JP2005158014A - Lane deviation arrester - Google Patents

Lane deviation arrester Download PDF

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Publication number
JP2005158014A
JP2005158014A JP2004084475A JP2004084475A JP2005158014A JP 2005158014 A JP2005158014 A JP 2005158014A JP 2004084475 A JP2004084475 A JP 2004084475A JP 2004084475 A JP2004084475 A JP 2004084475A JP 2005158014 A JP2005158014 A JP 2005158014A
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Japan
Prior art keywords
vehicle
lane
host vehicle
departure
target
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JP2004084475A
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Japanese (ja)
Inventor
Takeshi Iwasaka
Yoshitaka Kamimura
Shinko Ozaki
Atsushi Sadano
Takashi Sugano
吉孝 上村
温 定野
眞弘 尾崎
武志 岩坂
隆資 菅野
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Nissan Motor Co Ltd
日産自動車株式会社
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Priority to JP2003372851 priority Critical
Application filed by Nissan Motor Co Ltd, 日産自動車株式会社 filed Critical Nissan Motor Co Ltd
Priority to JP2004084475A priority patent/JP2005158014A/en
Publication of JP2005158014A publication Critical patent/JP2005158014A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To conduct braking control for preventing a lane deviation preventing the braking control for preventing the lane deviation from a continuous action, and agreeing to the intention of a driver. <P>SOLUTION: A lane lane deviation preventive apparatus provides a self-vehicle with a yaw moment to avoid the deviation in such a way that the self-vehicle may face toward a target passing point pT, being the central position of the farthest running lane, which is a recognizable range in front when the self-vehicle runs on a straight road and when yaw tendency is found. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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 host 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

In the conventional lane departure prevention device as described in Patent Document 1, braking control is performed for preventing departure for the purpose of preventing lane departure at that time. As a result, immediately after the lane departure prevention control, the braking control for preventing the departure may be activated again, that is, the braking control may be continuously activated, or the driver may suddenly operate the steering wheel. Here, the reason why the driver suddenly operates the steering wheel is that the deviation prevention control is different from the driver's intention.
The present invention has been made in view of the above-mentioned problems, and prevents the departure prevention control from continuously operating and performs the departure prevention control that matches the driver's intention. An object of the present invention is to provide a lane departure prevention device capable of

  The lane departure prevention device according to the present invention is a lane departure prevention device that applies a yaw moment to the host vehicle when the host vehicle tends to depart from the traveling lane, thereby avoiding the departure of the host vehicle from the traveling lane. . This lane departure prevention device applies the yaw moment so that the host vehicle is directed to a predetermined point in front of the traveling lane of the host vehicle.

According to the present invention, the yaw moment to be given to avoid the departure is set to a yaw moment that is in front of the traveling lane of the own vehicle and that the own vehicle faces a predetermined point set in advance. Control is performed until the host vehicle reaches the predetermined point. Therefore, the deviation can be reliably avoided by the one-time deviation avoidance control, and the control can be prevented from being operated continuously. .
In addition, after giving the yaw moment to avoid the departure, the control for the next departure avoidance does not intervene while heading for the predetermined point. It does not work.
Further, since there is a time margin while heading to the predetermined point, there is a margin for the operation by the driver himself. As a result, it is possible to prevent the driver from operating the steering wheel suddenly.

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.
1st Embodiment is a rear-wheel drive vehicle carrying the lane departure prevention apparatus of 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 a rear wheel drive vehicle equipped with a lane departure prevention apparatus to which the present invention is applied.
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 independently control the brake fluid pressure of each of the wheel cylinders 6FL to 6RR. When a brake fluid pressure command value is input from a braking / driving force control unit 8 described later, the brake fluid pressure control unit 7 The brake fluid pressure is also controlled according to the fluid pressure command value.

  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 independently control the drive torque of the rear wheels 5RL and 5RR, but when a drive torque command value is input from the braking / driving force control unit 8, the drive torque command value The drive wheel torque is controlled according to the above.
In addition, this vehicle is provided with an imaging unit 13 with an image processing function. The imaging unit 13 is 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 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 15. The navigation device 15 detects the longitudinal acceleration Xg, lateral acceleration Yg, and yaw rate φ ′ generated in the host vehicle. The navigation device 15 outputs the detected longitudinal acceleration Xg, lateral acceleration Yg, and yaw rate φ ′ to the braking / driving force control unit 8 together with road information.

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 Acc. , A steering angle sensor 19 for detecting the steering angle δ of the steering wheel 21, and wheel speed sensors 22FL to 22RR for detecting the rotational speed of the wheels 5FL to 5RR, that is, the wheel speed Vwi (i = fl, fr, rl, rr), In addition, a direction indication switch 20 for detecting a direction indication operation by the direction indicator is 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 directionality, the right direction is a positive value and the clockwise direction is a positive value unless otherwise specified.

  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 calculation 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 Xg, the lateral acceleration Yg and the yaw rate φ ′ obtained by the navigation device 15, the wheel speed Vwi, the steering angle δ, the accelerator opening Acc, the master cylinder hydraulic pressures Pmf, Pmr detected by the sensors. And the direction switch signal, the driving torque Tw from the driving torque control unit 12, and the yaw angle φ, the lateral displacement X, and the travel 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 (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 the 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. Further, a value used for navigation information in the navigation device 15 may be used as the vehicle speed V.
Subsequently, in step S3, a lane departure tendency is determined. Specifically, this is as follows.

As shown in FIG. 3, after a predetermined time Tt, the estimated lateral displacement xS of the center of gravity of the vehicle from the center position LN S of the traveling lane, a vehicle lateral displacement limit line with respect to the center position LN S traffic lane (the traveling lane side of the Boundary line) LN b position (hereinafter referred to as limit displacement) xL is defined. Here, the predetermined time Tt is, for example, 1 sec. Specifically, the estimated lateral displacement xS and limit displacement xL are calculated by the following equations (2) and (3).
xS = V × Tt × (φ−β × V × Tt) + x0 (2)
xL = ± (L−H) / 2 (3)

Here, x0 is the current (latest) lateral displacement of the host vehicle, L is the width of the traveling lane, and H is the width of the host vehicle (see FIG. 3). Further, xS, xL becomes a positive value when the central position LN S of the travel lane becomes a right value, a negative value when the central position LN S of the traveling lane to a value on the left. The travel lane width L is obtained by processing the image obtained by the imaging unit 13. Further, the traveling lane width L may be a value used for navigation information in the navigation device 15.

  Then, the estimated lateral displacement xS and the limit displacement xL are compared to determine the lane departure tendency. Here, when the absolute lateral displacement | xS | of the absolute value is equal to or larger than the absolute displacement | xL | (| xS | ≧ | xL |), it is determined that there is a possibility of deviation. In this case, the departure determination flag Fout is turned ON (Fout = ON), and at the same time, the timer is operated to measure the time TD in which the departure determination flag Fout is continuously ON. Here, when the time TD reaches a predetermined time, the departure determination flag Fout is determined to be ON, and otherwise, the departure determination flag Fout is set to OFF (Fout = OFF). If the absolute lateral displacement | xS | is less than the absolute displacement | xL | (| xS | <| xL |), it is determined that there is no possibility of deviation. In this case, the deviation determination flag Fout is turned OFF (Fout = OFF), and at the same time, the timer time TD is reset to zero.

