JP2010030386A - Lane deviation prevention device and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cause an action for changing lanes by a driver to coincide with an operation of lane deviation prevention control. <P>SOLUTION: The lane deviation prevention device determines a degree in the risk of the lane change when the device detects the driver's intention for changing lanes in a direction where the tendency of deviation from a driving lane occurs. When the device determines that the risk is high, the device performs the lane deviation prevention control. When the device determines the risk is low, the device does not perform the lane deviation prevention control (steps S4-S5). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

In the lane departure prevention device disclosed in Patent Document 1, when it is detected that the driver recognizes the lane departure by a steering operation or a turn signal operation by the driver, the lane departure prevention control by the steering torque is performed. It is finished (cancelled).
JP-A-2005-343303

By the way, in the device of Patent Document 1, since the lane departure prevention control is terminated when the driver performs a steering operation or the like for the lane change, after that, even when the driver stops the lane change from the driving situation or the like, The lane departure prevention control remains finished. However, the suspension of such lane departure prevention control gives the driver an uncomfortable feeling.
The subject of this invention is making the operation | movement of lane departure prevention control correspond with the action of the lane change by a driver | operator.

  In order to solve the above-mentioned problem, the present invention determines the degree of risk of lane change when detecting the driver's intention to change lane in a direction in which a tendency to deviate from the traveling lane is detected. When it is determined that the risk is high, the lane departure prevention control is activated, and when it is determined that the risk is low, the lane departure prevention control is suppressed.

  According to the present invention, the lane departure prevention control can be activated under a situation where the driver is likely to cancel the lane change, and the lane is assumed to be low when the driver is unlikely to cancel the lane change. Deviation prevention control can be suppressed.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
(Constitution)
The embodiment of the present invention is a rear wheel drive vehicle equipped with the lane departure prevention apparatus according to 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 the present embodiment.
In the figure, reference numeral 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, and 4 is a reservoir. Normally, the brake fluid pressure boosted by the master cylinder 3 is supplied to the wheel cylinders 6FL to 6RR of the wheels 5FL to 5RR in accordance with the depression amount of the brake pedal 1 by the driver. Further, a brake fluid pressure control unit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL to 6RR.

  The brake fluid pressure control unit 7 is, for example, a brake fluid pressure used for anti-skid control (ABS), traction control (TCS) or vehicle dynamics control (VDC). It uses a control unit. The braking fluid pressure control unit 7 individually controls the braking fluid pressures of the wheel cylinders 6FL to 6RR. And the brake fluid pressure control part 7 can control the brake fluid pressure independently. Further, when a braking fluid pressure command value is input from a braking / driving force control unit 8 described later, the braking fluid pressure control unit 7 can also control the braking fluid pressure according to the braking 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.

  Further, this vehicle is equipped 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 can also independently control the drive torque of the rear wheels 5RL and 5RR. Further, when a driving torque command value is input from the braking / driving force control unit 8, the driving torque control unit 12 can also control the driving wheel torque according to the driving torque command value. 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.

In addition, this vehicle is equipped with an imaging unit 13 with an image processing function. The imaging unit 13 detects the position of the host vehicle in the traveling lane. For example, the imaging unit 13 is configured to capture an image with a monocular camera including a CCD (Charge Coupled Device) camera. An imaging unit (front camera) 13 is installed in the front part of the vehicle.
The imaging unit 13 detects a lane marking such as a white line (lane marker) from the captured image in front of the host vehicle. The imaging unit 13 detects a traveling lane based on the detected lane marking. 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. Etc. 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. Further, the traveling lane curvature β can be calculated based on a steering angle δ of the steering wheel 21 described later.

  In addition, this vehicle is equipped with radar devices 14L and 14R that detect obstacles traveling in the side direction of the host vehicle. The radar devices 14L and 14R detect an obstacle (for example, an adjacent lane traveling vehicle) present at least in the blind spot area on the side surface of the host vehicle. For example, an obstacle detection range (obstacle detection area) is set on the rear side, and an obstacle (rear side vehicle) is detected within the obstacle detection range. The radar devices 14L and 14R detect, for example, a relative lateral position, a relative vertical position, a relative vertical speed, and a relative lateral speed with respect to the obstacle as information on the obstacle detected within the obstacle detection range. The radar devices 14 </ b> L and 14 </ b> R output obstacle detection results such as relative lateral positions to the braking / driving force control unit 8.

  Here, as long as the vehicle is located rearward from the host vehicle, the obstacle is a rearward obstacle. However, the rear side referred to in the present embodiment does not include the rear side that is extremely far from the host vehicle, and refers to the rear side that can be detected by the capability of the radar devices 14L and 14R, for example. Further, the rear side includes at least the rear side that affects the traveling state such as lane change of the host vehicle.

  In addition, this vehicle is equipped with a master cylinder pressure sensor 17 that detects an output pressure of the master cylinder 3, that is, a master cylinder hydraulic pressure Pm. The vehicle is also equipped with an accelerator opening sensor 18 that detects the amount of depression of the accelerator pedal, that is, an accelerator opening θt, and a steering angle sensor 19 that detects a steering angle (steering steering angle) δ of the steering wheel 21. Yes. In addition, this vehicle includes a direction indicator switch 20 that detects a driver's operation of a direction indicator (turn signal switch), and a rotation speed of each wheel 5FL to 5RR, so-called wheel speed Vwi (i = fl, fr, rl, Wheel speed sensors 22FL to 22RR for detecting rr) are mounted. These sensors and the like output the detected detection signal to the braking / driving force control unit 8.

Next, calculation processing performed by the braking / driving force control unit 8 will be described. FIG. 2 shows a calculation processing procedure performed by the braking / driving force control unit 8. For example, the arithmetic processing is executed by timer interruption every predetermined sampling time ΔT every 10 msec. Information obtained by the arithmetic processing is updated and stored in the storage device as needed, and necessary information is read from the storage device as needed.
As shown in FIG. 2, when the process is started, first, in step S1, various data are read from each sensor, controller, and control unit. Specifically, each wheel speed Vwi, steering angle δ, accelerator opening θt, master cylinder hydraulic pressure Pm and direction switch signal detected by each sensor, driving torque Tw from the driving torque control unit 12, and from the imaging unit 13 The detection result is read from the yaw angle φ, the lateral displacement X, the traveling lane curvature β, and the radar devices 14L and 14R.

