JP4747935B2 - Lane departure prevention device - Google Patents

Description

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

The lane departure prevention apparatus disclosed in Patent Document 1 gives a yaw moment to the host vehicle when the host vehicle determines that the host vehicle tends to depart from the traveling lane, and the host vehicle deviates from the traveling lane. Is avoiding.
JP 2003-154910 A

However, when the vehicle lane departure prevention control is performed in a situation where the vehicle's yaw angle with respect to the traveling lane becomes large, such as when the vehicle is traveling along a curve entrance, the time for the lane departure prevention control is shorter than the yaw angle. The driver may feel that. That is, the time for which the lane departure prevention control is transmitted to the occupant as a feeling of control is shortened, and the lane departure prevention control gives the occupant a feeling of strangeness.
In addition, it is conceivable that the start timing of the lane departure prevention control is made earlier than usual so that the time during which the lane departure prevention control is transmitted to the occupant as a sense of control is increased. ), The frequency of execution of the lane departure prevention control increases, and the lane departure prevention control gives the passenger a sense of incongruity.
An object of the present invention is to make it possible to adapt lane departure prevention control to the sense of control of an occupant.

In order to solve the above-described problem, the lane departure prevention apparatus according to the present invention performs lane departure prevention control for preventing the host vehicle from deviating from the traveling lane, and has a tendency for the host vehicle to deviate from the traveling lane. Control means for ending the lane departure prevention control according to a predetermined end condition even when the lane departure prevention control is not resolved, own vehicle state detection means for detecting the own vehicle state after the start timing of the lane departure prevention control, and the own vehicle Based on the host vehicle state detected by the state detection unit, a departure tendency expansion degree estimation unit that estimates an expansion degree of the departure tendency of the host vehicle with respect to the traveling lane, and a degree of increase of the departure tendency estimated by the departure tendency expansion degree estimation unit based on, and a control end condition correcting means for correcting the predetermined end condition, the control termination condition correcting means, in the predetermined end condition That the control end position in the lateral direction with respect to the traffic lane in the lane departure prevention control, and to correct such a distance from the center of the traffic lane as the expansion degree is increased.

  According to the present invention, the lane departure prevention control is terminated in accordance with the degree of expansion of the departure tendency of the host vehicle after the start of the lane departure prevention control. Even when the lane departure prevention control is performed in a situation where the yaw angle of the host vehicle is large, the lane departure prevention control can be adapted to the sense of control of the occupant.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
(First embodiment)
(Constitution)
1st Embodiment of this invention is a rear-wheel drive vehicle carrying the lane departure prevention apparatus based on this invention. This rear-wheel drive vehicle is equipped with an automatic transmission and a conventional differential gear, and a braking device capable of independently controlling the braking force of the left and right wheels for both the front and rear wheels.

FIG. 1 is a schematic configuration diagram showing the first embodiment.
In the figure, reference numeral 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, and 4 is a reservoir. Normally, the brake fluid pressure boosted by the master cylinder 3 according to the amount of depression of the brake pedal 1 by the driver is shown. It supplies to each wheel cylinder 6FL-6RR of each wheel 5FL-5RR. Further, a braking fluid pressure control unit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL-6RR, and the braking fluid pressure control unit 7 individually controls the braking fluid pressure of each wheel cylinder 6FL-6RR. It is also possible to control.

The brake fluid pressure control unit 7 uses a brake fluid pressure control unit used in, for example, anti-skid control (ABS), traction control (TCS), or vehicle dynamics control device (VDC). The brake fluid pressure control unit 7 can control the brake fluid pressure of each of the wheel cylinders 6FL to 6RR independently, but when a brake fluid pressure command value is input from the braking / driving force control unit 8 described later, The brake fluid pressure is controlled according to the brake fluid pressure command value.
For example, the brake fluid pressure control unit 7 includes an actuator in the hydraulic pressure supply system. Examples of the actuator include a proportional solenoid valve capable of controlling each wheel cylinder hydraulic pressure to an arbitrary braking hydraulic pressure.

  The vehicle is provided with a drive torque control unit 12. The drive torque control unit 12 controls the drive torque to the rear wheels 5RL and 5RR which are drive wheels by controlling the operating state of the engine 9, the selected gear ratio of the automatic transmission 10, and the throttle opening of the throttle valve 11. To do. The drive torque control unit 12 controls the operating state of the engine 9 by controlling the fuel injection amount and ignition timing, and simultaneously controlling the throttle opening. The drive torque control unit 12 outputs the value of the drive torque Tw used for control to the braking / driving force control unit 8.

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

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

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

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

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

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

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

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

Subsequently, in step S2, the vehicle speed V is calculated. Specifically, the vehicle speed V is calculated by the following equation (2) based on the wheel speed Vwi read in step S1.
For front wheel drive V = (Vwr1 + Vwrr) / 2
For rear wheel drive V = (Vwfl + Vwfr) / 2
... (1)
Here, Vwfl and Vwfr are the wheel speeds of the left and right front wheels, and Vwrl and Vwrr are the wheel speeds of the left and right rear wheels. That is, in the equation (1), the vehicle speed V is calculated as 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. For example, when an ABS (Anti-lock Brake System) control or the like is operating, an estimated vehicle speed estimated in the ABS control is used as the vehicle speed V.
Subsequently, in step S3, the yaw angle φ _front is calculated. Specifically, the yaw angle φ _front of the _host vehicle with respect to the far white line detected by the imaging unit 13 is calculated.

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

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

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

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

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

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

Subsequently, in step S6, the deviation tendency of the host vehicle from the traveling lane is determined. Specifically, by comparing the estimated lateral displacement Xs obtained in step S4, the threshold value X _L for determining the tendency to deviate is a lateral displacement limit distance used for calculation of the reference yaw moment Ms0 in step S5 , Determine the tendency to deviate. FIG. 4 shows the definition of values used in this process.

