JP4973338B2 - Lane departure prevention device - Google Patents

Description

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

As conventional lane departure prevention control, when the vehicle may deviate from the driving lane, the vehicle deviates from the driving lane by applying a braking force difference to the left and right wheels and applying a yaw moment to the vehicle. There is a thing which prevents this (for example, refer patent document 1).
JP 2003-154910 A

By the way, the lane departure prevention device for applying a yaw moment to the vehicle due to a braking force difference is supplemented to prevent the yaw moment to be applied to the vehicle from being insufficient due to a decrease in the pad μ of the brake device. Some control amounts are compensated by feedback control.
However, the value for compensating the control amount itself may vary, and in this case, the yaw moment becomes excessive. However, if the control amount compensation is not performed just because the yaw moment becomes excessive, the shortage of the yaw moment due to the decrease in the pad μ of the brake device cannot be compensated.
An object of the present invention is to prevent the yaw moment from becoming excessive even when the control amount compensation value itself varies.

  In order to solve the above-mentioned problem, the lane departure prevention apparatus according to the present invention calculates a compensation value for compensating the yaw moment by the compensation value calculation means based on the vehicle state, and uses the compensation value calculated by the compensation value calculation means. The control means performs lane departure prevention control so that the compensated yaw moment is applied to the vehicle, and the degree of dispersion of the compensation value calculated by the compensation value calculation means is estimated by the degree of dispersion estimation means to estimate the degree of dispersion. The higher the degree of variation estimated by the means, the higher the degree of restriction of the compensation value calculated by the compensation value calculating means.

  According to the present invention, when it is estimated that the variation degree of the compensation value becomes high, even if the compensation value varies by increasing the degree of limiting the compensation value, the control amount compensation is performed and the yaw due to the variation is obtained. It is possible to prevent the moment from becoming excessive.

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)
First, the first embodiment will be described.
(Constitution)
1st Embodiment 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. It supplies to each wheel cylinder 6FL-6RR of each wheel 5FL-5RR. Further, a braking fluid pressure control unit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL-6RR, and the braking fluid pressure control unit 7 controls the braking fluid pressure of each wheel cylinder 6FL-6RR. Individual control is also possible.

  The 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. This 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.
As described above, the imaging unit 13 detects the white line that forms the travel lane, and calculates the yaw φ _front based on the detected white line. Therefore, the yaw angle φ _front is greatly affected by the white line detection accuracy of the imaging unit 13. 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.

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 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.
In addition, the vehicle is provided with a radar 16 that measures the distance between the vehicle and a front obstacle. The radar 16 sweeps laser light forward, receives reflected light from a preceding obstacle, and measures the distance between the host vehicle and the front obstacle. The radar 16 then outputs the measurement result to the braking / driving force control unit 8. The measurement result by the radar 16 is used for processing of the ACC, the rear-end collision speed reduction brake device, and the like.

  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 degree θt, a steering wheel. 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 arithmetic process is updated and stored in the storage device as needed, and necessary information is read out from the storage device as needed.

First, in step S1, various data are read from each sensor, controller, or control unit. Specifically, the longitudinal acceleration Yg, lateral acceleration Xg, yaw rate φ ′ and road information obtained by the navigation device 14, road speed Vwi, steering angle δ, accelerator opening θt, master cylinder hydraulic pressure detected by each sensor 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 yaw angle φ _front is calculated. Specifically, the yaw angle φ _{front of the} 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, calculation instead of using the actual measurement values, based on the white line of the vehicle near the imaging unit 13 is captured, the 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)) (1)
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 near the vehicle, it is not limited to calculating the yaw angle φ _front using the lateral displacement X as shown in the equation (1). For example, a white line detected in the vicinity of the vehicle can be extended far away, and the yaw angle φ _front can be calculated based on the extended white line. V is a vehicle speed, for example, a vehicle speed calculated in step S3 described later. In this case, the process of step S2 is performed after the process of step S3 described later.

Subsequently, in step S3, 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
... (2)
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 (2), 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. A value used for navigation information in the navigation device 14 may be used as the vehicle speed V.
Subsequently, in step S4, an estimated lateral displacement is calculated. Specifically, using the travel lane curvature β obtained in step S1, the lateral displacement X _front of the current vehicle, the yaw angle φ _front obtained in step S2, and the vehicle speed V 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 to be applied to the vehicle as lane departure prevention control (hereinafter referred to as a reference yaw moment) is calculated.
In the lane departure prevention control, when the vehicle tends to deviate from the traveling lane, a predetermined yaw moment (predetermined lane departure prevention control amount) is given to the vehicle to prevent the vehicle from deviating from the traveling lane. In step S5, the yaw moment (reference yaw moment Ms0) is calculated based on the actual running state. FIG. 3 shows the definition of values used in this process.

