JP2010069983A - Drive assistance device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive assistance device which performs appropriate drive assistance control when a driver's driving intention is reduced. <P>SOLUTION: The drive assistance device configured to recognize the environment in front of an own vehicle to perform steering control for giving steering force to a steering mechanism and deceleration control for decelerating the own vehicle includes: a lane recognition means 110 which recognizes the traveling lane of the own vehicle; a target steering force setting means 140 which sets a target steering force so that the own vehicle travels along a target traveling position set within the traveling lane; a steering control means 160 which performs assignment of steering force to the steering mechanism based on the target steering force; a deceleration control means 190 which decelerates the own vehicle; and a driving intention determination means 180 which determines reduction in the driver's driving intention. The steering control means stops the assignment of steering force according to the determination of the reduction in driving intention, and the deceleration control means decelerates the own vehicle according to the determination of the reduction in driving intention. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a driving support device that performs steering control and deceleration control by recognizing an environment ahead of a host vehicle, and more particularly to a device that performs appropriate driving support when a driver's driving intention is reduced.

The driving support device performs driving support control such as steering assist based on environmental information in front of the host vehicle and the traveling state of the host vehicle.
Such a driving assistance device is only to assist or assist the driver's driving device, and continues to drive depending on the control of the driving assistance device, even though the driver's driving intention is reduced. Is not preferred.

On the other hand, for example, in Patent Document 1, in a vehicle steering control device, when the degree of decrease in driving intention is equal to or greater than a predetermined threshold for a predetermined determination time or more, prohibition of steering assist processing and notification by a notification means are provided. And determining the determination time according to road conditions such as travel speed and curve curvature.
JP 2007-168720 A

However, when the steering control is stopped immediately when the driver's driving intention is reduced as in the technique described in Patent Document 1, the vehicle falls into a state in which control is lost until the driving intention is recovered. The risk of lane departure and collision is great. Even when the driver's driving intention is recovered by an alarm or the like, there is a concern that the vehicle control may become unstable or dangerous depending on the vehicle state at that time.
The subject of this invention is providing the driving assistance apparatus which performs appropriate driving assistance control at the time of a driver's driving intention fall.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 recognizes the traveling lane of the host vehicle in a driving support device that recognizes the environment ahead of the host vehicle and applies steering force to the steering mechanism and performs deceleration control that decelerates the host vehicle. Lane recognizing means, target steering force setting means for setting a target steering force so that the host vehicle travels along a target travel position set in the travel lane, and a steering mechanism based on the target steering force. A steering control unit that applies a steering force; a deceleration control unit that decelerates the host vehicle; and a driving intention determination unit that determines a decrease in driving intention of the driver. The steering control unit responds to the determination of the decrease in driving intention. Then, the application of the steering force is stopped, and the deceleration control means decelerates the host vehicle in accordance with the determination of the decrease in driving intention.

  The invention of claim 2 recognizes the traveling lane of the host vehicle in a driving support device that recognizes the environment ahead of the host vehicle and applies steering force to the steering mechanism and performs deceleration control to decelerate the host vehicle. Lane recognizing means, first steering force setting means for setting a first steering force so that the host vehicle travels along a target travel position set in the travel lane, self-train from the travel lane A second steering force setting means for setting a second steering force in accordance with a deviation tendency of the vehicle, and a target for setting a target steering force including at least one of the first steering force and the second steering force Steering force setting means, steering control means for applying steering force to the steering mechanism based on the target steering force, deceleration control means for decelerating the host vehicle, and driving intention determination means for determining a driver's driving intention decrease The target steering force setting means includes The setting of the target steering force based on the first steering force is stopped and the target steering force based on the second steering force is set according to the determination of the decrease in driving intention. A driving assistance device characterized in that the host vehicle is decelerated in accordance with determination of a decrease in driving intention.

According to the present invention, the following effects can be obtained.
(1) Stop applying the steering force according to the determination of a decrease in driving intention, and decelerate the host vehicle, causing the driver to feel a sense of deceleration and promoting the recovery of the driving intention, and reducing the traveling speed of the vehicle Risk reduction.
(2) The setting of the target steering force based on the first steering force that causes the host vehicle to travel along the target travel position is stopped in response to the determination of a decrease in driving intention, and the first response according to the tendency to deviate from the travel lane By setting the target steering force based on the steering force of 2, the host vehicle has a tendency to deviate even in the state where the application of the first steering force is stopped to prevent the driver from relying on the control. In such a case, the deviation can be prevented by the second steering force, and the risk can be further reduced.