The departure tendency determination threshold value (lateral displacement limit distance) _XL is generally a value that can be grasped when the vehicle has a lane departure tendency, and is obtained as an experience value, an experimental value, or the like. For example, the departure tendency determination threshold value _XL is a value indicating the position of the boundary line of the traveling lane, and is calculated by the following equation (5).
X _L = (L−H) / 2 (5)
Here, L is the lane width of the travel lane (width between white lines forming the travel lane), and H is the width of the vehicle. The lane width L is obtained by processing the captured image by the imaging unit 13.

Then, when the estimated lateral displacement Xs is greater than or departure-tendency threshold value _{X L (| Xs | ≧ X} L), it is determined that there is a lane departure tendency, setting the departure flag Fout ON, the estimated lateral displacement If Xs is less than departure-tendency threshold value _{X L (| Xs | <X} L), it is determined that no lane departure tendency, setting the departure flag Fout to OFF.
Note that the lane departure tendency may be determined using the actual lateral displacement _Xfront (estimated lateral position Xs when Tt = 0) instead of the estimated lateral position Xs. In this case, when the actual lateral displacement _{X front} of or departure-tendency threshold value _{X L (| X front | ≧} X L), it is determined that there is a lane departure tendency, setting the departure flag Fout is turned ON .

Further, as a condition for enabling the departure determination flag Fout to be set to ON, after the departure determination flag Fout is set to OFF, the vehicle is not in a departure state ((| Xs | <X _L ) or (| X _front | <X _L )). In addition, as a condition that allows the departure determination flag Fout to be set to ON, a time condition such as a predetermined time has elapsed after the departure determination flag Fout is set to OFF can be added.

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

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

When the direction indicating switch 20 is not operated, the departure determination flag Fout is finally set based on the steering angle δ. That is, when the driver is steering in the departure direction, the driver is conscious when both the steering angle δ and the change amount of the steering angle (change amount per unit time) Δδ are equal to or greater than the set value. It is determined that the lane has changed, and the departure determination flag Fout is changed to OFF.
Subsequently, in step S7, the end timing of the output (giving) of the yaw moment to the host vehicle by the lane departure prevention control is determined.

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

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

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

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

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

  The increase side change limiter Lup, the maximum value limiter Lmax, and the decrease side change amount limiter Ldown are set as default values, and the set increase side change limiter Lup, maximum value limiter Lmax, and decrease side change limiter Ldown are set. The reference yaw moment Ms0 limited by the above is calculated as the target yaw moment Ms.

FIG. 7 shows a result obtained by limiting the reference yaw moment Ms0 with these limiters Lup, Lmax, and Ldown, that is, the target yaw moment Ms.
When the increase side change limiter Lup is small, the increase side inclination (increase rate) of the target yaw moment Ms is small, and when the decrease side change limiter Ldown is small, the decrease side inclination (decrease) of the target yaw moment Ms is reduced. Ratio) becomes smaller.

  Subsequently, in step S9, the end timing (predetermined end condition) of the output (giving) of the yaw moment to the host vehicle by the lane departure prevention control is corrected. Specifically, when the vehicle is in a departure state (when departure is determined), the degree of departure enlargement (the degree of departure increase) is predicted, and the yaw moment output is based on the degree of departure enlargement. Correct the end timing. FIG. 8 shows the processing procedure.

  As shown in FIG. 8, when the process is started, first, in step S21, it is determined whether or not the vehicle is in a lane departure state (whether lane departure has started). Specifically, it is determined whether or not the departure determination flag Fout set in step S6 has changed from OFF to ON. Here, the process of step S21 is repeated until it is determined that the vehicle is in a lane departure state (lane departure has started). If it is determined that the vehicle is in a lane departure state (lane departure has started), the process proceeds to step S22.

In step S22, the degree of deviation expansion of the host vehicle with respect to the travel lane is calculated (estimated) from the attitude of the host vehicle with respect to the travel lane (white line) at the time when it is determined in step S21 that the vehicle is in a lane departure state. Here, first, the yaw angle _φdepart formed by the traveling lane (white line) and the host vehicle is detected. The yaw angle _φdepart is detected by the imaging unit 13 ( _φdepart = _φfront ). Based on the detected yaw angle _φdepart , an estimated deviation expansion degree _EXdepart is set. Here, the estimated deviation expansion degree EX _department is a subsequent deviation expansion degree estimated when the _host vehicle is in a lane departure state.

FIG. 9 shows an example of the relationship between the yaw angle _φdepart and the estimated deviation expansion degree _EXdepart . As shown in FIG. 9, the yaw angle _φdepart and the estimated deviation expansion degree _EXdepartment are in a proportional relationship. With reference to such a characteristic diagram, the estimated deviation expansion degree EX _department is set based on the yaw angle _φdepart .
Thus, for example, as shown in FIG. 10, in the traveling state of the _host vehicle 101 in (a), the yaw angle φ _depart is φ _depart 1, and at this time, the estimated deviation corresponds to the yaw angle φ _depart. expanding degree _{EX depart} is set to estimated departure expanding degree _{EX depart} 1, the self as shown in the running condition of the vehicle 101, the yaw angle is greater than the yaw angle phi _depart 1 of the yaw angle phi _depart is (a) of (b) phi becomes the _{depart 2 (> φ depart 1)} , in accordance with the yaw angle phi _depart 2, estimated departure expanding degree _{EX depart} is estimated departure expanding degree _{EX depart} 1 large estimated departure expanding degree than _{EX depart} of (a) 2 (> EX _department 1).

Subsequently, in step S23, the control range of the lane departure prevention control (output end determination threshold value X _end ) set in step S7 is corrected based on the estimated departure enlargement degree EX _department set in step S22. Specifically, a gain K _wlimt for correcting the control range of the lane departure prevention control is calculated based on the estimated departure expansion degree EX _depart .