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. 4 shows an example of the gain K2. As shown in FIG. 4, the gain K2 becomes a small value in the low speed range, and when the vehicle speed V becomes a certain value, the gain K2 also increases as the vehicle speed V increases. It becomes a constant value.

Further, the lateral displacement limit distance _XL is a value that can be generally grasped as the vehicle tends to depart from the lane, and is obtained as an experience value, an experimental value, or the like. For example, the lateral displacement limit distance _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.

In FIG. 3, departure-tendency threshold value X _L has been set within the travel lane of the vehicle is not limited thereto, it may be set outside of the travel lane. Also, the departure tendency determination threshold value X _L is not limited to that in which the departure tendency is determined before the own vehicle deviates from the traveling lane, but for example, the departure tendency is determined after at least one of the wheels has deviated from the lane. May be set.

From the above, according to the equation (4), the estimated lateral displacement Xs and the difference between the lateral displacement limit distance X _L increases, the reference yaw moment Ms0 increases, also the relationship of estimated lateral displacement Xs and yaw angle phi _front from (the (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, a deviation tendency of the vehicle with respect to the traveling lane is determined. Specifically, the lateral displacement limit distance X _L used for calculation of the reference yaw moment Ms0 in step S5 and a departure-tendency threshold value, and this departure-tendency threshold value X _L, in step S4 The estimated lateral displacement Xs is compared to determine the departure tendency.
Setting (≧ _X L | | Xs), it is determined that there is a lane departure tendency, the ON and the departure flag Fout Here, when the estimated lateral displacement (absolute value) Xs is greater than or equal departure-tendency threshold value _{X L} and, when the estimated lateral displacement Xs is smaller 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, the actual lateral displacement (absolute _{value) X} If _front is above the threshold _{X L} for determining the tendency to deviate _{(| X front} | ≧ _X L), it is determined that there is a lane departure tendency, the departure flag Fout Set to ON.
Further, as a condition for enabling the departure determination flag Fout to be set to ON, after the departure determination flag Fout is set to OFF, the vehicle is not in a departure state ((| Xs | <X _L ) or (| X _front | <X _L )). In addition, as a condition that allows the departure determination flag Fout to be set to ON, a time condition such as a predetermined time has elapsed after the departure determination flag Fout is set to OFF can be added.

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

Further, the departure determination flag Fout may be finally set in consideration of the driver's intention to change the lane. For example, when the direction indicated by the direction switch signal (the blinker lighting side) and the direction indicated by the departure direction Dout are the same, it is determined that the driver has intentionally changed the lane, and the departure determination flag Fout is turned off. Change to That is, it is changed to 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 lane 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 the set value, the driver is conscious. Therefore, it is determined that the lane has been 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 vehicle in the lane departure prevention control is determined.
Based on the determination of the departure tendency in step S6, the lane departure tendency is resolved by the vehicle returning to the traveling lane or the vehicle changing lanes at the driver's intention (Fout = OFF). As a result, the lane departure prevention control is terminated, that is, the output (giving) of the yaw moment to the vehicle is terminated.

In step S7, in addition to the determination of such a deviation tendency, a lateral end for control end determination in which the absolute value of the actual lateral displacement _Xfront (estimated lateral position Xs when Tt = 0) is a predetermined threshold value. When the displacement is greater than or equal to X _end (| X _front | ≧ X _end ), it is determined that the end timing of the lane departure prevention control has come. And when it determines with it being the completion | finish timing of lane departure prevention control, the departure determination flag Fout is set to OFF.

Figure 5 shows the relationship between the lateral displacement _{X front} and control termination determination lateral displacement _{X end The.}
5, the control ends deviate from determining the lateral displacement _{X end-tendency} threshold value _{X L} to a value obtained by subtracting ls_w_LMT _{(= X} end -X _L) is from departure-tendency threshold value _{X L} It becomes the control range of the lane departure prevention control outside the traveling lane. Here, the lateral displacement X _end for determining the end of control is an experimental value or an empirical value.
Subsequently, in step S8, a target yaw moment 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, Assumes that the target yaw moment Ms) is continuously applied to the vehicle in order to avoid the lane departure of the vehicle, and thus, a series of processes performed from the start of control to the end of control. According to the 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. Further, the increase side change amount limiter Lup, the maximum value limiter Lmax, and the decrease side change amount limiter Ldown smooth the minimum yaw moment necessary for the vehicle to avoid deviation from the driving lane based on experience values and experimental values. To be changed
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 amount 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, a final target yaw moment is determined (target yaw moment is compensated).