  The present invention aims to provide a driving support device that performs appropriate driving support control when a driver's driving intention is lowered, and determines the steering assist force according to the lateral deviation of the host vehicle from the target travel position according to the arousal level reduction determination. The problem was solved by stopping the assignment, continuing the lane departure warning control, and decelerating the vehicle.

Embodiments of a driving support apparatus to which the present invention is applied will be described below.
FIG. 1 is a diagram illustrating a system configuration of a vehicle having a driving support apparatus according to an embodiment.
The driving support device of the embodiment is provided in an automobile such as a four-wheeled passenger car that steers the two front wheels, and performs steering assist control, lane departure prevention control, deceleration control, etc. based on the environment in front of the host vehicle. It is.

  The vehicle includes a steering mechanism 10, 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 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 EPS control unit 20 comprehensively controls an electric power steering device that generates a steering assist force in accordance with a driver's steering operation. The EPS control unit 20 is connected to an electric actuator 21, a torque sensor 22, 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 torque sensor 22 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 22 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, a steering angle sensor 35, 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 steering angle sensor 35 includes an encoder that detects the angular position of the steering shaft 12 (substantially equal to the angular position of the steering wheel 11).

The engine control unit 40 controls the engine, which is a driving power source for the vehicle, and its auxiliary equipment. The engine control unit 40 is connected to an ignition switch (not shown) for starting the engine.
The transmission control unit 50 controls the automatic transmission that changes the output of the engine and transmits it to the differential gear of the drive shaft.
The vehicle integration unit 60 controls the electrical components of the vehicle other than those related to each unit.

The vehicle also includes a driving support control unit 100 and an alarm device 200 described below.
The driving support control unit 100 constitutes the main body of the driving support device of the present embodiment. The driving support control unit 100 is connected to the EPS control unit 20, the operation control unit 30, the engine control unit 40, the transmission control unit 50, the vehicle integration unit 60, and the like described above via an in-vehicle LAN such as a CAN communication system. Various information and signals can be acquired.

  The driving support control unit 100 includes an environment recognition unit 110, a target travel position setting unit 120, a host vehicle traveling path estimation unit 130, a steering assist control unit 140, a departure prevention control unit 150, a steering force control unit 160, and a driving operation detection unit 170. , The wakefulness level lowering determination means 180, the deceleration control means 190, and the like are provided. Each of these elements may be configured as independent hardware, or part or all may be configured as common hardware.

The environment recognition unit 110 recognizes the shape of the traveling lane of the host vehicle based on image information obtained by capturing the front of the host vehicle. The environment recognition unit 110 functions as a lane recognition unit of the present invention.
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.

Moreover, the environment recognition means 110 recognizes the shape of the white line etc. which are arrange | positioned at the lane both ends ahead of the own 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 environment recognition unit 110 detects a pixel group of a white line portion based on pixel luminance data from reference image data. The orientation of the pixel group of the white line 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. Then, the position of the white line is detected by calculating the distance of the pixel group in the white line portion.
The environment recognition means 110 can continuously detect the position of the white line to set a plurality of lane candidate points in the traveling direction of the vehicle, ignore the lane candidate points that cannot be matched, and set the 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 target travel position setting unit 120 sets the target travel position Xc at the center in the width direction of the travel lane of the host vehicle set by the environment recognition unit 110.

The own vehicle traveling path estimating means 130 is based on information from the environment recognizing means 110, the running state of the vehicle detected by the vehicle speed sensor 32, the yaw rate sensor 33, the rudder angle sensor 35, etc., and known vehicle specifications. The vehicle traveling path is estimated.
The own vehicle traveling path is estimated by, for example, calculating the lateral position Xe of the own vehicle at the gaze distance Z in front of the vehicle.
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 estimated lateral position Xe of the host vehicle's center of gravity at the gaze distance Z is obtained by the following equation 1 using the handle angle α.