  Further, the departure direction Dout is determined based on the estimated lateral displacement xS. Specifically, when the estimated lateral displacement xS is a positive value, assuming that the host vehicle is laterally displaced rightward from the center of the lane, the rightward direction is the departure direction Dout (Dout = right), and the estimated lateral displacement xS is negative. In the case of the value, assuming that the host vehicle is laterally displaced leftward from the lane center, the leftward direction is set as the departure direction Dout (Dout = left).

Subsequently, in step S4, 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 S3, 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 S3, 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, if the steering angle δ and the change amount of the steering angle (change amount per unit time) Δδ are equal to or larger than the set value, the driver consciously changes the lane. The departure determination flag Fout is changed to OFF (Fout = OFF).

Subsequently, in step S5, a control method for determining whether or not to perform departure warning and departure avoidance braking control is determined.
Specifically, when the departure determination flag Fout obtained in step S4 is ON, it is determined that the departure warning is to be performed, and the target passing point and necessary are determined based on the road information ahead and the departure state of the host vehicle. A correct yaw angle ρ is set.
Here, the warning of deviation is an alarm given by sound or display. In addition, the target passing point is set based on the shape of the traveling path of the host vehicle. Specifically, the target passing point is set according to a straight road or a curved road.

  The straight road and the curved road are determined based on the traveling lane curvature β obtained in step S1. Specifically, the absolute value of the traveling lane curvature | β | is compared with a predetermined value | β0 |, and the traveling lane curvature | β | is equal to or smaller than the predetermined value | β0 | (| β | ≦ | β0 |). When the traveling lane curvature | β | is larger than a predetermined value | β0 | (| β |> | β0 |), the traveling road is determined to be a curved road.

(1-1) When the host vehicle is traveling on a straight road (see FIG. 4)
First, a target passing point is set. The center position of the farthest traveling lane that can be recognized in front of the host vehicle is set as the target passing point pT. Specifically, as shown in FIG. 4, the farthest recognizable range ahead of the host vehicle and a line perpendicular to the travel lane (the recognizable range farthest line), the center of the line and the travel lane, Is set as the target passing point pT. Here, the target passing point pT is a value set based on the performance of the imaging unit 13 (CCD camera), that is, the farthest point that can be recognized by the imaging unit 13 (CCD camera) (recognition limit point). And

Then, a target yaw angle φT is obtained from a straight line passing through the target passing point pT and the current host vehicle position (referred to as the host vehicle current position) p0. Here, an xy coordinate is defined in which the position where the current vehicle position p0 is projected onto the center of the travel lane is the origin, the travel direction is the y axis, and the direction perpendicular to the travel direction is the x axis. When the vehicle position p0 (x0, y0) and the target passing point pT (xT, yT) are set, the target yaw angle φT can be obtained as in the following equation (4).
φT = tan −1 {(x0−xT) / (y0−yT)} (4)

Since the current position p0 of the host vehicle is located at the origin in the traveling direction (y-axis), y0 is 0, and the target passing point pT is set at the center position of the traveling lane, so xT is 0. It is.
Then, using this target yaw angle φT, the yaw angle ρ necessary for making the host vehicle 100 face the target passing point pT is obtained by the following equation (5).
ρ = φT−φ (5)

For example, according to this equation (5), as shown in FIG. 4, when there is a tendency to deviate on the right side of the traveling lane, φT <0, φ> 0, so ρ <0 and counterclockwise. As a result, it is necessary to change the yaw angle by ρ.
For example, when the lateral displacement amount from the center of the traveling lane is large and the distance between the current position p0 of the host vehicle and the target passing point pT is short, the yaw angle ρ becomes a large value.
Note that the target passing point pT set by the braking / driving force control unit 8 is not limited to the present embodiment, and is set, for example, to a position where the target yaw angle φT> 0, that is, the sign of the yaw angle φ is reversed. For example, any position other than the center position of the traveling lane may be used.

(1-2) When the host vehicle is traveling on a curved road (see FIG. 5)
First, a target passing point is set. As shown in FIG. 5, and the vehicle lateral displacement limit line LN b in the traveling lane inner side portion, and the target passing point pT contact points between the straight line extended from the vehicle center of gravity (own vehicle current position p0) in the vehicle front To do. Then, a target yaw angle φT for the host vehicle to pass through the target passing point pT is obtained.

Here, similarly to the case where the host vehicle (1-1) travels on a straight road, the position where the host vehicle travels is projected on the center of the travel lane as the origin, and the travel direction is The xy coordinate is defined with the y (lower case) axis and the direction perpendicular to the traveling direction as the x (lower case) axis.
Furthermore, as shown in FIG. 5, arbitrary XY coordinates (X, Y: capital letters) are defined. That is, XY coordinates are defined as a global coordinate system using the xy coordinates as a local coordinate system.
In this case, the vehicle lateral displacement limit line LN b is shown as the following equation (6).
X 2 + Y 2 = {R− (L−H) / 2 × R / | R |} 2 (6)
Here, R is a radius from the origin of the XY coordinates of the global coordinate system to the center of the traveling lane, and is 1 / β.

A straight line (tangent line) that passes through the current position P0 (X0, Y0) of the host vehicle in the XY coordinate system and that touches the vehicle lateral displacement limit line LNb that can be expressed as the equation (6) is as follows. (7) Obtained as an equation.
Y = a × X + b
a = ± [{R− (L−H) / 2 × R / | R |} 2 / {(R−X0) 2 − (R− (L−H) / 2 × R / | R |) 2 } ] 1/2
b = −a × (R−X0)
... (7)
Here, the sign of the coefficient a is determined according to the value of R. That is, a> 0 when R> 0, and a <0 when R <0.

Then, using the coefficient a, the target yaw angle φT through which the host vehicle passes the target passing point pT is obtained as the following equation (8).
φT = tan −1 (1 / a) (8)
Then, using this target yaw angle φT, the yaw angle ρ necessary for making the host vehicle 100 face the target passing point pT is obtained by the following equation (9).
ρ = φT−φ (9)
For example, according to the equation (9), as shown in FIG. 5, when there is a tendency to deviate on the left side of the driving lane, since φT <0 and φ <0, ρ> 0 and clockwise. The result is that it is necessary to change the yaw angle by ρ.

(1-3) When there are a plurality of trajectories (curves, straight lines) (see FIG. 6)
Here, for the sake of simplicity, a case will be described in which the traveling road is a curved road with continuous curves, as shown in FIG.
In this case, as in the case where the above-mentioned (1-2) the vehicle is traveling on a curved path, the contact point between the straight line and the vehicle lateral displacement limit line LN b extended from the current vehicle position P0 in the vehicle front When trying to obtain it, the number of the contacts becomes plural. Therefore, a plurality of target passing points pT (in this example, two points P1 and P2) are obtained.