Figure 11 shows an example of the relationship between the estimated departure expanding degree _{EX depart} and gain _{K wlimt.} As shown in FIG. 11, the estimated gain _{K Wlimt} deviations larger degree _{EX depart} in a small region becomes constant small value in _{(EX depart} = 1), becomes a certain value estimated departure expanding degree _{EX depart,} estimated departure expanding As the degree EX _depart increases, the gain K _wlimt also increases. Thereafter, when the estimated deviation expansion degree EX _depart reaches a certain value, the gain K _wlimt becomes a large value and becomes a constant value. Referring to such a characteristic diagram, it sets the gain _{K Wlimt} based on estimated departure expanding degree _{EX depart.}

Then, based on the set gain K _wlimit , the output end determination threshold value X _end is corrected, specifically, the control range (X _end −X _L = ls_w_LMT) is corrected by the following equation (6).
Control range (control area) = K _wlimt · (X _end −X _L ) (6)
As a result, when the gain K _wlimt increases, the control range is increased and corrected from 1 · (X _end −X _L ) (= 1 · ls_w_LMT) to K _wlimt · (X _end −X _L ) (K _wlimt · ls_w_LMT). The Accordingly, the control range becomes larger (wider) as the estimated deviation expansion degree _EXdepart increases, that is, as the yaw angle _φdepart at the start of lane departure increases. That is, the threshold value X _end increases output end judgment for defining the control range starting departure-tendency threshold value X _L.

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

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

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

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

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

When the departure determination flag Fout is ON and the departure direction Dout is RIGHT, that is, when there is a lane departure tendency with respect to the white line on the right side, the target braking fluid pressure Psi (i = i = fl, fr, rl, rr) are calculated.
Psfl = Pmf + ΔPsf
Psfr = Pmf
Psrl = Pmr + ΔPsr
Psrr = Pmr
(12)

According to the equations (11) and (12), the braking force difference between the left and right wheels is generated so that the braking force of the wheel on the lane departure avoidance side is increased.
Further, here, as shown in the equations (11) and (12), the brake operation by the driver, that is, the target brake fluid pressure Psi (i = fl, fr) of each wheel in consideration of the brake fluid pressures Pmf and Pmr. , Rl, rr). Then, the braking / driving force control unit 8 uses the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) calculated for each wheel thus calculated as a braking fluid pressure command value to the braking fluid pressure control unit 7. Output.

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

On the other hand, the reference yaw moment Ms0 is calculated (step S5), and the target yaw moment Ms is calculated by subjecting the calculated reference yaw moment Ms0 to limiter processing (step S8). Further, the output end determination threshold value X _end for determining the yaw moment output end timing is corrected (step S7) based on the estimated deviation expansion degree EX _depart according to the yaw angle _φdepart (step S9). ). That is, the yaw moment output end timing is corrected.

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

(Function and effect)
Next, functions and effects will be described.
(1) lane departure prevention control when not corrected control range (when the gain _{K Wlimt} is 1, i.e. if the estimated departure expanding degree _{EX depart} and yaw angle phi _depart is small)
FIG. 12 shows the control range of the lane departure prevention control (FIG. 12A), the control time of the lane departure prevention control (control continuation time or control execution time) T _con 1 (FIG. 12B), and the lane. The target yaw moment Ms change in the departure prevention control ((c) in the figure) is shown.

As shown in FIG. 12, the lane departure prevention control is started when the host vehicle 101 exceeds point A (departure tendency determination threshold value X _L ), and reaches point B (output end determination threshold value X _end ). Then, the lane departure prevention control is finished ((a) in the figure). That is, the lane departure prevention control is performed by setting the range from the point A to the point B as the control range ls_w_LMT.
Accordingly, the control time T _con 1 of the lane departure prevention control becomes a value corresponding to the control range ls_w_LMT ((b) in the figure), and a predetermined amount (in the same figure) corresponding to the control range ls_w_LMT or the control time T _con 1 The hatching portion (c) yaw moment Ms is applied to the host vehicle 101.

(2) Lane departure prevention control when the control range is corrected (when the gain K _wlimt is larger than 1, that is, when the estimated deviation expansion degree _EXdepart and the yaw angle _φdepart are large)
FIG. 13 shows the control range of the lane departure prevention control (FIG. 13A), the control time T _con 2 of the lane departure prevention control (FIG. 13B), and the target yaw moment Ms change in the lane departure prevention control. ((C) of the figure) is shown.
As shown in FIG. 13, the lane departure prevention control is started when the host vehicle 101 exceeds the point A (departure tendency determination threshold value X _L ), and the point C (substantially corrected output end determination is performed). When the threshold value X _end ) is reached, the lane departure prevention control is terminated ((a) in the figure). In other words, the lane departure prevention control is performed with the control range K _wlimt · ls_w_LMT (here, K _wlimt > 1) between point A and point C.

Thereby, the control time T _con 2 of the lane departure prevention control becomes a value corresponding to the corrected control range K _wlimt · ls_w_LMT ((b) in the figure), that is, the estimated deviation expansion degree EX _depart (yaw angle φ The control time T _con 1 is longer than the control time T _con 1 when ( _depart ) is small (T _con 2> T _con 1), and a predetermined amount of yaw moment Ms corresponding to the control range K _wlimt ls_w_LMT or the control time T _con 2 is 101 (FIG. 3C). Therefore, as can be seen from a comparison between FIG. 12C and FIG. 13C, the total amount of yaw moment Ms at this time (the hatched portion in FIG. 13C) is also the estimated deviation expansion degree EX _depart ( The total amount of yaw moment Ms when the yaw angle _φdepart ) is small (the hatched portion in FIG. 12C) is larger.

  It should be noted that the lapse of control time of lane departure prevention control (point B in FIG. 12 or point C in FIG. 13) may be considered as the end of yaw moment output (timing), but is given to the host vehicle as lane departure prevention control. The time point when the yaw moment to be performed becomes 0 may be considered as the end of the yaw moment output (timing). In other words, the elapsed time of the control time of the substantial lane departure prevention control may be considered as the time when the yaw moment applied to the host vehicle becomes zero as the lane departure prevention control.

