JP4259290B2 - Lane departure prevention device - Google Patents

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 conventional lane departure prevention device, when the host vehicle may deviate from the driving lane, the vehicle deviates from the driving lane by giving a yaw moment to the host vehicle by controlling the braking force to the wheels. In addition, there is a device for notifying the driver that the host vehicle may deviate from the traveling lane by applying the yaw moment (see, for example, Patent Document 1).
JP 2000-33860 A

For example, in Patent Document 1, when there is a possibility that the own vehicle tends to deviate from the traveling lane, control for avoiding deviation is performed according to the operation state of the own vehicle and the driving operation state of the driver. However, if there is a possibility that the vehicle will deviate from the driving lane, if the control for avoiding the departure is activated only by looking at the operation state of the vehicle and the driving operation state of the driver, the road condition ahead Depending on the case, the control may be unnecessary. If unnecessary control is performed in this way, the driver feels uncomfortable.
Therefore, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a departure prevention device that can perform control for departure avoidance without causing the driver to feel uncomfortable.

The lane departure prevention apparatus according to the first aspect of the invention suppresses departure avoidance control for avoiding the departure of the host vehicle from the traveling lane when the preceding vehicle moves laterally.
Further, the lane departure prevention device according to the invention of claim 2 detects the lateral movement of the preceding vehicle by the preceding vehicle lateral movement detecting means, and the preceding vehicle lateral movement detecting means detects the lateral movement of the preceding vehicle, The control content of the departure avoidance control for avoiding the departure of the host vehicle from the traveling lane is changed by the control content changing means.
If there is an obstacle such as a stopped vehicle in the front lane or the roadside zone of the lane, or if the current lane is congested, the preceding vehicle will change its lane Avoid by moving. In the present invention, when such a lateral movement of the preceding vehicle is detected, the control content of the departure avoidance control is changed. Particularly, in the invention described in claim 1, the departure avoidance control is suppressed.

  According to the present invention, when lateral movement of a preceding vehicle is detected, the control content of control for avoiding lane departure is changed, so that obstacles existing ahead are avoided by giving priority to departure avoidance control. it can.

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.
The embodiment is a rear-wheel drive vehicle equipped with the lane departure prevention device of the present 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 an embodiment of a lane departure prevention apparatus of the present invention.
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 controls the braking fluid pressure of each wheel cylinder 6FL-6RR. Individual control is also possible.

  The braking fluid pressure control unit 7 uses a braking fluid pressure control unit used for antiskid control and traction control, for example. 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. For example, the imaging unit 13 is configured to capture an image with a monocular camera including a CCD (Charge Coupled Device) camera. This imaging part 13 is installed in the front part of the vehicle.

  The imaging unit 13 detects a lane marker such as a white line from a captured image in front of the host vehicle, and detects a traveling lane based on the detected lane marker. Further, the imaging unit 13 determines, based on the detected travel lane, an angle (yaw angle) φ between the travel lane of the host vehicle and the longitudinal axis of the host vehicle, a lateral displacement X from the center of the travel lane, and a travel lane curvature. β and the like are calculated. The imaging unit 13 outputs the calculated yaw angle φ, lateral displacement X, travel lane curvature β, and the like to the braking / driving force control unit 8.

  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 road information. Here, the road information includes road type information indicating the number of lanes and whether the road is a general road or a highway.

  The vehicle is provided with an ACC radar 15. The ACC radar 15 obtains information on the vehicle or obstacle ahead of the lane in which the host vehicle is currently traveling, and further on the adjacent lane. Specifically, the ACC radar 15 is used to obtain the presence / absence of a forward vehicle or an obstacle (hereinafter referred to as a forward vehicle or the like), a relative distance Lfr to the forward vehicle or the like, and a relative speed Vfr. The ACC radar 15 outputs these radar detection results to the braking / driving force control unit 8.

  Further, in this vehicle, a master cylinder pressure sensor 17 that detects an output pressure of the master cylinder 3, that is, master cylinder hydraulic pressures Pmf and Pmr, and an accelerator opening sensor 18 that detects an accelerator pedal depression amount, that is, an accelerator opening θt. The steering angle sensor 19 for detecting the steering angle δ of the steering wheel 21, the direction indicating switch 20 for detecting the direction indicating operation by the direction indicator, and the rotational speeds of the wheels 5FL to 5RR, so-called wheel speed Vwi (i = fl, Wheel speed sensors 22FL to 22RR for detecting fr, rl, rr) are provided. Detection signals detected by these sensors and the like are output to the braking / driving force control unit 8.

When the detected vehicle traveling state data has left and right directions, the left direction is the positive direction. That is, the yaw rate φ ′, the lateral acceleration Xg, and the yaw angle φ are positive values when turning left, and the lateral displacement X is a positive value when deviating leftward from the center of the traveling lane. The longitudinal acceleration Yg takes a positive value during acceleration and takes a negative value during deceleration.
Next, a calculation processing procedure performed by the braking / driving force control unit 8 will be described with reference to FIG. 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 arithmetic process is updated and stored in the storage device as needed, and necessary information is read out from the storage device as needed.

  First, in step S1, various data are read from each sensor, controller, or control unit. Specifically, the longitudinal acceleration Yg, lateral acceleration Xg, yaw rate φ ′ and road information obtained by the navigation device 14, presence / absence of a forward vehicle obtained by the ACC radar 15, relative distance Lfr and relative speed Vfr, The detected wheel speed Vwi, steering angle δ, accelerator opening θt, master cylinder hydraulic pressures Pmf, Pmr and direction switch signal, drive torque Tw from the drive torque control unit 12, yaw angle φ from the imaging unit 13, lateral The displacement X and the travel lane curvature β are read.

Subsequently, in step S2, the vehicle speed V is calculated. Specifically, the vehicle speed V is calculated by the following formula (1) 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. That is, for example, when ABS (Anti-lock Brake System) control or the like is operating, the estimated vehicle speed estimated in the ABS control is used as the vehicle speed V. A value used for navigation information in the navigation device 14 may be used as the vehicle speed V.
Subsequently, in step S3, the traveling environment is determined. Specifically, the type of road on which the host vehicle is traveling and the traveling lane of the host vehicle are detected. And from the detection result, the direction based on the safety degree is determined. The determination is made based on road information, that is, the number of lanes, road type information indicating whether the road is a general road or a highway, and image information obtained by the imaging unit 13. FIG. 3 shows a specific processing procedure for determining the driving environment.

First, in step S21, the currently traveling road type (general road or highway) is acquired from the road information obtained by the navigation device 14. Furthermore, in step S22, the number of lanes of the currently traveling road is acquired from the road information from the navigation device 14.
Subsequently, in step S23, a white line portion (lane marking line portion) is extracted from the captured image obtained by the imaging unit 13. Here, as shown in FIG. 4, a case where the host vehicle is traveling on a three-lane road on one side will be described as an example.
As shown in FIG. 4, the road is divided into first to fourth white lines LI1, LI2, LI3, and LI4 from the left side, and is configured as a three-lane road on one side. When the host vehicle travels on such a road, the captured image obtained for each lane is different. Further, the image formed by extracting the white line from the image also differs depending on the traveling lane.