For this reason, when the traveling road is a continuous curved road, the contact point farthest from the current host vehicle position P0 is set as the target passing point pT (P2 in this example). For the farthest target passing point pT, the yaw angle ρ necessary for the host vehicle 100 to head is obtained in the same manner as in (1-2) when the host vehicle is traveling on a curved road (see above). (See equation (9)).
For example, information that is a continuous curve of the travel path is obtained from the navigation information of the navigation device 15.

Subsequently, in step S6, a target yaw moment to be generated in the host vehicle is calculated. Specifically, the target yaw moment Ms is calculated by the following equation (10) based on the yaw angle ρ obtained in step S5.
Ms = Ka · ρ (10)
Here, Ka is a predetermined value larger than 0 (Ka> 0). For example, Ka is determined according to the vehicle speed V.
Further, the target yaw moment Ms obtained by the equation (10) is compared with a threshold value. Here, the comparison between the target yaw moment Ms and the threshold value is different depending on whether the traveling road is a straight road or a curved road.

(2-1) When the host vehicle is traveling on a straight road When the host vehicle is traveling on a straight road, the absolute value of the target yaw moment | Ms | is compared with the first threshold value MsL. When the target yaw moment | Ms | is less than the first threshold value MsL (| Ms | <MsL), the value of the target yaw moment Ms is maintained. On the other hand, when the target yaw moment | Ms | is equal to or greater than the first threshold value MsL (| Ms | ≧ MsL), the value of the target yaw moment Ms is replaced with the first threshold value MsL.
For example, when the target yaw moment | Ms | is equal to or greater than the first threshold value MsL (| Ms | ≧ MsL), the lateral displacement amount from the center of the traveling lane is large, and the host vehicle position p0 and the target passing point pT This is the case when the distance between is short.

(2-2) When the host vehicle is traveling on a curved road When the host vehicle is traveling on a curved road, the absolute value of the target yaw moment | Ms | is compared with the second threshold value MsC. When the target yaw moment | Ms | is less than the second threshold value MsC (| Ms | <MsC), the value of the target yaw moment Ms is maintained. On the other hand, when the target yaw moment | Ms | is equal to or greater than the second threshold value MsC (| Ms | ≧ MsC), the value of the target yaw moment Ms is replaced as follows.
The target yaw moment Ms is recalculated by replacing the width H of the host vehicle used to calculate the yaw angle ρ or the target yaw angle φT with H + dH (where dH> 0). Alternatively, the value of the target yaw moment Ms is replaced with the second threshold value MsC.
Subsequently, in step S7, 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.

(3-1) When the departure determination flag Fout is OFF (Fout = OFF), that is, when the determination result that there is no departure is obtained, as shown in the following equations (11) and (12), the target of each wheel The brake fluid pressure Psi (i = fl, fr, rl, rr) is set to the master cylinder fluid pressures Pmf, Pmr.
Psfl = Psfr = Pmf (11)
Psrl = Psrr = Pmr (12)
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.

(3-2) When the departure determination flag Fout is ON (Fout = ON), that is, when a determination result indicating departure is obtained, based on the target yaw moment Ms obtained in step S6, the front wheel target braking hydraulic pressure difference ΔPsf And the rear wheel target braking hydraulic pressure difference ΔPsr is calculated. Specifically, the target braking hydraulic pressure differences ΔPsf and ΔPsr are calculated by the following equations (13) to (16).
When | Ms | <Ms1, ΔPsf = 0 (13)
ΔPsr = Kbr · / T (14)
When | Ms | ≧ Ms1 ΔPsf = Kbf · Ms / | Ms | · (| Ms | −Ms1) / T (15)
ΔPsr = Kbr · Ms / | Ms | · Ms1 / T (16)
Here, Ms1 represents a setting threshold value. T represents a tread. The tread T is set to the same value for the front and rear wheels 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 the braking force difference between the left and right rear wheels. When the target yaw moment | Ms | is equal to or greater than the setting threshold value Ms1, a predetermined value is given to each target braking hydraulic pressure difference ΔPsf, ΔPsr, and a braking force difference is generated between the front, rear, left and right wheels. When the departure determination flag Fout is ON (Fout = ON), the target braking fluid pressure Psi (for each wheel) is calculated by the following equation (17) using the target braking fluid pressure difference ΔPsf, ΔPsr calculated as described above. i = fl, fr, rl, rr) is calculated.
Psfl = Pmf−ΔPsf / 2
Psfr = Pmf + ΔPsf / 2
Psrl = Pmr−ΔPsr / 2
Psrr = Pmr + ΔPsr / 2
... (17)

In the equation (17), the deceleration operation by the driver, that is, the target cylinder hydraulic pressure Psi (i = fl, fr, rl, rr) is calculated in consideration of the master cylinder hydraulic pressures Pmf, Pmr. Yes.
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 in step S7 as the 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 departure determination flag Fout is set based on the estimated departure time Tout, and the departure direction Dout is determined based on the estimated lateral displacement xS (step S3).
Further, the driver's intention to change lanes is determined based on the deviation direction obtained in this way and the direction indicated by the direction switch signal (the blinker lighting side) (step S4).

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. In this case, the departure determination flag Fout is changed to OFF.
Further, when the departure determination flag Fout is ON, 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 state of the departure determination flag Fout is maintained. For example, if 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 behavior of the vehicle is not the vehicle behavior due to the driver's intention such as a lane change by the driver. Therefore, when the departure determination flag Fout is ON, the state of the departure determination flag Fout is maintained.

  Then, control details for avoiding the departure are determined based on the departure determination flag Fout (step S5). Specifically, when the departure determination flag Fout is ON, it is determined that a departure warning is to be performed, and a target passage point and a necessary yaw angle ρ that are control targets for avoiding departure are set. Here, the target passing point and the necessary yaw angle ρ are set according to the shape of the traveling road. That is, when the traveling road is a straight road, the yaw angle ρ is calculated using the equation (5). When the traveling road is a curved road, the yaw angle ρ is calculated using the equation (9). Further, in the case where the travel path is composed of a continuous curve, the yaw angle ρ is calculated using the equation (9) for the farthest target passage point pT among the plurality of target passage points pT.

  Subsequently, the target yaw moment Ms is calculated based on the yaw angle ρ thus obtained (step S6). Then, the target braking fluid pressure Psi (i = fl, fr, rl, rr) of each wheel for realizing the target yaw moment Ms is calculated, and this target braking 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 S7). The braking fluid pressure control unit 7 individually controls the braking fluid pressures of the wheel cylinders 6FL to 6RR based on the braking fluid pressure command value.

As a result, when the traveling path is a straight road and there is a tendency to deviate, the vehicle behaves so as to face the center position of the farthest traveling lane in the recognizable range by the control for avoiding deviation. As shown.
Further, when the traveling road is a curved road and tends to deviate, the vehicle is in a position that can be recognized in front by the control for avoiding the deviation, and the side portion of the traveling lane (specifically, the vehicle The lateral displacement limit line LN b ) and the tangent line extending from the host vehicle show a behavior toward the contact position.
At this time, a warning is given by sound or display. For example, an alarm is started simultaneously with the vehicle behavior or at a predetermined timing prior to the vehicle behavior.

