JP2003040096A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a vehicle preventing a lowering of traveling stability of a vehicle caused by brake operation at the generation of an alarm on lane deviation. SOLUTION: This control device 1 for the vehicle provided with a lane deviation alarm means 2 for generating an alarm on the lane deviation of the vehicle, is provided with a braking force generating means for generating braking force of prescribed grade according to the brake operation quantity of a driver, and a braking force correcting means 6 for decrease-correcting the grade of braking force generated to fixed brake operation when the alarm is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle, and more particularly to a control device for a vehicle that issues an alarm regarding lane departure of the vehicle.

[0002]

2. Description of the Related Art A traveling position of a vehicle on a road is detected based on image information obtained by an in-vehicle camera, and an alarm is issued when the vehicle deviates from the lane or is about to depart from the lane. There is known a lane departure warning device that emits the above (Japanese Patent Laid-Open No. 6-28659).

[0003]

A driver who receives an alarm from such an alarm device, for example, about the lane departure, or about the lane departure, is reflexively braked. It turns out that I often step on. Such a braking operation may reduce the running stability of the vehicle depending on the situation. Especially when the friction coefficient of the road surface is small (low μ road), or
This tendency increases during turning of the vehicle.

The present invention has been made in view of the above problems, and provides a control device for a vehicle, which prevents a reduction in running stability of the vehicle due to a brake operation when an lane departure warning is issued. The purpose is to

[0005]

According to the present invention, there is provided a vehicle control device provided with lane departure warning means for issuing a warning regarding lane departure of a vehicle, the control device having a predetermined size in accordance with a brake operation amount of a driver. Braking force generating means for generating a braking force, and a braking force correction means for reducing the magnitude of the braking force generated for a certain brake operation when the alarm is generated. A vehicle controller is provided.

According to such a structure, even if the driver who receives the warning about the lane departure, such as when the vehicle departs from the lane or is about to depart, depresses the brake reflexively, it is generated by the brake operation. Since the magnitude of the braking force is reduced, it is possible to prevent the traveling stability of the vehicle from being lowered by the reflexive brake operation.

According to a preferred aspect of the present invention, there is further provided turning detection means for detecting turning of the vehicle, and the braking force correction means increases the correction amount of the reduction correction as the turning becomes larger. According to such a configuration, in a turning state where traveling stability is likely to be deteriorated by the brake operation,
Since the generation of the braking force is further suppressed, it is effectively suppressed that the traveling stability of the vehicle is reduced.

According to another preferred aspect of the present invention, it further comprises a friction coefficient detecting means for detecting a friction coefficient of the road surface, and the braking force correcting means has a smaller correction amount for the decrease correction as the friction coefficient is smaller. To increase. According to such a configuration, the braking force is further suppressed from being generated during traveling on a low μ road where the traveling stability is likely to be deteriorated by the brake operation, so that the traveling stability of the vehicle is effectively reduced. Suppressed.

According to another aspect of the present application, a vehicle equipped with a braking force correction means for correcting the braking force so that the larger the vehicle turns, the smaller the braking force generated for a constant braking operation. Lane departure warning means for issuing a warning regarding lane departure of a vehicle, and a correction amount by the braking force correction means when the warning is issued, when the warning is not issued. There is provided a control device for a vehicle, comprising: a correction amount adjusting means for increasing the amount.

According to another aspect of the present application, the braking force correcting means is provided for correcting the braking force so that the smaller the friction coefficient of the road surface, the smaller the braking force generated for a constant braking operation. A lane departure warning means for issuing a warning regarding a lane departure of a vehicle, and a correction amount by the braking force correction means when the warning is issued, which is not issued by the vehicle control device. A control device for a vehicle is provided, which is provided with a correction amount adjusting means for increasing the correction amount.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described in detail with reference to the drawings. First, Figure 1
The vehicle control device 1 according to the first embodiment of the present invention will be described with reference to FIGS. The control device of the first embodiment is
When the lane departure warning is activated, the hydraulic pressure from the master cylinder is reduced at a predetermined rate to reduce the braking force. FIG. 1 shows a control device 1 according to the first embodiment.
2 is a block diagram showing a schematic configuration of FIG.