First, if the pad μ of the brake device is in an ideal state (as per the model), the target yaw moment Msa (step S8 described above) is taken into account when the response delay of the actuator of the brake device (approximate as a first-order lag system) is taken into consideration. The actual yaw moment Msa ′ that is actually output with respect to the target yaw moment Ms) calculated in (5) is expressed by the following equation (6).
Msa ′ = t / (t + s) · Msa (6)
On the other hand, the actual yaw moment Msb actually generated in the vehicle, which can be estimated based on the deceleration ΔV and the driving force, is obtained by the following equations (7) and (8).
Msb = K _Msb · M · Tred / 2 (7)
K _Msb = ΔV− (RF (V) + WFet (Trq, Gear, Trm) + SF (Slunt)) / M (8)

  Here, RF (V) is a value with which the vehicle speed V is a variable, for example, a value indicating running resistance, and WFet (Trq, Gear) is an engine output torque (engine raw torque) Trq, a differential gear ratio Gear, and a transmission. The estimated driving force generated by the engine with the ratio Trm as a variable, SF (Slunt) is a force with which the gradient angle Slunt is a variable (force acting on the vehicle), and M is the vehicle weight.

FIG. 8 shows an example of the relationship between the vehicle speed V and RF (V).
As shown in FIG. 8, with the vehicle speed V, RF (V) also increases. Based on such a relationship, RF (V) corresponding to the vehicle speed V is calculated.
Further, WFet (Trq, Gear, Trm) is calculated as follows.
First, a torque value corresponding to the engine speed is calculated, and the engine output torque Trq is calculated by multiplying the calculated torque value by a correction coefficient corresponding to the throttle opening.

FIG. 9 shows an example of the relationship between the engine speed and the torque value. As shown in FIG. 9, the torque value increases with the engine speed. FIG. 10 shows an example of the relationship between the throttle opening and the correction coefficient. As shown in FIG. 10, the correction coefficient increases with the throttle opening, but in the region where the throttle opening is large, the increasing rate of the correction coefficient decreases.
Based on the relationship shown in FIGS. 9 and 10 as described above, the torque value corresponding to the engine speed is calculated, the correction coefficient corresponding to the throttle opening is calculated, and the calculated torque value is corrected. By multiplying the coefficient, the engine output torque Trq (= torque value × correction coefficient) is calculated.

The engine output torque Trq can also be calculated from the relationship between the engine speed and the throttle opening by a three-dimensional map showing the relationship between the engine speed, the throttle opening and the engine output torque Trq.
Subsequently, the axle torque pm_axle_force (= Trq × Gear × Trm) is calculated by multiplying the engine output torque Trq by the differential gear ratio Gear and the transmission ratio Trm.
Finally, WFet (Trq, Gear, Trm) is calculated by the following equation (9) using the axle torque pm_axle_force thus calculated.
WFet (Trq, Gear, Trm) = pm_axle_force / pm_tire_force / pm_weight (9)
Here, pm_tire_force is a tire radius, and pm_weight is a vehicle weight.

As described above, WFet (Trq, Gear, Trm) is calculated.
In addition, SF (Slunt) is calculated by multiplying the vehicle weight W by the angle (sin (Slunt) calculated by the gradient angle Slunt) (SF (Slunt) = W × sin (Slunt)).
The yaw moment compensation amount Msc is calculated by the following equation (10) using the actual yaw moment Msa ′ (see equation (6)) and Msb (see equation (7)) calculated as described above. .
Msc = Msa′−Msb (10)
Thus, the compensation amount Msc is calculated based on a value indicating the actual vehicle state such as the actual yaw moment Msb.

Further, the final target yaw moment Ms (left side) is determined by the following equation (11) using the target yaw moment Ms calculated in step S8 and the equation (10).
Ms = Ms + Msc (11)
That is, the final target yaw moment Ms is obtained by adding the compensation amount Msc to the target yaw moment Ms calculated in step S8. Thereby, the target yaw moment Ms compensated by the compensation amount Msc is obtained by feedback control.
For example, the relationship among the target yaw moment Msa (Ms), the actual yaw moments Msa ′ and Msb, and the compensation amount Msc calculated in step S8 is as shown in FIG.