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 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 wheel.
The vehicle speed V calculated in this way is preferably used during normal travel. For example, when the ABS 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 by a navigation device (not shown) may be used as the vehicle speed V.

Subsequently, in step S3, a lane departure tendency is determined. FIG. 3 shows the procedure of this determination process. FIG. 4 shows the definition of values used in this process.
As shown in FIG. 3, first, in step S21, an estimated lateral displacement Xs of the lateral position of the vehicle center of gravity after a predetermined time T is calculated. Specifically, using the yaw angle φ obtained in step S1, the traveling lane curvature β, the lateral displacement X of the current vehicle, and the vehicle speed V obtained in step S2, the estimated lateral displacement is given by the following equation (2). Xs is calculated.
Xs = Tt · V · (φ + Tt · V · β) + X (2)
Here, Tt is the vehicle head time for calculating the forward gaze distance. When this vehicle head time Tt is multiplied by the own vehicle speed V, a forward gazing distance is obtained. Further, the estimated lateral displacement from the center of the traveling lane after the vehicle head time Tt becomes the estimated lateral displacement Xs in the future. According to the equation (2), for example, the estimated lateral displacement Xs increases as the yaw angle φ increases.

Subsequently, in step S22, departure determination is performed. Specifically, the estimated lateral displacement Xs is compared with a predetermined departure tendency determination threshold value X _L. Here, departure-tendency threshold value X _L is generally a value that the vehicle can be grasped to be in the lane departure tendency. The departure tendency determination threshold value _XL is, for example, an experimental value or the like. Further, as a value indicating the position of the travel path of the boundary line, the following (3) can be calculated departure-tendency threshold value X _L by formula.
X _L = (L−H) / 2 (3)
Here, L is the lane width. H is the width of the vehicle. The lane width L is obtained by processing the captured image by the imaging unit 13. Further, the position of the vehicle can be obtained from the navigation device, and the lane width L can be obtained from the map data of the navigation device.

In FIG. 4, it is set departure-tendency threshold value X _L in the traveling lane of the own vehicle. However, the present invention is not limited to this, and can be set outside the traveling lane. Further, it is not limited to determining that the host vehicle has a departure tendency before deviating from the traveling lane, and for example, it may be determined that there is a departure tendency after at least one of the wheels deviates from the lane. In this case, the departure tendency determination threshold value X _L is set so as to obtain such a determination.

In step S22, when the estimated lateral displacement Xs is equal to or greater than the departure tendency determination threshold value X _L (| Xs | ≧ X _L ), it is determined that there is a lane departure tendency. Further, when the estimated lateral displacement Xs is smaller than departure-tendency threshold value _{X L (| Xs | <X} L), it determines that there is no lane departure tendency.
Subsequently, in step S23, a departure determination flag Fout is set. That is, if it is determined in step S22 that there is a lane departure tendency (| Xs | ≧ X _L ), the departure determination flag Fout is turned ON (Fout = ON). If it is determined in step S22 that there is no lane departure tendency (| Xs | <X _L ), the departure determination flag Fout is turned off (Fout = OFF).

By the processing of step S22 and step S23, for example, when the host vehicle moves away from the center of the lane and the estimated lateral displacement Xs becomes equal to or greater than the departure tendency determination threshold value X _L (| Xs | ≧ X _L ) The 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 lateral displacement Xs becomes less than the departure tendency determination threshold value X _L (| Xs | <X _L ), The departure determination flag Fout is turned off (Fout = OFF). For example, when a lane departure tendency is occurring, if the driver performs braking control to prevent departure described later, or if the driver himself performs an operation to avoid lane departure, the departure determination flag Fout is changed from ON. Turns off.

Subsequently, in step S24, the departure direction Dout is determined based on the lateral displacement X. Specifically, when the vehicle is laterally displaced leftward from the center of the lane, the direction is set as the departure direction Dout (Dout = left). Further, when the vehicle is laterally displaced from the center of the lane to the right, the direction is set to the departure direction Dout (Dout = right).
Subsequently, in step S4, an obstacle on the rear side is detected. Specifically, a rear side obstacle is detected based on the detection results (rear side obstacle detection information) of the radar devices 14L and 14R read in step S1. More specifically, when the deviation determination flag Fout set in step S3 is ON, when the radar devices 14L and 14R detect an obstacle on the rear side in the deviation direction Dout, the rear side obstacle detection is performed. The determination flag Fbs is set to ON (Fbs = ON).

  Here, the rear side obstacle detection determination flag Fbs can also be set based on the relative speed and distance output by the radar devices 14L and 14R with respect to the detected rear side obstacle. Specifically, the longitudinal distance Job between the host vehicle and the obstacle is less than a predetermined threshold value Jobb, and the vertical relative speed Vrob between the host vehicle and the obstacle is less than a predetermined threshold value Vrobth. In this case (Job <Jobth and Vrob <Vrobth), the rear side obstacle detection determination flag Fbs is set to ON (Fbs = ON). Here, the relative speed Vrob is a value that increases with a positive value as the speed of the host vehicle increases.

  Further, the rear side obstacle detection determination flag Fbs can be set based only on the distance from the rear side obstacle. Specifically, when the longitudinal distance Job between the host vehicle and the obstacle is less than a predetermined threshold value Job (Job <Job), the rear side obstacle detection determination flag Fbs is set to ON (Fbs = ON). ). When such a determination is made, a predetermined distance Job is set to a sufficient distance that allows the host vehicle to change lanes even when the relative speed between the host vehicle and the obstacle on the rear side is small. Further, assuming that there is almost no relative speed between the host vehicle and the obstacles on the rear side, the predetermined threshold Job can be set according to the speed of the host vehicle.

Subsequently, in step S5, the driver's intention to change lanes is determined. Specifically, the driver's intention to change the lane is determined as follows based on the direction switch signal and the steering angle δ obtained in step S1.
When 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 is intentionally changing the lane, and the departure determination flag Fout is set. Change to OFF (Fout = OFF). That is, it is changed to the determination result that there is no lane departure tendency. 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 there is a tendency to depart from the lane is maintained.