As shown in FIG. 1, the controller 1
Is a lane departure warning CPU 2 for generating a lane departure warning, and a braking force control actuator 4 for generating a braking force according to a driver's brake operation amount or the like.
And a braking force control CPU 6 that controls the braking force when the lane departure warning is issued.

The lane departure warning CPU 2 includes lane information generated by the lane recognition means 8 such as a vehicle-mounted white line detection CCD camera, vehicle speed information generated by the vehicle speed detection means 10 such as a wheel speed sensor, and a steering wheel. The steering angle information generated by the steering angle detecting means 12 such as an angle sensor is input. The lane information is information regarding whether or not the vehicle is traveling in the correct direction with respect to the lane, and the lane departure is determined based on this information. The lane recognizing means may be configured by a vehicle-mounted white line detecting CCD camera or another means such as a device for reading a lateral position signal from a road surface marker embedded along a road.

When it is determined that the vehicle deviates from the lane based on the lane information, the lane departure warning CPU 2 gives a warning to the display means 14 such as the display screen of the navigation device to the effect that the vehicle deviates from the lane. The alarm means 16 such as a loudspeaker displays a voice alarm, and a steering means 18 such as a motor for electric power steering.
Is operated to perform automatic steering control for returning the steering wheel from the departure direction.

Further, the braking force control CPU 6 has information regarding a departure warning from the lane departure warning CPU 2, turning information regarding a turning state of the vehicle generated by a turning state detecting means 20 such as a yaw rate sensor, and an accelerator opening degree. ,
Road surface information relating to the friction coefficient of the road surface generated by the road surface state detecting means 22 for detecting the friction coefficient of the road surface from the wheel speed and the like, and brake pedal operation information relating to the brake pedal operation by the driver from the brake pedal operation detecting means 24 are input. Is configured to. Further, the braking force control CPU 6 outputs a signal for controlling the operation of the braking force control actuator 4 that generates a braking force, and can change the magnitude of the braking force generated by a constant braking operation according to the situation. Is configured. Specifically, the braking force control CPU 6 corrects the braking force so that the braking force generated by a constant braking operation becomes smaller as the turning of the vehicle is larger and the friction coefficient of the road surface is smaller. Is configured to.

Next, the structure of the braking force control actuator 4 will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the braking force control actuator 4 of the control device 1 of the first embodiment.

As shown in FIG. 2, the braking force control actuator 4 includes a brake pedal 26, a master cylinder 28 connected to the brake pedal 26, and a hydraulic path 30 as in the case of an ordinary brake device. The wheel cylinder 32 is connected to the master cylinder 28 via the wheel cylinder 32. With these configurations, hydraulic pressure corresponding to the operation of the brake pedal 26 acts on the hall cylinder 32 to generate a braking force. Further, in the present embodiment, the hydraulic path 30
Branch path 36 in which the duty solenoid 34 is arranged
Is connected, and by operating the duty solenoid 34, a part of the brake fluid can be bypassed from the hydraulic path 30 from the master cylinder 28 to the wheel cylinder 32, and the braking force acting on the hall cylinder 32 can be reduced. Is configured. The duty solenoid 34 is fully closed at a duty ratio of 0, and its operation is controlled by the braking force control CPU 6. During the lane departure warning, the braking force control CPU 6 sets the duty solenoid 34 so that the larger the vehicle turns and the smaller the friction coefficient of the road surface, the smaller the braking force generated by a constant braking operation. Control to increase the duty ratio,
Correct the braking force. In addition, the bypassed brake fluid is returned to the brake fluid reservoir.

Next, the lane departure warning processing executed by the lane departure warning CPU 2 of the control device 1 will be described with reference to FIG. FIG. 3 is a flowchart of a lane departure warning process performed by the lane departure warning CPU 2.

First, the lane departure warning CPU 2 inputs lane information from the lane recognition means 8 (step S1), and detects the traveling position of the own vehicle in the lane based on the lane information (step S1) (step S1). S2), and then it is determined whether or not the own vehicle deviates from the traveling lane (step S3).