  That is, when the host vehicle 100A is traveling in the left lane in the traveling direction, the captured image P obtained by the imaging unit 13 of the host vehicle 100A is mainly the first as shown in FIG. , A unique image constituted by the second and third white lines LI1, LI2, and LI3. Further, when the host vehicle 100B is traveling in the central lane, the captured image P obtained by the imaging unit 13 of the host vehicle 100B is mainly the first, second, and second as shown in FIG. 3 and the fourth white line LI1, LI2, LI3, LI4. Further, when the host vehicle 100C is traveling in the right lane in the traveling direction, the captured image P obtained by the imaging unit 13 of the host vehicle 100C is mainly the second as shown in FIG. , A unique image constituted by the third and fourth white lines LI2, LI3, and LI4. Thus, the configuration of the white line in the image differs depending on the travel lane.

  Subsequently, in step S24, the host vehicle travel lane (host vehicle travel lane) is determined. Specifically, the host vehicle travel lane is determined based on the information obtained in steps S22 and S23. In other words, the host vehicle travel lane is determined based on the number of lanes of the road on which the host vehicle is currently traveling and the captured image (image obtained by extracting the white line) obtained by the imaging unit 13. For example, an image obtained in accordance with the number of lanes and the traveling lane is previously stored as image data, and the image data prepared in advance and the number of lanes on the road on which the host vehicle is currently traveling and the current obtained by the imaging unit 13 are stored. The captured vehicle image (image obtained by extracting the white line) is compared to determine the vehicle lane.

  Subsequently, in step S25, the degree of safety in the left-right direction viewed from the lane in which the host vehicle is traveling is determined. Specifically, the direction in which the degree of safety is low when the host vehicle deviates is held as information. Thus, when the safety level is low in the left direction when viewed from the lane in which the host vehicle is traveling, the direction is held as a low safety level direction (hereinafter referred to as an obstacle direction) Sout (Sout = left), when the safety degree is low in the right direction when viewed from the lane in which the host vehicle is traveling, the direction is held as an obstacle existence direction Sout (Sout = right). For example, the determination is made as follows.

  For example, in FIG. 4, when the host vehicle 100A is traveling in the left lane, the degree of safety is lower when the vehicle deviates to the left of the left lane than to deviate to the right of the left lane. This is because there is a road shoulder in the left direction of the left lane, and there is a high possibility that the road shoulder has a wall, a guardrail, an obstacle or a cliff. Therefore, when the host vehicle 100A is traveling in the left lane, it is determined that the obstacle existence direction Sout is the left direction (Sout = left).

In addition, when the host vehicle 100B is traveling in the central lane, the vehicle 100B is still in the road no matter which direction it deviates, so the safety degree is the same in either the left or right direction with respect to the current traveling lane. become.
Further, when the host vehicle 100C is traveling in the right lane, the degree of safety is lower in the right direction, that is, when the vehicle deviates to the opposite lane than when the vehicle deviates to the left direction, that is, the adjacent lane. Therefore, in this case, when the host vehicle 100C is traveling in the right lane, it is determined that the obstacle existence direction Sout is the right direction (Sout = right).

Moreover, when compared with ordinary roads and expressways, the width of shoulders on ordinary roads is narrower than that of expressways, there are many obstacles on the shoulders, and there are also pedestrians. For this reason, deviating to the shoulder side on a general road is less safe than deviating to the shoulder side on an expressway.
Further, when compared by the number of lanes, the safety degree is lower when the left side is the road shoulder and the right direction is one lane on the opposite lane. In this case, it is determined that both the left and right directions are the obstacle existence direction Sout (Sout = both).

  For example, since there is often no median strip or guard rail on a one-lane road, a captured image when traveling on the one-lane road is as shown in FIG. That is, the captured image when traveling on one lane road is the same as the captured image obtained by the imaging unit 13 of the vehicle 100A traveling on the left lane of the one lane road. Therefore, when it is assumed that the vehicle travels on a general road and an expressway, the obstacle direction of existence Sout cannot be determined only by the captured image. For this reason, the number of lanes of the road on which the vehicle is currently traveling is obtained from the navigation device 14, and it is determined whether the currently traveling road is a one-lane road or a one-lane road. Thus, when driving on a one-lane road on one side, it can be determined that the degree of safety is also low in the right direction.

The travel environment is determined in step S3 shown in FIG. 2 according to the processing procedure shown in FIG.
Subsequently, in step S4, a lateral displacement amount dXfr and a lateral displacement speed Vxfr of the preceding vehicle or the like are calculated. Specifically, the lateral movement amount dXfr of the preceding vehicle or the like is detected from the lateral movement of the preceding vehicle or the like using the detection result of the ACC radar 15. Further, the lateral displacement dXfr is time-differentiated to calculate a lateral displacement speed Vxfr of a preceding vehicle such as a preceding vehicle.

Subsequently, in step S5, the behavior of the preceding vehicle or the like is determined. Specifically, the following equations (2) and (3) are compared using the lateral movement amount dXfr and the lateral displacement speed Vxfr of the preceding vehicle or the like calculated in step S4.
dXfr> dXth_fr (2)
Vxfr> Vxth_fr1 (3)
Here, dXth_fr and Vxth_fr1 are comparison threshold values (set threshold values). When both the formulas (2) and (3) are established, it is determined that the preceding vehicle or the like has moved sideways in the adjacent lane corresponding to the situation ahead of the preceding vehicle or the like. For example, as a lateral movement operation of a preceding vehicle or the like to an adjacent lane here, there is an obstacle ahead of the preceding vehicle or the like, an operation for avoiding it, or the front of the traveling lane of the preceding vehicle or the like is congested. There is an operation to avoid it.

  When it is determined that the preceding vehicle or the like has moved laterally to the adjacent lane, a flag indicating the lateral movement direction (hereinafter referred to as a preceding vehicle or the like lateral movement direction flag) Ffr1 is set. For example, when the preceding vehicle or the like moves to the right adjacent lane, the preceding vehicle etc. lateral movement direction flag Ffr1 is set to right (Ffr1 = right). Further, when the preceding vehicle or the like moves to the left adjacent lane, the preceding vehicle or the like lateral movement direction flag Ffr1 is set to left (Ffr1 = left). When it is determined that the preceding vehicle or the like has not moved laterally to the adjacent lane, the preceding vehicle or the like lateral movement direction flag Ffr1 is set to 0 (Ffr1 = 0).

Subsequently, in step S6, a lane departure tendency is determined. The procedure of this determination process is specifically as shown in FIG.
First, in step S41, the estimated departure time Tout is calculated. Specifically, the deviation predicted time Tout is calculated by the following equation (4) using dx as the change amount of the lateral displacement X (change amount per unit time), L as the lane width, and the lateral displacement X. (See FIG. 7 for values of X, dx, and L).
Tout = (L / 2−X) / dx (4)

According to the equation (4), the deviation of the vehicle 100 laterally displaced by X from the center of the lane (X = 0) to the outer position area (for example, the road shoulder) separated from the current position by the distance L / 2. The predicted time Tout can be obtained.
Note that the lane width L is obtained by the imaging unit 13 processing the captured image. Further, the position of the vehicle may be obtained from the navigation device 14 or the lane width L may be obtained from the map data of the navigation device 14.