  When the direction indicating switch 20 is not operated, the driver's intention to change the lane is determined based on the steering angle δ. Specifically, when the driver is steering in the departure direction, when both the steering angle δ and the change amount of the steering angle (change amount per unit time) Δδ are equal to or larger than a set value, the driver Is intentionally changing the lane, and the departure determination flag Fout is changed to OFF (Fout = OFF). Note that the driver's intention may be determined based on the steering torque.

  In this manner, when the departure determination flag Fout is ON, when it is determined that the driver has not intentionally changed the lane, the departure determination flag Fout is maintained ON. When the departure determination flag Fout is ON, when it is determined that the driver has intentionally changed the lane, the departure determination flag Fout is changed from ON to OFF. However, if the rear side obstacle detection determination flag Fbs is set to ON in step S4, the departure determination flag Fout is not changed to OFF (maintains ON). That is, even when it can be determined that the driver is consciously changing the lane, if a rear side obstacle is detected in the lane to be changed (if Fbs = ON), the deviation is detected. The determination flag Fout is not changed to OFF.

Subsequently, in step S6, when the departure determination flag Fout set (maintained) in step S4 is ON, sound output or display output is performed as an alarm for avoiding lane departure.
As will be described later, when the departure determination flag Fout is ON, the application of the yaw moment to the host vehicle is started as the lane departure prevention control. Therefore, the alarm is output simultaneously with the application of the yaw moment to the host vehicle. However, the present invention is not limited to this. For example, the alarm output timing can be made earlier than the start timing of applying the yaw moment to the vehicle.

Subsequently, in step S7, it is determined whether or not deceleration control of the host vehicle is performed as lane departure prevention control. In the lane departure prevention control of the present embodiment, the host vehicle is decelerated by deceleration control for the purpose of preventing the host vehicle from deviating from the lane. In step S7, it is determined whether or not to perform the deceleration control. Specifically, whether or not the subtraction value (| Xs | −X _L ) obtained by subtracting the lateral displacement limit distance X _L from the estimated lateral displacement Xs calculated in step S3 is equal to or larger than the deceleration control determination threshold value Xβ. Determine.

  Here, the deceleration control determination threshold value Xβ is a value set according to the travel lane curvature β. FIG. 5 shows an example of the relationship between the travel lane curvature β and the deceleration control determination threshold value Xβ. As shown in the figure, when the traveling lane curvature β is small, the deceleration control determination threshold value Xβ is a certain large value. When the travel lane curvature β becomes larger than a certain value, the travel lane curvature β increases while the deceleration control determination threshold value Xβ decreases. When the traveling lane curvature β further increases, the deceleration control determination threshold value Xβ becomes a certain small value. Furthermore, the deceleration control determination threshold value Xβ can be reduced as the vehicle speed V increases.

In step S7, when the subtraction value (| Xs | −X _L ) is equal to or greater than the deceleration control determination threshold value Xβ (| Xs | −X _L ≧ Xβ), it is determined that the deceleration control is performed, and the deceleration control is performed. The operation determination flag Fgs is set to ON (Fgs = ON). When the subtraction value (| Xs | −X _L ) is less than the deceleration control determination threshold value Xβ (| Xs | −X _L <Xβ), it is determined not to perform the deceleration control, and the deceleration control operation determination is made. The flag Fgs is set to OFF (Fgs = OFF).

When the estimated lateral displacement Xs is equal to or greater than the departure tendency determination threshold value X _L in step S3 (| Xs | ≧ X _L ), the departure determination flag Fout is set to ON. On the other hand, when the subtraction value (| Xs | −X _L ) is equal to or greater than the deceleration control determination threshold value Xβ, the deceleration control operation determination flag Fgs is set to ON. From these relationships, even if the departure determination flag Fout is set to ON, the setting is made after the deceleration control operation determination flag Fgs is set to ON. That is, in relation to the yaw moment application to the host vehicle that is performed when a deviation determination flag Fout, which will be described later, is turned on, the yaw moment is applied to the host vehicle after the deceleration control of the host vehicle is performed. .

Subsequently, in step S8, a target yaw moment Ms to be given to the host vehicle as lane departure prevention control is calculated. The target yaw moment Ms is a yaw moment that can sufficiently prevent the host vehicle from deviating from the lane. Specifically, by using the estimated lateral displacement Xs and lateral displacement limit distance X _L obtained in step S3, the target yaw moment Ms is calculated by the following equation (4).
Ms = K1 · K2 · (| Xs | −X _L ) (4)

  Here, K1 is a proportional gain determined from vehicle specifications, and K2 is a gain that varies according to the vehicle speed V. FIG. 6 shows an example of the gain K2. As shown in the figure, in the low speed range, the gain K2 has a certain large value. Further, when the vehicle speed V becomes larger than a certain value, the gain K2 decreases with an increase in the vehicle speed V. Then, when a certain vehicle speed V is reached, the gain K2 becomes a certain small value.

Subsequently, in step S9, the target yaw moment is corrected.
Here, the processing of the lane departure prevention control in the present embodiment is processing on the premise that the processing routine of the lane departure prevention control is executed a plurality of times before the own vehicle completes the departure avoidance from the traveling lane. Yes. That is, in the lane departure prevention control, a yaw moment (specifically, the target yaw moment Ms) that changes in accordance with the departure state is continuously and sequentially applied to the own vehicle, and the departure of the own vehicle from the traveling lane is avoided. Has been completed. The processing of step S9 and step S10 described later is for correcting the target yaw moment on the premise of the processing content of such lane departure prevention control.

  FIG. 7 shows the procedure of this correction process. As shown in the figure, first, in step S31, it is determined whether or not the target yaw moment Ms is larger than zero. If the target yaw moment Ms is greater than zero (Ms> 0), the process proceeds to step S32. Otherwise (Ms = 0), the process shown in FIG. 7 (the process of step S9) is terminated.

