JP2009280077A - Lane deviation prevention device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lane deviation prevention device capable of properly determining a steering retaining state by a driver in a short time. <P>SOLUTION: The lane deviation prevention device includes a lane setting means 110 setting a traveling lane for one's own vehicle, a steering angle detection means 150 detecting a steering angle by the steering operation of the driver, a torque detection means 140 detecting input torque by the steering operation of the driver, a deviation determination means 130 determining the inclination of the one's own vehicle to deviate from the traveling lane, a steering control means 170 imparting steering torque in the form of pulse to a steering mechanism 10 in the direction of preventing a deviation when the inclination toward deviation is determined by the deviation determination means, and a steering retaining state detection means 160 determining the deterioration of the steering retaining state by the driver in the case where the displacement amount of the steering angle in imparting the steering torque in the form of pulse is not less than a predetermined threshold value or the input torque is not more than a predetermined threshold value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lane departure prevention apparatus provided in a vehicle such as an automobile, and more particularly to a device that generates a pulsating steering torque when a departure tendency of a host vehicle from a traveling lane (lane) is determined.

The lane departure prevention device recognizes the shape of the lane ahead of the host vehicle, and outputs a warning or returns a steering torque in a direction to return the host vehicle to the center of the lane when a tendency to depart from the lane of the host vehicle is determined. It is given to the steering mechanism.
For example, Patent Document 1 describes that when the estimated traveling path of the host vehicle deviates from a lane recognized by a stereo camera, a steering target position is set on the lane center side to perform steering control.

  Further, the lane departure prevention device, in order to increase the degree of freedom of operation by the driver, generates, for example, a pulsed steering torque at the time of determination of the departure tendency, and informs the driver of the departure tendency by vibration of the steering wheel. Some steering operations for returning to the center are performed by the driver himself.

  However, the magnitude of such a pulsed steering torque is set on the assumption that the state in which the driver holds the steering wheel (steering state) is normal. For this reason, for example, if the steering torque is generated when the steered state is lowered, such as when the driver releases it, there is a concern that a large steering angle is generated in the steering mechanism, and the behavior and the course of the vehicle are greatly disturbed. .

On the other hand, it can be considered that the above-described problem can be solved if it is possible to determine a decrease in the steering state of the driver.
For example, in Patent Literature 2, in a steer-by-wire system, when a current value of a reaction force motor connected to a steering wheel continues a predetermined current value that balances inertia and friction of the steering wheel for a predetermined time, release is determined. It is described.
Patent Document 3 describes that the steering state of the steering wheel by the driver is detected based on the work amount that is the product of the differential value of the steering angle and the steering input torque.
JP 2007-261449 A JP 2007-15529 A JP 2004-175122 A

However, since all of the above-described methods for determining the steered state require a certain amount of time for the determination, the steering torque is generated by the lane departure prevention control during the detection determination, and the vehicle behavior until the detection determination is completed. Etc. may be disturbed.
The subject of this invention is providing the lane departure prevention apparatus which can determine appropriately the steering state by a driver | operator in a short time.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 is a lane departure prevention apparatus that applies steering torque to a steering mechanism so as to prevent a departure from the traveling lane of the host vehicle, and obtains environmental information in front of the host vehicle and sets the traveling lane of the host vehicle. Lane setting means for detecting, a steering angle detecting means for detecting a steering angle by a driver's steering operation, a departure determining means for determining a departure tendency of the host vehicle from the traveling lane, and the departure determining means exhibit the departure tendency. And a steering control means for applying a pulsed steering torque to the steering mechanism in a direction to prevent deviation when determined, and a displacement amount of the steering angle when the pulsed steering torque is applied is a predetermined threshold value or more. In this case, a lane departure prevention device comprising: a steered state determining unit that determines a decrease in the steered state by the driver.

  According to a second aspect of the present invention, in a lane departure prevention apparatus that applies steering torque to a steering mechanism so as to prevent a departure from the traveling lane of the host vehicle, environmental information in front of the host vehicle is acquired to set the traveling lane of the host vehicle. A lane setting means for detecting, a torque detecting means for detecting an input torque due to a steering operation by the driver, a departure determining means for determining a departure tendency of the host vehicle from the traveling lane, and the departure determining means for determining the departure tendency. A steering control means for applying a pulsed steering torque to the steering mechanism in a direction to prevent deviation, and the input torque when the pulsed steering torque is applied is equal to or less than a predetermined threshold value. A lane departure prevention apparatus comprising: a steered state determining unit configured to determine a decrease in a maintained steered state by a driver.