If it is determined NO in step S3, that is, if the vehicle has not deviated, the process proceeds to step S4, and the primary departure warning determination flag Fn1 and the secondary departure warning determination flag Fn2.
To reset. On the other hand, if YES in step S3, that is, if it is determined that the vehicle deviates, the process proceeds to step S5.
It is determined whether the deviation amount is larger than a predetermined value. If NO in step S5, that is, if it is determined that the departure amount is less than or equal to the predetermined value, the process proceeds to step S6, and it is determined whether or not the vehicle is moving in the departure direction. This determination is made based on the signal from the steering angle sensor 12 and the like.

If it is determined in step S6 that the vehicle is not moving in the departure direction, that is, if the driver is aware of the departure, it is determined that the vehicle position is being corrected, and the process returns. If YES in step S6, that is, if it is determined that the vehicle is moving in the departure direction, it is determined that the driver is not aware of the departure and the vehicle is moving in the departure direction, and the primary departure warning determination flag Fn1 is set to 1 And a warning sound indicating that the vehicle is slightly deviating from the lane, for example, an onomatopoeic of "rattle" is generated from the alarm means 16 such as a speaker, and the process proceeds to step S8, and the secondary deviation warning determination flag F is set.
Reset n2.

If YES in step S5, that is, if it is determined that the departure amount is larger than the predetermined value, the process proceeds to step S9, and it is determined whether or not the vehicle is moving in the departure direction. This determination is made based on the signal from the steering angle sensor 12 and the like.

If it is determined NO in step S9, that is, if it is determined that the vehicle is not moving in the departure direction, the driver notices the departure, determines that the vehicle position is being corrected, and returns. If YES in step S9, that is, if it is determined that the vehicle is moving in the departure direction, it is determined that the driver is not aware of the departure and the vehicle is moving in the departure direction, and in step S10, the vehicle is in the direction opposite to the departure direction. After performing the automatic steering, the process proceeds to step S11, the secondary departure warning determination flag Fn2 is set to 1, and the warning means 16 such as a speaker
An alarm sound indicating that the vehicle is deviating significantly from the lane, for example, a continuous alarm sound is generated, and then the process proceeds to step S12,
The primary departure warning determination flag Fn1 is reset. Thus, in this embodiment, when the lane departure warning is issued, the primary departure warning determination flag Fn1 or the secondary departure warning determination flag Fn2 is set to 1.

Next, a braking force control process performed by the braking force control CPU 6 of the control device 1 will be described with reference to FIG. FIG. 4 is a flowchart of the braking force control process performed by the braking force control CPU 6.

First, the braking force control CPU 6 inputs the departure warning determination flag from the lane departure warning CPU 2 (step S13), and the turning state detection means 20 and the road surface state detection means 22 determine the turning amount of the vehicle. And the road surface information regarding the friction coefficient of the traveling road surface are input (step S14). The turning information may be obtained from the steering angle sensor 12. Next, in step S15, it is determined whether or not the lane departure warning is issued by determining whether or not either the primary departure warning determination flag Fn1 or the secondary departure warning determination flag Fn2 is 1. If NO in step S15, that is, if the lane departure warning is not issued, the process proceeds to step S16, and the duty solenoid 34 is operated so that the normal braking force corresponding to the brake pedal operation amount is generated.
The duty ratio of 0 (fully closed) and step S17
Then, the duty solenoid 3 at the set duty ratio
4 is activated.

On the other hand, if YES in step S15, that is, if the lane departure warning is being issued, the process proceeds to step S18, and is generated by a constant brake operation as the turning of the vehicle is larger and the friction coefficient of the road surface is smaller. The duty ratio (duty of braking) of the duty solenoid 34 is determined based on the turning information and the road surface information so that the braking force becomes small. That is, the larger the turning, and the lower the road surface friction coefficient μ, the larger the duty ratio is set. Next, in step S17, the duty solenoid 34 is operated at the duty ratio set in step S18.

According to the first embodiment having such a structure, slips during turning and traveling on a low μ road,
Even when the brake is operated reflexively by the lane departure warning in a situation where spin, lock, etc. are likely to occur, the braking effect is weakened according to the turning and the road surface μ, so the running stability of the vehicle deteriorates. It gets harder.