In addition, the vehicle traveling path estimation unit 130 may estimate the lateral position using the yaw rate detected by the yaw rate sensor 33 as shown in the following equation 2, instead of estimating the lateral position using the steering wheel angle. it can.

Xe = Z ² γ / 2V (Formula 2)
Xe: Estimated lateral position of the center of gravity of the vehicle at the gaze distance Z [m]
Z: Gaze distance [m]
γ: vehicle yaw rate [rad / sec]

The steering assist control unit 140 determines the deviation based on the lateral deviation between the target travel position Xc set by the target travel position setting unit 120 and the lateral position Xe of the host vehicle estimated by the host vehicle traveling path estimation unit 130. The target steering torque τc in the direction of reducing the steering torque is set and provided to the steering force control means 160. The steering assist control unit 140 functions as a target steering force setting unit and a first steering force setting unit of the present invention.
The steering assist control means 140 sets the target steering torque τc using, for example, the following formula 3.

τc = G ₃ · (Xc−Xe) ³ (Equation 3)
τc [Nm]: Target steering torque G ₃ : Tertiary control gain Xc [m]: Target travel position Xe [m]: Estimated lateral position of own vehicle

The departure prevention control unit 150 uses the target travel position Xc set by the target travel position setting unit 120 and the lateral position Xe of the host vehicle estimated by the host vehicle traveling path estimation unit 130 from the travel lane of the host vehicle. The tendency to deviate is determined. For example, the departure prevention control unit 150 compares the lateral deviation between the target travel position Xc and the estimated lateral position Xe of the host vehicle with the lane width detected by the environment recognition unit 110 to determine the departure tendency.
When it is determined that there is a tendency to deviate, the departure prevention control unit 150 sets the pulse-like target steering torque τp in a direction to return the host vehicle to the inside of the lane, and provides departure prevention control to the steering force control unit 160. Do. The departure prevention control means 150 functions as the second steering force setting means of the present invention.

The steering force control means 160 instructs the EPS control unit 20 on the instruction current value based on the target steering torque τc set by the steering assist control means 140 and the target steering torque τp set by the departure prevention control means 150. The electric actuator 21 is driven to apply a steering torque to the steering mechanism 10.
Further, the steering force control unit 160 has a function of stepwise stopping the application of the steering torque based on the target steering torque τc and the target steering torque τp in accordance with the determination of the arousal level decrease by the arousal level decrease determination unit 180. It has. This point will be described in detail later.

  The driving operation detection means 170 detects information related to the driving operation of the driver such as the output value of the torque sensor 22 via the EPS control unit 20 and the like, and provides it to the arousal level decrease determination means 180.

The arousal level decrease determination means 180 detects the arousal level as an index indicating the driver's driving intention. The arousal level decrease determination means 180 functions as a driving intention determination means of the present invention. For example, the awakening level decrease determination unit 180 determines that the driver's steering input torque detected by the torque sensor 22 is not more than a predetermined value (substantially no operation) for a predetermined determination time or longer. It is determined that the degree of awakening is decreasing.
The arousal level decrease determination unit 180 has a function of changing the control state of the steering force control unit 160 and the deceleration control unit 190 in accordance with the result of the awakening level decrease determination. This point will be described in detail later.
Further, the arousal level lowering determination means 180 has a function of detecting a driver's awakening (awakening level and recovery of driving intention) based on detection of steering input torque from the driver, detection of an accelerator operation, a brake operation, and the like. Yes.

  The deceleration control means 190 controls the HCU 31 via the operation control unit 30 to generate a brake braking force to decelerate the vehicle. This point will be described in detail later.

  The alarm device 200 outputs an alarm to the driver in response to the arousal level reduction determination unit 180 by the arousal level reduction determination unit 180. The alarm device 200 includes, for example, a speaker that emits an alarm sound, a warning lamp that performs an alarm by lighting and flashing, and the like.

The driving support control unit 100 according to the embodiment has a function of stopping the steering assist control and executing the deceleration control while the departure prevention control is continued when the driver's arousal level is lowered (driving intention is lowered).
FIG. 2 is a flowchart showing the control when the driver's arousal level is reduced. Hereinafter, the steps will be described step by step.