  Subsequently, in step S42, a departure determination flag is set. Specifically, the predicted departure time Tout is compared with a predetermined first departure determination threshold value Ts. Here, if the predicted departure time Tout is less than the first departure determination threshold value Ts (Tout <Ts), it is determined that the departure (there is a departure tendency) and the departure determination flag Fout is turned on (Fout = ON). . If the predicted departure time Tout is equal to or greater than the first departure determination threshold value Ts (Tout ≧ Ts), it is determined that there is no departure (no departure tendency) and the departure determination flag Fout is turned off (Fout = OFF).

  By the process of step S42, for example, when the host vehicle moves away from the center of the lane and the predicted departure time Tout becomes less than the first departure determination threshold value Ts (Tout <Ts), the departure determination flag Fout is turned ON. (Fout = ON). Further, when the own vehicle (the own vehicle in the state where Fout = ON) returns to the lane center side and the estimated departure time Tout becomes equal to or longer than the first departure determination threshold value Ts (Tout ≧ Ts), the departure determination. The flag Fout is turned off (Fout = OFF). For example, when there is a tendency to deviate, if the braking control for avoiding deviation described later is performed, or if the driver himself performs an avoidance operation, the deviation determination flag Fout is changed from ON to OFF.

The first departure determination threshold value Ts can be changed. That is, for example, the first departure determination threshold value Ts can be set based on the safety degree obtained in step S3.
Subsequently, in step S43, 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).

As described above, the lane departure tendency is determined in step S6.
Subsequently, in step S7, the driver's intention to change lanes is determined. Specifically, based on the direction switch signal and the steering angle δ obtained in step S1, the driver's intention to change lanes is determined as follows.
If the direction indicated by the direction switch signal (the blinker lighting side) is the same as the direction indicated by the departure direction Dout obtained in step S6, it is determined that the driver has intentionally changed the lane, and the departure determination flag Fout is changed to OFF (Fout = OFF). That is, it is changed to a determination result that there is no deviation.

If the direction indicated by the direction switch signal (the blinker lighting side) is different from the direction indicated by the departure direction Dout obtained in step S6, the departure determination flag Fout is maintained and the departure determination flag Fout is kept ON. (Fout = ON). That is, the determination result that deviates is maintained.
When the direction indicating switch 20 is not operated, the driver's intention to change lanes is determined based on the steering angle δ. That is, when the driver is steering in the departure direction, the driver is conscious when both the steering angle δ and the change amount of the steering angle (change amount per unit time) Δδ are equal to or greater than the set value. And the departure determination flag Fout is changed to OFF (Fout = OFF).

  As described above, when the departure determination flag Fout is ON, when the driver has not intentionally changed the lane, the departure determination flag Fout is maintained ON. However, even if the driver does not change the lane consciously because the change amount Δδ of the steering angle is less than the set value, and the departure determination flag Fout is originally turned ON, A driver support device (driver support control) such as an automatic control device or a preceding vehicle tracking control device is in operation, and the driver's vehicle is following the vehicle ahead by the driver support device. The lane change direction of the host vehicle coincides with the direction indicated by the lateral movement direction flag Ffr1 of the preceding vehicle obtained in step S5, and the lane change destination adjacent lane is determined from the determination result of the travel environment in step S3. If the lane is in the same direction as the current driving lane of the host vehicle, that is, if the lane change destination is not the oncoming lane, the departure determination flag Fout is set to OFF (Fout = OFF). Thus, even when it can be determined that the driver has not intentionally changed the lane when the departure determination flag Fout is ON, the departure determination flag Fout is set to OFF when the predetermined condition is satisfied. To do. As will be described later, when the departure determination flag Fout is ON, control for avoiding departure is activated, so that the departure determination flag Fout is set to OFF when the predetermined condition is satisfied as described above. In this case, the control for avoiding the deviation does not operate.

Subsequently, in step S8, a control method for avoiding deviation is determined. Specifically, whether or not to perform a departure warning or braking control for avoiding departure, and further, when performing braking control for avoiding departure, the braking control method is determined.
Here, the control content for departure avoidance is determined based on the obstacle existence direction Sout obtained in step S3, the departure direction Dout obtained in step S4, and the departure judgment flag Fout obtained in step S7.
For example, when the departure determination flag Fout is ON (Tout <Ts), a departure warning is performed. For example, an alarm is given by sound or display. Then, when the departure determination flag Fout is ON (Tout <Ts), a braking control method for departure avoidance is determined based on the obstacle existence direction Sout and the departure direction Dout. This will be described in detail later.

Subsequently, in step S9, a target yaw moment to be generated in the host vehicle is calculated. This target yaw moment is a yaw moment to be given to the host vehicle in order to avoid departure.
Specifically, the target yaw moment Ms is calculated by the following equation (5) based on the lateral displacement X and the change amount dx obtained in step S1.
Ms = K1 · X + K2 · dx (5)
Here, K1 and K2 are gains that vary according to the vehicle speed V. FIG. 8 shows an example of the gains K1 and K2. As shown in FIG. 8, for example, the gains K1 and K2 are small values in the low speed range. When the vehicle speed V reaches a certain value, the gains K1 and K2 increase in response to the increase in the vehicle speed V, and then constant when the vehicle speed V reaches a certain value. Value.

Subsequently, in step S10, a deceleration for avoiding deviation is calculated. That is, the braking force applied to the left and right wheels for the purpose of decelerating the host vehicle is calculated. Here, the target braking fluid pressures Pgf and Pgr that give such braking force to both the left and right wheels are calculated. The target braking hydraulic pressure Pgf for the front wheels is calculated by the following equation (6).
Pgf = Kgv · V + Kgx · dx (6)
Here, Kgv and Kgx are conversion coefficients that are set based on the vehicle speed V and the lateral change amount dx, respectively, for converting the braking force into the braking hydraulic pressure. FIG. 9 shows an example of the conversion coefficients Kgv and Kgx. As shown in FIG. 9, for example, the conversion coefficients Kgv and Kgx become large values in the low speed range, and when the vehicle speed V reaches a certain value, it decreases as the vehicle speed V increases, and then reaches a certain vehicle speed V. It becomes a constant value.

Then, based on the target braking hydraulic pressure Pgf for the front wheels, the target braking hydraulic pressure Pgr for the rear wheels considering the front-rear distribution is calculated.
Thus, in step S10, deceleration for avoiding deviation (specifically, target braking hydraulic pressures Pgf, Pgr) is obtained.
Subsequently, in step S11, a target brake hydraulic pressure for each wheel is calculated. In other words, the final braking fluid pressure is calculated based on the presence or absence of the departure avoidance braking control. Specifically, it is calculated as follows.