In step S32, it is determined whether or not the departure determination flag Fout is ON. If the departure determination flag Fout is ON (Fout = ON), the process proceeds to step S33. If the departure determination flag Fout is OFF (Fout = OFF), the process shown in FIG. 7 (the process of step S9) is terminated.
In step S33, it is determined whether or not the rear side obstacle detection determination flag Fbs is ON. If the rear side obstacle detection determination flag Fbs is ON (Fbs = ON), the process proceeds to step S34. When the rear side obstacle detection determination flag Fbs is OFF (Fbs = OFF), the process shown in FIG. 7 (the process of step S9) is terminated.

In step S34, the gain is set in accordance with the amount of change in the steering angle from the start of control (when Fout is turned ON). Specifically, the gain is increased as the amount of change in the steering angle from the start of control increases. FIG. 8 shows an example of the relationship between the steering angle change amount Δθ1 from the start of control and the gain K _str . As shown in the figure, the gain K _str has a small value in the region where the steering angle change amount Δθ1 is small. When the steering angle change amount Δθ1 reaches a certain value, the gain K _str increases with the steering angle change amount Δθ1. When the steering angle variation Δθ1 is reached, the gain K _str becomes a constant large value. Thus, as a rule, the gain K _str increases as the steering angle change amount Δθ1 increases.

In step S35, the target yaw moment is corrected using the gain _Kstr set in step S34. Specifically, the target yaw moment Ms is corrected by the following equation (5).
Ms = Ms · K _str (5)
Here, Ms on the right side of the equation (5) is the target yaw moment calculated in step S8.
In step S36, a correction execution determination flag Fh is set corresponding to the correction in step S35. That is, when the target yaw moment is corrected in step S35, the correction execution determination flag Fh is set to ON (Fh = ON). Then, the process shown in FIG. 7 (the process of step S9) is terminated.

As a result of the processing in step S9 (FIG. 7), when the target yaw moment Ms is greater than zero, the departure determination flag Fout is ON, and the rear side obstacle detection determination flag Fbs is ON (step S31). To Step S33), the gain K _str is set according to the change amount Δθ1 of the steering angle from the start of the control (Step S34). That is, when the lane departure prevention control is activated due to the lane departure tendency of the host vehicle and there is a rear side obstacle in the adjacent lane in the departure direction, the amount of change in the steering angle from the start of the control The gain K _str is set according to Δθ1. As a general rule, the gain K _str is set to a larger value as the steering angle change amount Δθ1 becomes larger. Then, the target yaw moment Ms is corrected using the gain K _str thus set (step S35). As a result, the target yaw moment Ms increases as the change amount Δθ1 of the steering angle from the start of control increases. At this time, the correction execution determination flag Fh is set to ON (step S36). If there is no such correction (if any of the determination processes in steps S31, S32, and S33 is “NO”), the target yaw moment Ms remains the value calculated in step S8. is there.

  Subsequently, in step S10, a control end gradient is set. FIG. 9 shows the procedure of this setting process. As shown in the figure, first, in step S41, it is determined whether or not the departure determination flag Fout is OFF. If the departure determination flag Fout is OFF (Fout = OFF), the process proceeds to step S42. If the departure determination flag Fout is ON (Fout = ON), the process shown in FIG. 9 (the process of step S10) is terminated.

In step S42, it is determined whether or not the correction execution determination flag Fh is ON. That is, it is determined whether or not the target yaw moment Ms has been corrected in step S9. If the correction execution determination flag Fh is ON, the process proceeds to step S43. Otherwise (Fh = OFF), the process proceeds to step S46.
In step S43, it is determined whether or not the target yaw moment Ms is greater than zero. If the target yaw moment Ms is greater than zero (Ms> 0), the process proceeds to step S44. Otherwise (Ms = 0), the process proceeds to step S46.

In step S44, the control end gradient is set in accordance with the amount of change in the steering angle from the end of control (when Fout changes from ON to OFF). Specifically, the control end gradient is increased as the change amount of the steering angle from the start of control increases. Figure 10 shows an example of the relationship between the change amount Δθ2 of the steering angle from the end of the lane departure prevention control and the control ends gradient L _DEC. As shown in the figure, in the region where the steering angle change amount Δθ2 is small, the control end gradient L _DEC has a small value. When the steering angle change amount Δθ2 reaches a certain value, the control end gradient L _DEC increases with the steering angle change amount Δθ2. When the steering angle change amount Δθ2 is reached, the control end gradient L _DEC becomes a constant large value. Thus, as a rule, the control end gradient L _DEC increases as the steering angle change amount Δθ2 increases. Thus, the control end gradient L _DEC is set, and the process proceeds to step S45.
Note that the steering angle change amount Δθ2 here is related to the return steering because the driver normally performs the return steering to return the vehicle to the own lane at the end of the lane departure prevention control. become.

Further, when it is determined in step S42 that the correction execution determination flag Fh is ON, or in step S46 that proceeds when the target yaw moment Ms is zero in step S43, the normal control end gradient _LDEC is set. For example, the normal control end gradient L _DEC is a value equal to or smaller than the control end gradient L _DEC set when the steering angle change amount θ2 is zero in the step S44. Further, if the target yaw moment Ms is zero (if “No” in the determination process in step S43), the control end process using the control end gradient L _DEC can be omitted.

Subsequently, in Step S45, it corrects the control slope of the lane departure prevention control using the control end gradient L _DEC set in the step S44 or step S46. Specifically, the target yaw moment Ms is calculated by the following equation (6).
Ms = Ms−L _DEC (6)
Here, when the control end gradient L _DEC is set in the step S44 (assuming Fh = ON), the target yaw moment Ms is corrected in the step S9. Therefore, the target calculated by the equation (6) is used. yaw moment Ms becomes so the target yaw moment Ms is corrected to a value obtained by subtracting the control ends gradient L _DEC.

When the departure determination flag Fout is OFF, the correction execution determination flag Fh is ON, and the target yaw moment Ms is greater than zero by the processing in step S10 (FIG. 9) (steps S41 to S43). ), The control end gradient L _DEC is set according to the steering angle change Δθ2 from the end of the control (step S44). That is, if the target yaw moment Ms is corrected on the assumption that there is a rear side obstacle (rear side vehicle) in the adjacent lane in the departure direction in step S9, the target yaw moment Ms is larger than zero. The control end gradient L _DEC is set according to the amount of change Δθ2 in the steering angle from the end of the control. As a general rule, the control end gradient L _DEC is set to a larger value as the steering angle change amount Δθ2 increases. At the end of the control, a process for reducing the target yaw moment Ms is performed using the control end gradient L _DEC set as described above (step S45). Thus, as the change amount Δθ2 of the steering angle from the end of the control increases, the reduction rate of the target yaw moment Ms at the end of the control increases.