Next, effects of the first embodiment will be described.
As described above, when the road is a straight road and there is a tendency to deviate, the yaw moment for avoiding the deviation so that the host vehicle faces the center of the farthest running lane that can be recognized ahead Is given to the subject vehicle.
As a result, the control for avoiding the departure is performed until the host vehicle reaches the predetermined point. Therefore, the departure can be reliably avoided by the control for avoiding the departure once, and the control is continuously operated. Can be prevented. Furthermore, after the yaw moment is applied to avoid the departure, the next departure avoidance control does not intervene while the vehicle is heading toward the center of the lane of travel. The control for is not activated. Furthermore, since there is a time allowance while the host vehicle goes to the center position of the traveling lane, there is a margin for the operation by the driver himself. As a result, it is possible to prevent the driver from operating the steering wheel suddenly.

Further, when the traveling road is a curved road and tends to deviate, it is a position in the recognizable range ahead of the host vehicle, and the contact position between the side portion of the traveling lane and the line extending from the host vehicle (predetermined) A yaw moment for avoiding departure is given to the host vehicle so that the host vehicle is directed to a point.
As a result, the control for avoiding the departure is performed until the host vehicle reaches the predetermined point. Therefore, the departure can be reliably avoided by the control for avoiding the departure once, and the control is continuously operated. Can be prevented. Furthermore, after the yaw moment is applied to avoid the departure, the control for avoiding the next departure does not intervene while the vehicle is heading to the predetermined point. The control is not activated. Furthermore, since the vehicle has a time margin while the host vehicle goes to the contact position between the side portion of the traveling lane and the tangent line extending from the host vehicle, there is a margin for the operation by the driver himself. As a result, it is possible to prevent the driver from operating the steering wheel suddenly.

  Further, as described above, the target yaw moment Ms is limited to be a predetermined value or less (see step S6). Specifically, when the host vehicle is traveling on a straight road, when the target yaw moment | Ms | is equal to or greater than the first threshold value MsL (| Ms | ≧ MsL), only the yaw angle φ is used as a variable. The target yaw moment Ms is replaced, or the value of the target yaw moment Ms is replaced with the first threshold value MsL. When the host vehicle is traveling on a curved road, when the target yaw moment | Ms | is equal to or greater than the second threshold value MsC (| Ms | ≧ MsC), the width H of the host vehicle is set to H + dH (here Therefore, the target yaw moment Ms is recalculated by replacing dH> 0), or the value of the target yaw moment Ms is replaced by the second threshold value MsC.

  If the yaw moment applied to the vehicle for avoiding departure increases, it is considered that the driver feels uncomfortable. In addition, if the yaw moment applied to the vehicle for avoiding the departure is too large, it is considered that the driver suddenly operates the steering wheel in the direction opposite to the departure avoidance direction. Therefore, by limiting the target yaw moment Ms so as to be less than the predetermined value, it is possible to prevent the driver from feeling uncomfortable, and the driver suddenly operates the steering wheel in the direction opposite to the departure avoidance direction. Is prevented.

If thus limits the target yaw moment Ms, especially when traveling road is a curved road will impart the target yaw moment Ms as the vehicle faces the outside of the vehicle lateral displacement limit line LN b viewed from the driving lane center However, at least deviation from the driving lane can be avoided. As a result, it is possible to suppress the yaw moment to be applied to the vehicle while preventing an illusion that the driver deviates from the traveling lane. In addition, such determination of the target yaw moment Ms is, in other words, even when the target yaw moment Ms is changed to less than a predetermined value when the host vehicle is traveling on a curved road, at least the host vehicle is moved from the end of the travel path. it can be said that decision to the target yaw moment Ms that faces the predetermined point between the vehicle lateral displacement limit line LN b.

Next, a second embodiment will be described.
As in the first embodiment, the second embodiment is a rear wheel drive vehicle equipped with a lane departure prevention device. And in 2nd Embodiment, the yaw moment for a deviation avoidance is provided to the own vehicle also considering the presence of the front obstacle ahead of the own vehicle, for example, a parked vehicle.
FIG. 7 is a schematic configuration diagram illustrating a rear wheel drive vehicle according to the second embodiment.
In 2nd Embodiment, the radar 31 which measures the distance between the front obstruction with respect to the own vehicle and the said own vehicle for ACC (adaptive cruise control), a rear-end collision speed reduction brake device, etc. is provided. The radar 31 has a distance D between the position of a predetermined part of the appearance shape of the front obstacle and the own vehicle, a relative speed Vc with the front obstacle, and a line connecting the own vehicle and the front obstacle in the traveling direction of the own vehicle. The angle θ made with respect to the angle is detected. The radar 31 outputs these values to the braking / driving force control unit 8.

  FIG. 8 shows a calculation processing procedure of the braking / driving force control unit 8 in the second embodiment. This calculation process is executed by a timer interrupt every predetermined sampling time ΔT every 10 msec., For example. Although no communication processing is provided in the processing shown in FIG. 8, information obtained by the arithmetic processing is updated and stored in the storage device as needed, and necessary information is read out from the storage device as needed.

  In the second embodiment, the driving environment recognition is performed as step S11 instead of the departure tendency determination process (the process of step S3 in FIG. 2) performed by the braking / driving force control unit 8 in the first embodiment. And running state recognition processing. The processing of driving environment recognition and driving state recognition is as follows. In step S1 and step S2, various data are read from each sensor, controller and control unit, and the vehicle speed V is calculated as in the first embodiment.

(4-1) Driving environment recognition (see FIG. 9)
Here, for the sake of simplicity, a case will be described in which the traveling road is a straight road as shown in FIG. Then, xy coordinates are defined with the lane center as the origin, the traveling direction as the y-axis, and the direction perpendicular to the traveling direction as the x-axis. Then, the position of the host vehicle 100, the position of the front obstacle 200, and the positional relationship between the host vehicle 100 and the front obstacle 200 are obtained using the xy coordinates. In the present embodiment, the front obstacle 200 is a parked vehicle 200.

(4-1-1) traveling lane from the captured image of the detected image pickup unit 13 of the position of the vehicle (center position of the travel lane) LN S detects the position (vehicle current current own vehicle 100 with respect to the lane LN S Position) p0 (x0,0) is obtained. Here, the current position p0 (x0, 0) of the host vehicle is at the center of gravity of the host vehicle.

(4-1-2) Detection of Position of Parked Vehicle (Front Obstacle) The position of the parked vehicle 200 is detected from the obstacle information of the radar 31. Specifically, as the position of the parked vehicle 200, a position of a predetermined portion having an outer diameter shape that identifies the parked vehicle 200 is obtained. Here, the positions of the predetermined parts are the three corners of the parked vehicle 200, that is, the two corners pa and pb at the front end of the parked vehicle 200 when viewed from the host vehicle 100, and the rear end of the parked vehicle 200 when viewed from the host vehicle 100. Therefore, it becomes one corner point pc on the traveling lane side.