Next, a control device for a vehicle according to a second embodiment of the present invention will be described with reference to FIGS. The control device according to the second embodiment includes a so-called brake assist device, and when the lane departure warning is activated, the braking force from the brake assist device is reduced at a predetermined rate to reduce the total amount of the brake braking force. Is. The basic configuration of the control device of the second embodiment is the same as the configuration of the control device of the first embodiment shown in FIG.

Next, the configuration of the braking force control actuator 42 of the second embodiment will be described with reference to FIG. Figure 5
FIG. 7 is a block diagram showing a configuration of a braking force control actuator 42 of the control device 1 of the second embodiment.

As shown in FIG. 5, the braking force control actuator 42 has the same structure as a normal braking device.
The brake pedal 26, a master cylinder 28 connected to the brake pedal 26, and a wheel cylinder 32 connected to the master cylinder 28 via a hydraulic path 30 are provided. With these configurations, hydraulic pressure corresponding to the operation of the brake pedal 26 acts on the hall cylinder 32 to generate a braking force. Furthermore, as described above, in the second embodiment, the brake assist device is provided.
In this brake assist device, a pump 46 driven by a motor 44 pressurizes a part of the brake fluid in a brake fluid reservoir 48, and the pressure generated by the brake fluid is supplied to a duty solenoid 50 controlled by a braking force control CPU 62. Through the wheel cylinder 3 at a predetermined ratio
It is configured so that the braking force is assisted by sending it to 2 and a larger braking force is obtained when the brake pedal is suddenly depressed. The duty ratio (assist amount) of the duty solenoid 50 is determined based on the signal from the brake pedal operation detecting means 24. In the present embodiment, when the lane departure warning is issued, the braking force control CPU 62 controls the duty solenoid 50 so that the duty ratio becomes smaller as the vehicle makes a larger turn, the friction coefficient of the road surface becomes smaller, and the brake assist is performed. The braking force is reduced and corrected so that the total amount of the braking force generated by a constant braking operation is reduced.

Next, the braking force control (assist amount control) processing performed by the braking force control CPU 62 of the control device will be described with reference to FIG. FIG. 6 shows a braking force control CPU 62.
5 is a flowchart of a braking force control process performed by the. In addition,
The control device of the second embodiment also performs the same lane departure warning process as the control device of the first embodiment.

First, the braking force control CPU 62 inputs the departure warning determination flag from the lane departure warning CPU 2 (step S20), and the turning state detecting means 20, the road surface state detecting means 22 and the brake pedal operation detecting means 24 are operated. , Turning information of the vehicle, road surface information regarding the friction coefficient of the traveling road surface, and brake operation information regarding the operation amount and operation speed of the brake pedal are input (step S2).
1). Next, in step S22, it is determined whether the operation amount of the brake pedal is larger than a predetermined amount and the operation speed of the brake pedal is larger than the predetermined speed, so that the brake pedal is suddenly depressed greatly and an emergency brake requiring brake assist is performed. It is determined whether or not the state.
The predetermined amount and the predetermined speed are experimentally obtained in advance as values for detecting the emergency braking state.

If NO in step S22, that is, if it is determined not to be in the emergency braking state, the process proceeds to step S23, the duty ratio of the duty solenoid 50 is set to 0 (fully closed), and the set duty ratio 0 is set in step S24. The duty solenoid 50 is operated with. That is, brake assist is not performed.

On the other hand, if YES in step S22, that is, if it is determined that the vehicle is in the emergency braking state, step S2
5, the duty ratio (assist amount) of the duty solenoid 50 according to the operation amount of the brake pedal and the predetermined speed is determined. This duty ratio is also determined in advance by experiments or the like. For example, when both the operation amount and the operation speed are "large", 100%, when one of the operation amount and the operation speed is "large", 80%, and when one of the operation amount and the operation speed is "medium", 50%, 30% when both the operation amount and the operation speed are "small".

Next, in step S26, the primary departure warning determination flag Fn1 and the secondary departure warning determination flag Fn.
By determining whether any of 2 is 1,
It is determined whether or not a lane departure warning has been issued. Step S
If NO in 26, that is, if the lane departure warning is not issued, the process proceeds to step S24, the duty solenoid 50 is operated at the duty ratio set in step S25, and the normal brake is not corrected based on the lane departure warning. Assist is performed.

