JP2008006857A - Lane deviation prevention device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably suppress lane deviation prevention control based on steering operation of a driver. <P>SOLUTION: The lane deviation prevention device corrects a standard steering angle δ<SB>latch</SB>on the basis of steering angle change occurring (for example, occurring due to torque steering) in relation to execution of lane deviation prevention control (steps S23, S24). According to a compared result between the corrected standard steering angle δ<SB>latch</SB>and a steering angle δ by the steering operation of the driver, the control contents of lane deviation prevention control is changed (steps S25, S26). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lane departure prevention apparatus for preventing a departure when a host vehicle is about to depart from a traveling lane.

As a lane departure prevention device, when it is determined that the host vehicle tends to depart from the driving lane, a braking force difference is generated between the left and right wheels, and a yaw moment is applied to the host vehicle, so that the host vehicle deviates from the driving lane. There is a device that prevents this (see, for example, Patent Document 1).
JP 2003-154910 A

By the way, in the lane departure prevention apparatus, when the steering operation for changing the lane by the driver is detected after starting the lane departure prevention control (starting to give the yaw moment), specifically, the steering angle δ is predetermined. Is detected, the lane departure prevention control is suppressed to reflect the driver's intention and the steering intervention by the driver is made effective.
Here, when a braking force difference is generated between the left and right wheels as lane departure prevention control, torque steer is generated. Then, steering may occur in the direction opposite to the steering direction (lane change side) intended by the driver due to the torque steer.

Therefore, in such a case, the lane departure prevention control is performed at a timing when a steering angle greater than a predetermined threshold value to the lane change side of the driver is detected based on the steering angle at the start of the lane departure prevention control. If it is going to suppress, unless the driver | operator overcomes the steering which generate | occur | produces by the said torque steer, and a driver | operator increases, it will not come to detecting the lane change intention by this driver | operator.
Furthermore, although the lane departure prevention control is suppressed at the time of lane change, the driver gets a steering feeling before the suppression starts, and the lane departure prevention control gives the driver a sense of incongruity. End up.
The subject of this invention is performing appropriately suppression of lane departure prevention control based on a driver | operator's steering operation.

  In order to solve the above-described problem, the lane departure prevention apparatus according to the present invention performs lane departure prevention control for preventing the host vehicle from deviating from the traveling lane and detects a steering operation by the driver. Performs lane departure prevention control according to the detection, and the steering operation by the driver is detected in consideration of a steering angle change generated in connection with the execution of the lane departure prevention control.

  Further, the lane departure prevention apparatus according to the present invention includes a control means for performing lane departure prevention control for preventing the own vehicle from deviating from the traveling lane, a steering state detection means for detecting a steering state of the driver, Control content change means for changing the control content of the control means based on a comparison result between a value indicating the steering state detected by the steering state detection means and a predetermined threshold, and implementation of the lane departure prevention control Threshold correction means for correcting the predetermined threshold on the basis of a change in steering angle that occurs in association with the steering angle.

According to the present invention, the control content of the lane departure prevention control is changed on the basis of the comparison result between the value indicating the steering state of the driver and the predetermined threshold value, while the lane departure prevention control is performed. By correcting a predetermined threshold value based on the steering angle change generated in this way, the steering state of the driver can be detected in consideration of the steering angle change, and based on the detected steering state of the driver Thus, the control content of the lane departure prevention control can be changed.
Thereby, the lane departure prevention control based on the driver's steering operation can be appropriately suppressed.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
(First embodiment)
(Constitution)
1st Embodiment of this invention is a rear-wheel drive vehicle carrying the lane departure prevention apparatus based on this invention. This rear-wheel drive vehicle is equipped with an automatic transmission and a conventional differential gear, and a braking device capable of independently controlling the braking force of the left and right wheels for both the front and rear wheels.
FIG. 1 is a schematic configuration diagram showing the first embodiment.
In the figure, reference numeral 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, and 4 is a reservoir. Normally, the brake fluid pressure boosted by the master cylinder 3 according to the amount of depression of the brake pedal 1 by the driver is shown. It supplies to each wheel cylinder 6FL-6RR of each wheel 5FL-5RR. Further, a braking fluid pressure control unit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL-6RR, and the braking fluid pressure control unit 7 individually controls the braking fluid pressure of each wheel cylinder 6FL-6RR. It is also possible to control.

  The brake fluid pressure control unit 7 uses a brake fluid pressure control unit used in, for example, anti-skid control (ABS), traction control (TCS), or vehicle dynamics control device (VDC). The brake fluid pressure control unit 7 can control the brake fluid pressure of each of the wheel cylinders 6FL to 6RR independently, but when a brake fluid pressure command value is input from the braking / driving force control unit 8 described later, The brake fluid pressure is controlled according to the brake fluid pressure command value.

For example, the brake fluid pressure control unit 7 includes an actuator in the hydraulic pressure supply system. Examples of the actuator include a proportional solenoid valve capable of controlling each wheel cylinder hydraulic pressure to an arbitrary braking hydraulic pressure.
The vehicle is provided with a drive torque control unit 12. The drive torque control unit 12 controls the drive torque to the rear wheels 5RL and 5RR which are drive wheels by controlling the operating state of the engine 9, the selected gear ratio of the automatic transmission 10, and the throttle opening of the throttle valve 11. To do. The drive torque control unit 12 controls the operating state of the engine 9 by controlling the fuel injection amount and ignition timing, and simultaneously controlling the throttle opening. The drive torque control unit 12 outputs the value of the drive torque Tw used for control to the braking / driving force control unit 8.

The drive torque control unit 12 can control the drive torque of the rear wheels 5RL and 5RR independently. However, when a drive torque command value is input from the braking / driving force control unit 8, the drive torque is controlled. Drive wheel torque is also controlled according to the command value.
In addition, this vehicle is provided with an imaging unit 13 with an image processing function. The imaging unit 13 is provided for detecting the position of the host vehicle in the traveling lane for detecting the lane departure tendency of the host vehicle. The imaging unit 13 is configured to capture an image with a monocular camera including a CCD (Charge Coupled Device) camera installed so as to capture the front of the host vehicle. The imaging unit (front camera) 13 is installed in the front part of the vehicle.