As described above, as the yaw angle φ _depart at the start of lane departure or lane departure prevention control increases, the output end determination threshold value X _end corresponding to the lateral position with respect to the traveling lane is increased to increase the lane departure. The control range of the prevention control (the range in the lateral direction with respect to the driving lane) increases, the control time of the lane departure prevention control becomes longer, that is, the yaw moment output end timing becomes longer, or the yaw moment (control amount) of the lane departure prevention control ), The vehicle lane departure prevention control is performed even when the lane departure prevention control is performed in a situation where the vehicle yaw angle is large with respect to the traveling lane, such as when the host vehicle is traveling along a curve entrance. The lane departure prevention control can be adapted to the occupant's sense of control by suppressing the time that is transmitted to the occupant as a sense of control.

The first embodiment can also be realized by the following configuration.
In other words, in the first embodiment, the estimated deviation expansion degree _EXdepartment is set based on the yaw angle _φdepart (step S9). On the other hand, the estimated deviation expansion degree _EXdepart may be set based on the lateral speed Xv or lateral acceleration Xg (particularly the lateral speed or lateral acceleration at the start of lane departure or lane departure prevention control) with respect to the traveling lane. it can. Here, the lateral velocity Xv is obtained, for example, by differentiating the estimated lateral position Xs and the actual lateral displacement X _front .

FIG. 14 shows an example of the relationship between the lateral velocity Xv and the estimated deviation expansion degree _EXdepart . As shown in FIG. 14, the lateral velocity Xv and the estimated deviation expansion degree EX _department are in a proportional relationship. With reference to such a characteristic diagram, the estimated deviation enlargement degree EX _department is set based on the lateral velocity Xv.
Further, the estimated deviation expansion degree _EXdepart is obtained based on the yaw angle _φdepart at the start of the lane departure or at the start of the lane departure prevention control, the lateral speed Xv, etc., but after the start of the lane departure or during the lane departure prevention control. The estimated deviation expansion degree _EXdepart can be updated based on the yaw angle _φdepart , the lateral velocity Xv, and the like. For example, after the start of lane departure or during lane departure prevention control, the yaw angle φ _depart , the lateral speed Xv, etc. that change from time to time are detected by feedback processing, and the estimated deviation expansion degree EX _depart is updated based on the detected values Go. As a result, the yaw moment output end timing is corrected based on the latest estimated departure expansion degree _EXdepartment after the start of lane departure or during lane departure prevention control. In addition, the maximum value of the estimated deviation expansion degree _EXdepart after the start of the lane departure or during the lane departure prevention control is detected, and the yaw moment output end timing is corrected using the detected maximum estimated deviation expansion degree _EXdepart. You can also

Further, the target yaw angle (end yaw angle) at the end of the lane departure prevention control can be corrected by correcting the predetermined termination condition of the lane departure prevention control. For example, when the target yaw angle at the normal end of the lane departure prevention control is set to 0 °, the target yaw angle is corrected so as to become an angle inclined in the traveling lane as the estimated departure expansion degree EX _department increases.

  In the description of the first embodiment, the processing in FIG. 2 of the braking / driving force control unit 8 performs lane departure prevention control for preventing the own vehicle from deviating from the traveling lane and has a predetermined end. Control means for ending the lane departure prevention control according to conditions is realized, and the process of step S22 of the braking / driving force control unit 8 detects the host vehicle state after the start timing of the lane departure prevention control. Based on the own vehicle state detecting means and the own vehicle state detected by the own vehicle state detecting means, the deviation tendency enlargement degree estimating means for estimating the degree of enlargement of the departure tendency of the own vehicle with respect to the traveling lane is realized, The process of step S23 of the force control unit 8 is performed based on the degree of expansion of the departure tendency estimated by the departure tendency expansion degree estimation means. It is realized a control end condition correcting means for correcting the predetermined termination condition.

In the description of the first embodiment, the output end determination threshold value X _end increases as the estimated deviation increase degree EX _depart increases. As the degree of expansion of the departure tendency estimated by the estimation unit increases, the predetermined end condition is relaxed, and the control end condition correction unit corrects the end timing of the lane departure prevention control that is the predetermined end condition. And the control end condition correcting means corrects the control end position in the lateral direction with respect to the travel lane of the lane departure prevention control which is the predetermined end condition.
Further, the first embodiment realizes that the lane departure prevention control is terminated in accordance with the degree of expansion of the departure tendency of the host vehicle with respect to the traveling lane after the start of the lane departure prevention control.

(Second Embodiment)
Next, a second embodiment will be described.
(Constitution)
Similar to the first embodiment, the second embodiment is a rear wheel drive vehicle equipped with the lane departure prevention apparatus according to the present invention.
In the second embodiment, the processing procedure of the arithmetic processing performed by the braking / driving force control unit 8 is the same as the processing procedure shown in FIG. 2 and is the same processing procedure as in the first embodiment. The correction of the yaw moment output end timing in step S9 is different from that in the first embodiment.
That is, in the second embodiment, in step S9, the yaw moment output end timing is corrected by correcting the decreasing side change amount limiter Ldown set in step S8.