If there is no rear side obstacle in the adjacent lane in the departure direction and the target yaw moment Ms is not corrected (in the case of “NO” in the determination process of step S42), the control ends (at the normal end) The target yaw moment Ms of) decreases with the normal control end gradient _LDEC . As described above, when the control end gradient L _DEC is set based on the change amount Δθ2 of the steering angle from the end of the control, the reduction rate of the target yaw moment Ms is the target yaw at the normal end. It always becomes larger than the decreasing rate of the moment Ms. That is, the control end gradient always increases.

  Note that the lane departure prevention control ends when the departure determination flag Fout changes from ON to OFF, but the lateral position at the end of the control is usually different from the lateral position at the start of the control. This is because in the present embodiment, the presence or absence of a deviation tendency is determined based on the forward gazing point (step S3). Normally, the lateral position at the end of control is the lateral position at the start of control. Than outside.

Subsequently, in step S11, deceleration of deceleration control performed as lane departure prevention control is calculated. In the present embodiment, the braking force generated in both the left and right wheels is calculated in order to realize the deceleration. Specifically, target braking hydraulic pressures Pgf and Pgr for generating such a braking force on both the left and right wheels are calculated. With respect to the target braking hydraulic pressure Pgf for the front wheels, the estimated lateral displacement Xs and lateral displacement limit distance X _L calculated in step S3 and the deceleration control determination threshold value Xβ obtained in step S7 are as follows ( 7) Calculate according to the equation.
Pgf = Kgv · Kgx · (| Xs | −X _L −Xβ) (7)

  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. 11 shows an example of the conversion coefficient Kgv. As shown in the figure, for example, the conversion coefficient Kgv has a small value in the low speed range. When the vehicle speed V reaches a certain value, the conversion coefficient Kgv increases with the vehicle speed V. When the vehicle speed V is reached thereafter, the conversion coefficient Kgv becomes a large 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.

Subsequently, in step S12, a target brake hydraulic pressure for each wheel is calculated. That is, the final braking fluid pressure is calculated based on the presence or absence of braking control for preventing lane departure. Specifically, it is calculated as follows.
When the departure determination flag Fout is OFF, that is, when the determination result that there is no lane departure tendency is obtained, as shown in the following equations (8) and (9), the target brake fluid pressure Psi (i = fl, fr, rl, rr) are set to the brake fluid pressures Pmf, Pmr.
Psfl = Psfr = Pmf (8)
Psrl = Psrr = Pmr (9)
Here, Pmf is the brake fluid pressure for the front wheels. Further, Pmr is the braking fluid pressure for the rear wheels, and is a value calculated based on the braking fluid pressure Pmf for the front wheels in consideration of the front-rear distribution. For example, if the driver is operating a brake, the brake fluid pressures Pmf and Pmr are values corresponding to the amount of brake operation (master cylinder fluid pressure Pm).

On the other hand, when the departure determination flag Fout is ON, that is, when the determination result that the lane departure tendency is generated is obtained, first, based on the target yaw moment Ms, the front wheel target braking fluid pressure difference ΔPsf and the rear wheel target braking fluid The pressure difference ΔPsr is calculated. Specifically, the target braking hydraulic pressure differences ΔPsf and ΔPsr are calculated by the following equations (10) to (13).
If | Ms | <Ms1, ΔPsf = 0 (10)
ΔPsr = Kbr · Ms / T (11)
When | Ms | ≧ Ms1 ΔPsf = Kbf · (Ms / | Ms |) · (| Ms | −Ms1) / T (12)
ΔPsr = Kbr · (Ms / | Ms |) · Ms1 / T (13)
Here, Ms1 represents a setting threshold value. T represents a tread. The tread T has the same value before and after for convenience. Kbf and Kbr are conversion coefficients for the front wheels and the rear wheels when the braking force is converted into the braking hydraulic pressure, and are determined by the brake specifications.

  Thus, the braking force generated on the wheels is distributed according to the magnitude of the target yaw moment Ms. When the target yaw moment Ms is less than the setting threshold value Ms1, the front wheel target braking hydraulic pressure difference ΔPsf is set to zero, a predetermined value is given to the rear wheel target braking hydraulic pressure difference ΔPsr, and a braking force difference is generated between the left and right rear wheels. Let 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 brake 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 with reference to the deceleration control operation determination flag Fgs obtained in step S7.

That is, when the departure determination flag Fout is ON, that is, the determination result that the lane departure tendency is generated, when the deceleration control operation determination flag Fgs is OFF, that is, only the yaw moment is applied to the vehicle. When performing, the target brake hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated by the following equation (14).
Psfl = Pmf
Psfr = Pmf + ΔPsf
Psrl = Pmr
Psrr = Pmr + ΔPsr
(14)

When the departure determination flag Fout is ON and the deceleration control operation determination flag Fgs is ON, that is, when the vehicle is decelerated while giving a yaw moment to the vehicle, the target of each wheel is expressed by the following equation (15). The brake fluid 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
(15)

  Further, as shown in the equations (14) and (15), the brake operation by the driver, that is, the target brake fluid pressure Psi (i = fl, fr, rl) of each wheel in consideration of the brake fluid pressures Pmf, Pmr. , Rr). Then, the braking / driving force control unit 8 uses the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) calculated for each wheel thus calculated as a braking fluid pressure command value to the braking fluid pressure control unit 7. Output.