The imaging unit 13 detects a lane marking such as a white line (lane marker) from the captured image in front of the host vehicle, and detects a traveling lane based on the detected white line. Furthermore, the imaging unit 13 determines, based on the detected travel lane, an angle (yaw angle) φ _front between the travel lane of the _host vehicle and the longitudinal axis of the host vehicle, a lateral displacement X _{front with} respect to the travel lane, and a travel lane curvature. β and the like are calculated.

Thus, the imaging unit 13 detects the white lines that form a travel lane, based on the white lines that the detected, calculates the yaw angle phi _front. The imaging unit 13 outputs the calculated yaw angle φ _front , lateral displacement X _front, travel lane curvature β, and the like to the braking / driving force control unit 8.
In the present invention, the lane marker may be detected by detection means other than image processing. For example, the lane marker may be detected by a plurality of infrared sensors attached to the front of the vehicle, and the traveling lane may be detected based on the detection result.

  Further, the present invention is not limited to the configuration in which the traveling lane is determined based on the white line. In other words, if there is no white line (lane marker) on the road to recognize the driving lane, the information on the road shape and surrounding environment obtained by image processing and various sensors, the driving range suitable for driving and driving A person may estimate the travel range where the vehicle should travel and determine the travel lane. For example, when there is no white line on the runway and both sides of the road are separated, the asphalt portion of the runway is determined as the travel lane. Moreover, what is necessary is just to determine a driving lane in consideration of the information, when there is a guardrail, a curb, etc.

Further, the traveling lane curvature β may be calculated based on a steering angle δ of the steering wheel 21 described later.
The vehicle is provided with a navigation device 14. The navigation device 14 detects the longitudinal acceleration Yg or lateral acceleration Xg generated in the host vehicle or the yaw rate φ ′ generated in the host vehicle. The navigation device 14 outputs the detected longitudinal acceleration Yg, lateral acceleration Xg, and yaw rate φ ′ to the braking / driving force control unit 8 together with the road information.
Each value may be detected by a dedicated sensor. That is, the longitudinal acceleration Yg and the lateral acceleration Xg may be detected by the acceleration sensor, and the yaw rate φ ′ may be detected by the yaw rate sensor.

  Further, the vehicle includes a master cylinder pressure sensor 17 that detects an output pressure of the master cylinder 3, that is, a master cylinder hydraulic pressure Pm, an accelerator pedal depression amount that detects an accelerator pedal depression amount, that is, an accelerator opening .theta. A steering angle sensor 19 for detecting a steering angle (steering angle) δ of the wheel 21, a direction indicating switch 20 for detecting a direction indicating operation by a direction indicator, and a rotation speed of each of the wheels 5FL to 5RR, so-called wheel speed Vwi (i = Wheel speed sensors 22FL to 22RR that detect = fl, fr, rl, rr) are provided. Detection signals detected by these sensors and the like are output to the braking / driving force control unit 8.

  Next, calculation processing (processing routine) performed by the braking / driving force control unit 8 will be described. FIG. 2 is a flowchart showing the procedure of the arithmetic processing. This calculation process is executed by a timer interrupt every predetermined sampling time ΔT every 10 msec., For example. Although no communication process is provided in the process shown in FIG. 2, information obtained by the calculation process is updated and stored in the storage device as needed, and necessary information is read out from the storage device as needed.

As shown in FIG. 2, when the process is started, first, in step S1, various data are read from each sensor, controller, and control unit. Specifically, the longitudinal acceleration Yg, the lateral acceleration Xg, the yaw rate φ ′ and road information obtained by the navigation device 14, the wheel speeds Vwi, the steering angle δ, the accelerator opening θ, the master cylinder hydraulic pressure detected by the sensors. The Pm and direction switch signals, the driving torque Tw from the driving torque control unit 12, and the lateral displacement X _front and the traveling lane curvature β are read from the imaging unit 13.

Subsequently, in step S2, the vehicle speed V is calculated. Specifically, the vehicle speed V is calculated by the following equation (2) based on the wheel speed Vwi read in step S1.
For front wheel drive V = (Vwr1 + Vwrr) / 2
For rear wheel drive V = (Vwfl + Vwfr) / 2
... (1)
Here, Vwfl and Vwfr are the wheel speeds of the left and right front wheels, and Vwrl and Vwrr are the wheel speeds of the left and right rear wheels. That is, in the equation (1), the vehicle speed V is calculated as an average value of the wheel speeds of the driven wheels. In this embodiment, since the vehicle is a rear-wheel drive vehicle, the vehicle speed V is calculated from the latter equation, that is, the wheel speed of the front wheels.

The vehicle speed V calculated in this way is preferably used during normal travel. For example, when an ABS (Anti-lock Brake System) control or the like is operating, an estimated vehicle speed estimated in the ABS control is used as the vehicle speed V.
Subsequently, in step S3, the yaw angle φ _front is calculated. Specifically, the yaw angle φ _front of the _host vehicle with respect to the far white line detected by the imaging unit 13 is calculated.

Incidentally, thus calculated yaw angle phi _front is made to the measured value by the imaging unit 13, instead of using the actual measurement values, based on the white line in the vicinity of the imaging unit 13 is captured, to calculate a yaw angle phi _front You can also. That is, for example, the yaw angle φ _front is calculated by the following equation (1) using the lateral displacement X _front read in step S1.
φ _front = tan ⁻¹ (V / dX ′ (= dY / dX)) (2)
Here, dX is a change amount per unit time of the lateral displacement X, dY is a change amount in the traveling direction per unit time, and dX ′ is a differential value of the change amount dX.

Further, when the yaw angle φ _front is calculated based on the white line in the vicinity, it is not limited to calculating the yaw angle φ _front using the lateral displacement X as shown in the equation (2). For example, a white line detected in the vicinity can be extended far away, and the yaw angle φ _front can be calculated based on the extended white line. V is the vehicle speed calculated in step S2.

Subsequently, in step S4, an estimated lateral displacement is calculated. Specifically, using the travel lane curvature β obtained in step S1 and the lateral displacement X _front of the current vehicle, the vehicle speed V obtained in step S2, and the yaw angle φ _front obtained in step S3, The estimated lateral displacement Xs is calculated by the equation (3).
Xs = Tt · V · (φ _front + Tt · V · β) + X _front (3)
Here, Tt is the vehicle head time for calculating the forward gaze distance. When this vehicle head time Tt is multiplied by the own vehicle speed V, a forward gazing distance is obtained. That is, the estimated lateral displacement from the center of the traveling lane after the vehicle head time Tt becomes the estimated lateral displacement Xs in the future. According to this equation (3), the larger the yaw angle _{phi front,} estimated lateral displacement Xs increases.