FIG. 15 shows a processing procedure for correcting the yaw moment output end timing in the second embodiment.
As shown in FIG. 15, first, similarly to the first embodiment, in step S21, it is determined whether or not the vehicle is in a lane departure state (lane departure has started), and in the subsequent step S22, the estimated departure is determined. Sets the degree of enlargement _EXdepart .
Then, in the second embodiment, subsequently at step S31, based on the estimated departure expanding degree _{EX depart} set at step S22, it corrects the decreasing side variation limiter Ldown. Specifically, with the gain _{K Ldown} in accordance with the estimated departure expanding degree _{EX depart,} it corrects the decreasing side variation limiter Ldown based on the gain _{K Ldown.}

Figure 16 shows an example of the relationship between the estimated departure expanding degree _{EX depart} and gain _{K Ldown.} As shown in FIG. 16, the estimated gain _{K Ldown} deviations larger degree _{EX depart} in a small region is a constant large value in _{(EX depart} = 1), it becomes a certain value estimated departure expanding degree _{EX depart,} estimated departure expanding As the degree EX _depart increases, the gain K _ldown decreases, and when the estimated deviation expansion degree EX _depart reaches a certain value, the gain K _ldown becomes a small value and a constant value. Referring to such a characteristic diagram, it sets the gain _{K Ldown} based on estimated departure expanding degree _{EX depart.}

Then, based on the set gain gain K _ldown , the decrease side change limiter Ldown is corrected by the following equation (13).
Ldown = _Kldown · Ldown (13)
As a result, when the gain K _ldown increases, the decrease side change limiter Ldown is corrected to decrease. Thus, the larger the estimated departure expanding degree _{EX depart,} i.e., the larger the yaw angle phi _depart at lane departure start, decrease-side variation limiter Ldown is small. In the second embodiment, the yaw moment output end timing is corrected by correcting the decrease on the decrease side change amount limiter Ldown in this manner.

FIG. 17 shows the target yaw in the lane departure prevention control when the yaw moment output end timing is corrected by correcting the decrease side change amount limiter Ldown (when the estimated departure expansion degree _EXdepart and the yaw angle _φdepart are large). The change of moment Ms is shown. In the second embodiment, since the control range ls_w_LMT is not corrected, the control range of the lane departure prevention control is as shown in FIG. 12A, and the control time of the lane departure prevention control is as shown in FIG. As shown in (b). However, the target yaw moment Ms (FIG. 17) in the lane departure prevention control in the second embodiment is different from that in FIG. 12 (c).

  In other words, the decrease-side change amount limiter Ldown is corrected so that the decrease-side inclination of the target yaw moment Ms in the second embodiment is the same as the decrease-side inclination of the target yaw moment Ms in FIG. As can be seen from the comparison, it becomes smaller. Thereby, the yaw moment output end timing, that is, the time until the target yaw moment Ms becomes 0 becomes longer.

Thus, lane departure beginning or the lane departure prevention control at the start of the yaw angle phi _depart increases, by decreasing the decreasing side variation limiter Ldown, a longer control time of lane departure prevention control, or the lane Since the total amount of yaw moment (control amount) for departure prevention control is increased, lane departure prevention control was performed in a situation where the yaw angle of the host vehicle increased with respect to the traveling lane, such as when the host vehicle traveled along a curve entrance. Even in this case, it is possible to suppress the time that the lane departure prevention control is transmitted to the occupant as a control feeling, and to adapt the lane departure prevention control to the occupant control feeling.

The second embodiment can also be realized by the following configuration.
That is, in the second embodiment, since it is assumed that the decrease side change limiter Ldown is corrected, in the limit process performed in step S8, at least only the decrease side change limiter Ldown (decrease side change limiter Ldown). The target yaw moment Ms may be calculated by setting only Ldown as a default value).

In the description of the second embodiment, the larger the estimated departure expanding degree EX _depart, to reduce the decrease side variation limiter Ldown, the control means, during the lane departure prevention control of the lane departure prevention control When the control amount is continuously changed and the control amount is decreased at the end of the lane departure prevention control, the control end condition correction means corrects the decrease rate that is a predetermined end condition. Has realized that.

(Third embodiment)
Next, a third embodiment will be described.
(Constitution)
Similar to the first embodiment, the third embodiment is a rear wheel drive vehicle equipped with the lane departure prevention apparatus according to the present invention.
In the third embodiment, the processing procedure of the arithmetic processing performed by the braking / driving force control unit 8 is the same as the processing procedure shown in FIG. 2 and is the same processing procedure as in the first embodiment. The correction of the yaw moment output end timing in step S9 is different from that in the first embodiment.
That is, in the second embodiment, the yaw moment output end timing is corrected in step S9 by maintaining (holding) the reference yaw moment Ms0 at the end of the lane departure prevention control for a predetermined time.

FIG. 18 shows a processing procedure for correcting the yaw moment output end timing in the third embodiment.
As shown in FIG. 18, first, similarly to the first embodiment, in step S21, it is determined whether or not the vehicle is in a departure state (lane departure has started), and in step S22, the estimated departure is enlarged. The degree EX _department is set.
In the third embodiment, subsequently, in step S41, the yaw moment at the end of the lane departure prevention control (specifically, the target yaw moment) is determined based on the estimated departure expansion degree _EXdepart set in step S22. Ms0) hold time (hold time) is set.

Figure 19 shows an example of the relationship between the estimated departure expanding degree _{EX depart} the holding time _{T hold.} As shown in FIG. 19, in a region where the estimated deviation expansion degree _EXdepart is small, the holding time _Thold is 0, and when the estimated deviation expansion degree _EXdepart has a certain value, the holding time T is increased with the increase in the estimated deviation expansion degree _{EXdepart. Hold} also increases, and when the estimated deviation expansion degree EX _department reaches a certain value, the holding time T _hold becomes a large value and a constant value. With reference to such a characteristic diagram, the holding time T _hold is set based on the estimated deviation expansion degree EX _department .

  Subsequently, in step S42, it is determined whether or not the departure determination flag Fout has changed from ON to OFF. Here, when the departure determination flag Fout is turned from ON to OFF, that is, when it is the end timing of the lane departure prevention control, the process proceeds to step S43. Otherwise (the departure determination flag Fout is kept ON). ), The process starts again from step S21.

  In step S43, it is determined to hold the reference yaw moment Ms0 calculated in step S5 for the holding time Thold set in step S41 (hold the previous value). As a result, the reference yaw moment Ms0 at the time when the departure determination flag Fout changes from ON to OFF is held for the holding time Thold, and based on the held reference yaw moment Ms0, the vehicle is controlled as lane departure prevention control. A yaw moment is applied.