Note that the target braking hydraulic pressures of the wheels shown in the equations (14) and (15) show that when the departure direction Dout is left (Dout = left), that is, a lane departure tendency occurs with respect to the left lane. If it is. For example, when the departure direction Dout is right, the target brake hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel corresponding to the equation (14) is calculated by the following equation (16).
Psfl = Pmf + ΔPsf
Psfr = Pmf
Psrl = Pmr + ΔPsr
Psrr = Pmr
... (16)

(Operation and action)
While the vehicle is traveling, various data are read (step S1) and the vehicle speed V is calculated (step S2). Further, the departure tendency is determined based on the estimated lateral displacement Xs (departure determination flag Fout is set, step S3). Further, a rear side obstacle is detected (a rear side obstacle detection judgment flag Fbs is set, step S4). Then, the driver's intention to change the lane is detected from the steering operation or the like, and the determination result of the departure tendency is changed based on the detection result (the departure determination flag Fout is changed, step S5). At this time, even when it can be determined that the driver is intentionally changing the lane, when an obstacle on the rear side is detected in the lane to be changed (when Fbs = ON), The departure determination flag Fout is not changed to OFF.

  On the other hand, on the basis of the estimated lateral displacement Xs, deceleration control operation determination is performed (deceleration control operation determination flag Fgs is set, step S7), and deceleration of the deceleration control is calculated (step S11). Further, the target yaw moment Ms is calculated based on the estimated lateral displacement Xs (step S8), and the target yaw moment Ms is corrected as appropriate (step S9).

Then, an alarm is output based on the state of the departure determination flag Fout (step S6). Further, based on the states of the departure determination flag Fout and the deceleration control operation determination flag Fgs, the target braking fluid pressure Psi (i = fl, fr) of each wheel based on the target yaw moment Ms and the deceleration (target braking fluid pressure Pgf). , Rl, rr), and outputs the calculated target brake fluid pressure Psi (i = fl, fr, rl, rr) of each wheel to the brake fluid pressure control unit 7 (step S12). Thereby, a yaw moment is given to the own vehicle according to the lane departure tendency of the own vehicle, and the own vehicle is decelerated depending on the case. When the end timing of the lane departure prevention control is reached (Fout = OFF), the target yaw moment Ms is decreased with a predetermined control end gradient L _DEC as the control end process (step S10). That is, the braking force or the braking fluid pressure is decreased.

  In the lane departure prevention control as described above, the lane departure prevention control is not activated when the driver's intention to change the lane is detected when the lane departure tendency is occurring (Fout is switched from ON to OFF). To change). However, even if a driver's intention to change lanes is detected when a lane departure tendency occurs, the lane departure prevention control is activated when an obstacle is detected at the rear side of the host vehicle. (Fout is kept ON). As a result, even when the driver is not aware of the vehicle traveling behind the host vehicle and intends to change the lane to the lane on which the vehicle is traveling, the yaw moment is applied to the host vehicle by the lane departure prevention control. It is possible to prevent the host vehicle from approaching a vehicle traveling on the rear side. Furthermore, the driver can notice the presence of the vehicle on the rear side through the change in the behavior of the host vehicle due to the application of the yaw moment.

  In the lane departure prevention control, the target yaw moment Ms is increased as the steering angle change Δθ1 from the start of the control increases. FIG. 12 shows the vehicle behavior of the host vehicle 100 during lane departure prevention control. As shown in the figure, in the lane departure prevention control when an obstacle is detected on the rear side of the host vehicle (Fout = ON and Fbs = ON), the amount of change Δθ1 in the steering angle from the start of the control is The larger the value is, the larger the target yaw moment Ms is.

As a result, even if the driver continues steering operation without recognizing the existence of a vehicle traveling on the rear side, the yaw moment adapted to such a situation is applied to the host vehicle. Can be granted. As a result, the host vehicle can be appropriately prevented from approaching the rear side traveling vehicle, and the driver can be appropriately made aware of the presence of the rear side vehicle.
Meanwhile, in the lane departure prevention control, when the control end, thereby reducing the target yaw moment Ms with a control end gradient L _DEC. At this time, as shown in FIG. 12, if the rear yaw obstacle is detected in the adjacent lane in the departure direction and the target yaw moment Ms is corrected, the control end gradient L _{DEC is set} to the normal one. Smaller than that. In addition, the control end gradient L _DEC is increased as the steering angle change amount Δθ2 from the end of the control increases.

As described above, when a rear side obstacle is detected in the adjacent lane in the departure direction, the target yaw moment Ms is increased in accordance with the amount of change Δθ1 in the steering angle from the start of control. For this reason, when the lane departure prevention control is subsequently ended, the target yaw moment Ms is increased according to the steering angle change Δθ1 from the start of the control at the end of the control. Therefore, if the target yaw moment Ms is decreased with the normal control end gradient L _DEC from the end of the lane departure prevention control, there is a high possibility that the host vehicle will return too much into the lane.

For this reason, if the rear yaw obstacle is detected in the adjacent lane in the departure direction and the target yaw moment Ms is corrected, the control end gradient L _DEC is made smaller than that in the normal time. Yes. Thereby, it can prevent that the own vehicle returns too much into the own lane. Further, as the change amount Δθ2 of the steering angle from the end of the control increases, the control end gradient L _DEC is increased, so that the target yaw moment Ms is reduced by adapting to the driver's large return steering. be able to. As a result, even when the driver steers largely back, the host vehicle can be properly returned to the host lane.

FIG. 13 shows the change over time of the target yaw moment Ms. As shown in the figure, when a rear side obstacle is detected in the adjacent lane in the departure direction, the target yaw moment Ms is changed from the control start time at the end of the lane departure prevention control (Fout = OFF). It increases corresponding to the change amount Δθ1 of the steering angle. As a result, if the target yaw moment Ms is decreased with the normal control end gradient L _DEC (solid line after Fout = OFF in the figure) from the end of the lane departure prevention control (after Fout = OFF in the figure). ), There is a high possibility that the host vehicle will return too much into the lane. On the other hand, when the target yaw moment Ms is corrected by detecting the rear side obstacle in the adjacent lane in the departure direction by applying the present invention, the control end gradient L _{DEC is set} to the normal time. It is smaller than the ones. Further, the control end gradient L _DEC is increased as the steering angle change amount Δθ2 from the end of the control increases (the one-dot chain line after Fout = OFF in the figure). As a result, it is possible to prevent the host vehicle from returning too much into the host lane, and even if the driver steers back greatly, the target yaw moment Ms is reduced and the host vehicle is reduced in the host lane. Can be properly returned to.