Subsequently, in step S10, the degree of variation of the yaw moment compensation amount Msc is calculated (estimated).
As shown in the equation (10), the yaw moment compensation amount Msc is obtained by using the actual yaw moment Msb, and the actual yaw moment Msb is obtained by the equations (7) and (8). . As shown in the equation (8), the actual yaw moment Msb has RF (V) indicating running resistance and WFet (Trq, Gear, Trm) indicating estimated driving force as variables. From the above, it can be seen that the compensation amount Msc of the yaw moment is affected by the element RF (V) indicating the running resistance and the elements WFet (Trq, Gear, Trm) indicating the estimated driving force.

The element RF (V) indicating the running resistance and the element WFet (Trq, Gear, Trm) indicating the estimated driving force vary mainly due to external factors. Here, external factors include a situation where the change in running resistance is nonlinear, a large lateral acceleration of the vehicle, a large steering angle, a large yaw rate, a large curvature of the traveling path, and a large yaw jerk. (It must be a predetermined value or more).
Thus, the element RF (V) indicating the running resistance and the element WFet (T) indicating the estimated driving force
rq, Gear, Trm), that is, the compensation amount Msc of the yaw moment varies mainly due to external factors.

FIG. 12 shows an example of the relationship between the lateral acceleration, the steering angle, the yaw rate, the curvature of the travel path, and the degree of variation.
As shown in FIG. 12, when the lateral acceleration, steering angle, yaw rate or curvature of the road is small, the degree of variation is low, and when the lateral acceleration, steering angle, yaw rate or curvature of the road becomes a certain value, these lateral accelerations The degree of variation increases with the steering angle, the yaw rate, or the curvature of the travel path. When the lateral acceleration, the steering angle, the yaw rate, or the curvature of the travel path is reached, the degree of variation becomes a constant value at a certain high value.

  Further, as an external factor that causes the element WFet (Trq, Gear, Trm) indicating the estimated driving force to vary, there is an outside air temperature outside the passenger compartment. For example, when the outside air temperature is outside a predetermined temperature range (for example, 4 ° C. to 30 ° C.), or when the traveling altitude is equal to or higher than the predetermined altitude, the degree of variation increases. The outside air temperature is detected by a temperature sensor or the like, and the traveling altitude is obtained from the information of the navigation system.

FIG. 13 shows an example of the relationship between the traveling altitude and the degree of variation.
As shown in FIG. 13, when the traveling altitude is equal to or higher than a predetermined altitude, the degree of variation becomes high.
In step S11, the compensation amount Msc is limited according to the degree of variation detected in step S10. Specifically, the maximum value of the compensation amount Msc is limited by an upper limit value that changes according to the degree of variation.

FIG. 14 shows an example of the relationship between the degree of variation and the maximum value (upper limit value) of the compensation amount Msc.
As shown in FIG. 14, the maximum value becomes a large value in a region where the variation degree is low, and when the variation degree becomes a certain value, the maximum value becomes smaller as the variation degree becomes higher. The value is a constant value with a small value.
Alternatively, the maximum value of the yaw moment compensation amount Msc is limited by the following equation (12).
Msc = Msc · K _Msc (12)
Here, K _Msc is a gain that decreases as the degree of variation increases (K _Msc ≦ 1).

FIG. 15 shows an example of the relationship between the degree of variation and the gain _KMsc .
As shown in FIG. 15, the gain K _Msc becomes a large value in a region where the variation degree is low, and when the variation degree becomes a certain value, the gain K _Msc becomes smaller as the variation degree becomes higher and then reaches a certain variation degree. The gain K _Msc becomes a constant value with a small value.
Alternatively, the compensation amount Msc of the yaw moment can be limited by the same method as that for setting the target yaw moment Ms in step S8.

Here, the limiting method will be described with reference to FIGS.
When the yaw moment compensation amount Msc is obtained as a changing value as shown in FIG. 16 according to the equation (10), as shown in FIG. 17, the yaw moment compensation amount Msc increases (control start or control). An increase-side change amount limiter Lup _Msc set as a limiter for limiting an increase rate of the first half value), a maximum value limiter Lmax _Msc set as a limiter for limiting the maximum value of the yaw moment compensation amount Msc (the value of the middle control), Further, the yaw moment compensation amount Msc is limited by a decrease side change amount limiter Ldown _Msc set as a limiter for limiting the decrease rate (the value at the end of control or the latter half of the control) of the yaw moment compensation amount Msc.