  Subsequently, in step S5, a yaw moment (hereinafter referred to as a reference yaw moment) applied to the host vehicle as lane departure prevention control is calculated. In the lane departure prevention control, when the own vehicle tends to deviate from the traveling lane, a predetermined yaw moment (predetermined lane departure prevention control amount) is given to the own vehicle so that the own vehicle deviates from the traveling lane. In step S5, the yaw moment (reference yaw moment Ms0) is calculated based on the actual running state.

Specifically, for calculating a reference yaw moment Ms0 by the following equation (4) based on the estimated lateral displacement Xs obtained and lateral displacement limit distance X _L in the step S4.
Ms0 = K1 · K2 · (| Xs | −X _L ) −ΔMd (4)
Here, K1 is a proportional gain determined from vehicle specifications, and K2 is a gain that varies according to the vehicle speed V. FIG. 3 shows an example of the gain K2. As shown in FIG. 3, for example, the gain K2 has a small value in the low speed range, decreases when the vehicle speed V reaches a certain value, decreases with an increase in the vehicle speed V, and then increases to a certain value at a certain vehicle speed V. It becomes. Further, ΔMd is a yaw moment correction amount set according to the driving operation state of the driver in step S9 described later.

According to the (4) equation, the larger the difference between estimated lateral displacement Xs and lateral displacement limit distance X _L is, the reference yaw moment Ms0 becomes large, from the relationship between estimated lateral displacement Xs and yaw angle phi _front ( wherein (3) reference expression), the larger the yaw angle _{phi front,} the reference yaw moment Ms0 increases.
Further, the reference yaw moment Ms0 is calculated by the above equation (4) when the departure determination flag Fout set in step S6 described later is ON, and the reference yaw moment Ms0 is set to 0 when the departure determination flag Fout is OFF. Set.

Subsequently, in step S6, the deviation tendency of the host vehicle from the traveling lane is determined. Specifically, by comparing the estimated lateral displacement Xs obtained in step S4, the threshold value X _L for determining the tendency to deviate is a lateral displacement limit distance used for calculation of the reference yaw moment Ms0 in step S5 , Determine the tendency to deviate. FIG. 4 shows the definition of values used in this process.
The departure tendency determination threshold value (lateral displacement limit distance) _XL is generally a value that can be grasped when the vehicle has a lane departure tendency, and is obtained as an experience value, an experimental value, or the like. For example, the departure tendency determination threshold value _XL is a value indicating the position of the boundary line of the traveling lane, and is calculated by the following equation (5).
X _L = (L−H) / 2 (5)
Here, L is the lane width of the travel lane (width between white lines forming the travel lane), and H is the width of the vehicle. The lane width L is obtained by processing the captured image by the imaging unit 13.

Then, when the estimated lateral displacement Xs is greater than or departure-tendency threshold value _{X L (| Xs | ≧ X} L), it is determined that there is a lane departure tendency, setting the departure flag Fout ON, the estimated lateral displacement If Xs is less than departure-tendency threshold value _{X L (| Xs | <X} L), it is determined that no lane departure tendency, setting the departure flag Fout to OFF.
Incidentally, departure-tendency threshold value X _L is set to the lane width L, it may be set outside the lane. Further, the departure tendency determination threshold value _XL may be set so that it is determined that there is a lane departure tendency after at least one vehicle wheel comes out of the lane.

Further, the determination of the lane departure tendency can be performed using the actual lateral displacement X _front (the estimated lateral position Xs when Tt = 0) instead of the estimated lateral position Xs. In this case, when the actual lateral displacement _{X front} of or departure-tendency threshold value _{X L (| X front | ≧} X L), it is determined that there is a lane departure tendency, setting the departure flag Fout is turned ON .
Further, as a condition for enabling the departure determination flag Fout to be set to ON, after the departure determination flag Fout is set to OFF, the vehicle is not in a departure state ((| Xs | <X _L ) or (| X _front | <X _L )). In addition, as a condition that allows the departure determination flag Fout to be set to ON, a time condition such as a predetermined time has elapsed after the departure determination flag Fout is set to OFF can be added.

After setting the departure determination flag Fout as described above, the departure direction Dout is determined based on the lateral displacement X. Specifically, when the vehicle is laterally displaced from the center of the lane to the left, the direction is set as the departure direction Dout (Dout = LEFT), and when the vehicle is laterally displaced from the center of the lane to the right, the direction is changed to the departure direction Dout. (Dout = RIGHT).
When anti-skid control (ABS), traction control (TCS), or vehicle dynamics control (VDC) is operating, the departure determination flag Fout is turned off so as not to operate the lane departure prevention control. It may be set to.

  Further, the departure determination flag Fout may be finally set in consideration of the driver's intention to change the lane. For example, when the direction indicated by the direction switch signal (the blinker lighting side) and the direction indicated by the departure direction Dout are the same, it is determined that the driver has intentionally changed the lane, and the departure determination flag Fout is turned off. Change to That is, it is changed to a determination result that there is no lane departure tendency. When the direction indicated by the direction switch signal (the blinker lighting side) is different from the direction indicated by the departure direction Dout, the departure determination flag Fout is maintained and the departure determination flag Fout is kept ON. That is, the determination result that there is a tendency to depart from the lane is maintained.

  When the direction indicating switch 20 is not operated, the departure determination flag Fout is finally set based on the steering angle δ. That is, when the driver is steering in the lane departure direction, both the steering angle δ and the change amount (change amount per unit time) Δδ of the steering angle are set values (steering angle δs, change amount Δδs). ) In the above case, it is determined that the driver has intentionally changed the lane, and the departure determination flag Fout is changed to OFF.

Subsequently, in step S7, the end timing of the output (giving) of the yaw moment to the host vehicle by the lane departure prevention control is determined.
Based on the determination of the departure tendency in the step S6, the lane departure tendency is resolved by the host vehicle returning to the traveling lane or the host vehicle changing the lane at the driver's intention (Fout = OFF Thus, the lane departure prevention control is finished, that is, the output (giving) of the yaw moment to the host vehicle is finished. In step S7, in addition to the determination of the departure tendency, when the amount of lateral displacement of the host vehicle in the traveling lane exceeds a predetermined amount, it is determined that the lane departure prevention control is finished. Specifically, first, an output end determination threshold value X _end for determining the end (end position) of yaw moment output is set. Subsequently, when the actual lateral displacement X _front is equal to or greater than the output end determination threshold value X _end (| X _front | ≧ X _end ), it is determined that the end timing of the lane departure prevention control is reached, and the departure determination flag Fout Is set to OFF.