  According to a third aspect of the present invention, in a lane departure prevention apparatus that applies steering torque to a steering mechanism so as to prevent a departure from the traveling lane of the host vehicle, environmental information in front of the host vehicle is acquired and the traveling lane of the host vehicle is set. Lane setting means for detecting, steering angle detecting means for detecting a steering angle by a driver's steering operation, torque detecting means for detecting an input torque by a driver's steering operation, and a deviation tendency of the own vehicle from the traveling lane. A departure determining means for determining, a steering control means for applying a pulsed steering torque to the steering mechanism in a direction to prevent departure when the departure determining means determines the departure tendency, and the pulsed steering torque Steered state detecting means for determining a decrease in the steered state by the driver when the amount of displacement of the steering angle when the value of A lane departure prevention apparatus, characterized in that it comprises.

The invention according to claim 4 is characterized in that the steering control means reduces or stops the pulsed steering torque when the steered state detecting means determines that the steered state is lowered. The lane departure prevention device according to any one of claims 1 to 3.
According to a fifth aspect of the present invention, the steered state detecting means includes a first steered state lowering and a second steered state having a steered state lower than the first steered state lowered by setting a predetermined threshold value. The steering control means executes first steering state reduction control that outputs a warning while applying the pulse-shaped steering torque when the first steering state reduction is determined. Further, when it is determined that the second steered state lowering is performed, second steered state lowering control for reducing or stopping the pulsed steering torque is executed. It is a lane departure prevention apparatus of any one of the above.

According to the present invention, the following effects can be obtained.
(1) When pulsed steering torque is applied, if the driver's steering state is good, the steering angle displacement is relatively small, but the steering state is lowered as when the hand is released. If so, the displacement of the steering angle increases. For this reason, according to the present invention, the steering torque is applied by determining the decrease in the steering holding state by the driver when the displacement amount of the steering angle when the pulsed steering torque is applied is equal to or greater than a predetermined threshold. Immediately after that, it is possible to appropriately determine the decrease in the steered state.
(2) When a pulsed steering torque is applied, if the steering state by the driver is good, the reaction force of the steering torque is reflected relatively large in the input torque, whereas the steering state is lowered. If it is, the reaction force due to the steering torque is less likely to be reflected in the input torque, and the input torque is substantially zero in the hand-off state. For this reason, according to the present invention, when the input torque when the pulsed steering torque is applied is equal to or less than the predetermined threshold value, it is determined immediately after the steering torque is applied by determining that the steering state is lowered by the driver. A decrease in the rudder state can be appropriately determined.
(3) When the amount of displacement of the steering angle when the pulsed steering torque is applied is equal to or greater than a predetermined threshold value and the input torque is equal to or smaller than the predetermined threshold value, it is determined by determining that the steering state is lowered by the driver. The accuracy of rudder state determination can be further improved.

(4) By reducing or stopping the pulsed steering torque when it is determined that the steered state has been lowered, it is possible to prevent the steering angle from changing greatly and disturbing the behavior and course of the vehicle, thereby improving safety. It can be improved.
(5) When the first steered state lowering and the second steered state lowering lower in the steered state are determined by setting the predetermined threshold, and the first steered state lowering is determined. The first steered state lowering control that outputs a warning while applying the pulsed steering torque to the vehicle is executed, and when the second steered state lowering is determined, the pulsed steering torque is reduced or stopped. By executing the second steering wheel state lowering control, the driver's attention is raised and the consciousness is raised when the steering state is lowered to such an extent that it is not necessary to reduce or stop the pulsed steering torque. Steering operation for prevention can be urged.

  An object of the present invention is to provide a lane departure prevention device that can appropriately determine the state of steering maintained by a driver in a short time, an input torque sensor value when a pulsed steering torque is applied to a steering mechanism by departure prevention control, and The problem was solved by determining a decrease in the steering holding state based on a change in at least one of the steering wheel angle.