(Modification of the embodiment)
(1) In this embodiment, the degree of risk for a lane change is determined based on the direction of departure from the travel lane and the obstacles detected in the rear side of the host vehicle, particularly the vehicle. On the other hand, the obstacle can be a human or the like. In addition, the degree of risk with respect to lane change can be determined based on an object other than an obstacle, for example, a traveling environment.

(2) In this embodiment, when a rear side obstacle is detected in the lane to be changed (when Fbs = ON), that is, when the risk of changing the lane is high, the departure determination result of the departure determination result The flag Fout is not changed to OFF but is kept ON. In other words, the lane departure prevention control is activated (the operation is allowed) by maintaining the departure determination. On the other hand, the lane departure prevention control can be operated as long as the risk of lane change is high regardless of the departure determination result.

(3) In this embodiment, the departure determination flag Fout is changed from ON to OFF as suppression of lane departure prevention control. That is, the lane departure prevention control is not activated (discontinued). On the other hand, as control of lane departure prevention control, the control amount (for example, yaw moment) of lane departure prevention control can be reduced. Moreover, the operation timing of lane departure prevention control can be delayed as suppression of lane departure prevention control. That is, it is possible to delay the timing for turning on the departure determination flag Fout. Moreover, the operation time of lane departure prevention control can be shortened as suppression of lane departure prevention control.

(4) In this embodiment, the yaw moment is applied to the host vehicle due to the braking force difference. On the other hand, a yaw moment can be given to the own vehicle by a driving force difference or a steering operation.
In this embodiment, the process of step S3 of the braking / driving force control unit 8 realizes a lane departure tendency determination means for determining the departure tendency of the host vehicle with respect to the traveling lane. Further, the processing of step S12 of the braking / driving force control unit 8 performs lane departure prevention control for preventing the departure of the host vehicle from the traveling lane when the lane departure tendency determining means determines that a lane departure tendency has occurred. The deviation prevention control means to perform is realized. Further, the process of step S5 of the braking / driving force control unit 8 realizes a lane change intention detecting means for detecting the driver's intention to change the lane in the direction in which the tendency to deviate from the traveling lane. Yes. Further, the processes of steps S4, S5 and S9 of the braking / driving force control unit 8 determine the degree of risk of the lane change when the lane change intention detection means detects the driver's intention to change the lane. When the risk determination means determines that the risk is high, the lane departure prevention control is activated, and when the risk determination means determines that the risk is low, the lane departure prevention control is suppressed. Control correction means is realized.

  Further, in this embodiment, when it is determined that the own vehicle has a tendency to deviate from the traveling lane, and the driver's intention to change the lane in the direction in which the deviating tendency occurs is detected, A lane departure prevention method that activates a lane departure prevention control that prevents a deviation of the host vehicle from the traveling lane if the lane change risk is high, and suppresses the lane departure prevention control if the lane change risk is low. Realized.

(Effect in embodiment)
(1) Even when it can be determined that the driver is intentionally trying to change lanes, when an obstacle on the rear side is detected in the lane to be changed (when Fbs = ON), The departure determination flag Fout is not changed to OFF. Thus, the lane departure prevention control is activated. That is, when the risk determination means detects the driver's intention to change lanes in a direction in which a tendency to deviate from the traveling lane, the risk determination means determines the degree of risk of the lane change. The control correction means activates the lane departure prevention control when it is determined that the risk is high. Further, when it is determined that the risk is low, the control correction unit suppresses the lane departure prevention control. As a result, the lane departure prevention control can be activated under a situation where the driver is likely to cancel the lane change, and the lane departure prevention control is performed under a situation where the driver is unlikely to cancel the lane change. Can be suppressed. As a result, it is possible to prevent the lane departure prevention control from causing the driver to feel uncomfortable.

(2) The ON state of the departure determination flag Fout is maintained or changed based on an obstacle on the rear side of the lane to be changed to determine the operation of the lane departure prevention control. That is, the degree of lane change risk is determined based on the information detected by the obstacle detection means in the direction of departure from the traveling lane and detected behind the host vehicle. Thereby, the degree of the risk of lane change can be appropriately determined by using the obstacle on the rear side of the host vehicle as a reference. Further, in the prior art, even when an obstacle exists behind the host vehicle, the lane departure prevention control is stopped when the driver's intention to change the lane such as a steering operation is detected. Such discontinuation of the lane departure prevention control gives the driver an uncomfortable feeling. However, the lane departure prevention control can be stopped without giving the driver a sense of incongruity by appropriately determining the degree of lane change risk based on the obstacles behind the host vehicle.

(3) The obstacle detection means detects the presence of an obstacle behind the host vehicle. When the presence of an obstacle on the rear side is detected in the lane to be changed (if Fbs = ON), the departure determination flag Fout is not changed to OFF (maintained ON), Lane departure prevention control is activated. Further, when the presence of an obstacle on the rear side is not detected in the lane to be changed (when Fbs = OFF), the departure judgment flag Fout is changed to OFF so that the lane departure prevention control is not activated. I have to. That is, when the presence of an obstacle on the rear side of the host vehicle is detected, it is determined that the risk of lane change is high, and when the presence of an obstacle on the rear side of the host vehicle is not detected, the lane change is performed. The risk is determined to be low. Thereby, the degree of the risk of lane change can be appropriately determined by using the detection state of the obstacle on the rear side of the host vehicle as a reference.

(4) The obstacle detection means detects at least one of the distance and relative speed between the obstacle on the rear side of the host vehicle and the host vehicle. Then, the rear side obstacle detection determination flag Fbs is set based on at least one of the distance and the relative speed between the rear side obstacle and the own vehicle. That is, the degree of lane change risk is determined based on at least one of the distance and relative speed between the obstacle behind the host vehicle and the host vehicle. Accordingly, it is possible to appropriately determine the presence of an obstacle on the rear side of the host vehicle that determines whether the operation of the lane departure prevention control is enabled.

(5) In the lane departure prevention control in which the operation is maintained by detecting the obstacle on the rear side, the gain K _str is increased and the target yaw moment is increased as the change amount of the steering angle from the start of the control increases. Correction is performed to increase Ms. That is, when it is determined that the risk of lane change is high, the control amount of the lane departure prevention control increases as the steering wheel increases in the direction in which the departure tendency with respect to the traveling lane is increased. It is corrected to. As a result, even if the driver continues to steer the steering wheel without recognizing the presence of an obstacle on the rear side and continues to change lanes, the lane departure is controlled with a control amount adapted to such a situation. Prevention control is possible. Thereby, it is possible to appropriately prevent the host vehicle from approaching the obstacle on the rear side, and to appropriately notify the driver of the presence of the obstacle on the rear side.