<Step S01: Determination of flag 1>
The awakening level decrease determination means 180 determines whether or not the flag 1 set in step S03 and step S08 described later is 1.
If flag 1 = 1, it is determined that sudden deceleration control, which will be described later, has already been performed due to a decrease in the driver's arousal level, and the process proceeds to step S09. If flag 1 ≠ 1, the process proceeds to step S02.

<Step S02: Judgment of Declining Driver Intention>
Based on the output history of the torque sensor 22 acquired via the driving operation detection unit 170, the awakening level decrease determination unit 180 performs the above-described driver awakening level decrease determination.
If it is determined that the degree of arousal (driving intention) is reduced, the process proceeds to step S04, and otherwise, the process proceeds to step S03.

<Step S03: Return of steering assist control, flag 1 = 0>
The awakening level decrease determination unit 180 issues an instruction to the steering force control unit 160 to execute the application of the steering torque to the steering mechanism 10 based on the target steering torque τc set by the steering assist control unit 140.
Further, the arousal level lowering determination means 180 sets the flag 1 to 0.
Thereafter, the process returns, and the processes after step S01 are repeated.

<Step S04: Alarm output>
The awakening level decrease determination means 180 issues an instruction to the alarm device 200 to output an alarm. This warning is continued until the driver's awakening is detected (until no lower intention is determined in step S02).
Thereafter, the process proceeds to step S05.

<Step S05: Stop steering assist control / continue deviation prevention control>
The steering force control means 160 receives the fact that the arousal level decrease determination means 180 has determined that the driver's arousal level has decreased, and applies steering torque to the steering mechanism 10 based on the target steering torque τc set by the steering assist control means 140. Cancel. At this time, the steering force control means 160 continues to apply the steering torque based on the target steering torque τp set by the departure prevention control means 150.
Thereby, the steering force control means 160 does not apply the steering torque to the steering mechanism 10 in a state where the departure determination in the departure prevention control means 150 is not established, and when the departure determination is established, the pulse-like steering torque It will be in a state to give.
Thereafter, the process proceeds to step S06.

<Step S06: Deceleration control operation>
The deceleration control means 190 operates a deceleration control that slowly decelerates the vehicle. The deceleration control is performed by the deceleration control means 190 controlling the HCU 31 via the operation control unit 30 and generating a braking force on the hydraulic service brake of each wheel. The deceleration in this deceleration control is set to be approximately the same as that of the engine brake, for example.
Thereafter, the process proceeds to step S07.

<Step S07: Time Required Determination>
The awakening level decrease determination means 180 is substantially equal to the time required after the first determination of awakening level decrease in step S02 (the time after the steering assist control is stopped, the time after the deceleration control is activated). Is equal to the predetermined value T set in advance. If the required time exceeds T, the process proceeds to step S08. If the required time is equal to or less than T, the process returns and repeats the processes after step S01.

<Step S08: Rapid deceleration control / flag 1 = 1>
The deceleration control means 190 performs sudden deceleration control having a larger deceleration than the above-described deceleration control in order to prompt the driver to be more awake. In the rapid deceleration control, a deceleration G of about 0.5 G, for example, is applied for about 0.5 seconds, for example, by the hydraulic service brake of each wheel.
Further, the arousal level lowering determination means 180 sets the flag 1 to 1.
Thereafter, the process proceeds to step S09.

<Step S09: Deviation prevention control prohibition / deceleration control prohibition>
The steering force control unit 160 prohibits the application of the steering torque based on the target steering torque τp set by the departure prevention control unit 150 and stops any steering force application.
Moreover, the deceleration control means 190 prohibits the deceleration control started in step S06 and stops the generation of the braking force.
Thereafter, the process returns, and the processes after step S01 are repeated.

When the awakening level decrease determination means 180 detects a decrease in the driver's awakening level by the routine described above, the driving support device first stops the steering assist control and performs the deceleration control to prompt the driver to awaken. At this time, the departure prevention control is continued, and when the departure tendency of the own vehicle from the traveling lane is determined, a pulse-like steering torque toward the center of the lane is given, and an alarm to the driver and the own vehicle Deviation prevention is achieved. If the driver's arousal level does not improve even after a certain period of time has elapsed in this state, all the steering force application is stopped after the rapid deceleration control is performed.
Further, when the driver's arousal level improvement means 180 detects an increase in the driver's arousal level in this process, the control of the driving support device returns to the normal state, the steering assist control and the departure prevention control are performed, and the deceleration control is performed. And sudden deceleration control is prohibited.