Embodiments of a lane departure prevention apparatus to which the present invention is applied will be described below.
In the embodiment, the vehicle provided with the lane departure prevention device is, for example, an automobile such as a four-wheel passenger car that steers the front two wheels.
FIG. 1 is a diagram illustrating a system configuration of a vehicle having a lane departure prevention apparatus according to an embodiment.
The lane departure prevention device alerts the driver of the departure and returns the vehicle to the center of the lane when a tendency of the vehicle to depart from the driving lane is determined. Power).
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 steers by rotating the housing H by pushing and pulling the knuckle arm of the housing H.

  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. The torque sensor 12 has a torsion bar that is twisted by the torque acting on the steering shaft 12, and detects the torque by detecting the torsion angle of the torsion bar. 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-side unit 60 controls the electrical components of the vehicle other than those related to each unit.

The lane departure prevention apparatus of the embodiment includes a departure prevention control unit 100 described below.
The departure prevention control unit 100 is connected to the above-described EPS control unit 20, the operation control unit 30, the engine control unit 40, the transmission control unit 50, and the vehicle integration unit 60 via an in-vehicle LAN such as a CAN communication system, for example. Various information and signals can be acquired.
The departure prevention control unit 100 includes a lane setting unit 110, a vehicle lateral position detection unit 120, a departure determination unit 130, an input torque detection unit 140, a steering angle detection unit 150, a steering state detection unit 160, and a steering control unit 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 lane setting 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 lane setting 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 processed image data to the lane setting 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 lane setting unit 110 detects 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 lane setting unit 110 sets the travel lane of the host vehicle by recognizing the shape of the white lines 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.
The lane setting means 110 detects the white line L 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 L 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 lane setting means 110 can continuously detect white line positions to set a plurality of lane candidate points in the traveling direction of the vehicle, ignore lane candidate points that cannot be matched, and set lane candidate points. The area that does not exist is subjected to a predetermined complement process to recognize the lane shape ahead of the host vehicle.

  The own vehicle lateral position detecting means 120 detects the lateral position of the own vehicle in the lane set by the lane setting means 110. The detection of the lateral position of the host vehicle is based on information from the lane setting means 110, the running state of the vehicle detected by the steering angle sensor 21, the vehicle speed sensor 32, the yaw rate sensor 33, and the known vehicle specifications. This is to estimate the traveling path of the host vehicle.

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 vehicle traveling path is estimated by, for example, calculating the lateral position 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 1.

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 departure determination unit 130 uses the host vehicle lateral position detection unit 120 to determine the departure tendency of the host vehicle from the traveling lane set by the lane setting unit 110.
The departure determination means 130 obtains the own vehicle side end position based on the lateral position Xe of the own vehicle at the gaze distance Z estimated by the own vehicle lateral position detection means 120, and the own vehicle side end position is the lane setting means 110. The departure determination is established when the vehicle departs from the set lane.

  The input torque detection means 140 acquires the output value of the torque sensor 23 through CAN communication with the EPS control unit 20. Based on the output value of the torque sensor 23, the input torque detection means 140 detects the input torque of the steering operation input to the steering wheel 11 by the driver.

  The steering angle detection means 150 acquires the output value of the steering angle sensor 22 through CAN communication with the EPS control unit 20. The steering angle detection means 150 detects the steering angle (the rotation angle (steering wheel angle) of the steering wheel 11) in the steering mechanism 10 based on the output value of the steering angle sensor 22.

The steered state detection means 160 detects a decrease in the steered state of the steering wheel 11 by the driver based on the input torque and the handle angle when the electric actuator 21 applies a pulsed steering torque to the steering mechanism 10. Is. The decrease in the steered state includes, for example, a state in which the driver has completely released his hand from the steering wheel 11 and a state in which the steered force is reduced due to the driver's consciousness of driving.
The detection of the steered state will be described in detail later.

  The steering control means 170 uses the lane setting means 110, the own vehicle lateral position detection means 120, the departure determination means 130, the input torque detection means 140, the steering angle detection means 150, the steered state detection means 160, etc. When the above is established, the electric actuator 21 is caused to generate a pulse-like output steering torque via the EPS control unit 20.