(1) When the departure determination flag Fout is OFF (Fout = OFF), that is, when a determination result indicating that there is no departure is obtained, as shown in the following equations (7) and (8), the target braking fluid for each wheel The pressure Psi (i = fl, fr, rl, rr) is set to the master cylinder hydraulic pressure Pmf, Pmr.
Psfl = Psfr = Pmf (7)
Psrl = Psrr = Pmr (8)
Here, Pmf is the master cylinder hydraulic pressure for the front wheels. Pmr is a master cylinder hydraulic pressure for the rear wheels, and is a value calculated based on the master cylinder hydraulic pressure Pmf for the front wheels in consideration of the front-rear distribution.

(2) When the departure determination flag Fout is ON (Fout = ON), that is, when a determination result indicating departure is obtained, first, based on the target yaw moment Ms, the front wheel target brake fluid pressure difference ΔPsf and the rear wheel target brake fluid The pressure difference ΔPsr is calculated. Specifically, the target braking hydraulic pressure differences ΔPsf and ΔPsr are calculated by the following equations (9) to (12).
In the case of Ms <Ms1, ΔPsf = 0 (9)
ΔPsr = 2 · Kbr · Ms / T (10)
When Ms ≧ Ms1 ΔPsf = 2 · Kbf · (Ms−Ms1) / T (11)
ΔPsr = 2 · Kbr · Ms1 / T (12)
Here, Ms1 represents a setting threshold value. T represents a tread. The tread T is set to the same value before and after for simplicity. 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.

  Thus, the braking force applied to the wheels is distributed according to the magnitude of the target yaw moment Ms. That is, when the target yaw moment Ms is less than the setting threshold value Ms1, the front wheel target braking fluid pressure difference ΔPsf is set to 0, a predetermined value is given to the rear wheel target braking fluid pressure difference ΔPsr, and a braking force difference is generated between the left and right rear wheels. Further, when the target yaw moment Ms is equal to or larger than the setting threshold value Ms1, a predetermined value is given to each target braking hydraulic pressure difference ΔPsr, ΔPsr, and a braking force difference is generated 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 target brake fluid pressure differences ΔPsf, ΔPsr calculated as described above and the target brake fluid pressures Pgf, Pgr for deceleration. ) Is calculated. Specifically, the final target brake hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated based on the braking control method determined in step S8.
Here, the braking control method determined in step S8 will be described.

In step S8, a braking control method is determined based on the obstacle direction existing direction Sout and the departure direction Dout. Here, the braking control method will be described with respect to the values of the obstacle existence presence direction Sout and the deviation direction Dout.
(First Case) In the case where the existence direction Sout such as an obstacle does not coincide with the departure direction Dout, a yaw moment for avoiding departure is applied to the vehicle until the departure determination flag Fout is turned off. Brake control (hereinafter referred to as deviation avoidance yaw control) is performed.
Here, the magnitude of the yaw moment applied to the vehicle in order to avoid the departure is the target yaw moment Ms. The yaw moment is applied to the vehicle by making a difference in the braking force applied to the left and right wheels. Specifically, as described above, when the target yaw moment Ms is less than the setting threshold value Ms1, a braking force difference is generated between the left and right rear wheels to apply the target yaw moment Ms to the vehicle. When the target yaw moment Ms is equal to or greater than the setting threshold value Ms1, a braking force difference is generated between the front, rear, left and right wheels, and the target yaw moment Ms is applied to the vehicle.
Here, the case where the departure determination flag Fout is changed from ON to OFF means that when there is a departure tendency, braking control for avoiding departure is performed, or the driver himself performs an avoidance operation. It is.

(Second Case) If the departure determination flag Fout is originally turned ON in step S7, the departure determination flag Fout is changed to OFF by satisfying the predetermined condition, that is, braking for avoiding departure. When the control is deactivated, if the obstacle lane presence direction Sout does not coincide with the departure direction Dout in the lane to which the lane is changed after that, the departure avoidance flag is used until the departure determination flag Fout is turned OFF. Perform yaw control.
In this case, a lane departure tendency is determined using a departure determination threshold value (Ts + dTs1) obtained by adding a certain set amount (hereinafter referred to as a first set amount) dTs1 to the first departure determination threshold value Ts. Thereby, when the predicted departure time Tout becomes shorter than the departure determination threshold value (Ts + dTs1) (Tout <(Ts + dTs1)), the departure avoidance yaw control is activated.

(Third Case) In the case where the obstacle existence direction Sout and the departure direction Dout coincide with each other and the road type R obtained in Step S3 is a general road, the departure avoidance flag Fout is turned off until the departure determination flag Fout is turned OFF Perform yaw control.
Further, a second departure judgment threshold value Tr (Ts>Tr> 0) less than the first departure judgment threshold value Ts is defined, and the predicted departure time Tout is smaller than the second departure judgment threshold value Tr. When this occurs (Tout <Tr), in addition to the departure avoidance yaw control, braking control for decelerating the vehicle (hereinafter referred to as departure avoidance deceleration control) is performed. This departure avoidance deceleration control is performed by applying the same level of braking force to the left and right wheels.

  (Fourth Case) When the obstacle direction is in the same direction Sout and the departure direction Dout and the road type R obtained in step S3 is an expressway, the departure avoidance flag is turned off until the departure determination flag Fout is turned off. Perform yaw control. Further, when the predicted departure time Tout becomes 0, the departure avoidance deceleration control is performed in addition to the departure avoidance yaw control.

  (Fifth Case) If the road type R obtained in step S3 is a highway and if it is original in step S7, the departure determination flag Fout is turned on, but the departure by satisfying the predetermined condition When the determination flag Fout is changed to OFF, that is, when the braking control for avoiding departure is inactivated, the obstacle direction of existence Sout coincides with the departure direction Dout in the subsequent lane change destination lane. When this is the case, the departure avoidance yaw control is performed until the departure determination flag Fout is turned off.

  Here, the lane departure tendency is determined using a departure determination threshold value (Ts + dTs2) obtained by adding a set amount (hereinafter referred to as a second set amount) dTs2 to the first departure determination threshold value Ts. Accordingly, when the predicted departure time Tout becomes shorter than the departure determination threshold value (Ts + dTs2) (Tout <(Ts + dTs2)), departure avoidance yaw control is performed. Further, when the predicted departure time Tout becomes 0, the departure avoidance deceleration control is performed in addition to the departure avoidance yaw control.

  In step S8, various braking control methods are determined in accordance with the values of the obstacle existence direction Sout and the departure direction Dout. In other words, depending on the values of the obstacle existence direction Sout and the departure direction Dout, only the departure avoidance yaw control, or the combination of the departure avoidance yaw control and the departure avoidance deceleration control, the braking control method for departure avoidance. Is determined.