  And about each position pa, pb, pc of the predetermined part of the outer-diameter shape which identifies the detected parked vehicle 200, distances Da, Db, Dc from the current position p0 of the own vehicle and an angle θa with respect to the traveling direction of the own vehicle 100, θb and θc are obtained. That is, the distance Da between the left front end position pa of the parked vehicle 200 and the host vehicle current position p0, the distance Db between the right front end position pb of the parked vehicle 200 and the host vehicle current position p0, and the right rear end position pc of the parked vehicle 200 The distance Dc between the host vehicle current position p0, the angle θa between the straight line connecting the host vehicle current position p0 and the left front end position pa of the parked vehicle 200 and the travel direction of the host vehicle 100, the host vehicle current position p0 and the parked vehicle 200 The angle θb formed between the straight line connecting the right front end position pb of the vehicle and the traveling direction of the host vehicle 100, and the straight line connecting the host vehicle current position p0 and the right rear end position pc of the parked vehicle 200 and the traveling direction of the host vehicle 100 are An angle θc formed is obtained.

(4-1-3) Positional relationship between the host vehicle and the parked vehicle The position of the host vehicle obtained in the above (4-1-1) and the position of the parked vehicle obtained in the above (4-1-2). A two-dimensional map is created from the above, and the positional relationship between the host vehicle 100 and the parked vehicle 200 is obtained. Here, each position pa, pb, pc of the parked vehicle 200 is obtained as coordinates in the xy coordinate system. In the case of FIG. 9, the positions pa, pb, pc of the parked vehicle 200 are the left front end position pa (xa, ya) of the parked vehicle 200, the right front end position pb (xb, yb) of the parked vehicle 200, and It can be obtained as the right rear end position pc (xc, yc) of the parked vehicle 200. As a result, the positional relationship between the host vehicle 100 and the parked vehicle 200 is as follows: the host vehicle current position p0 as the position of the host vehicle 100 and the positions pa, pb, pc on the parked vehicle 200 in the xy coordinate system. Obtained as a relationship.

The information on the positions pa, pb, and pc of the parked vehicle 200 indicates that the parked vehicle 200 exists in the traveling lane in front of the host vehicle 100. For example, referring to the information on the travel lane width L, it can be seen that the parked vehicle 200 exists in the travel lane in front of the host vehicle 100.
As described above, the traveling environment such as the presence or absence of a parked vehicle in front of the host vehicle can be recognized.

(4-2) Traveling state recognition (see FIG. 4 or FIG. 9)
In the running state recognition process, the same process as the departure tendency determination process (the process in step S3 in FIG. 2) in the first embodiment is performed.
That is, the estimated lateral displacement xS and the limit displacement xL after a predetermined time Tt are defined. Here, the predetermined time Tt is, for example, 1 sec. Specifically, the estimated lateral displacement xS and limit displacement xL are calculated by the above equations (2) and (3).

  Then, the estimated lateral displacement xS and the limit displacement xL are compared to determine the lane departure tendency. Here, when the absolute lateral displacement | xS | of the absolute value is equal to or larger than the absolute displacement | xL | (| xS | ≧ | xL |), it is determined that there is a possibility of deviation. In this case, the departure determination flag Fout is turned ON (Fout = ON), and at the same time, the timer is operated to measure the time TD in which the departure determination flag Fout is continuously ON. Here, when the time TD reaches a predetermined time, the departure determination flag Fout is determined to be ON, and otherwise, the departure determination flag Fout is set to OFF (Fout = OFF). If the absolute lateral displacement | xS | is less than the absolute displacement | xL | (| xS | <| xL |), it is determined that there is no possibility of deviation. In this case, the deviation determination flag Fout is turned OFF (Fout = OFF), and at the same time, the timer time TD is reset to zero.

  Further, the departure direction Dout is determined based on the estimated lateral displacement xS. Specifically, when the estimated lateral displacement xS is a positive value, assuming that the host vehicle is laterally displaced rightward from the center of the lane, the rightward direction is the departure direction Dout (Dout = right), and the estimated lateral displacement xS is negative. In the case of the value, assuming that the host vehicle is laterally displaced leftward from the lane center, the leftward direction is set as the departure direction Dout (Dout = left).

  The departure determination flag Fout may be determined without depending on the time TD. That is, the deviation determination flag Fout is set to ON (Fout = ON) on condition that the estimated absolute lateral displacement | xS | is equal to or greater than the absolute value limit displacement | xL | (| xS | ≧ | xL |). When the estimated absolute lateral displacement | xS | is less than the absolute limit displacement | xL | (| xS | <| xL |), the departure determination flag Fout is turned off (Fout = OFF).

As described above, the driving environment recognition process and the driving state recognition process are performed in step S11.
In subsequent step S4, the driver's intention to change lanes is determined in the same manner as in the first embodiment.
Subsequently, in step S5, a control method for determining whether or not to perform departure warning and departure avoidance braking control is determined.
Specifically, as in the first embodiment described above, when the departure determination flag Fout obtained in step S4 is ON, it is determined that a departure warning is to be performed, and the road information and the vehicle Based on the departure state, a target passing point and a necessary yaw angle ρ are set. Here, the deviation warning is an alarm given by sound or display. In addition, the target passing point is set based on the shape of the traveling path of the host vehicle. Specifically, a target passing point is set according to a straight road or a curved road.

  On the other hand, here, as a process specific to the second embodiment, the target passing point and the necessary yaw angle ρ are considered in consideration of the information on the traveling ring and the traveling state (lane departure tendency) obtained in step S11. Set. The setting of the target passing point and the necessary yaw angle ρ will be described next for each of the straight road and the curved road.

(5-1) When the host vehicle travels on a straight road and there is no parked vehicle ahead (see FIG. 4)
When the host vehicle travels on a straight road and there is no parked vehicle ahead, the same calculation as in (1-1) When the host vehicle travels on a straight road (see FIG. 4), A target passing point pT and a necessary yaw angle (hereinafter referred to as a first yaw angle) ρ are obtained.

(5-2) When the host vehicle travels on a straight road and the host vehicle may come into contact with a parked vehicle existing ahead (see FIG. 10)
First, a target passing point pT ′ (xT ′, yT ′) for preventing the own vehicle from contacting the parked vehicle is set. xT ′ and yT ′ are expressed by the following equation (18).
xT ′ = xc− (H / 2 + Hm) × xc / | xc |
yT '= yc
... (18)

Here, xc is the right rear end position of the parked vehicle 200 in the x coordinate. Hm is a margin for passing the side of the front obstacle, that is, a distance between the right rear end position xc of the parked vehicle 200 and the side end of the host vehicle 100. For example, as shown in FIG. 11, the distance Hm is set to a larger value as the vehicle speed of the host vehicle increases.
With the above settings, the target passing point pT ′ is set to a point offset in the x direction by (H / 2 + Hm) from the right rear end position pc of the parked vehicle 200.
When the right rear end position pc of the parked vehicle 200 cannot be recognized, the target passing point pT ′ (xT ′, yT) at which the host vehicle 100 does not contact the parked vehicle 200 with reference to the right front end position pb of the parked vehicle 200. ') Is set.