Subsequently, in step S12, when the departure determination flag Fout is ON, sound output or display output is performed as an alarm for avoiding lane departure.
Note that, when the departure determination flag Fout is ON, the application of the yaw moment to the host vehicle is started as the lane departure avoidance control. Therefore, 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, for example, the start timing of the yaw moment application.
Subsequently, in step S13, 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 (13) and (14), the target braking of each wheel is performed. The hydraulic pressure Psi (i = fl, fr, rl, rr) is set to the braking hydraulic pressure Pmf, Pmr.
Psfl = Psfr = Pmf (13)
Psrl = Psrr = Pmr (14)
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. The front wheel target braking hydraulic pressure difference ΔPsf and the rear wheel target braking hydraulic pressure difference ΔPsr are calculated based on the target yaw moment Ms and the compensation amount Msc calculated in step S9 (specifically, the compensation amount Msc limited in step S10). . Specifically, the target braking hydraulic pressure differences ΔPsf and ΔPsr are calculated by the following equations (15) and (16).
ΔPsf = 2 · Kbf · (Ms + Msc) · FR _ratio ) / T (15)
ΔPsr = 2 · Kbr · ((Ms + Msc) · (1-FR _ratio )) / T (16)

Here, the front-rear wheel hydraulic pressure distribution ratio FR _ratio is a front-rear distribution value set by an experimental value, an empirical value, or the like. 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 hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated using the calculated target brake hydraulic 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 (17). (I = fl, fr, rl, rr) is calculated.
Psfl = Pmf
Psfr = Pmf + ΔPsf
Psrl = Pmr
Psrr = Pmr + ΔPsr
... (17)

Further, 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 = fl, fr, rl, rr) of each wheel is calculated by the following equation (18).
Psfl = Pmf + ΔPsf
Psfr = Pmf
Psrl = Pmr + ΔPsr
Psrr = Pmr
... (18)
According to the equations (17) and (18), the braking force difference between the left and right wheels is generated so that the braking force of the wheels on the lane departure avoidance side is increased.

  Further, here, as shown in the equations (17) and (18), 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 φ _front are calculated (steps S2 and S3). Subsequently, an estimated lateral displacement (estimated departure 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, a reference yaw moment Ms0 is calculated (step S5), the calculated reference yaw moment Ms0 is subjected to limiter processing to obtain a target yaw moment Ms, and further compensation is performed to obtain a final target yaw moment Ms ( = Ms + Msc) (steps S8 and S9). At this time, the degree of variation of the compensation amount Msc used for compensation is calculated, and the compensation amount Msc is limited according to the degree of variation (steps S10 and S11).

Based on the determination result of the lane departure tendency, an alarm is output (step S12), and the target brake hydraulic pressure Psi (i = fl, fr, rl) of each wheel is determined based on the target yaw moment Ms (= Ms + Msc). , Rr), and outputs the calculated target brake fluid pressure Psi (i = fl, fr, rl, rr) of each wheel to the brake fluid pressure controller 7 (step S12). As a result, a yaw moment is applied to the vehicle according to the lane departure tendency of the vehicle. At this time, the yaw rate has a value in which a change in the pad μ is compensated by feedback control. When the yaw moment output end timing is reached (| X _front | ≧ X _end ), the application of the yaw moment to the vehicle ends, and the lane departure prevention control ends (step S7).

(Function and effect)
The action and effect are as follows.
As described above, the final target yaw moment Ms (= Ms + Msc) is calculated by performing compensation, and the compensation amount Msc used for the compensation is limited according to the degree of variation. Specifically, the maximum value of the compensation amount Msc is reduced as the degree of variation increases. Alternatively, as the degree of variation increases, the gain is reduced to suppress the fluctuation of the compensation amount Msc (as a result, the compensation amount Msc is suppressed from increasing).

  FIG. 18 shows a change in yaw moment (particularly focusing on Msc (specifically, Ms + Msc)) when the compensation amount Msc is not corrected (restricted) (conventional example). FIGS. 19 and 20 show results of applying the present invention, and show changes in yaw moment when the compensation amount Msc is limited according to the degree of variation in the compensation amount Msc. Specifically, FIG. 19 shows a change in yaw moment (particularly focusing on Msc (specifically, Ms + Msc)) when the maximum value of the compensation amount Msc is limited in accordance with the degree of variation in the compensation amount Msc. FIG. 20 shows a change in yaw moment (particularly focusing on Msc (specifically, Ms + Msc)) when the gain is reduced and the compensation amount Msc is limited in accordance with the degree of variation in the compensation amount Msc.

As can be seen from comparison with FIG. 18, from the results of FIGS. 19 and 20, the target yaw moment Ms (== finally calculated) is limited by limiting the compensation amount Msc according to the variation degree of the compensation amount Msc. Ms + Msc) is restricted from increasing.
As a result, even if the compensation amount Msc varies depending on the vehicle state, it is possible to prevent the compensation amount Msc, which is an insufficient amount of yaw moment, from being excessively increased. Can be prevented from becoming unsmooth, and the lane departure prevention control can prevent the driver from feeling uncomfortable.