In step S11, the target braking fluid pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated in accordance with the various braking control methods.
For example, in the deviation avoidance yaw control in the case of the first and second cases, the target braking fluid pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated by the following equation (13).
Psfl = Pmf
Psfr = Pmf + ΔPsf
Psrl = Pmr
Psrr = Pmr + ΔPsr
(13)

In the case of the third to fifth cases, the deviation avoidance yaw control and the departure avoidance deceleration control are performed. In this case, the target braking fluid for each wheel is expressed by the following equation (14). The pressure Psi (i = fl, fr, rl, rr) is calculated.
Psfl = Pmf + Pgf / 2
Psfr = Pmf + ΔPsf + Pgf / 2
Psrl = Pmr + Pgr / 2
Psrr = Pmr + ΔPsr + Pgr / 2
(14)
Further, as shown by the equations (13) and (14), the deceleration operation by the driver, that is, the target brake fluid pressure Psi (i = fl, fr, rl, rr) is calculated.

The above is the process of step S11. Thus, in step S11, the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated based on the state of the departure determination flag Fout. When the departure determination flag Fout is ON, the target braking fluid pressure Psi (i = fl) of each wheel corresponding to various braking control methods determined according to the values of the obstacle existence existence direction Sout and the departure direction Dout. , Fr, rl, rr).
The above is the calculation processing by the braking / driving force control unit 8. Then, the braking / driving force control unit 8 uses the target braking fluid pressure Psi (i = fl, fr, rl, rr) calculated for each wheel calculated in step S11 as a braking fluid pressure command value to the braking fluid pressure control unit 7. Output.

The lane departure prevention apparatus as described above generally operates as follows.
First, various data are read from each sensor, controller, and control unit (step S1). Subsequently, the vehicle speed V is calculated (step S2).
Subsequently, the traveling environment is determined, and the direction with a low safety level (the obstacle existing direction Sout) is determined (step S3, FIG. 3). For example, when the host vehicle 100A is traveling in the left lane in FIG. 4, the obstacle direction Sout is set to the left.

Subsequently, the lateral movement amount dXfr and the lateral displacement speed Vxfr of the preceding vehicle or the like are obtained (step S4), and the behavior of the preceding vehicle or the like is determined based on the lateral movement amount dXfr and the lateral displacement speed Vxfr. Whether it is moving or not, and if it is further moving laterally, its direction is determined (step S5).
Subsequently, the departure determination flag Fout is set based on the departure predicted time Tout, and the departure direction Dout is determined based on the lateral displacement X (step S6, FIG. 4). Then, the driver's intention to change the lane is determined based on the departure direction Dout and the direction indicated by the direction switch signal (the blinker lighting side) (step S7). Here, when the driver is intentionally changing the lane, the departure determination flag Fout is changed to OFF, and when the departure behavior of the vehicle is not considered to be a vehicle behavior due to the driver's intention such as a lane change by the driver, The departure determination flag Fout is turned on (maintained).

  In addition, even when it is considered that the departure behavior of the vehicle is not a vehicle behavior due to the driver's intention such as a lane change by the driver, driver support devices (driver support control) such as an automatic inter-vehicle control device and a preceding vehicle tracking control device are used. Since the vehicle is in operation and the vehicle is following the vehicle ahead by the driver support device, the lane change direction of the vehicle and the lateral movement direction flag Ffr1 of the preceding vehicle obtained in step S5 are obtained. And the adjacent lane to which the lane is changed is a lane that is in the same direction as the current lane of the host vehicle, that is, the lane change destination is If it is not the oncoming lane, the departure determination flag Fout is turned off.

  Subsequently, based on the departure determination flag Fout and the departure direction Dout, the presence / absence of alarm start for departure avoidance, the presence / absence of braking control for departure avoidance, and the method for executing the braking control for departure avoidance are determined. (Step S8). Then, a target yaw moment Ms is calculated based on the lateral displacement X and the change amount dx (step S9), and a deceleration for avoiding deviation is calculated (step S10).

Then, a target braking hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel for realizing the braking control method determined based on the departure determination flag Fout and the departure direction Dout is calculated, and the calculated target is calculated. The brake fluid pressure Psi (i = fl, fr, rl, rr) is output to the brake fluid pressure controller 7 as a brake fluid pressure command value (step S11).
The brake fluid pressure control unit 7 individually controls the brake fluid pressures of the wheel cylinders 6FL to 6RR based on the brake fluid pressure command value. Thereby, when the own vehicle tends to deviate, the own vehicle shows a predetermined vehicle behavior according to the traveling environment and the longitudinal acceleration Yg.

Here, the vehicle behavior when the braking control is performed in the first to fifth cases will be described.
As described above, the case of the first case is a case where the obstacle existence direction Sout and the departure direction Dout do not match. Here, a case of a three-lane road will be described as an example. As shown in FIG. 10, in the case of a three-lane road, the host vehicle 100A traveling in the left lane (the host vehicle 100A at the intermediate position in FIG. 10) tends to deviate in the right direction. Alternatively, as shown in FIG. 10, in a three-lane road, the host vehicle 100C traveling in the right lane (the host vehicle 100C in the uppermost position in FIG. 10) tends to deviate in the left direction. Alternatively, as shown in FIG. 10, in the three-lane road, the host vehicle B traveling in the central lane tends to deviate leftward or rightward. In this case, deviation avoidance yaw control is performed. Thereby, the own vehicle can avoid deviation. On the other hand, the driver can feel the departure avoidance operation of the vehicle as the acceleration in the lateral direction or the deceleration in the traveling direction, and can know that the own vehicle tends to depart.

  In FIG. 10, the black wheels indicate the wheels to which the hydraulic pressure is generated and the braking force is applied. That is, when either one of the left and right wheels is a black wheel, there is a difference in hydraulic pressure or braking force between the left and right wheels. In this case, a yaw moment is given to the vehicle. Even if the left and right wheels are black wheels, there may be a difference in the hydraulic pressure values. In this case, it is confirmed that the vehicle is being subjected to deceleration control while a yaw moment is applied to the vehicle. Show. This relationship is the same in subsequent drawings.

  Further, as described above, the second case is a lane that has been changed to a lane with braking control for avoiding departure in an inoperative state, and the obstacle existence direction Sout and the departure direction Dout do not match. Is the case. Here, a case of a three-lane road will be described as an example. That is, this is a case where the own vehicle 100A (the own vehicle 100A at the intermediate position in FIG. 10) that has changed to the left lane on the three-lane road tends to deviate in the right direction. Alternatively, as shown in FIG. 10, the host vehicle 100 </ b> C (the host vehicle 100 </ b> C at the top position in FIG. 10) that has changed to the right lane on a three-lane road tends to deviate to the left. Alternatively, as shown in FIG. 10, the host vehicle B, which has changed to a central lane on a three-lane road, tends to deviate leftward or rightward. In this case, deviation avoidance yaw control is performed. At this time, when the departure prediction time Tout becomes shorter than the departure determination threshold value (Ts + dTs1) obtained by adding the first set amount dTs1 to the first departure determination threshold value Ts (Tout <(Ts + dTs1)). The yaw control for avoidance is performed. By performing departure avoidance yaw control in this way, the host vehicle can avoid departure even in a lane that has been changed to a lane where braking control for avoiding departure is deactivated. On the other hand, the driver can feel the departure avoidance operation of the vehicle as the acceleration in the lateral direction or the deceleration in the traveling direction, and can know that the own vehicle tends to depart.