(6) When the target yaw moment Ms is corrected by detecting the rear side obstacle in the adjacent lane in the departure direction, the control end gradient L _DEC is made smaller than that at the normal time. That is, when the lane departure prevention control is finished after correcting the control amount of the lane departure prevention control to be increased and increased as the steering amount increases, the lane departure prevention control is terminated more than when the lane departure prevention control is finished without performing the correction. Corrections are made so that the rate of decrease of the control amount increases. Thereby, it can prevent that the own vehicle returns too much into the own lane.

(7) The control end gradient L _DEC is increased as the amount of change Δθ2 in the steering angle from the end of the control increases. That is, the reduction rate of the control amount of the lane departure prevention control is increased as the steering wheel return steering amount in the direction of the own lane increases. As a result, even when the driver greatly steers back, the control amount of the lane departure prevention control can be reduced in conformity with the steering. As a result, even when the driver steers largely back, the host vehicle can be properly returned to the host lane.
(8) Based on the steering operation of the steering wheel, the driver's intention to change lanes is detected. Thereby, even when the driver changes the lane in the departure direction without operating the direction indicator, the driver's intention to change the lane can be detected.

It is a figure which shows the structure of the vehicle of embodiment of this invention. It is a flowchart which shows the process sequence of a braking / driving force control unit. It is a flowchart which shows the processing content of determination of the lane departure tendency by the braking / driving force control unit. It is a diagram used for explanation of the estimated lateral displacement Xs and deviation judgment threshold value X _L. FIG. 5 is a characteristic diagram showing a relationship between a travel lane curvature β and a deceleration control determination threshold value Xβ. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K2. It is a flowchart which shows the processing content of the correction | amendment of the target yaw moment by the braking / driving force control unit. FIG. 6 is a characteristic diagram showing a relationship between a steering angle change amount Δθ1 and a gain K _str from the start of lane departure prevention control. It is a flowchart which shows the processing content of the control end gradient setting by a braking / driving force control unit. It is a characteristic diagram showing the relationship between the amount of change Δθ2 of the steering angle from the end of the lane departure prevention control and the control ends gradient L _DEC. It is a characteristic view which shows the relationship between the vehicle speed V and the gain Kgv. It is a figure which shows the vehicle behavior by the lane departure prevention control to which this invention is applied. It is a characteristic view which shows the time-dependent change of the target yaw moment used for description of the comparison with a prior art example and the application example of this invention.

Explanation of symbols

  6FL to 6RR wheel cylinder, 7 braking fluid pressure control unit, 8 braking / driving force control unit, 9 engine, 12 driving torque control unit, 13 imaging unit, 14L, 14R radar device, 17 master cylinder pressure sensor, 18 accelerator opening sensor , 19 Steering angle sensor, 22FL-22RR Wheel speed sensor

Claims (9)

Lane departure tendency determination means for determining the departure tendency of the host vehicle with respect to the traveling lane;
When the lane departure tendency determining means determines that a departure tendency has occurred, a lane departure prevention device comprising lane departure prevention control means for performing lane departure prevention control for preventing the departure of the host vehicle from the traveling lane,
Furthermore, a lane change intention detection means for detecting a driver's intention to change lanes in a direction in which a deviation tendency is generated with respect to the travel lane,
When the lane change intention detection means detects the driver's intention to change lanes, a risk determination means for determining the degree of risk of the lane change;
When the risk determination means determines that the risk is high, the control correction means that operates the lane departure prevention control and suppresses the lane departure prevention control when the risk determination means determines that the risk is low;
A lane departure prevention apparatus comprising: An obstacle detection means for detecting information related to an obstacle on the rear side of the host vehicle in a departure direction with respect to the traveling lane;
2. The lane departure according to claim 1, wherein the risk determination unit determines the degree of the risk based on information on an obstacle behind the host vehicle detected by the obstacle detection unit. Prevention device. The obstacle detection means detects the presence of an obstacle behind the host vehicle,
The risk determination means determines that the risk is high when the obstacle detection means detects the presence of an obstacle on the rear side of the own vehicle, and the obstacle detection means determines that the obstacle detection means The lane departure prevention apparatus according to claim 2, wherein when the presence of a side obstacle is not detected, it is determined that the risk is low. The obstacle detection means detects either the distance and relative speed between the obstacle on the rear side of the host vehicle and the host vehicle,
The risk determining means determines the degree of the risk based on at least one of a distance and a relative speed between an obstacle on the rear side of the own vehicle detected by the obstacle detecting means and the own vehicle. The lane departure prevention apparatus according to claim 2 or 3, characterized in that   When the risk determination unit determines that the risk is high, the control correction unit increases the steering wheel in a direction in which the control amount of the lane departure prevention control is deviating from the traveling lane. The lane departure prevention device according to any one of claims 1 to 4, wherein the lane departure prevention device is corrected so as to increase as the steering amount increases.   The control correction means corrects the control amount of the lane departure prevention control so as to increase as the steering amount increases, and then ends the lane departure prevention control without performing the correction when ending the lane departure prevention control. 6. The lane departure prevention apparatus according to claim 5, wherein correction is performed such that the rate of decrease of the control amount is greater than when the control is finished.   The lane departure prevention apparatus according to claim 6, wherein the control correction means increases the decreasing rate of the control amount as the steering wheel switching back steering amount in the lane direction increases.   The lane departure prevention device according to any one of claims 1 to 7, wherein the lane change intention detection means detects the driver's intention to change lanes based on a steering operation of a steering wheel. .   When it is determined that the vehicle has a tendency to deviate from the driving lane, and the driver's intention to change the lane in the direction in which the tendency to deviate is detected, the risk of the lane change is increased. For example, a lane departure prevention method is provided which operates lane departure prevention control for preventing a departure of the host vehicle from the traveling lane, and suppresses the lane departure prevention control if the risk of lane change is low.

Images