FIG. 5 shows the relationship between the position of the host vehicle 101, the departure tendency determination threshold value _XL, and the output end determination threshold value _Xend .
Vehicle 101 is now exceeds the lane departure prevention control departure-tendency threshold value X _{L (white} line 102 positions or the white line 102 near) as shown in FIG. 5 is started (the yaw moment to the host vehicle 101 is applied When the host vehicle 101 further reaches the output end determination threshold value X _end shown in FIG. 5, the lane departure prevention control ends (the application of the yaw moment to the host vehicle 101 ends). ). Accordingly, the output end decision threshold _{X end} value obtained by subtracting the departure-tendency threshold value _{X L} from ls_w_LMT _{(= X} end -X _L) is the control range of the lane departure prevention control.
Subsequently, in step S8, a target yaw moment that is finally used as a control command value is set.

The lane departure prevention control of the present embodiment is based on the premise that the lane departure prevention control processing routine (the processing routine of FIG. 2) is executed a plurality of times before completion of lane departure avoidance, that is, yaw moment (specifically, Is premised on avoiding lane departure of the host vehicle by continuously applying the target yaw moment Ms) to the host vehicle successively, and from this, a series of operations performed from the start of control to the end of control. With this processing routine, the yaw moment (control amount) gradually increases and then gradually decreases.
In step S8, on the premise that such a yaw moment output form is used, a target yaw moment Ms is calculated by performing a limiter process on the reference yaw moment Ms0 calculated in step S5. For this reason, first, a limiter for performing the limiter process is set as a default value.

FIG. 6 shows a change with time of the reference yaw moment Ms0.
As shown in FIG. 6, an increase side change amount limiter Lup is set as a limiter for limiting an increase rate of the reference yaw moment Ms0 on the increase side (value at the start of control or the first half of control), and the maximum value (control) of the reference yaw moment Ms0 The maximum value limiter Lmax is set as a limiter that limits the value of the middle plate), and the decrease-side change amount limiter Ldown is set as a limiter that limits the decrease rate of the reference yaw moment Ms0 on the decrease side (value at the end of control or the latter half of the control). .

  Here, the increase side change amount limiter Lup and the decrease side change amount limiter Ldown correspond to the change amount within one processing routine time of the lane departure prevention control. Further, the increase side change amount limiter Lup, the maximum value limiter Lmax, and the decrease side change amount limiter Ldown are based on experience values, experimental values, etc., and provide the minimum yaw moment necessary for the vehicle to avoid deviation from the driving lane. Determined to be smooth.

The increase side change limiter Lup, the maximum value limiter Lmax, and the decrease side change amount limiter Ldown are set as default values, and the set increase side change limiter Lup, maximum value limiter Lmax, and decrease side change limiter Ldown are set. The reference yaw moment Ms0 limited by the above is calculated as the target yaw moment Ms.
FIG. 7 shows a result obtained by limiting the reference yaw moment Ms0 with these limiters Lup, Lmax, and Ldown, that is, the target yaw moment Ms.
When the increase side change limiter Lup is small, the increase side inclination (increase rate) of the target yaw moment Ms is small, and when the decrease side change limiter Ldown is small, the decrease side inclination (decrease) of the target yaw moment Ms is reduced. Ratio) becomes smaller.

In step S9, a yaw moment correction amount is calculated. FIG. 8 shows the processing procedure.
As shown in FIG. 8, when the process is started, first, in step S21, it is determined whether or not the vehicle is in a lane departure state. Specifically, it is determined whether or not the departure determination flag Fout set in step S6 has changed from OFF to ON. Here, the process of step S21 is repeated until it is determined that the vehicle is in a lane departure state. If it is determined that the vehicle is in a lane departure state, the process proceeds to step S22.

Subsequently, in step S22, the steering angle δ when it is first determined in step S21 that the vehicle is in the lane departure state is latched as a reference steering angle δ _latch (an initial value is stored).
Subsequently, in step S23, the steering angle δ is compared with the reference steering angle δ _latch while it is determined that the vehicle is in a lane departure state (during departure), and the steering (steering) direction is the original lane ( It is determined whether or not the vehicle is on the side of the lane where the host vehicle returns after avoidance of departure. If the steering direction is the original lane side, the process proceeds to step S24. If not (the steering direction is the lane side in the lane departure direction (lane change side)), the process proceeds to step S25.

In step S24, the current steering angle δ is latched (updated) as the reference steering angle δ _latch . Then, the process proceeds to step S25.
In step S25, an additional steering amount Δδ is calculated. Specifically, the current steering angle δ and the reference steering angle δ _latch are compared, and steering (addition) occurs on the lane side (lane change side) in the lane departure direction with reference to the reference steering angle δ _latch. If so, the additional steering amount Δδ is calculated by the following equation (6).
Δδ = | δ _latch −δ | (6)
Subsequently, in step S26, when the additional steering amount Δδ is calculated in step S25, the yaw moment correction amount ΔMd is calculated based on the additional steering amount Δδ.

  FIG. 9 shows an example of the relationship between the additional steering amount Δδ and the yaw moment correction amount ΔMd. As shown in FIG. 9, the yaw moment correction amount ΔMd becomes a certain small value in the region where the additional steering amount Δδ is small, and when the additional steering amount Δδ reaches a certain value, the yaw moment correction amount Δδ increases as the additional steering amount Δδ increases. The moment correction amount ΔMd also increases. Thereafter, when the steering amount Δδ increases and reaches a certain value, the yaw moment correction amount ΔMd becomes a constant value with a large value. With reference to such a characteristic diagram, the yaw moment correction amount ΔMd is set based on the additional steering amount Δδ.