  Further, as described above, the third case is a case where the obstacle existence direction Sout matches the departure direction Dout and the road type R is a general road. That is, as shown in FIG. 11, when the host vehicle 100 is traveling in one lane on one side such that the left side is the road shoulder A and the right side is the opposite lane (the center lane L5 side), the host vehicle 100 ( This is the case where the host vehicle 100 at the uppermost position in FIG. 11 tends to deviate leftward or the vehicle (the host vehicle 100 at the intermediate position in FIG. 11) tends to deviate to the right.

  In this case, deviation avoidance yaw control is performed. Further, when the predicted departure time Tout becomes shorter than the second departure determination threshold Tr, departure avoidance deceleration control is performed in addition to departure avoidance yaw control. Thereby, the own vehicle avoids deviation. On the other hand, the driver can feel the departure avoidance operation of the vehicle as the acceleration in the lateral direction or the deceleration in the traveling direction, and can know that the own vehicle tends to depart.

  In addition, as described above, the fourth case is a case where the obstacle existence direction Sout matches the departure direction Dout and the road type R is a highway. That is, as shown in FIG. 10, in the three-lane road, the own vehicle 100A traveling in the left lane (the own vehicle 100A in the uppermost position in FIG. 10) tends to deviate in the left direction. Alternatively, as shown in FIG. 10, in the three-lane road, the own vehicle 100C traveling in the right lane (the own vehicle 100C at the intermediate position in FIG. 10) tends to deviate in the right direction.

  In this case, deviation avoidance yaw control is performed. Thereby, the own vehicle can avoid deviation. Further, when the predicted departure time Tout becomes 0, that is, when it is determined that the host vehicle has deviated from the traveling lane, the departure avoidance deceleration control is performed in addition to the departure avoidance yaw control. Thereby, the own vehicle avoids deviation. On the other hand, the driver can feel the departure avoidance operation of the vehicle as the acceleration in the lateral direction or the deceleration in the traveling direction, and can know that the own vehicle tends to depart.

  Further, as described above, the fifth case is a lane in which the road type R is an expressway and the lane is changed with the braking control for avoiding departure being inactivated and the direction in which an obstacle exists. This is a case where Sout and deviation direction Dout coincide. That is, this is a case where the own vehicle 100A (the own vehicle 100A in the uppermost position in FIG. 10) whose lane is changed to the left lane on the three-lane road tends to deviate in the left direction. Alternatively, as shown in FIG. 10, the host vehicle 100 </ b> C (the host vehicle 100 </ b> C at an intermediate position in FIG. 10) that has changed to the right lane on a three-lane road tends to deviate in the right direction.

  In this case, deviation avoidance yaw control is performed. At this time, when the departure prediction time Tout becomes shorter than the departure determination threshold (Ts + dTs2) obtained by adding the second set amount dTs2 to the first departure determination threshold Ts (Tout <(Ts + dTs2)). The yaw control for avoidance is performed. Further, when the predicted departure time Tout becomes 0, that is, when it is determined that the host vehicle has deviated from the traveling lane, the departure avoidance deceleration control is performed in addition to the departure avoidance yaw control. By performing the departure avoidance yaw control and, in some cases, the departure avoidance deceleration control, the vehicle can avoid the departure even in the lane where the lane change is made with the braking control for departure avoidance being inactivated. On the other hand, the driver can feel the departure avoidance operation of the vehicle as the acceleration in the lateral direction or the deceleration in the traveling direction, and can know that the own vehicle tends to depart.

  In addition to the braking control for avoiding the deviation as described above, a warning is given by sound and display. For example, the alarm is started at a predetermined timing simultaneously with the start of the brake control or prior to the brake control. For example, in the case of the second case, that is, in the case of a lane that has been changed to a lane with braking control for departure avoidance in the non-operating state, the presence direction Sout of the obstacles and the departure direction Dout do not match. When the departure prediction time Tout becomes shorter than the third departure determination threshold Tss (Tss> Ts> 0) larger than the first departure determination threshold Ts (Tout <Tss), an alarm is started.

Here, the own vehicle behavior realized by the control of the second and fifth cases will be specifically described with reference to FIG.
As shown in FIG. 12, the own vehicle 100 follows the preceding vehicle 101 by the operation of a driver assistance device (driver assistance control) such as an inter-vehicle automatic control device or a preceding vehicle tracking control device, and the lane of the own vehicle 100 is changed. If the direction and the lateral movement direction of the preceding vehicle 101 (the direction indicated by the lateral movement direction flag Ffr1 of the preceding vehicle, etc.) match, it is determined that the driver has not intentionally changed the lane. Even when the departure determination flag Fout is maintained ON, the departure determination flag Fout is turned OFF (see step S7). As a result, the departure avoidance yaw control or the like for avoiding the departure of the vehicle 100 may be deviated because the own vehicle 100 may deviate from the lane. Controls are not activated. Thereby, the own vehicle 100 can follow the preceding vehicle 101 by changing lanes as indicated by an arrow T1 in FIG.

  On the other hand, after the own vehicle 100 changes lanes, deviation avoidance yaw control for avoiding deviation is performed in accordance with normal conditions. As a result, even when the vehicle 100 also changes its lane following the preceding vehicle 101 on a curved road as shown in FIG. 12, if the vehicle 100 tends to deviate as shown by the arrow T2 in FIG. Deviation avoidance yaw control or the like for avoiding departure is activated in accordance with normal conditions. For example, in the second case, when the departure prediction time Tout becomes smaller than the departure determination threshold (Ts + dTs1) obtained by adding the first set amount dTs1 to the first departure determination threshold Ts ( Tout <(Ts + dTs1)), deviation avoidance yaw control is activated. Accordingly, it is possible to avoid the departure of the host vehicle in a lane that has been changed to a lane that has been set in a non-actuated braking control for avoiding the departure.

Next, the effect in this embodiment is demonstrated.
As described above, due to the operation of the driver assistance device (driver assistance control) such as the inter-vehicle automatic control device and the preceding vehicle following control device, the own vehicle 100 follows the preceding vehicle 101, and the lane change direction of the own vehicle 100 is determined. If the direction of movement of the preceding vehicle 101 (the direction indicated by the lateral movement direction flag Ffr1 of the preceding vehicle, etc.) matches, it is assumed that the host vehicle 100 may deviate from the lane. The deviation avoidance yaw control or the like is activated during the lane change, so that the departure avoidance yaw control or the like is not activated (see the second case and the fifth case, FIG. 12).