In the third embodiment, the reference yaw moment Ms0 at the time when the departure determination flag Fout is changed from ON to OFF is not decreased as described above, and is held as it is for the holding time Thold, and the held reference yaw moment is maintained. A yaw moment is applied to the host vehicle based on Ms0.
FIG. 20 shows a change in the target yaw moment Ms at that time. In the third embodiment, since the control range ls_w_LMT is not corrected, the control range of the lane departure prevention control is as shown in FIG. 12A, and the control time of the lane departure prevention control is as shown in FIG. As shown in (b). However, the target yaw moment Ms (FIG. 17) in the lane departure prevention control in the third embodiment is different from FIG. 12 (c).

That is, by maintaining the reference yaw moment Ms0 for the holding time Thold from the time when the departure determination flag Fout is turned from ON to OFF, as can be seen from comparison with the target yaw moment Ms of FIG. The output time of the target yaw moment Ms becomes longer according to the holding time Thold.
As described above, the larger the yaw angle phi _depart at lane departure start or the lane departure prevention control starting, by increasing the holding time Thold, a longer control time of lane departure prevention control, or the lane departure prevention control Because the total amount of yaw moment (control amount) increases, even when the lane departure prevention control is performed in a situation where the yaw angle of the host vehicle is large relative to the traveling lane, such as the host vehicle traveling at the entrance of the curve, It is possible to suppress the time that the lane departure prevention control is transmitted to the occupant as a control feeling, and to adapt the lane departure prevention control to the occupant control feeling.

The third embodiment can also be realized by the following configuration.
That is, in the third embodiment, the total amount of yaw moment is corrected by increasing the holding time Thold. On the other hand, the total amount of braking force and brake fluid pressure for applying the yaw moment can be corrected. That is, the holding time is determined by focusing on the braking force and the brake hydraulic pressure, not the yaw moment.

In the description of the third embodiment, the larger the estimated departure expanding degree EX _depart, prolonging the holding time Thold, the control means, during the lane departure prevention control a control amount of the lane departure prevention control When continuously changing, the control end condition correcting means corrects the control duration by the control amount at the end of the lane departure prevention control which is a predetermined end condition.

(Fourth embodiment)
Next, a fourth embodiment will be described.
(Constitution)
As in the first embodiment, the fourth embodiment is a rear wheel drive vehicle equipped with the lane departure prevention apparatus according to the present invention.
In the fourth embodiment, the yaw moment output end timing (predetermined end condition) corrected based on the yaw angle _φdepart or the estimated deviation expansion degree _EXdepart is further corrected based on the driving operation state of the driver.

FIG. 21 shows a calculation process performed by the braking / driving force control unit 8 according to the fourth embodiment.
The basic part of the arithmetic processing performed by the braking / driving force control unit 8 of the fourth embodiment shown in FIG. 21 is the arithmetic processing performed by the braking / driving force control unit 8 of the first embodiment shown in FIG. Although the same, in the calculation process shown in FIG. 21 in the fourth embodiment, in particular, step S51 and step S52 are provided after step S9. In the following description, in the arithmetic processing shown in FIG. 21 in the fourth embodiment, those given the same reference numerals as those in the arithmetic processing shown in FIG. 2 in the first embodiment are the same unless otherwise specified. It is.

As shown in FIG. 21, in step S51, the driving operation state is detected. Specifically, as shown in the following (14), the amount of change (for example, 0.2 seconds) of the steering angle δ (detected value of the steering angle sensor 19) read in step S1 within a predetermined time T _str 1 (for example, 0.2 seconds). The steering speed Δ _str is calculated based on the difference between the current value δ _now of the steering angle δ and the value δ _tstr of a predetermined time ago.
_{Δ str = | (δ now -δ} tstr) / T str | ··· (14)
In step S52, the yaw moment output end timing corrected in step S9 is further corrected based on the driving operation state. FIG. 22 shows the processing procedure.

As shown in FIG. 22, first in step S61, it sets the steering determining threshold value _{delta Str_th} for comparing the steering speed delta _str calculated at step S51. The steering determination threshold value _{Δstr_th} is, for example, an experimental value or an empirical value, and is a value with which it can be determined that the driver performs a steering operation.
Subsequently, in step S62, it compares the calculated steering speed delta _str steering determining threshold value _{delta Str_th} at step S51. Here, when the steering speed delta _str is less steering determining threshold value _{Δ str_th (Δ str ≦ Δ str_th} ), the process proceeds to step S63, otherwise _{(Δ str>} Δ str_th), the process proceeds to step S64.

In step S63, 1 is set to the correction gain _{K override,} in step S64, sets a predetermined value of less than 1 in the correction gain _{K override} (e.g. 0.5). Then, the process proceeds to step S65.
Incidentally, when the steering speed delta _str is greater than steering judgment threshold value _{Δ str_th (Δ str> Δ str_th} ), although setting the predetermined value of less than 1 in the correction gain _{K override} (step S62, step S64 ), when the steering speed delta _str is greater than steering judgment threshold value _{delta Str_th,} it is also possible to set a value corresponding to the steering speed delta _str or the difference _{(Δ str} -Δ str_th) to the correction gain _{K override} .

In step S65, the yaw moment output end timing corrected in step S9 is further corrected based on the correction gain _Koverride . Here, the as in the first embodiment, based on the estimated departure expanding degree _{EX depart,} to calculate the gain _{K Wlimt} for correcting the control range, the correction yaw moment output end timing using the calculated gain _{K Wlimt} If it is, the gain K _wlimt is corrected by the correction gain K _override as shown in (15) below.
K _wlimt = K _override · K _wlimt (15)

Further, as described above in the second embodiment, based on the estimated departure expanding degree _{EX depart,} to calculate the gain _{K Ldown} to correct the decrease side variation limiter Ldown, yaw moment output finish by using the calculated gain _{K Ldown} If you are correct timing, to correct the gain _{K Ldown} by the correction gain _{K override} as follows (16).
K _ldown = K _override · K _ldown (16)