  In addition, as described above, the degree of variation of the compensation amount Msc is estimated based on at least one of the vehicle's lateral acceleration, steering angle, yaw rate, travel path curvature, yaw jerk, travel altitude, and outside air temperature. Yes. The element RF (V) indicating the running resistance and the element WFet (Trq, Gear, Trm) indicating the driving resistance and the like used for calculating the compensation amount Msc are the vehicle lateral acceleration, the steering angle, the yaw rate, and the driving path. Since it is easily affected by curvature, york jerk, traveling altitude, or outside air temperature, the degree of variation in compensation amount Msc can be reduced by using the vehicle's lateral acceleration, steering angle, yaw rate, curvature of the road, yaw jerk, traveling altitude, or outside temperature. Thus, it is possible to appropriately estimate and it is possible to accurately prevent the compensation amount Msc from becoming excessive.

  In the description of the embodiment, the process of step S6 of the braking / driving force control unit 8 realizes a lane departure tendency determining means for determining a departure tendency of the vehicle with respect to the traveling lane. When the lane departure tendency determining means determines that the departure tendency is high, the processes in steps S5 and S8 are yaw moment calculation for calculating the yaw moment to be given to the vehicle as the lane departure prevention control according to the degree of the departure tendency. The processing of step S9 of the braking / driving force control unit 8 realizes a compensation value calculation means for calculating a compensation value for compensating the yaw moment calculated by the yaw moment calculation means based on the vehicle state. The process of step S13 of the braking / driving force control unit 8 is performed by the compensation value calculating means. And a control means for performing lane departure prevention control so that the yaw moment compensated by the issued compensation value is applied to the vehicle, and the process of step S10 of the braking / driving force control unit 8 performs the compensation value calculation. The variation degree estimating means for estimating the degree of dispersion of the compensation value calculated by the means is realized, and the processing in step S11 of the braking / driving force control unit 8 increases the degree of variation estimated by the variation degree estimating means. Limiting means for increasing the degree of limitation of the compensation value calculated by the compensation value calculating means is realized.

(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 end timing of the lane departure prevention control (control operation time of the lane departure prevention control) is changed in response to limiting the yaw moment compensation amount Msc. For example, 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 that of the first embodiment. In step S21 following step S11, the end timing of the lane departure prevention control is changed.

FIG. 21 shows a processing procedure of the braking / driving force control unit 8 in the second embodiment.
As shown in FIG. 21, in step S21 following step S11, the end timing of the lane departure prevention control is changed.
In step S11, as in the first embodiment, the yaw moment compensation amount Msc is limited by using the upper limit value, gain, or limiters Lup _Msc , Lmax _Msc, and Ldown _Msc . Thus, by limiting the yaw moment compensation amount Msc using the upper limit value, gain or limiter Lup _Msc , Lmax _Msc and Ldown _Msc (particularly Lup _Msc , Lmax _Msc ), the yaw moment compensation amount Msc is This is smaller than the original yaw moment compensation amount Msc (value calculated by the above equation (10)).
In response to this, first, an integral value (cut integral value) of the amount reduced by applying the restriction in step S11 is calculated.
Subsequently, in step S21, the end timing of the lane departure prevention control, that is, the control end determination lateral displacement _Xend is changed according to the calculated integrated value.

FIG. 22 shows an example of the relationship between the integral value and the lateral displacement X _end for determining the end of control.
As shown in FIG. 22, in the region where the integral value is small, the lateral displacement X _end for control end determination becomes a small value (normally used value), and when the integral value reaches a certain value, the lateral displacement X for control end determination together with the integral value. _{When the end} also increases and then reaches a certain integral value, the lateral displacement X _end for determining the end of control becomes a constant value with a certain large value.
Thus, as the integrated value increases, the lateral displacement X _end for control end determination is increased. Thus, the end timing of the lane departure prevention control is changed to be delayed as the integrated value increases.

(Operation, action and effect)
The operation, action and effect are as follows.
Particularly in the second embodiment, when the compensation amount Msc for compensating the target yaw moment Ms is limited according to the degree of variation of the compensation amount Msc, an integrated value of the amount reduced by the limitation is calculated, and The end timing of the lane departure prevention control is changed according to the calculated integral value. Specifically, the end timing of the lane departure prevention control is delayed as the integral value increases, that is, as the degree of restriction of the compensation amount Msc increases.