Through the processing in step S9 described above, the steering angle δ at the start of lane departure (at the start of lane departure determination) is set as the initial value of the reference steering angle δ _latch (step S22), and then the set reference steering angle δ is set. _{The latch} is compared with the current steering angle δ (at the time of each sampling process). When the steering direction is the original lane (the lane where the vehicle returns after avoiding departure), the reference steering angle δ is determined by the current steering angle δ. _{The latch} is updated (steps S23 and S24). Then, the steering angle δ at the time of each sampling process and the reference steering angle δ _latch are compared. If steering (addition) occurs on the lane side (lane change side) in the lane departure direction, An additional steering amount Δδ is calculated (step S25, equation (6)). Then, the yaw moment correction amount ΔMd is set based on the calculated additional steering amount Δδ (step S26).

Subsequently, in step S10, when the departure determination flag Fout is ON, sound output or display output is performed as an alarm for avoiding lane departure.
When the departure determination flag Fout is ON, that is, when the absolute value | Ms | of the target yaw moment Ms is larger than 0, the yaw moment (target yaw moment Ms) is applied to the host vehicle as lane departure prevention control. Since it starts, the alarm is output simultaneously with the application of the yaw moment to the host vehicle. However, the alarm output timing is not limited to this, and may be earlier than the start timing of the yaw moment application, for example.

Subsequently, in step S11, a target brake hydraulic pressure for each wheel is calculated. Specifically, it is calculated as follows.
When the departure determination flag Fout is OFF, that is, when the target yaw moment Ms is 0 (when lane departure prevention control is not performed), as shown in the following equations (7) and (8), the target braking of each wheel The hydraulic pressure Psi (i = fl, fr, rl, rr) is set to the braking hydraulic pressure Pmf, Pmr.
Psfl = Psfr = Pmf (7)
Psrl = Psrr = Pmr (8)
Here, Pmf is the brake fluid pressure for the front wheels. Further, Pmr is the braking fluid pressure for the rear wheels, and is a value calculated based on the braking fluid pressure Pmf for the front wheels in consideration of the front-rear distribution. For example, if the driver is operating a brake, the brake fluid pressures Pmf and Pmr are values corresponding to the amount of brake operation (master cylinder fluid pressure Pm).

On the other hand, when the departure determination flag Fout is ON, that is, when the absolute value | Ms | of the target yaw moment Ms is larger than 0 (when the determination result that there is a lane departure tendency is obtained), the setting is made in the step S8. Based on the target yaw moment Ms, the front wheel target braking hydraulic pressure difference ΔPsf and the rear wheel target braking hydraulic pressure difference ΔPsr are calculated. Specifically, the target braking hydraulic pressure differences ΔPsf and ΔPsr are calculated by the following equations (9) and (10).
ΔPsf = 2 · Kbf · (Ms · FR _ratio ) / T (9)
ΔPsr = 2 · Kbr · (Ms · (1-FR _ratio )) / T (10)

Here, FR _ratio indicates a setting threshold value. T represents a tread. The tread T is set to the same value before and after for convenience. Kbf and Kbr are conversion coefficients for the front wheels and the rear wheels when the braking force is converted into the braking hydraulic pressure, and are determined by the brake specifications. The target braking hydraulic pressure differences ΔPsr and ΔPsr are values for determining the distribution of the braking force applied to each wheel according to the magnitude of the target yaw moment Ms, and are values for generating a braking force difference between the front, rear, left and right wheels. .

Then, the final target brake fluid pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated using the calculated target brake fluid pressure differences ΔPsf, ΔPsr. Specifically, when the departure determination flag Fout is ON and the departure direction Dout is LEFT, that is, when there is a lane departure tendency with respect to the white line on the left side, the target braking hydraulic pressure Psi of each wheel is expressed by the following equation (11). (I = fl, fr, rl, rr) is calculated.
Psfl = Pmf
Psfr = Pmf + ΔPsf
Psrl = Pmr
Psrr = Pmr + ΔPsr
(11)

When the departure determination flag Fout is ON and the departure direction Dout is RIGHT, that is, when there is a lane departure tendency with respect to the white line on the right side, the target braking fluid pressure Psi (i = i = fl, fr, rl, rr) are calculated.
Psfl = Pmf + ΔPsf
Psfr = Pmf
Psrl = Pmr + ΔPsr
Psrr = Pmr
(12)
According to the equations (11) and (12), the braking force difference between the left and right wheels is generated so that the braking force of the wheel on the lane departure avoidance side is increased.
Further, here, as shown in the equations (11) and (12), the brake operation by the driver, that is, the target brake fluid pressure Psi (i = fl, fr) of each wheel in consideration of the brake fluid pressures Pmf and Pmr. , Rl, rr). Then, the braking / driving force control unit 8 uses the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) calculated for each wheel thus calculated as a braking fluid pressure command value to the braking fluid pressure control unit 7. Output.

(Operation)
The operation is as follows.
While the vehicle is running, various data are read (step S1), and the yaw angle and vehicle speed V are calculated (steps S2 and S3). Subsequently, an estimated lateral displacement (deviation estimated value) Xs is calculated (step S4), and a lane departure tendency is determined (setting of the departure determination flag Fout) based on the calculated estimated lateral displacement Xs. The determination result of the departure tendency (the departure determination flag Fout) is corrected based on the driver's intention to change lanes (step S6).

On the other hand, the reference yaw moment Ms0 is calculated (step S5), and the target yaw moment Ms is calculated by subjecting the calculated reference yaw moment Ms0 to limiter processing (step S8). Further, an output end determination threshold value X _end for determining the yaw moment output end timing is calculated (step S7).
Here, the yaw moment correction amount ΔMd is calculated based on the additional steering amount Δδ generated after departure from the lane (step S9), and the reference yaw moment Ms0 is corrected based on the calculated yaw moment correction amount ΔMd (see above). Step S5).

Based on the determination result of the lane departure tendency, a warning is output (step S10), and the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated based on the target yaw moment Ms. And the calculated target brake fluid pressure Psi (i = fl, fr, rl, rr) of each wheel is output to the brake fluid pressure controller 7 (step S11). Thereby, a yaw moment is given to the own vehicle in accordance with the lane departure tendency of the own vehicle. When the yaw moment output end timing comes (| X _front | ≧ X _end ), the application of the yaw moment to the host vehicle ends, and the lane departure prevention control ends.