Hereinafter, departure prevention control in the lane departure prevention apparatus of the embodiment will be described.
FIG. 2 is a flowchart showing departure prevention control. Hereinafter, the steps will be described step by step.
<Step S01: Self-vehicle position detection in lane>
The departure determination unit 130 acquires the lateral position Xe of the host vehicle in front of the gaze distance Z calculated by the host vehicle lateral position detection unit 120, and then proceeds to step S02.
<Step S02: Judgment of establishment of lane departure determination>
When the side end of the host vehicle departs from the lane in front of the gazing distance Z, the departure determination unit 130 proceeds to step S03 assuming that the departure determination has been established, and otherwise proceeds to step S12.

<Step S03: Determine release flag>
The steering control means 170 confirms the current release flag. The hand release flag is set to 1 when the steered state detection means 160 detects the hand release state by the driver (second steered state lowered state according to the present invention), and is set to 0 in other cases. It is.
If the release flag is 1, the process proceeds to step S04, and if it is 0, the process proceeds to step S06.

<Step S04: Steering torque generation stop>
The steering control means 170 stops generating the pulsed steering torque when the departure determination is established. Thereafter, the process proceeds to step S05.
<Step S05: Alarm output>
The steering control means 170 activates an alarm device (not shown) that warns the driver of a departure tendency by, for example, light or sound. Thereafter, the process ends (returns), and the process returns to step S01.

<Step S06: Generation of pulsed steering torque>
The steering control means 170 performs CAN communication with the EPS control unit 20 to output a pulse instruction value, and drives the electric actuator 21 to give the steering mechanism 10 a single rectangular pulse-like steering torque. The pulse instruction value includes information regarding the timing for generating the pulsed steering torque and the magnitude of the steering torque. The magnitude of the pulsed steering torque is, for example, about 1.0 N · m on the axis of the steering shaft 12, and the time from the start to the end of application is, for example, about 100 msec.
Thereafter, the process proceeds to step S07.

<Step S07: Determination of release state determination>
The steered state detection means 160 determines a hand release state (second steered state decrease) by the driver.
The determination of the release state is performed based on the input torque and the handle angle when the pulsed steering torque is applied to the steering mechanism 10 in step S06.
Hereinafter, the principle of steering state detection based on the input torque and the steering wheel angle will be described.

FIG. 3 is a schematic diagram showing the relationship between the driver and the steering mechanism when the steering holding state is normal.
FIG. 3A is a schematic view of the state in which the driver holds the steering wheel as viewed from above, and FIG. 3B is a dynamic schematic view thereof.
As shown in FIG. 3A, the driver Dr holds the steering wheel 11 with his arm A. When a pulsed steering torque is applied to the steering shaft 12 by the electric actuator 21, the driver Dr normally applies a restoring force corresponding to the displacement to the steering wheel 11 in order to maintain the angle of the steering wheel 11. The person Dr can be expressed as a spring in the dynamic model.

FIG. 4 is a graph showing an example of a history of a pulse instruction value, a torque sensor value, and a steering wheel angle value when the steered state is normal.
When the driver Dr is normally holding the steering wheel, when the pulsed steering torque is applied, the driver Dr tries to maintain the angular position of the steering wheel 11, so that the change in the steering wheel angle is a predetermined value. It is smaller than the determination threshold. At this time, the torque sensor 23 detects the torque applied by the driver to maintain the angular position of the steering wheel 11 (reaction force against the output steering torque), so the torque sensor value is determined from a predetermined determination threshold. Is also big.

FIG. 5 is a schematic diagram showing the relationship between the driver and the steering mechanism in the released state.
FIG. 5A is a schematic view of the state where the driver has let go of the steering wheel as viewed from above, and FIG. 5B is a dynamic schematic view thereof.
In the released state, the driver A's arm A is separated from the steering wheel 11, so that in the mechanical model shown in FIG. 5B, the spring corresponding to the driver Dr in FIG. The steering wheel 11 is connected only to the steering shaft 12.