If YES in step S26, that is, if the lane departure warning is issued, the process proceeds to step S27, in which the braking force by the brake assist becomes smaller as the turning (yaw rate) of the vehicle is larger and the friction coefficient of the road surface is smaller. As described above, the duty ratio (the amount of brake assist) of the duty solenoid 50 is reduced and corrected based on the turning information and the road surface information. Next, in step S24, the duty solenoid 50 is operated at the duty ratio set in step S27 to perform brake assist. This decrease correction of the duty ratio is performed by multiplying the duty ratio set in step S25 by a predetermined coefficient determined in advance by experiments or the like. The predetermined coefficient is, for example,
0.3 when the turning condition is “large” and the road surface μ is “small”,
0.5 when the turning condition is “large” and the road surface μ is “large”,
0.7 when the turning condition is “small” and the road surface μ is “small”,
0.8 when the turning condition is “small” and the road surface μ is “large”
It is set like this.

According to the second embodiment having such a structure, slips during turning, traveling on a low μ road, and the like,
Even when the brake is operated reflexively by the lane departure warning in a situation where spin, lock, etc. are likely to occur, the brake assist amount is reduced according to the turning and road surface friction coefficient μ, so the running stability of the vehicle Is less likely to decrease.

Finally, a vehicle control system according to a third embodiment of the present invention will be described with reference to FIGS. 7 and 8. The control device of the third embodiment is premised on a brake system by a brake-by-wire that reduces the braking force during a turn or on a low μ road. When the lane departure warning is activated, a duty that controls the braking force of the brake is used. The duty ratio of the solenoid is reduced by a predetermined ratio to reduce the braking force. The basic configuration of the control device of the third embodiment is the same as the configuration of the control device of the first embodiment shown in FIG. 1 except that it is such a brake-by-wire.

Next, the configuration of the braking force control actuator 43 of the third embodiment will be described with reference to FIG. Figure 7
FIG. 9 is a block diagram showing a configuration of a braking force control actuator 43 of the control device of the third embodiment.

As shown in FIG. 7, the braking force control actuator 43 is a brake-by-wire, and based on a signal from the brake pedal operation detecting means 24 for detecting the operation amount and operation speed of the brake pedal, Motor 5
The pump 54 driven by 2 pressurizes the brake fluid in the brake fluid reservoir 56, and the pressure of this brake fluid is supplied to the wheel cylinder 32 at a predetermined ratio via the duty solenoid 58 controlled by the braking force control CPU 63. The braking force is obtained by sending it. And
In the present embodiment, when the lane departure warning is issued, the braking force control CPU 63 controls the duty solenoid 58 so that the duty ratio becomes smaller as the vehicle turns larger and the road friction coefficient becomes smaller. The braking force is reduced, and the braking force is reduced and corrected so that the braking force generated by a constant braking operation becomes small.

Next, with reference to FIG. 8, a braking force control process performed by the braking force control CPU 63 of the control device will be described. FIG. 8 is a flowchart of the braking force control process performed by the braking force control CPU 63. The control device of the third embodiment also performs the same lane departure warning process as the control device of the first embodiment.

First, the braking force control CPU 63 inputs the departure warning determination flag from the lane departure warning CPU 2 (step S30), and the turning state detecting means 20, the road surface state detecting means 22, and the brake pedal operation detecting means 24 are inputted. Then, the turning information of the vehicle, the road surface information about the friction coefficient of the traveling road surface, and the brake operation information about the operation amount and the operation speed of the brake pedal are input (step S31). Next, in step S32, the duty solenoid 34 is based on the turning information and the road surface information so that the larger the vehicle turns and the smaller the friction coefficient of the road surface, the smaller the braking force generated by the constant brake operation. Determines the duty ratio (how effective the brake is). The duty ratio is set in advance by experiments or the like. For example, when the turning state is “large” and the road surface μ is “small”, 80%, and when the turning state is “large” and the road surface μ is “large”. 85%, 95% when the turning state is “small” and the road surface μ is “small”, and 100% when the turning state is “small” and the road surface μ is “large”.