Further, the protruding amount Hs of the parked vehicle 200 to the traveling lane side can be obtained by the following equation (19).
Hs = L / 2− || cc |
Or Hs = L / 2− | xb |
... (19)

Then, from the straight line passing through the target passing point pT ′ (xT ′, yT ′) for preventing the host vehicle 100 from contacting the parked vehicle 200 and the host vehicle current position p0 (x0, 0), the target is expressed by the following equation (20). The yaw angle φT ′ can be obtained.
φT ′ = tan −1 {(x0−xT ′) / (y0−yT ′)} (20)
Note that y0 is 0 because the current position p0 of the host vehicle is located at the origin in the traveling direction (y-axis).
Then, using this target yaw angle φT ′, a yaw angle (hereinafter, referred to as a second yaw angle) ρ ′ necessary for making the host vehicle 100 face the target passing point pT ′ is obtained by the following equation (21). .
ρ ′ = φT′−φ (21)

On the other hand, assuming that there is no parked vehicle 200 ahead, the first yaw angle ρ is calculated in the same manner as in (1-1) or (5-1) described above.
Then, when the own vehicle 100 tends to deviate in the direction in which the parked vehicle 200 exists, the absolute value of the first yaw angle ρ is compared with the absolute value of the second yaw angle ρ ′, and the larger yaw angle is compared. Determine the angle as the required yaw angle. Further, when there is a deviation tendency of the host vehicle 100 in the direction opposite to the direction in which the parked vehicle 200 exists, the absolute value of the first yaw angle ρ is compared with the absolute value of the second yaw angle ρ ′. The smaller yaw angle is determined as the required yaw angle. As a result, as shown in FIG. 10, when there is a tendency for the vehicle to deviate in the direction opposite to the direction in which the parked vehicle 200 exists, the absolute value of the second yaw angle ρ ′ is smaller. Two yaw angles ρ ′ are necessary yaw angles.

In this way, by determining the necessary yaw angle by comparing the first yaw angle ρ and the second yaw angle ρ ′ and controlling the departure avoidance based on the yaw angle, during the departure avoidance control, The own vehicle 100 passes farther than the parked vehicle 200.
As described above, when a parked vehicle is present on a straight traveling path, the yaw angle necessary for avoiding the departure is obtained based on the relationship between the parked vehicle and the departure tendency.

(5-3) When the vehicle travels on a curved road and there is no parked vehicle ahead (see FIG. 5)
When the host vehicle 100 travels on a curved road and the parked vehicle 200 does not exist ahead, the same calculation as in (1-2) When the host vehicle travels on a curved road (see FIG. 5). Thus, the target passing point pT and the necessary yaw angle (hereinafter referred to as the third yaw angle) ρ are obtained.

(5-4) When the host vehicle travels on a curved road and the host vehicle may come into contact with a parked vehicle existing ahead (see FIG. 12)
First, as in FIG. 5, as shown in FIG. 12, XY coordinates are defined as a global coordinate system with xy coordinates as local coordinate systems.
The left front end position pa (xa, ya) of the parked vehicle 200, the right front end position pb (xb, yb) of the parked vehicle 200 obtained in the above-mentioned (4-1-2) in the xy coordinate system, and The right rear end position pc (xc, yc) of the parked vehicle 200 is converted into the XY coordinate system, and the left front end position Pa (Xa, Ya) of the parked vehicle 200 and the right front end position Pb (Xb of the parked vehicle 200). , Yb) and the right rear end position Pc (Xc, Yc) of the parked vehicle 200 are obtained.

Subsequently, a target passing point for preventing the host vehicle 100 from contacting the parked vehicle 200 is set.
Here, first, similarly to the above-described (5-2), a point offset from the parked vehicle 200 in the x direction is obtained. Specifically, for each of the right front end position Pb and the right rear end position Pc of the parked vehicle 200, as a point offset in the x direction by (H / 2 + Hm), the target passing point Pb ′ (Xb ′, Yb ′), Pc '(Xc', Yc ') is obtained. Here, Xb ′, Yb ′, Xc ′, and Yc ′ can be expressed as the following equation (22).
Xb ′ = Xb + (H / 2 + Hm) × cos Θb
Yb ′ = Yb + (H / 2 + Hm) × sin Θb
Xc ′ = Xc + (H / 2 + Hm) × cos Θc
Yc ′ = Yc + (H / 2 + Hm) × sin Θc
(22)

  Here, Θb is an angle formed by the X axis and a straight line connecting the origin of the XY coordinate and the target passage point Pb ′, and Θc is the origin of the XY coordinate and the target passage point Pc ′. This is the angle formed by the connecting straight line and the X axis. As shown in FIG. 12, the angles Θb and Θc are positive values in the counterclockwise direction, and are larger than 90 ° and smaller than 180 ° (90 ° <Θb, Θc <180 °).

Then, target yaw angles φTb and φTc for the host vehicle to pass through the target passing points Pb ′ (Xb ′, Yb ′) and Pc ′ (Xc ′, Yc ′) are obtained by the following equation (23).
φTb = tan −1 {(X0−Xb ′) / (Y0−Yb ′)}
φTc = tan −1 {(X0−Xc ′) / (Y0−Yc ′)}
(23)
When the own vehicle 100 tends to deviate in the direction in which the parked vehicle 200 exists, the absolute target yaw angle φTb is compared with the absolute yaw angle φTc, and the larger yaw angle is determined as the target yaw angle. Confirm as the angle φT ′. Further, when the own vehicle 100 tends to deviate in the direction opposite to the direction in which the parked vehicle 200 exists, the absolute target yaw angle φTb is compared with the absolute yaw angle φTc, and the smaller yaw angle is compared. The angle is determined as the target yaw angle φT ′.

Then, using the determined target yaw angle φT ′, a yaw angle (hereinafter referred to as a fourth yaw angle) ρ ′ necessary to make the host vehicle 100 face the target passing point Pb ′ or the target passing point Pc ′. Obtained by the following equation (24).
ρ ′ = φT′−φ (24)
On the other hand, assuming that there is no parked vehicle 200 ahead, the third yaw angle ρ is calculated in the same manner as in the above (1-2) or (5-3).

  When there is a tendency to deviate from the host vehicle 100 in the direction in which the parked vehicle 200 exists, the absolute value of the third yaw angle ρ is compared with the absolute value of the fourth yaw angle ρ ′. Determine the angle as the required yaw angle. Further, when there is a deviation tendency of the host vehicle 100 in the direction opposite to the direction in which the parked vehicle 200 exists, the absolute value of the third yaw angle ρ is compared with the absolute value of the fourth yaw angle ρ ′. The smaller yaw angle is determined as the required yaw angle. Thereby, as shown in FIG. 12, when the own vehicle 100 tends to deviate in a direction opposite to the direction in which the parked vehicle 200 exists, the fourth yaw angle ρ ′ becomes a necessary yaw angle.

In this way, by determining the necessary yaw angle by comparing the third yaw angle ρ and the fourth yaw angle ρ ′ and controlling the departure avoidance based on the yaw angle, during the departure avoidance control, The own vehicle 100 passes farther than the parked vehicle 200.
As described above, when a parked vehicle is present on the curved traveling path, the yaw angle necessary for avoiding the departure is obtained based on the relationship between the parked vehicle and the departure tendency.