  For example, as shown in FIG. 12, when there is an obstacle such as a stopped vehicle 102 ahead, or the current traveling lane is congested, the preceding vehicle 101 changes the lane (sideways) To avoid). For this reason, when the host vehicle 100 follows the preceding vehicle 101 whose lane is changed as described above, the departure avoidance yaw control or the like is not activated during the lane change, so that Similarly, obstacles and the like existing ahead can be avoided as a result. As a result, the departure avoidance yaw control or the like does not operate when there is an obstacle or the like ahead, so that it is possible to perform the departure avoidance yaw control or the like without causing the driver to feel uncomfortable. In addition, when the driver's assistance control that follows the preceding vehicle is performed, if the preceding vehicle changes lanes, the departure avoidance control is not activated and the own vehicle also follows the preceding vehicle and changes lanes. In addition, by performing the departure avoidance yaw control or the like as the normal departure avoidance control in the changed lane, the effect of the departure avoidance control can be exhibited without impairing the effect of the driver assistance control. That is, the driver assistance control and the departure avoidance control can be performed without losing the reliability of the driver.

  Further, in this way, the host vehicle does not operate the deviation avoidance yaw control or the like in response to the lateral movement of the preceding vehicle, but as described above, the lateral movement of the preceding vehicle is changed to the lateral movement of the preceding vehicle. This is detected when the amount dXfr and the lateral displacement speed Vxfr are larger than predetermined threshold comparison threshold values dXth_fr and Vxth_fr1, respectively (see the expressions (2) and (3)). This makes it possible to distinguish between a preceding vehicle with low straight-ahead stability that is simply staggered in the lateral direction and a preceding vehicle that avoids turning, and detects only the lateral movement of the preceding vehicle that avoids turning, so that deviation avoidance yaw control Etc. can be disabled. As a result, it is possible to reliably avoid an obstacle existing in front of the obstacle when there is an obstacle existing in the front while preventing the deviation avoidance yaw control from being unnecessarily stopped. become.

  Further, as described above, when the departure determination flag Fout is ON, that is, when there is a departure tendency, the obstacle direction of existence Sout and the departure direction Dout do not match (the first and second cases). Yaw control for avoiding deviation is performed. On the other hand, even when there is a tendency to deviate (deviation judgment flag Fout is ON), if the obstacle direction of existence Sout coincides with the deviating direction Dout (the third, fourth and fifth cases), it is for avoiding the deviation. Braking control for avoiding departure is performed by combining yaw control and departure avoidance deceleration control. Specifically, the departure avoidance deceleration control is intervened at a predetermined timing after the start of departure avoidance yaw control.

  Therefore, the departure direction Dout indicates the direction in which there is an obstacle that the own vehicle may come into contact with when the own vehicle deviates. As a result, the existence direction Sout of the obstacle and the departure direction Dout coincide with each other. The braking control performed in this case is braking control when there is a tendency to deviate in the direction in which an obstacle exists. In such a case, departure avoidance deceleration control is performed in addition to departure avoidance yaw control. In this way, by performing departure avoidance deceleration control in addition to departure avoidance yaw control, it is possible to prevent the own vehicle and an obstacle from suddenly approaching even if the own vehicle deviates from the traveling lane. In this way, by performing braking control for preventing lane departure in consideration of the traveling environment of the host vehicle, safety can be improved while preventing lane departure.

Specifically, when there is a tendency to deviate to the shoulder side of the road, by intervening departure avoidance deceleration control after starting departure avoidance yaw control, even if the own vehicle deviates from the driving lane, It is possible to prevent sudden approach to an obstacle outside the road.
Similarly, when there is a tendency to deviate to the oncoming lane side, the departure avoidance deceleration control is intervened after the departure avoidance yaw control is started, so that even if the own vehicle deviates from the driving lane, It is possible to prevent the vehicle from suddenly approaching the oncoming vehicle.

  Further, when the vehicle is traveling on a one-lane road, the departure-avoidance deceleration control is intervened after the departure-avoidance yaw control is started regardless of the left-right direction. As a result, even when the host vehicle deviates from the driving lane, the host vehicle can be prevented from suddenly approaching an obstacle outside the road, or the host vehicle can be prevented from suddenly approaching an oncoming vehicle. .

Further, after the departure avoidance yaw control is started, the departure avoidance deceleration control is frequently operated by intervening the departure avoidance deceleration control only when a certain situation (specifically, Tout <Tr) is reached. Can be prevented (the third case). Thereby, it can prevent that the control for deviation avoidance gives trouble to a driver | operator.
Further, as described above, when the estimated departure time Tout becomes 0, that is, when it is determined that the host vehicle has deviated from the traveling lane, the departure avoidance deceleration control is performed in addition to the departure avoidance yaw control. (The fourth and fifth cases). Since the vehicle speed is high on a highway, if it deviates from the driving lane, there is a possibility that the vehicle will protrude greatly out of the road. For this reason, when it is determined that the host vehicle has deviated from the driving lane, it is possible to prevent the host vehicle from greatly protruding outside the road by intervening the departure avoidance deceleration control.

The embodiment of the present invention has been described above. However, the present invention is not limited to being realized as the above-described embodiment.
That is, in the above-described embodiment, braking control (departure avoiding yaw control) for applying a yaw moment for avoiding departure to the vehicle and braking control (departure avoiding deceleration control) for decelerating to avoid departure. The combination method, the operation sequence, and the control amount (the magnitude of the yaw moment and the magnitude of the deceleration) were specifically explained. However, the present invention is not limited to this.

  Further, in the above-described embodiment, a case has been described in which the departure avoidance yaw control of the own vehicle is not operated when the preceding vehicle changes lanes. However, it is not limited to this. That is, the deviation avoidance yaw control of the host vehicle is operated on condition that the lateral movement amount dXfr and the lateral displacement speed Vxfr of the preceding vehicle are larger than predetermined threshold comparison threshold values dXth_fr and Vxth_fr1, respectively. Do not let it. As a result, even when the preceding vehicle simply avoids a stop vehicle or the like in the roadside zone without changing the driving lane, the deviation avoidance yaw control or the like of the own vehicle does not operate. By doing in this way, the own vehicle can also avoid the stop vehicle etc. of a roadside belt | band | zone like a preceding vehicle.

  In the above-described embodiment, the lateral movement of the preceding vehicle is detected when the lateral movement amount dXfr and the lateral displacement speed Vxfr of the preceding vehicle become larger than predetermined comparison threshold values dXth_fr and Vxth_fr1, respectively. However, it is not limited to this. That is, when the lateral movement amount dXfr of the preceding vehicle becomes larger than a predetermined threshold value for comparison dXth_fr, or the lateral displacement speed Vxfr of the preceding vehicle becomes larger than a predetermined threshold value for threshold comparison Vxth_fr1. It may be determined that the preceding vehicle has moved laterally (for example, lane change).

  In the above-described embodiment, the case where the host vehicle is performing driver assistance control that follows the preceding vehicle as a condition that the host vehicle does not operate the deviation avoidance yaw control or the like has been described. However, it is not limited to this. That is, even if the driver's assistance control for following the preceding vehicle is not performed, the own vehicle does not operate the deviation avoidance yaw control or the like as long as other conditions such as detecting the lateral movement of the preceding vehicle are satisfied. You may do it.