In consideration of the fact that the yaw moment output end timing is delayed as the gain _Kldown decreases, the _calculation is actually performed using the reciprocal of the correction gain _Kldown as shown in the following equation (17).
K _ldown = (1 / K _override ) · K _ldown (17)
In addition, as in the third embodiment, the holding time T _hold is calculated based on the estimated deviation expansion degree EX _department , and the yaw moment output end timing is corrected using the calculated holding time T _hold . In this case, the holding time T _hold is corrected by the correction gain K _override as shown in (18) below.
T _hold = K _override · T _hold (18)

In the fourth embodiment, the yaw moment output end timing corrected based on the estimated deviation expansion degree EX _department is further corrected based on the steering angle δ indicating the driving operation state of the driver. Specifically, when the steering speed is _large, by setting the _{K override} to a smaller value, corrected to a small value of gain _{K Wlimt} and holding time _{T hold,} or to correct the _{K Ldown} to a large value, the estimated departure The yaw moment output end timing corrected based on the enlargement degree EX _depart is corrected again in an earlier direction.

As a result, even when correction is made so that the yaw moment output end timing is delayed based on the estimated deviation expansion degree _EXdepartment in step S9, the change amount or the steering speed of the steering angle δ is determined by this step S51 and step S52. If it is larger, it is assumed that the driver has the intention of driving (the driving intention is high), and the corrected yaw moment output end timing is corrected in the direction of earlier, that is, the estimated deviation expansion degree EX _depart The correction of the yaw moment output end timing based on is suppressed.
As a result, when the driver intends to perform a driving operation, the lane departure prevention control can be prevented from becoming troublesome by the lane departure prevention control being lengthened.

The fourth embodiment can also be realized by the following configuration.
That is, in step S51, the steering speed Δ _str 2 is calculated based on the amount of steering change within a longer time T _str 2 (> T _str 1, for example, 2 seconds) in response to a slower steering operation. (Equation (19) below).
Δ _str 2 = | (δ _now −δ _tstr 2) / T _str 2 | (19)
Here, δ _tstr 2 is the steering angle δ before time T _str 2.

In the fourth embodiment, the steering speed Δ _str is calculated based on the steering angle δ, and the calculated steering speed Δ _str is compared with the steering determination threshold value Δ _{str_th} to determine the driving operation of the driver. Judgment is made. On the other hand, a second steering determination threshold value Δ _{str_th} 2 can be provided in addition to the steering determination threshold value (hereinafter referred to as the first steering determination threshold value) Δ _{str_th} . . In this case, the second steering determination threshold value Δ _{str_th} 2 is set to a value larger than the first steering determination threshold value Δ _{str_th} (Δ _{str_th} 2> Δ _{str_th} ), and the steering speed Δ _str is set to the first value. If the steering determination threshold value 2 is less than or equal to Δ _{str_th} 2 (Δ _str ≦ Δ _{str_th} 2), the correction gain K _override is set to 1, otherwise (Δ _str > Δ _{str_th} 2). _A value close to 0 or 0 is set to _overlap .

In this way, when the change amount or the steering speed of the steering angle δ is very large, it is corrected based on the estimated deviation expansion degree EX _depart that the driver's intention to drive is very high. The yaw moment output end timing is corrected again in a faster direction, that is, the correction of the yaw moment output end timing based on the estimated deviation expansion degree _EXdepartment is more strongly suppressed. In some cases, the yaw moment output end timing based on the estimated deviation expansion degree _EXdepartment is not corrected.

Further, variation in the accelerator opening degree (e.g., the accelerator operating speed) delta _theta and the amount of change in braking operation (e.g., a brake operating speed) based on the delta _Brk, it is also possible to determine the driving operation intention of the driver. That is, the accelerator operation state and the brake operation state can be used as an index for determining the driver's intention to drive. In this case, the accelerator operation state is detected by the accelerator opening sensor 18, and the brake operation state is detected by the brake operation sensor.

In this case, for example, as follows (20), calculates a change amount delta _theta accelerator opening, also as described below (21), calculates the amount of change delta _Brk of brake operation.
_{Δ θ = | (θ now -θ} tθ) / T θ | ··· (20)
_{Δ Brk = | (Brk now -Brk} tbrk) / T Brk | ··· (21)
Here, theta _now is the current value of the accelerator opening theta, theta _T.theta is the predetermined time T _theta previous accelerator opening theta. Brk _now is the current value of the brake operation position Brk, and Brk _tbrk is the brake operation position Brk before a predetermined time T _Brk .

Further, a plurality of indicators for determining the driver's intention to drive are obtained. For example, the above-described Δ _str , Δ _str 2, Δ _θ , Δ _Brk are obtained, and the correction gain K _override is obtained based on the respective indicators for determination. The correction gain _Koverride can be selected (for example, select low), and the yaw moment output end timing can be further corrected using the selected correction gain _Koverride . In this way, the optimum yaw moment output end timing can be achieved by referring to the determination index of the driving operation intention of a plurality of drivers.

  In the description of the fourth embodiment, the steering angle sensor 19, the accelerator opening sensor 18, and the brake operation sensor detect the driving operation intention detection that detects the driving operation intention of the driver based on the driving operation state of the driver. The control end condition correction unit is configured to suppress correction of a predetermined end condition when the driving operation intention detection unit detects the driver's driving operation intention.