  FIG. 23 shows a change in the target yaw moment Ms. In the figure, the solid line shows the result obtained by the second embodiment, that is, the change in the target yaw moment Ms when the compensation amount Msc is limited and the end timing of the lane departure prevention control is delayed, A dotted line indicates a change in the target yaw moment Ms when the compensation amount Msc is not limited. The alternate long and short dash line indicates a change in the target yaw moment Ms when the normal lane departure prevention control ends.

As shown in FIG. 23, the end timing of the lane departure prevention control is delayed so that the control amount corresponding to the integrated value of the amount reduced by limiting the compensation amount Msc is compensated.
As a result, the effect in the first embodiment, that is, the feeling of pressing the vehicle due to the yaw moment, is prevented from becoming smooth, and the lane departure prevention control prevents the driver from feeling uncomfortable. While maintaining the effect of doing so, by delaying the end timing of the lane departure prevention control, a predetermined control amount (integrated value of yaw moment) is ensured, and vehicle departure can be reliably prevented. .
The second embodiment can also be realized by the following configuration.

That is, in the second embodiment, the end timing of the lane departure prevention control is delayed by changing the lateral displacement X _end for control end determination. However, it is not limited to this. That is, as the integrated value increases, the control range ls_w_LMT (= X _end −X _L ) of the lane departure prevention control can be increased. Alternatively, the end timing of the lane departure prevention control is determined based on the control time from the start of the lane departure prevention control, and the control time is increased as the integrated value increases. Alternatively, the end timing of the lane departure prevention control is determined based on whether or not the yaw angle of the vehicle with respect to the traveling lane has reached a predetermined yaw angle (for example, 0 °). Increase the corner. Alternatively, the end timing of the lane departure prevention control is determined based on whether the yaw angle of the vehicle with respect to the traveling lane has reached a predetermined yaw angle (for example, 0 °) and a predetermined time has passed thereafter, and the integrated value is The larger the time is, the longer the predetermined time is.

(Third embodiment)
Next, a third embodiment will be described.
(Constitution)
The third embodiment is a rear wheel drive vehicle equipped with the lane departure prevention apparatus according to the present invention, as in the first embodiment.
In the third embodiment, the compensation amount Msc is offset corrected. For example, 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 that of the first embodiment. In step S31 following step S9, the compensation amount Msc is offset corrected.

FIG. 24 shows a processing procedure of the braking / driving force control unit 8 in the third embodiment.
As shown in FIG. 24, in step S31 following step S9, the compensation amount Msc is offset-corrected.
As described above, the compensation amount Msc is obtained by using the actual yaw moment Msb (see the equation (10)), and the actual yaw moment Msb is obtained by the equation (7). The actual yaw moment Msb is calculated using K _Msb (see the above equation (8)), and is zero when the lane departure prevention control is not operated (before the lane departure prevention control operation). become.
Based on such a relationship, before the lane departure prevention control operation, when the actual yaw moment Msb calculated using K _Msb shows a certain value Msb _off other than zero, after the lane departure prevention control operation, By subtracting the value Msb _off from the actual yaw moment Msb, the compensation amount Msc is offset-corrected.

Alternatively, as described above, the actual yaw moment Msb must be zero when the lane departure prevention control is not operated (before the lane departure prevention control operation), that is, according to the above equation (8). Since the deceleration ΔV and the value [(RF (V) + WFet (Trq, Gear, Trm) + SF (Slunt)) / M] must be equivalent, before the lane departure prevention control operation, the value [(RF If (V) + WFet (Trq, Gear, Trm) + SF (Slunt)) / M] is different from the deceleration ΔV, the difference (ΔV− (RF (V) + WFet (Trq, Gear, Trm) + SF (Slunt) )) / M) is subtracted from the value [(RF (V) + WFet (Trq, Gear, Trm) + SF (Slunt)) / M] or K _Msb after the lane departure prevention control operation. Thus, the offset correction of the compensation amount Msc is performed.
The above processing is based on the premise that K _Msb and actual yaw moment Msb are sequentially calculated even before the lane departure prevention control operation.

(Operation, action and effect)
The operation, action and effect are as follows.
In particular, in the third embodiment, the offset correction of the compensation amount Msc is performed based on the value before the lane departure prevention control operation.
FIG. 25 shows the change in yaw moment.
As shown in FIG. 25, when the actual yaw moment Msb used for calculating the compensation amount Msc is viewed before the lane departure prevention control in which the target yaw moment Msa or the like is not calculated, the actual yaw moment Msb is a value other than zero. May be indicated. In such a case, the value Msb _off , which is the actual yaw moment Msb calculated using K _Msb before the lane departure prevention control operation, is subtracted from the actual yaw moment Msb after the lane departure prevention control operation to compensate. Offset correction of the amount Msc is performed.

