be vibrated, an alarm can be issued, and lane departure can be prevented.
(2) By increasing and correcting the steering torque setting gain for the tertiary control in the direction to prevent the departure from the driving lane according to the increase in the lateral speed V_lat, the marginal time until the lateral speed V_lat is greatly increased If it is short, a large steering torque can be applied in the restoring direction to prevent lane departure.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) The configuration of the lane departure prevention control device and the content of the control are not limited to the configuration of the first embodiment described above, but can be changed as appropriate. For example, in the first embodiment, the steering torque τ2 proportional to the lateral speed is applied. However, the present invention is not limited to this, and other configurations may be used as long as the steering force can be obtained according to the increase in the lateral speed. . For example, a steering force proportional to the second or higher power value of the lateral speed may be applied .
(2) the actual Example 1, although the lane recognition means detects the lane shape using a stereo camera, the present invention is not limited to this, for example, map data and the host vehicle that has been prepared for the navigation system etc. You may make it detect a lane shape based on the positioning information of a position.
(3) The configuration of the actuator that applies the steering torque to the steering mechanism is not limited to the column assist type as in the first embodiment . For example, a pinion assist type that drives a pinion shaft connected to the steering shaft, a steering shaft A double pinion type that drives a pinion that is independent of the pinion connected to the rack, a rack direct acting type that drives the steering rack itself in a straight traveling direction, and the like may be used.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the system configuration | structure of the vehicle containing Example 1 of the lane departure prevention control apparatus to which this invention is applied. It is a figure which shows an example of the planar arrangement | positioning of the own vehicle and a driving lane. It is a typical top view which shows the effect of the lateral position damping control in the lane departure prevention control apparatus of Example 1. FIG. 3 is a flowchart illustrating lateral position damping control in the lane departure prevention control device according to the first embodiment. It is a figure which shows the system configuration | structure of the vehicle containing the reference example of the lane departure prevention control apparatus to which this invention is applied. It is a graph which shows the change of the steering torque with respect to the deviation at the time of correcting the gain of tertiary control with the lane departure prevention control device of a reference example . It is a typical top view which shows the relationship between the own vehicle side position and the departure determination threshold value in the lane departure prevention control apparatus of a reference example . It is a flowchart which shows change control of the departure prevention threshold value and gain in the lane departure prevention control apparatus of a reference example .

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Steering mechanism 11 Steering wheel 12 Steering shaft 13 Steering gear box 14 Tie rod FW Front wheel H Housing 20 Electric power steering (EPS) control unit 21 Electric actuator 22 Steering angle sensor 23 Torque sensor 30 Steering control unit 31 Hydraulic control unit (HCU) )
32 Vehicle speed sensor 33 Yaw rate sensor 34 Lateral acceleration (lateral G) sensor 40 Engine control unit 50 Transmission control unit 60 Vehicle integration unit 61 Turn signal switch 100 Lane departure prevention control unit 110 Environment recognition means 120 Own vehicle travel path estimation means 130 Deviation control Steering force calculation means 140 Lateral speed detection means 150 Lateral speed control steering force calculation means 160 Target steering force setting means 170 Steering force control means 200 Lane departure prevention control unit 210 Gain correction means 220 Deviation determination means 230 Threshold correction means

Claims (3)

In the lane departure prevention control device for applying a steering force to the steering mechanism so as to prevent the departure from the traveling lane of the host vehicle,
Lateral speed detecting means for detecting the lateral speed of the host vehicle with respect to the travel lane;
A first steering force setting that sets a first steering force in a direction that prevents deviation from the traveling lane by integrating the deviation between the target lateral position set in the traveling lane and the lateral position of the host vehicle. Means,
Second steering force setting means for setting a second steering force in a direction to prevent deviation from the travel lane based on the lateral speed;
Steering force control means for applying a steering force to the steering mechanism based on the first steering force and the second steering force ;
The steering force control means adds the steering force based on the first steering force and the second steering force only when the vehicle detects the lateral speed in a direction deviating from the travel lane. about
Lane departure prevention control apparatus according to claim. The steering force control means stops applying the steering force based on the second steering force when the host vehicle is traveling in the center of the lane, and controls the steering force based on the first steering force. The lane departure prevention control device according to claim 1, wherein: Provided with a turn signal operation detecting means for detecting a turn signal operation by a driver,
The steering force control unit, when the turn signal operation is detected according to claim 1 or claim 2, characterized in that to stop the application of the steering force based on the second steering force Lane departure prevention control device .

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