1 is a schematic configuration diagram illustrating a vehicle according to a first embodiment of the present invention. It is a flowchart which shows the processing content of the control unit of the lane departure prevention apparatus of a vehicle. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K2. It is a diagram used for explanation of the estimated lateral displacement Xs and the departure tendency determination threshold value X _L. Is a diagram showing the relationship between the departure-tendency threshold value X _L and the output end decision threshold X _end the vehicle position. FIG. 6 is a characteristic diagram showing a change with time of a reference yaw moment Ms0. It is a characteristic view which shows the time-dependent change of the target yaw moment Ms obtained by the limiter process. It is a flowchart which shows the processing content of the correction process of the yaw moment output completion timing by the said control unit. It is a characteristic view which shows the relationship between yaw angle (phi) _depart and estimated deviation expansion degree _EXdepart . It is the figure used for description of the relationship between yaw angle (phi) _depart and estimated deviation expansion degree _EXdepart . It is a characteristic diagram showing the relationship between the estimated departure expanding degree _{EX depart} and gain _{K wlimt.} When the control range of the lane departure prevention control is not corrected, the control range ((a)) of the lane departure prevention control, the control time T _con 1 ((b)) of the lane departure prevention control, and the target yaw in the lane departure prevention control It is a figure which shows moment Ms change ((c)). When correcting the control range of the lane departure prevention control, the control range ((a)) of the lane departure prevention control, the control time T _con 2 ((b)) of the lane departure prevention control, and the target yaw in the lane departure prevention control It is a figure which shows moment Ms change ((c)). It is a characteristic view which shows the relationship between the lateral speed Xv and the estimated deviation expansion degree _EXdepart . It is a flowchart which shows the processing content of the correction process of the yaw moment output completion timing by the control unit in 2nd Embodiment. It is a characteristic diagram showing the relationship between the estimated departure expanding degree _{EX depart} and gain _{K Ldown.} FIG. 10 is a characteristic diagram showing a change in target yaw moment Ms in lane departure prevention control when yaw moment output end timing is corrected in the second embodiment. It is a flowchart which shows the processing content of the correction process of the yaw moment output completion timing by the control unit in 3rd Embodiment. It is a characteristic diagram showing the relationship between the estimated departure expanding degree _{EX depart} the holding time _{T hold.} It is a characteristic figure showing change of target yaw moment Ms in lane departure prevention control at the time of correcting yaw moment output end timing in a 3rd embodiment. It is a flowchart which shows the processing content of the control unit in 4th Embodiment. It is a flowchart which shows the processing content of the correction process of the yaw moment output end timing based on a driving | running operation state by the control unit in 4th Embodiment.

Explanation of symbols

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

Claims (7)

Control that performs lane departure prevention control for preventing the host vehicle from deviating from the traveling lane and that terminates the lane departure preventing control according to a predetermined termination condition even if the departure tendency of the host vehicle from the traveling lane is not resolved. Means,
Own vehicle state detection means for detecting the own vehicle state after the start timing of the lane departure prevention control;
Based on the own vehicle state detected by the own vehicle state detecting means, a deviation tendency expansion degree estimating means for estimating the degree of expansion of the departure tendency of the own vehicle with respect to the traveling lane;
Control end condition correcting means for correcting the predetermined end condition based on the degree of expansion of the deviation tendency estimated by the departure tendency expansion degree estimating means;
With
The control end condition correcting means corrects the control end position in the lateral direction with respect to the travel lane in the lane departure prevention control which is the predetermined end condition so that the greater the degree of enlargement , the farther from the center of the travel lane. A lane departure prevention apparatus characterized by: Control that performs lane departure prevention control for preventing the host vehicle from deviating from the traveling lane and that terminates the lane departure preventing control according to a predetermined termination condition even if the departure tendency of the host vehicle from the traveling lane is not resolved. Means,
Own vehicle state detection means for detecting the own vehicle state after the start timing of the lane departure prevention control;
Based on the own vehicle state detected by the own vehicle state detecting means, a deviation tendency expansion degree estimating means for estimating the degree of expansion of the departure tendency of the own vehicle with respect to the traveling lane;
Control end condition correction means for correcting the timing when the control amount of the lane departure prevention control becomes zero based on the degree of expansion of the departure tendency estimated by the departure tendency expansion degree estimation means;
With
The control means continuously changes the control amount of the lane departure prevention control during the lane departure prevention control, and decreases the control amount at the end of the lane departure prevention control,
The control end condition correcting means to correct the ratio of the reduced to the enlarged degree becomes higher increases small, the timing of the control amount of the lane departure prevention control is zero, the larger the slower the expansion degree A lane departure prevention apparatus characterized by correcting so that Control that performs lane departure prevention control for preventing the host vehicle from deviating from the traveling lane and that terminates the lane departure preventing control according to a predetermined termination condition even if the departure tendency of the host vehicle from the traveling lane is not resolved. Means,
Own vehicle state detection means for detecting the own vehicle state after the start timing of the lane departure prevention control;
Based on the own vehicle state detected by the own vehicle state detecting means, a deviation tendency expansion degree estimating means for estimating the degree of expansion of the departure tendency of the own vehicle with respect to the traveling lane;
Control end condition correction means for correcting the timing when the control amount of the lane departure prevention control becomes zero based on the degree of expansion of the departure tendency estimated by the departure tendency expansion degree estimation means;
With
The control means continuously changes the control amount of the lane departure prevention control during the lane departure prevention control,
The control end condition correction means corrects the control continuation time according to the control amount at the time when the end condition of the lane departure prevention control is satisfied so as to increase as the degree of enlargement increases, thereby controlling the control amount of the lane departure prevention control. The lane departure prevention apparatus according to claim 1, wherein the lane departure prevention device is corrected so that the timing at which the zero becomes zero becomes slower as the enlargement degree increases. The lane departure prevention apparatus according to any one of claims 1 to 3 , wherein the host vehicle state detection means detects a yaw angle of the host vehicle with respect to the travel lane. The lane departure prevention apparatus according to any one of claims 1 to 3 , wherein the host vehicle state detection means detects at least one of a lateral speed and a lateral acceleration of the host vehicle. Driving operation intention detection means for detecting the driver's driving operation intention based on the driving operation state of the driver is provided, and the control end condition correction means detects the driving operation intention of the driver by the driving operation intention detection means. If, lane departure prevention apparatus according to any one of claim 1 to 5, characterized in that to suppress the correction of the predetermined termination condition. The lane departure prevention according to claim 6 , wherein the driving operation intention detection unit detects the driving operation intention based on at least one of a steering operation state, an accelerator operation state, and a brake operation state. apparatus.

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