(Function and effect)
Next, functions and effects will be described.
Lane departure start with setting the [delta] steering angle (lane departure determination start time) as the initial value of the reference steering angle [delta] _latch, and [delta] the steering angle of the set reference steering angle [delta] _latch and the current (at each sampling) If the steering direction is the original lane side, the reference steering angle δ _latch is updated with the current steering angle δ (steps S21 to S24). Then, the steering angle δ at the time of each sampling process and the reference steering angle δ _latch are compared. If steering (addition) occurs on the lane side (lane change side) in the lane departure direction, The additional steering amount Δδ is calculated, and the yaw moment correction amount ΔMd is set based on the calculated additional steering amount Δδ (steps S25 and S26).

That is, as long as the steering direction is the original lane side, the reference rudder angle δ _latch is updated with the current rudder angle δ, while the steering is increased to the lane side in the lane departure direction (lane change side). Is generated, the additional steering amount Δδ is calculated based on the latest reference steering angle δ _latch .
As a result, torque steer is generated due to the execution of the lane departure prevention control (occurred due to the occurrence of a braking force difference between the left and right wheels), and the steering direction intended by the driver (lane change side) by the torque steer When steering (steering) occurs in the opposite direction, the reference rudder angle δ _latch is updated by steering by the torque steer (to the original lane side).

In such a situation, when the driver increases and steers to the lane side (lane change side) in the lane departure direction, the increased steering amount Δδ is set based on the updated reference rudder angle δ _latch. The yaw moment correction amount ΔMd is calculated based on the calculated additional steering amount Δδ. In other words, the yaw moment correction amount ΔMd corresponding to the increased steering amount Δδ is calculated immediately after the driver starts increasing the steering.

  Then, based on the yaw moment correction amount ΔMd calculated in this way, the reference yaw moment Ms0 is corrected, and on the basis of the corrected reference yaw moment Ms0, the yaw moment Ms applied to the host vehicle as lane departure prevention control is calculated. Therefore (step S8), immediately after the driver starts to increase and steer, the yaw moment Ms is corrected to decrease according to the increased steering amount Δδ, and the lane departure prevention control is suppressed.

FIG. 10 shows the change over time of the steering angle δ when the driver performs the steering operation for changing the lane during the lane departure prevention control. FIG. 10 (a) shows the result of applying the present invention. FIG. (B) shows the result of conventional technology (control release when the steering angle δ is equal to or greater than the predetermined value δs).
As shown in FIG. 5A, when the present invention is applied, a steering angle (steering angle caused by torque steer) is generated in the lane departure avoidance direction after the lane departure prevention control. By updating the angle δ _latch , when the driver turns and steers, the lane departure prevention control starts to be suppressed from the steering start timing.

  Here, FIG. 11 shows a change with time of the target yaw moment Ms. As shown in FIG. 11 as a change from a two-dot broken line to a dotted line, when the driver starts to increase steering, the target yaw moment Ms is corrected to decrease based on the increased steering amount Δδ, and lane departure prevention control is performed. It will be suppressed. Further, as indicated by a dotted line in FIG. 7, the target yaw moment Ms is corrected to decrease based on the additional steering amount Δδ.

  On the other hand, as shown in FIG. 10B, in the conventional case, after the lane departure prevention control, a steering angle (steering angle due to torque steer) is generated in the lane departure avoidance direction, so that the driver increases steering. Even if it starts, it takes time for the lane departure prevention control and the driver's steering to cancel each other and the steering angle to reach the threshold value δs. Lane departure prevention control starts to be suppressed.

As described above, by applying the present invention, torque steer is generated by performing the lane departure prevention control, and steering is generated in the opposite direction to the steering direction (lane change side) intended by the driver by the torque steer. Even in this case, the lane departure prevention control can be suppressed by a steering operation to the lane change side by the driver without giving the driver a feeling of steering catch.
In addition, the said embodiment can also be implement | achieved by the following structures.

That is, in the first embodiment, after the lane departure prevention control, the reference steering angle δ _latch when the driver's steering operation is started is set as a threshold value, and the target yaw moment is corrected to decrease (lane departure). However, the present invention is not limited to this. For example, it may be smaller corrected based on the reference steering angle [delta] _latch which latches the steering angle threshold (set value .delta.s) in the lane departure determination of the step S6. Specifically, the steering angle threshold value is changed to (δs−δ _latch ). As a result, if the steering angle increases to some extent after the driver's steering operation is started, the departure determination flag Fout is turned OFF, so the lane departure prevention control is released, and the driver changes lanes without feeling uncomfortable. Can do.

In the first embodiment, the steering angle δ of the lane departure prevention control is latched as the reference steering angle δ _latch . That is, the reference rudder angle δ _latch is corrected based on the rudder angle δ that changes in connection with the execution of the lane departure prevention control. On the other hand, the reference steering angle δ _latch can be corrected based on the control amount of the lane departure prevention control, specifically, the target yaw moment Ms. Specifically, the reference rudder angle δ _latch is corrected in the lane departure avoidance direction as the target yaw moment Ms increases.

Here, FIG. 12 shows an example of the relationship between the target yaw moment Ms and the steering angle δ that changes toward the lane departure avoidance side. As shown in FIG. 12, as the target yaw moment Ms increases, the steering angle δ changes toward the lane departure avoidance side. This is because as the target yaw moment Ms increases, the steering angle (steering angle in the lane departure avoidance direction) generated by torque steer increases.
Therefore, the larger the target yaw moment Ms is the reference steering angle [delta] _latch is corrected to the lane departure avoidance direction, the reference steering angle [delta] _latch is the steering angle that changes by the torque steer caused by the implementation of the lane departure prevention control The added value is an appropriate value as a threshold for detecting the steering operation by the driver.

In the first embodiment, a case is described in which the reference rudder angle δ _latch is corrected on the assumption that the driver steers to the lane change side during the lane departure prevention control. On the other hand, even when the driver steers to the lane departure avoidance side (original lane side) during the lane departure prevention control, it is effective to correct the reference steering angle δ _latch as described above. Here, when the driver steers to the lane departure avoidance side (original lane side) during the lane departure prevention control, for example, after the start of the lane departure prevention control, the driver himself / herself to prevent departure. This is a case where the steering operation is performed on the lane side. Also in this case, by correcting the reference rudder angle δ _latch as described above, the lane departure prevention control can be suppressed without giving the driver a feeling of steering catch.