(5-5) When there are a plurality of tracks (curves, straight lines) and there is no parked vehicle ahead (see FIG. 6)
When there are a plurality of tracks (curves, straight lines), that is, for example, when the traveling road is a curved road with continuous curves as shown in FIG. 6, when the parked vehicle 200 does not exist ahead on the curved road. The target passage point pT and the necessary yaw angle ρ are obtained by the same calculation as in (1-3) where there are a plurality of trajectories (curves, straight lines) (see FIG. 6).

(5-6) When there are a plurality of tracks (curves, straight lines) and the own vehicle may come into contact with a parked vehicle existing ahead (see FIG. 13).
Here, for the sake of simplicity, a case will be described in which the traveling road is a curved road having continuous curves as shown in FIG.
In this case, in the same manner as in the case where (5-4) the host vehicle travels on a curved road and the host vehicle may come into contact with a parked vehicle ahead, the vehicle forward from the current host vehicle position P0. the extended line and the vehicle lateral displacement limit line LN b and sought contacts to the number of contacts is a plurality. Therefore, a plurality of target passing points pT (in this example, two points P1 and P2) are obtained.

  For this reason, when the traveling road is a continuous curved road, the contact point farthest from the current host vehicle position P0 is set as the target passing point pT (P2 in this example). Then, with respect to the target passing point pT (P2), as shown in FIG. 13, when the parked vehicle 200 exists, the above-described (5-4) parked vehicle in which the host vehicle travels on a curved road and exists ahead. As in the case where there is a possibility that the host vehicle may come into contact with the vehicle, the necessary yaw angle ρ or ρ ′ through which the host vehicle 100 passes is obtained (see the formula (24) and the like).

As described above, in step S5, the necessary yaw angle ρ or ρ ′ is obtained based on the shape of the traveling road such as a straight road and a curved road, the traveling environment, and the traveling state (lane departure tendency).
Subsequently, in step S6, a target yaw moment to be generated in the host vehicle is calculated as in the first embodiment described above. That is, for example, based on the yaw angle ρ or ρ ′ obtained in step S5, the target yaw moment Ms is calculated by the equation (10).

When ρ ′ is obtained as a necessary yaw angle, the target yaw moment Ms is calculated using the yaw angle ρ ′ instead of the yaw angle ρ in the equation (10).
Subsequently, in step S7, the target brake fluid pressure of each wheel is calculated in the same manner as in the first embodiment described above.
The above is the calculation processing by the braking / driving force control unit 8 in the second embodiment. Then, the braking / driving force control unit 8 uses the target braking fluid pressure Psi (i = fl, fr, rl, rr) calculated in step S7 as the braking fluid pressure command value to the braking fluid pressure control unit 7. Output.

The lane departure prevention apparatus according to the second embodiment as described above operates as follows in outline.
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 departure determination flag Fout is set based on the estimated departure time Tout, and the departure direction Dout is determined based on the estimated lateral displacement xS. Further, the positional relationship between the host vehicle and the front obstacle is obtained (step S11).

Further, the driver's intention to change lanes is determined based on the deviation direction obtained in this way and the direction indicated by the direction switch signal (the blinker lighting side) (step S4).
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. In this case, the departure determination flag Fout is changed to OFF.

  Further, when the departure determination flag Fout is ON, 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 state of the departure determination flag Fout is maintained. For example, if 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 behavior of the vehicle is not the vehicle behavior due to the driver's intention such as a lane change by the driver. Since the departure determination flag Fout is ON, the state of the departure determination flag Fout is maintained.

  Then, control details for avoiding the departure are determined based on the departure determination flag Fout (step S5). Specifically, when the departure determination flag Fout is ON, it is determined that a departure warning is to be performed, and a target passing point and a necessary yaw angle ρ or ρ ′ as a control target for avoiding departure are set. . Here, the target passing point and the necessary yaw angle ρ or ρ ′ are set according to the traveling road shape, the road information ahead, and the departure warning of the host vehicle.

That is, when the traveling road is a straight road and there is no parked vehicle ahead, the yaw angle ρ is calculated using the equation (5).
Further, when the traveling road is a straight road and the own vehicle may come into contact with a parked vehicle existing ahead, the yaw angle ρ ′ is calculated by the equation (21), and (5) The yaw angle ρ is calculated by the equation, and one of the yaw angles is made the final yaw angle from the relationship between the direction in which the host vehicle tends to deviate and the position of the parked vehicle.

Further, when the traveling road is a curved road and there is no parked vehicle ahead, the yaw angle ρ is calculated by the equation (9).
Further, when the traveling road is a curved road and the own vehicle may come into contact with a parked vehicle existing ahead, the yaw angle ρ ′ is calculated using the equation (24), and ( 9) The yaw angle ρ is calculated by the equation (9), and one of the yaw angles is made the final yaw angle from the relationship between the direction in which the host vehicle deviates and the position of the parked vehicle.

Further, in the case where the traveling path is composed of a continuous curve and there is no parked vehicle ahead, the yaw angle is calculated from the above equation (9) for the farthest target passage point pT among the plurality of target passage points pT. ρ is calculated.
In addition, when there is a parked vehicle with respect to the farthest target passing point pT among the plurality of target passing points pT, the traveling path is composed of a continuous curve. The yaw angle ρ ′ is calculated using the equation (24), and the yaw angle ρ is calculated using the equation (9). From the relationship between the direction in which the host vehicle has a tendency to deviate and the position of the parked vehicle, either yaw is calculated. Make the angle the final yaw angle.

Subsequently, the target yaw moment Ms is calculated based on the yaw angle ρ or ρ ′ thus determined (step S6). Then, the target braking fluid pressure Psi (i = fl, fr, rl, rr) of each wheel for realizing the target yaw moment Ms is calculated, and this target braking 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 S7). The braking fluid pressure control unit 7 individually controls the braking fluid pressures of the wheel cylinders 6FL to 6RR based on the braking fluid pressure command value.
As a result, when there is a parked vehicle in front of the host vehicle and there is a tendency to deviate, the vehicle will behave toward a point where it does not come into contact with the parked vehicle by control for deviating. At this time, a warning is given by sound or display. For example, an alarm is started simultaneously with the vehicle behavior or at a predetermined timing prior to the vehicle behavior.

Next, the effect in 2nd Embodiment is demonstrated.
As described above, a target passing point is set in consideration of the presence of a front obstacle in front of the host vehicle, for example, a parked vehicle, and a yaw angle for avoiding deviation is obtained based on the set target passing point. ing. Thereby, control for deviation avoidance is performed until the vehicle reaches a predetermined point while preventing the vehicle from contacting the parked vehicle. Thereby, it is possible to prevent the driver from operating the steering wheel suddenly with respect to the parked vehicle during the control for avoiding deviation.

Further, as described above, Hm is defined as a margin for passing through the side of the parked vehicle, and the Hm is set to a larger value as the vehicle speed of the host vehicle increases (see FIG. 11). Thereby, the target passing point set based on the parked vehicle is set farther from the parked vehicle as the host vehicle speed increases.
Generally, when a driver passes by a parked vehicle, the driver passes away from the parked vehicle as the vehicle speed increases. For this reason, setting the target passing point further away from the parked vehicle becomes more consistent with the driving feeling of the driver as the host vehicle speed increases.