According to the embodiment described above, the following effects can be obtained.
(1) Stop applying the steering torque based on the target steering torque τc that is set so that the host vehicle travels along the target travel position Xc according to the determination of the awakening level, and decelerate the host vehicle. Thus, the driver can feel a sense of deceleration and wake up, and the vehicle traveling speed can be reduced to reduce the risk.
(2) Only when the determination of departure from the travel lane is established, the application of the steering torque based on the target steering torque τc that causes the host vehicle to travel along the target travel position is stopped according to the determination of the arousal level lowering. Even if the steering assist control for maintaining the lane is stopped in order to prevent the driver from relying on the control by applying the steering torque based on the pulse target steering torque τp, the host vehicle When there is a tendency to deviate, the deviation can be prevented by the pulsed steering torque based on the deviating prevention control, and the risk can be further reduced.

(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 method for determining the driver's intention to drive is not limited to the method for detecting the history of the steering input torque as in the embodiment, but may be another method. For example, it is possible to determine a decrease in driving intention based on a change in rudder angle or other driving operation, to detect a specific action such as a decrease in arousal level based on image data obtained by imaging the driver, or physiological information about the driver May be used to determine a decrease in driving intention. Further, the index indicating the driving intention is not limited to the arousal level as in the embodiment, and for example, the degree of ambiguity can be used.
(2) Although the deceleration control and the rapid deceleration control are performed by generating the braking force of the hydraulic service brake in the embodiment, the present invention is not limited to this. The braking force may be generated by other methods such as engine output suppression by cutting, stopping the energization of the drive motor or operating the electric power regenerative brake, downshifting the transmission, and dynamic braking of the electric parking brake. .

It is a figure which shows the system configuration | structure of the vehicle which has the Example of the driving assistance device to which this invention is applied. It is a flowchart which shows the operation | movement at the time of the driver alertness fall in the driving assistance device of FIG.

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 Torque sensor 30 Stabilization control unit 31 HCU 32 Vehicle speed sensor 33 Yaw rate sensor 34 Horizontal G Sensor 35 Steering angle sensor 40 Engine control unit 50 Transmission control unit 60 Vehicle integration unit 100 Driving support control unit 110 Environment recognition unit 111 Stereo camera 112 Image processing unit 120 Target travel position setting unit 130 Own vehicle travel path estimation unit 140 Steering assist control Means 150 Deviation prevention control means 160 Steering force control means 170 Driving operation detection means 180 Arousal level decrease judgment means 19 Deceleration control means 200 warning device

Claims (2)

In a driving support device that recognizes the environment ahead of the host vehicle and applies a steering force to the steering mechanism and a deceleration control that decelerates the host vehicle,
Lane recognition means for recognizing the traveling lane of the host vehicle,
Target steering force setting means for setting a target steering force so that the host vehicle travels along a target travel position set in the travel lane;
Steering control means for applying a steering force to the steering mechanism based on the target steering force;
Deceleration control means for decelerating the host vehicle;
Driving intention determination means for determining a driver's driving intention decline,
The steering control means stops applying the steering force according to the determination of the drive intention decrease,
The deceleration control means decelerates the host vehicle according to the determination of the decrease in driving intention. In a driving support device that recognizes the environment ahead of the host vehicle and applies a steering force to the steering mechanism and a deceleration control that decelerates the host vehicle,
Lane recognition means for recognizing the traveling lane of the host vehicle,
First steering force setting means for setting a first steering force so that the host vehicle travels along a target travel position set in the travel lane;
Second steering force setting means for setting a second steering force in accordance with a tendency of the vehicle to depart from the travel lane;
Target steering force setting means for setting a target steering force including at least one of the first steering force and the second steering force;
Steering control means for applying a steering force to the steering mechanism based on the target steering force;
Deceleration control means for decelerating the host vehicle;
Driving intention determination means for determining a driver's driving intention decline,
The target steering force setting means cancels the setting of the target steering force based on the first steering force and sets the target steering force based on the second steering force in response to the determination of the decrease in driving intention. ,
The deceleration control means decelerates the host vehicle according to the determination of the decrease in driving intention.

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