Next, in step S33, the primary departure warning determination flag Fn1 and the secondary departure warning determination flag Fn.
By determining whether any of 2 is 1,
It is determined whether or not a lane departure warning has been issued. Step S
If NO in 33, that is, if the lane departure warning is not issued, the process proceeds to step S34, and the duty set in step S32 is set so that the normal (when the lane departure warning is not activated) braking force corresponding to the brake pedal operation amount is generated. The duty solenoid 58 is operated at a rate.

On the other hand, if YES at step S33, that is, if the lane departure warning is issued, the routine proceeds to step S35, where the duty ratio set at step S32 is multiplied by a correction value of 0.8 to set the duty ratio set at step S32. Is reduced and the process proceeds to step S34, where the duty solenoid 58 is operated at the reduced duty ratio.

According to the third embodiment having such a configuration, slips during turning, traveling on a low μ road, and the like,
Even if the brake is operated reflexively by the lane departure warning in a situation where spin, lock, etc. are likely to occur, the braking effect is further weakened according to the turning and the road surface μ,
The running stability of the vehicle is less likely to decrease.

The present invention is not limited to the above-described embodiments, but various changes and modifications can be made within the scope of the matters described in the claims.

In the above embodiment, the alarm is issued when the own vehicle actually deviates from the traveling lane, but the present invention may be configured such that the control device predicts the deviation and issues an alarm. In this case, it is determined in step S3 of the flowchart of FIG. 3 whether or not the time A is less than the predetermined value T0 until the departure from the lane, and if YES,
In step S5, it is determined whether or not the time A is smaller than the boundary value T1 smaller than T0.
Then, the process proceeds to step S9.

In the first and second embodiments, when the lane departure warning is issued, the duty ratio is changed according to the turning condition and the road friction coefficient. However, when the lane departure warning is issued. The duty ratio may be changed at a constant rate.

[0049]

According to the present invention, there is provided a vehicle control device which prevents a reduction in the running stability of a vehicle due to a brake operation when an lane departure warning is issued.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a braking force control actuator of the control device of the first embodiment.

FIG. 3 is a flowchart of a lane departure warning process performed by a lane departure warning CPU.

FIG. 4 is a flowchart of a braking force control process performed by a braking force control CPU according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of a braking force control actuator of a control device according to a second embodiment.

FIG. 6 is a flowchart of a braking force control process performed by a braking force control CPU of the second embodiment.

FIG. 7 is a block diagram showing a configuration of a braking force control actuator of a control device according to a third embodiment.

FIG. 8 is a flowchart of a braking force control process performed by a braking force control CPU according to a third embodiment.

[Explanation of symbols]

1: Control device 2: CPU for lane departure warning 4: Actuator for controlling braking force 6: CPU for controlling braking force

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60R 21/00 B60R 21/00 626G 628 628C 628F 630 630D G08G 1/16 G08G 1/16 C

Claims (5)

[Claims] 1. A vehicle control device comprising lane departure warning means for issuing a warning regarding lane departure of a vehicle, wherein braking force generation for producing a braking force of a predetermined magnitude according to a brake operation amount of a driver. A vehicle control device comprising: a means and a braking force correction means for reducing and correcting a magnitude of a braking force generated in response to a constant brake operation when the alarm is issued. 2. The vehicle control according to claim 1, further comprising turning detection means for detecting turning of the vehicle, wherein the braking force correction means increases the correction amount of the decrease correction as the turning becomes larger. apparatus. 3. The friction coefficient detecting means for detecting a friction coefficient of a road surface is further provided, and the braking force correcting means increases the correction amount of the reduction correction as the friction coefficient is smaller. The vehicle control device described. 4. A vehicle control device comprising a braking force correction means for correcting the braking force so that the larger the vehicle turns, the smaller the braking force generated for a constant braking operation. Lane departure warning means for issuing a warning regarding lane departure of the vehicle, and correction amount adjusting means for increasing the correction amount by the braking force correction means when the warning is issued, compared to when the warning is not issued. And a control device for a vehicle. 5. A vehicle control device comprising a braking force correction means for correcting the braking force so that the smaller the friction coefficient of the road surface, the smaller the braking force generated for a constant braking operation. A lane departure warning means for issuing an lane departure warning of the vehicle; and a correction amount adjustment for making the correction amount by the braking force correction means larger when the warning is issued than when the warning is not issued. And a control unit for the vehicle.