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, the case where the yaw moment is applied to the host vehicle by adjusting the braking force has been described. However, it is not limited to this. For example, the yaw moment may be applied to the host vehicle by adjusting the rotation of the steering shaft.
In the above-described embodiment, the target yaw moment Ms is limited based on the threshold values MsL and MsC. However, it is not limited to this. That is, for example, the target yaw moment Ms may be limited based on other conditions without being based on the threshold values MsL and MsC.

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. Further, an engine brake that performs braking control by changing a valve timing of the engine, a speed change brake that operates like a bu engine brake by changing a speed ratio, or an air brake may be used.
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 S4). 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.

It is a schematic block diagram which shows 1st Embodiment 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 lane departure prevention apparatus in the said 1st Embodiment. It is the figure used for description of determination of a lane departure tendency. It is the figure used for description of the setting of the target passage point and required yaw angle (rho) when a travel path is a straight road. It is the figure used for description of the setting of the target passage point and the necessary yaw angle ρ when the traveling road is a curved road. It is the figure used for description of the setting of the target passing point in case a curve continues, and required yaw angle (rho). It is a schematic block diagram which shows 2nd Embodiment 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 lane departure prevention apparatus in the said 2nd Embodiment. It is the figure used for description of the process of the driving | running | working state recognition in the processing content of the braking / driving force control unit in the said 2nd Embodiment. It is the figure used for description of the setting of the target passage point and required yaw angle (rho) when a travel path is a straight road and there is a parked vehicle on the straight road. It is a characteristic view which shows the relationship between Hm which says the allowance margin at the time of passing the side of a front obstruction, and vehicle speed. It is the figure used for description of the setting of the target passage point and required yaw angle (rho) (ρ ') when a travel path is a curved road and there is a parked vehicle on the curved road. It is the figure used for description of the setting of the target passing point and the necessary yaw angle ρ (ρ ′) when there is a parked vehicle on a traveling path with continuous curves.

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 15 Navigation device 17 Master cylinder pressure sensor 18 Accelerator opening sensor 19 Steering angle sensor 22FL to 22RR Wheel speed sensor 31 Radar

Claims (9)

  1. In the lane departure prevention device for giving a yaw moment to the own vehicle and avoiding the departure of the own vehicle from the traveling lane when the own vehicle tends to deviate from the traveling lane,
    A lane departure prevention apparatus characterized in that the yaw moment is applied so that the host vehicle is directed to a predetermined point that is in front of a travel lane of the host vehicle.
  2.   The lane departure prevention apparatus according to claim 1, wherein the predetermined point is in an area recognizable from the host vehicle.
  3.   3. The lane departure prevention device according to claim 1, wherein when the travel lane is a straight road, the predetermined point is a center position of the travel lane.
  4.   3. The lane departure prevention device according to claim 1, wherein when the travel lane is a curved road, a contact point of a tangent extending from the own vehicle to an inner side portion of the travel lane is the predetermined point.
  5.   The lane departure prevention apparatus according to any one of claims 1 to 4, wherein the predetermined point is a point determined based on an obstacle ahead of the host vehicle.
  6.   When there is an obstacle ahead of the host vehicle, the first candidate point in the area recognizable from the host vehicle and the second candidate point determined based on the obstacle ahead of the host vehicle are candidates for the predetermined point. 2. The lane departure prevention apparatus according to claim 1, wherein a candidate point selected from among the candidate points is a candidate point where the host vehicle passes further with respect to the obstacle.
  7.   The lane departure prevention apparatus according to any one of claims 1 to 6, wherein the yaw moment is limited to be less than a predetermined value.
  8. A determination means for determining a tendency of departure from the traveling lane of the host vehicle;
    Setting means for setting the predetermined point when the determining means determines that the host vehicle may deviate from the driving lane;
    Braking means for applying the yaw moment so that the host vehicle is directed to the predetermined point set by the setting means;
    A lane departure prevention device according to any one of claims 1 to 7, further comprising:
  9. In the setting means, an angle formed between a line connecting the predetermined point and the own vehicle position and the traveling lane of the own vehicle is opposite to an angle formed between the longitudinal axis of the own vehicle and the traveling lane of the own vehicle. The lane departure prevention apparatus according to claim 8, wherein the predetermined point is set as described above.
JP2004084475A 2003-10-31 2004-03-23 Lane deviation arrester Pending JP2005158014A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2003372851 2003-10-31
JP2004084475A JP2005158014A (en) 2003-10-31 2004-03-23 Lane deviation arrester

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2004084475A JP2005158014A (en) 2003-10-31 2004-03-23 Lane deviation arrester

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007008281A (en) * 2005-06-29 2007-01-18 Toyota Motor Corp Driving assistance system for vehicle
JP2009176189A (en) * 2008-01-28 2009-08-06 Advics Co Ltd Road traveling predicted locus deriving device, road traveling predicted locus deriving method and road traveling predicted locus deriving program
JP2010033443A (en) * 2008-07-30 2010-02-12 Nissan Motor Co Ltd Vehicle controller
JP2011195017A (en) * 2010-03-19 2011-10-06 Hitachi Automotive Systems Ltd Apparatus and method for controlling vehicle
WO2013076908A1 (en) * 2011-11-25 2013-05-30 日産自動車株式会社 Lane deviation prevention device
JP2013173520A (en) * 2012-01-25 2013-09-05 Denso Corp Lane departure control system and lane departure control program
JP2013173519A (en) * 2012-01-25 2013-09-05 Denso Corp Lane departure control system and lane departure control program
CN106080595A (en) * 2015-05-01 2016-11-09 丰田自动车株式会社 Controlling device for vehicle running

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007008281A (en) * 2005-06-29 2007-01-18 Toyota Motor Corp Driving assistance system for vehicle
JP4654796B2 (en) * 2005-06-29 2011-03-23 トヨタ自動車株式会社 Vehicle driving support device
JP2009176189A (en) * 2008-01-28 2009-08-06 Advics Co Ltd Road traveling predicted locus deriving device, road traveling predicted locus deriving method and road traveling predicted locus deriving program
JP2010033443A (en) * 2008-07-30 2010-02-12 Nissan Motor Co Ltd Vehicle controller
JP2011195017A (en) * 2010-03-19 2011-10-06 Hitachi Automotive Systems Ltd Apparatus and method for controlling vehicle
WO2013076908A1 (en) * 2011-11-25 2013-05-30 日産自動車株式会社 Lane deviation prevention device
JP2013173520A (en) * 2012-01-25 2013-09-05 Denso Corp Lane departure control system and lane departure control program
JP2013173519A (en) * 2012-01-25 2013-09-05 Denso Corp Lane departure control system and lane departure control program
CN106080595A (en) * 2015-05-01 2016-11-09 丰田自动车株式会社 Controlling device for vehicle running
JP2016210255A (en) * 2015-05-01 2016-12-15 トヨタ自動車株式会社 Vehicle travel control device

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