FIG. 6 is a graph showing an example of the history of the pulse instruction value, torque sensor value, and steering wheel angle value in the released state.
In the hand-off state, when a pulsed steering torque is applied, the angular position of the steering wheel 11 is displaced more than a predetermined determination threshold value because the driver Dr does not hold it. At this time, the torque sensor value is smaller than a predetermined determination threshold because the torque sensor 23 detects substantially only the inertial force of the steering wheel 11 and the friction of the rotation support portion.
In the case shown in FIG. 6, after the first pulsed steering torque is applied, the hand-off state is immediately determined and the generation of the steering torque is stopped, so that the second and subsequent steering torques are generated. Not.

On the basis of the principle described above, the steered state detection means 160 establishes the hand release determination when the input torque at the time of applying the steering torque is equal to or smaller than a predetermined determination threshold and the steering wheel angle is equal to or larger than the predetermined determination threshold. Let
If the hand release determination is established, the process proceeds to step S11, and if not, the process proceeds to step S08.

<Step S08: Release flag ← 0>
The steering control means 170 sets the hand release flag to 0. Thereafter, the process proceeds to step S09.

<Step S09: Determination of establishment of weak steering determination>
The steered state detection means determines a weak steered state (first steered state drop) positioned between the normal steered state and the hand-off state.
The determination of the weak steering state is performed based on the input torque and the steering wheel angle when the pulsed steering torque is applied to the steering mechanism 10 in step S06 as in the case of the hand release state determination.
Here, the determination threshold value of the input torque in the weak steering state determination is set to be larger than the determination threshold value in the hand-off state determination. In addition, the steering angle determination threshold in the weak steering state determination is smaller than the determination threshold in the hand-off state determination.
If the weak steering state determination is established, the process proceeds to step S10. If not established, the process is terminated and the process returns to step S01.
<Step S10: Alarm output>
The steering control means 170 operates the alarm device described above. Thereafter, the process ends, and the process returns to step S01.

<Step S11: Release flag ← 1>
The steering control means 170 sets the hand release flag to 1. Thereafter, the process ends, and the process returns to step S01.
<Step S12: Release flag ← 0>
The steering control means 170 sets the hand release flag to 0. Thereafter, the process ends, and the process returns to step S01.

According to the embodiment described above, the following effects can be obtained.
(1) When the displacement amount of the steering wheel angle when the pulse-shaped steering torque is applied is equal to or greater than a predetermined threshold and the torque sensor value is equal to or smaller than the predetermined threshold, By determining (state reduction), the steered state can be accurately determined in a short time after applying the pulsed steering torque.
(2) When the released state is determined, by reducing or stopping the pulsed steering torque, it is possible to prevent the steering angle from changing greatly and disturbing the behavior and the course of the vehicle, thereby improving safety. .
(3) When a weakly steered state is determined by determining a weakly steered state (first steered state drop) positioned between the normal steered state and the hand-off state by setting a predetermined threshold. By outputting an alarm while applying pulsed steering torque, the driver's attention is raised and the driver's consciousness is improved when the steered state is lowered to the extent that it is not necessary to stop the pulsed steering torque. Steering operation for can be urged.

(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) Although the embodiment determines the decrease in the steered state using both the input torque and the steering angle, any one of these may be used to determine the decrease in the steered state. .
(2) Although the embodiment stops applying the pulsed steering torque when it is determined that the steered state has been lowered due to handing off, the present invention is not limited to completely stopping the application of the steering torque. Alternatively, the generation of pulsed steering torque may be continued after the steering torque is reduced.
(3) In the embodiment, the environment is recognized by the stereo camera. However, the present invention is not limited to this, and for example, information on the traveling lane of the host vehicle such as map data and GPS prepared for the navigation device is used. It is good also as a structure acquired from a positioning apparatus.
(4) 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 embodiment. For example, the pinion assist type that drives the pinion shaft connected to the steering shaft, the steering shaft A double pinion type that drives a pinion that is independent of the connected pinion, a rack direct-acting type that drives the steering rack itself in a straight direction, or the like may be used.
(5) The departure determination means of the embodiment estimates the own vehicle traveling path, and establishes the departure determination when the own vehicle traveling path deviates from the lane in front of the own vehicle. The departure determination may be performed by other methods. For example, the departure determination may be established when the current lateral position of the host vehicle enters a predetermined departure determination range. Also, the method for estimating the traveling path of the vehicle is not limited to that in the embodiment, and other methods such as estimation from the yaw rate may be used.