  Further, in the above-described embodiment, a specific example in which the departure avoidance control of the own vehicle is suppressed or the control content of the departure avoidance control is changed when the preceding vehicle moves sideways is an example in which the departure avoidance control is not activated. Yes. However, it is not limited to this. For example, the magnitude of the braking force of departure avoidance yaw control or departure avoidance deceleration control is reduced to suppress departure avoidance control or change the departure determination threshold value to delay the generation of yaw control. Good.

  In the above-described embodiment, the case where the lateral movement amount dXfr and the lateral displacement speed Vxfr of the preceding vehicle or the like are obtained by using the ACC radar 15 has been described. However, it is not limited to this. For example, the lateral movement amount dXfr and the lateral displacement speed Vxfr of the preceding vehicle or the like are obtained based on the captured image of the camera mounted on the own vehicle in order to recognize the surrounding environment, or the preceding vehicle or the like and the own vehicle are used. The lateral movement amount dXfr and the lateral displacement speed Vxfr of the preceding vehicle or the like may be obtained based on the information on the inter-vehicle communication.

  In the above-described embodiment, the brake structure is described as a brake structure using fluid pressure. However, it goes without saying that the present invention is not limited to this. For example, an electric friction brake that presses the friction material against the rotating body of the wheel side member by an electric actuator, a regenerative brake that generates an electric braking action, or a power generation brake may be used. Also, an engine brake that performs braking control by changing the valve timing of the engine, a speed change brake that acts like an engine brake by changing the speed ratio, or an air brake may be used.

Further, in the above-described embodiment, the estimated departure time Tout is calculated based on the lateral displacement X and the amount of change dx (see the equation (4)). However, the deviation prediction time Tout may be obtained by other methods. For example, the predicted departure time Tout may be obtained based on the yaw angle φ, the travel lane curvature β, the yaw rate φ ′, or the steering angle δ.
In the above-described embodiment, the driver's intention to change the lane is obtained based on the steering angle δ and the change amount Δδ of the steering angle (see step S7). However, the driver's intention to change lanes may be obtained by other methods. For example, the driver's intention to change the lane may be obtained based on the steering torque.

In the above-described embodiment, the target yaw moment Ms is calculated based on the lateral displacement X and the change amount dx (see the above formula (5)). However, the target yaw moment Ms may be obtained by other methods. For example, as shown in the following equation (15), the target yaw moment Ms may be calculated based on the yaw angle φ, the lateral displacement X, and the travel lane curvature β.
Ms = K3 · φ + K4 · X + K5 · β (15)
Here, K3, K4, and K5 are gains that vary according to the vehicle speed V.

In the above-described embodiment, the target braking hydraulic pressure Pgf for the front wheels is described using a specific equation (see the equation (6)). However, it is not limited to this. For example, the target braking hydraulic pressure Pgf for the front wheels may be calculated by the following equation (16).
Pgf = Kgv · V + Kgφ · φ + Kgβ · β (16)
Here, Kgφ and Kgβ are conversion coefficients for converting braking force into braking hydraulic pressure, which are set based on the yaw angle φ and the travel lane curvature β, respectively.

In the above-described embodiment, the target brake hydraulic pressure differences ΔPsf and ΔPsr between the front wheels and the rear wheels are calculated in order to realize the deviation avoidance yaw control (see the above formulas (9) and (10)). However, it is not limited to this. For example, the deviation avoidance yaw control may be realized only by the target brake hydraulic pressure difference ΔPsf of the front wheels. In this case, the target brake hydraulic pressure difference ΔPsf of the front wheels is calculated by the following equation (17).
ΔPsf = 2 · Kbf · Ms / T (17)

  In the description of the above-described embodiment, the processing of steps S4 and S5 of FIG. 2 of the braking / driving force control unit 8 and the ACC radar 15 detect the preceding vehicle lateral movement detecting means for detecting the lateral movement of the preceding vehicle. 2 is realized, and the process of steps S6 to S11 in FIG. 2 of the braking / driving force control unit 8 changes the control content of the departure avoidance control when the preceding vehicle lateral movement detecting means detects the lateral movement of the preceding vehicle. Realizes content change means.

It is a schematic block diagram which shows embodiment of the vehicle carrying the lane departure prevention apparatus of this invention. It is a flowchart which shows the processing content of the braking / driving force control unit which comprises the said lane departure prevention apparatus. It is a flowchart which shows the processing content of the driving environment determination of the said braking / driving force control unit. It is a figure which shows the vehicle which is drive | working the one side 3 lane road. It is a figure which shows the picked-up image which a vehicle obtains in each lane position, when a vehicle drive | works the said one side 3 lane road. It is a flowchart which shows the processing content of the deviation tendency determination of the said braking / driving force control unit. It is the figure used for description of deviation prediction time Tout. It is a characteristic view which shows the characteristic of the gains K1 and K2 used for calculation of the target yaw moment Ms. It is a characteristic view which shows the characteristic of the conversion factors Kgv and Kgx used for calculation of the target brake hydraulic pressure Pgf. It is the figure used for description of the vehicle behavior at the time of the 1st, 2nd, 4th, and 5th case. It is the figure used for description of the vehicle behavior at the time of the 3rd case. It is the figure used for description of an effect | action and an effect.

Explanation of symbols

6FL to 6RR Wheel cylinder 7 Braking fluid pressure control unit 8 Braking / driving force control unit 9 Engine 12 Drive torque control unit 13 Imaging unit 14 Navigation device 15 ACC radar 17 Master cylinder pressure sensor 18 Accelerator opening sensor 19 Steering angle sensor 22FL 22RR Wheel speed sensor

Claims (6)

  A lane departure prevention apparatus characterized by suppressing departure avoidance control for avoiding a departure of the host vehicle from a traveling lane when a preceding vehicle moves laterally. Preceding vehicle lateral movement detecting means for detecting lateral movement of the preceding vehicle;
When the preceding vehicle lateral movement detection means detects lateral movement of the preceding vehicle, control content changing means for changing the control content of the departure avoidance control for avoiding the departure of the own vehicle from the traveling lane;
A lane departure prevention device characterized by comprising:   The lane departure prevention apparatus according to claim 2, wherein the control content changing means stops the departure avoidance control.   The control content changing means stops the deviation avoidance control when the own vehicle is controlling to follow the preceding vehicle and the preceding vehicle lateral movement detecting means detects a lateral movement of the preceding vehicle. The lane departure prevention device according to claim 2 or 3, The preceding vehicle lateral movement detecting means detects a lateral movement amount of the preceding vehicle,
The control content changing means changes the control content when a lateral movement amount of the preceding vehicle detected by the preceding vehicle lateral movement detection means is larger than a predetermined lateral movement amount. The lane departure prevention apparatus according to any one of the above. The preceding vehicle lateral movement detecting means detects a lateral movement speed of the preceding vehicle,
6. The control content change unit according to claim 2, wherein the control content is changed when a lateral movement speed of the preceding vehicle detected by the preceding vehicle lateral movement detection unit is larger than a predetermined lateral movement speed. The lane departure prevention apparatus according to any one of the above.

Images