  In the description of the first embodiment, the processing in FIG. 2 of the braking / driving force control unit 8 realizes a control means for performing lane departure prevention control for preventing the own vehicle from deviating from the traveling lane. The steering angle sensor 19 realizes a steering state detecting means for detecting the steering state of the driver, and the processing of step S9 of the braking / driving force control unit 8 is performed by the steering state detected by the steering state detecting means. The control content changing means for changing the control content of the control means is realized based on the comparison result between the value indicating the value and a predetermined threshold value, and the processing of step S23 and step S24 of the braking / driving force control unit 8 is realized. Implements threshold correction means for correcting the predetermined threshold based on a change in steering angle that occurs in connection with the execution of the lane departure prevention control. Further, the processing of step S23 and step S24 of the steering angle sensor 19 and the braking / driving force control unit 8 realizes a steering angle detection means for detecting the steering angle.

(Second Embodiment)
Next, a second embodiment will be described.
(Constitution)
Similar to the first embodiment, the second embodiment is a rear wheel drive vehicle equipped with the lane departure prevention apparatus according to the present invention.
In the second embodiment, the yaw moment correction amount ΔMd is calculated in consideration of the traveling environment in which the correction steering is easily applied by the driver. Here, the correction steering is steering for the driver to maintain the traveling state of the host vehicle, or steering for correcting the disturbance of the steering, and in this embodiment, the increase in the lane change is performed. Steering is separate from steering.

The calculation of the yaw moment correction amount ΔMd is performed, for example, in step S26 of FIG. FIG. 13 shows a processing procedure in step S26 in the second embodiment.
As shown in FIG. 13, when the process is started, first, in step S31, a corrected steering index is set based on the traveling environment. Specifically, the corrected steering index is set based on the degree of variation in wheel speed (the degree of fluctuation in increase / decrease).

FIG. 14 shows an example of the relationship between the variation degree of the wheel speed and the corrected steering index Dr. As shown in FIG. 14, in a region where the variation degree of the wheel speed is small, the corrected steering index Dr becomes a certain small value, and when the variation degree of the wheel speed becomes a certain value, the corrected steering is increased as the variation degree of the wheel speed increases. When the index Dr increases and then the degree of variation in wheel speed reaches a certain value, the corrected steering index Dr becomes a large value and a constant value. With reference to such a characteristic diagram, the corrected steering index Dr is set based on the variation degree of the wheel speed.
Subsequently, in step S32, a correction gain (correction coefficient) is set based on the corrected steering index Dr set in step S31.

  FIG. 15 shows an example of the relationship between the corrected steering index Dr and the correction gain Kd. As shown in FIG. 15, in a region where the corrected steering index Dr is small, the correction gain Kd is a certain large value (specifically, Kd = 1), and when the corrected steering index Dr is a certain value, the corrected steering index Dr. When the correction gain Kd decreases with respect to the increase, and then the corrected steering index Dr reaches a certain value, the correction gain Kd becomes a small value and a constant value. With reference to such a characteristic diagram, the correction gain Kd is set based on the corrected steering index Dr.

In step S33, the yaw moment correction amount ΔMd is calculated based on the correction gain Kd set in step S32. Specifically, the yaw moment correction amount ΔMd is calculated (corrected) based on the following (13).
ΔMd = Kd · ΔMd (13)
Here, ΔMd on the right side (before correction) is a value calculated based on the additional steering amount Δδ, as in the first embodiment (step S26).

(Operation, action and effect)
Next, the operation, action and effect will be described.
In particular, in the second embodiment, the corrected steering index Dr increases as the degree of variation in wheel speed increases (step S31, FIG. 14), and the corrected gain Kd decreases as the corrected steering index Dr increases ( Step S32, FIG. 15). As the correction gain Kd decreases, the yaw moment correction amount ΔMd decreases (step S33, equation (13)).

  Here, FIG. 16 shows the relationship between the additional steering amount Δδ and the yaw moment correction amount ΔMd. As can be seen from comparison with the case of FIG. 9 (when the yaw moment correction amount ΔMd is not corrected), as shown in FIG. The change in the yaw moment correction amount ΔMd with respect to the change in the additional steering amount Δδ is suppressed. As a result, the correction amount of the reference yaw moment Ms0 with respect to the additional steering amount Δδ is reduced (see the above equation (4)).

  Here, if the surface of the traveling road is uneven due to the provision of rumble strips, botsdots, or the like on the surface of the traveling road, the driver may apply correction steering. On the other hand, on a road with unevenness on the surface, the wheel speed varies, and the higher the unevenness level, the higher the wheel speed variation. The rumble strips are uneven portions artificially disposed on or in the vicinity of the lane marking line, and the botsdots are heels that are struck on the road in order to recognize the traveling lane.

  For this reason, when the degree of variation in the wheel speed is high, the yaw moment correction amount ΔMd is reduced by increasing the correction steering index Dr, assuming that the driver is applying correction steering, and the reference The correction amount of the yaw moment Ms0 is reduced. As a result, it is possible to prevent the driver's corrected steering during the lane departure prevention control from being detected as an additional steering by the driver (positive detection as a positive steering operation), that is, lane departure prevention control. The driver's steering in the middle is differentiated into additional steering and corrected steering, and the additional steering by the driver can be detected with high sensitivity.

In addition, the said embodiment can also be implement | achieved by the following structures.
That is, in the second embodiment, the unevenness of the road surface is detected (predicted) or the corrected steering index Dr is set based on the degree of variation in the wheel speed. On the other hand, when the white line recognized by the imaging unit 13 is discrete (for example, when bottling is recognized), it is assumed that the traveling road surface has irregularities, and the corrected steering index Dr is set (large). Value).

  Further, the corrected steering index Dr can be set based on the road R (road radius). FIG. 17 shows an example of the relationship between the road R and the corrected steering index Dr. As shown in FIG. 17, as the road R increases, the corrected steering index Dr decreases as a quadratic function. With reference to such a characteristic diagram, the corrected steering index Dr is set based on the road R. As a detection method of the road R, a value obtained from a captured image of the imaging unit 13, a detection value estimated by a steering angle (for example, travel lane curvature), or a value obtained based on the yaw rate and the vehicle speed (for example, travel lane) Curvature) or a value obtained based on the lateral acceleration and the vehicle speed (for example, travel lane curvature).

  Here, as the road R on the travel path becomes smaller, the driver applies corrected steering. As described above, when the road R (road radius) is small, it is assumed that the driver is applying corrected steering. By increasing the corrected steering index Dr, the yaw moment correction amount ΔMd is decreased and the correction amount of the reference yaw moment Ms0 is decreased. Accordingly, it is possible to prevent the driver's correction steering caused by the road R during the lane departure prevention control from being detected as the additional steering by the driver.