It is a figure which shows the system configuration | structure of a vehicle provided with the Example of the lane departure prevention apparatus to which this invention is applied. It is a flowchart which shows the departure prevention control of the lane departure prevention apparatus of FIG. It is a schematic diagram which shows the relationship between a driver | operator and a steering mechanism in case the steering state by a driver | operator is normal. It is a graph which shows an example of the history of a pulse directions value, a torque sensor value, and a steering wheel angle value when a steering maintenance state by a driver is normal. It is a schematic diagram which shows the relationship between a driver | operator and a steering mechanism in the steering-holding state fall state which the driver | operator released. It is a graph which shows an example of the history of a pulse directions value, a torque sensor value, and a steering wheel angle value in a steering maintenance state fall state which a driver gave up.

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 device 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 integrated unit 100 Deviation prevention control unit 110 Lane setting means 120 Own vehicle lateral position detection means 130 Deviation judgment means 140 Input torque detection Means 150 Steering angle detecting means 160 Steering state detecting means 170 Steering control means Dr Driver A Arm

Claims (5)

In a lane departure prevention device for applying a steering torque to a steering mechanism so as to prevent a departure from the traveling lane of the host vehicle,
Lane setting means for acquiring environmental information in front of the host vehicle and setting the traveling lane of the host vehicle;
Steering angle detection means for detecting the steering angle by the steering operation of the driver;
Deviation determination means for determining a deviation tendency of the host vehicle from the traveling lane;
Steering control means for applying a pulsed steering torque to the steering mechanism in a direction to prevent departure when the departure determining means determines the departure tendency;
A lane departure characterized by comprising: a steered state determining means for determining a decrease in the steered state by the driver when the amount of displacement of the steering angle when the pulsed steering torque is applied is equal to or greater than a predetermined threshold. Prevention device. In a lane departure prevention device for applying a steering torque to a steering mechanism so as to prevent a departure from the traveling lane of the host vehicle,
Lane setting means for acquiring environmental information in front of the host vehicle and setting the traveling lane of the host vehicle;
Torque detection means for detecting an input torque due to the steering operation of the driver;
Deviation determination means for determining a deviation tendency of the host vehicle from the traveling lane;
Steering control means for applying a pulsed steering torque to the steering mechanism in a direction to prevent departure when the departure determining means determines the departure tendency;
A lane departure prevention device, comprising: a steered state determining unit that determines a decrease in the steered state by the driver when the input torque when the pulsed steering torque is applied is equal to or less than a predetermined threshold value. . In a lane departure prevention device for applying a steering torque to a steering mechanism so as to prevent a departure from the traveling lane of the host vehicle,
Lane setting means for acquiring environmental information in front of the host vehicle and setting the traveling lane of the host vehicle;
Steering angle detection means for detecting the steering angle by the steering operation of the driver;
Torque detection means for detecting an input torque due to the steering operation of the driver;
Deviation determination means for determining a deviation tendency of the host vehicle from the traveling lane;
Steering control means for applying a pulsed steering torque to the steering mechanism in a direction to prevent departure when the departure determining means determines the departure tendency;
A steered state for determining a decrease in the steered state by the driver when a displacement amount of the steering angle when the pulsed steering torque is applied is equal to or greater than a predetermined threshold and the input torque is equal to or smaller than a predetermined threshold. A lane departure prevention device comprising: a detecting means. The steering control means reduces or stops the pulse-like steering torque when the steered state detecting means determines that the steered state is lowered. 4. The lane departure prevention apparatus according to any one of the preceding claims. The steered state detecting means determines at least a first steered state decrease and a second steered state lower lower steered state than the first steered state decrease by setting a predetermined threshold,
The steering control means executes first steered state lowering control that outputs a warning while applying the pulsed steering torque when it is determined that the first steered state lowering is performed, and further the second 4. Any one of claims 1 to 3, wherein, when it is determined that the steered state of the vehicle is lowered, the second steered state lowering control is executed to reduce or stop the pulsed steering torque. The lane departure prevention device according to item.

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