Further, the corrected steering index Dr can be set based on the vehicle speed V. FIG. 18 shows an example of the relationship between the vehicle speed V and the corrected steering index Dr. As shown in FIG. 18, the corrected steering index Dr decreases as the vehicle speed V increases. With reference to such a characteristic diagram, the corrected steering index Dr is set based on the vehicle speed V.
As a result, when the vehicle speed V is low, the correction steering by the driver is likely to be added, and by increasing the correction steering index Dr, the yaw moment correction amount ΔMd is decreased and the correction amount of the reference yaw moment Ms0 is decreased. . Thereby, it is possible to prevent the driver's correction steering caused by low-speed traveling during the lane departure prevention control from being detected as additional steering by the driver.

Further, a plurality of corrected steering indexes Dr are obtained based on the wheel speed variation degree, the road R and the vehicle speed V as described above, and one corrected steering index Dr is selected from among them, or a plurality of corrected steering indexes are selected. It is also possible to obtain one corrected steering index Dr by weighting Dr, and calculate the yaw moment correction amount ΔMd based on the one corrected steering index Dr.
In addition, the corrected steering index Dr may be set based on values other than the road surface state on which the host vehicle specifically travels as described above, the traveling road shape, and the traveling state of the host vehicle, for example, the lateral acceleration itself. it can.

  In the description of the second embodiment, the process of step S31 of the braking / driving force control unit 8 realizes a corrected steering detecting means for detecting the corrected steering that the driver uses to maintain the traveling state of the host vehicle. The processing of step S32 and step S33 of the braking / driving force control unit 8 is based on the change in the steering angle that occurs in connection with the execution of the lane departure prevention control when the corrected steering detection means detects the corrected steering. Threshold correction means for suppressing the correction of a predetermined threshold based on the above is realized.

1 is a schematic configuration diagram illustrating a vehicle according to a first embodiment of the present invention. It is a flowchart which shows the processing content of the control unit of the lane departure prevention apparatus of a vehicle. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K2. It is a diagram used for explanation of the estimated lateral displacement Xs and the departure tendency determination threshold value X _L. Is a diagram showing the relationship between the departure-tendency threshold value X _L and the output end decision threshold X _end the vehicle position. FIG. 6 is a characteristic diagram showing a change with time of a reference yaw moment Ms0. It is a characteristic view which shows the time-dependent change of the target yaw moment Ms obtained by the limiter process. It is a flowchart which shows the processing content of the calculation process of the yaw moment correction amount by the said control unit. FIG. 6 is a characteristic diagram showing a relationship between an additional steering amount Δδ and a yaw moment correction amount ΔMd. It is a characteristic view which shows the steering angle change used for description of the effect | action and effect in 1st Embodiment. It is a characteristic view which shows the change of the target yaw moment Ms used for description of the effect | action and effect in 1st Embodiment. It is a characteristic view showing the relationship between the target yaw moment Ms and the steering angle δ that changes to the lane departure avoidance side. It is a flowchart which shows the processing content of the calculation process of the yaw moment correction amount by the control unit in 2nd Embodiment. It is a characteristic view showing the relationship between the variation degree of the wheel speed and the corrected steering index Dr. It is a characteristic view showing the relationship between the corrected steering index Dr and the correction gain Kd. FIG. 10 is a characteristic diagram showing a relationship between an additional steering amount Δδ and a yaw moment correction amount ΔMd in the second embodiment. FIG. 5 is a characteristic diagram showing a relationship between a road surface R and a corrected steering index Dr. It is a characteristic view showing the relationship between the vehicle speed V and the corrected steering index Dr.

Explanation of symbols

  6FL to 6RR wheel cylinder, 7 braking fluid pressure control unit, 8 braking / driving force control unit, 9 engine, 12 driving torque control unit, 13 imaging unit, 17 master cylinder pressure sensor, 18 accelerator opening sensor, 19 steering angle sensor, 22FL-22RR Wheel speed sensor

Claims (7)

  In addition to performing lane departure prevention control for preventing the host vehicle from deviating from the traveling lane, and detecting steering operation by the driver, lane departure prevention control is performed in accordance with the detection, and the driving A lane departure prevention apparatus characterized in that a steering operation by a person is detected in consideration of a steering angle change that occurs in connection with the execution of the lane departure prevention control. Control means for performing lane departure prevention control for preventing the own vehicle from deviating from the traveling lane;
Steering state detecting means for detecting the steering state of the driver;
Control content changing means for changing the control content of the control means based on a comparison result between a value indicating the steering state detected by the steering state detecting means and a predetermined threshold value;
Threshold correction means for correcting the predetermined threshold based on a steering angle change generated in connection with the execution of the lane departure prevention control;
A lane departure prevention apparatus comprising:   The steering state detecting means detects a steering angle by a driver's steering operation as a value indicating the steering state, and the threshold value correcting means has a steering angle that changes in connection with the execution of the lane departure prevention control. The lane departure prevention apparatus according to claim 2, wherein the predetermined threshold value is corrected based on the lane departure prevention apparatus.   4. The lane departure prevention apparatus according to claim 2, wherein the threshold value correction unit corrects the predetermined threshold value according to a control amount of the lane departure prevention control. 5.   The control means, as the lane departure prevention control, applies a yaw moment in the lane departure avoidance direction to the host vehicle by generating a braking force difference between the left and right wheels, and torque steer during the lane departure prevention control. And the steering angle is changed in the lane departure avoidance direction due to the torque steer, and the threshold correction means is configured to perform the predetermined operation based on the steering angle change in the lane departure avoidance direction due to the torque steer. The lane departure prevention apparatus according to any one of claims 2 to 4, wherein the threshold value is corrected.   And a correction steering detection unit that detects a correction steering for the driver to maintain the traveling state of the host vehicle. The threshold correction unit is configured to detect the correction steering when the correction steering detection unit detects the correction steering. The lane departure prevention apparatus according to any one of claims 2 to 5, wherein correction of a predetermined threshold value based on a change in steering angle that occurs in connection with execution of departure prevention control is suppressed.   The corrected steering detection means detects the corrected steering based on at least one of a road surface state on which the host vehicle travels, a road surface shape on which the host vehicle travels, and a traveling state of the host vehicle. 6. A lane departure prevention device according to 6.

Images