As a result, the compensation amount Msc can be prevented from becoming excessive, the feeling of pressing the vehicle due to the yaw moment is prevented from becoming smooth, and the lane departure prevention control makes the driver feel uncomfortable. Can be prevented.
Note that the offset correction of the compensation amount Msc is performed by using the value Msb _off when the degree of variation obtained from the lateral acceleration, the steering angle, the yaw rate, the curvature of the travel path, etc. (FIG. 12 etc.) is below a predetermined value. You can also That is, the value Msb _off that realizes the offset correction of the compensation amount Msc is updated only when the variation degree is equal to or less than a predetermined value (see FIG. 25).

In addition, the said embodiment can also be implement | achieved by the following structures.
That is, in the above-described embodiment, the degree of variation is calculated based on travel resistance and the like, estimated driving force, more specifically, lateral acceleration, steering angle, yaw rate, and curvature of the travel path. However, it is not limited to this. For example, the degree of variation can be calculated based on the operating state of the power steering. In the power steering system, the hydraulic power steering pump is driven according to the steering, and as a result, the driving loss of the hydraulic power steering pump affects the yaw moment, so the compensation amount depends on the operating state of the power steering. The degree of variation in Msc can also be calculated.

In addition, when the vehicle is traveling in a curve, the tire motion itself is likely to have a nonlinear behavior, and further, depending on the vehicle weight, the air pressure, and the suspension behavior, the tire installation status may vary. Therefore, the degree of variation can also be calculated based on the curve running state and the vehicle weight, air pressure, and tire installation state.
In addition, the compensation amount Msc can be limited (corrected) in consideration of the hysteresis in the relationship between the degree of variation and a value changed according to the degree of variation, for example, the gain K _Msc . For example, as shown in FIG. 26, would otherwise, but if you have to change the gain K _Msc depending on the degree of variation (if reduced), the gain K _Msc will not become larger than a predetermined value, the gain K _Msc Do not change.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing a configuration of a vehicle equipped with a lane departure prevention apparatus to which the present invention is applied, according to a first embodiment of the present invention. It is a flowchart which shows the processing content of the braking / driving force control unit of the said lane departure prevention apparatus. It is a figure explaining lane width L and lateral displacement X. It is a characteristic view which shows the relationship between the own vehicle speed V and the gain K2. Is a characteristic diagram showing the relationship between the lateral displacement _{X front} and control termination determination lateral displacement _{X end The.} 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 characteristic view which shows the relationship between the vehicle speed V and RF (V). It is a characteristic view which shows the relationship between an engine speed and a torque value. It is a characteristic view which shows the relationship between a throttle opening and a correction coefficient. FIG. 6 is a characteristic diagram showing a relationship among a target yaw moment Msa (Ms), actual yaw moments Msa ′ and Msb, and a compensation amount Msc. FIG. 6 is a characteristic diagram showing a relationship between lateral acceleration, steering angle, yaw rate, curvature of a traveling road, and variation degree. It is a characteristic view which shows the relationship between driving | running | working height and a dispersion | variation degree. It is a characteristic view showing the relationship between the degree of variation and the maximum value (upper limit value) of the compensation amount Msc. It is a characteristic view which shows the relationship between a dispersion _| variation degree and gain _KMsc . It is a characteristic view which shows the time-dependent change of the compensation amount Msc. It is a characteristic view which shows a time-dependent change of the compensation amount Msc obtained by the limiter process. FIG. 10 is a characteristic diagram showing a change in yaw moment when the compensation amount Msc is not corrected. FIG. 11 is a characteristic diagram showing a change in yaw moment when the maximum value of the compensation amount Msc is limited. It is a characteristic view showing a change in yaw moment when the gain is reduced and the compensation amount Msc is limited. It is a flowchart which shows the processing content of the braking / driving force control unit in the 2nd Embodiment of this invention. FIG. 6 is a characteristic diagram showing a relationship between an integral value and a lateral displacement X _end for determining control end. FIG. 6 is a characteristic diagram showing a change in yaw moment when the end timing of lane departure prevention control is delayed. It is a flowchart which shows the processing content of the braking / driving force control unit in the 3rd Embodiment of this invention. FIG. 11 is a characteristic diagram showing a change in yaw moment used to explain offset correction of a compensation amount Msc. FIG. 10 is a characteristic diagram used for explaining that the gain _KMsc is changed in consideration of hysteresis in the relationship between the degree of variation and the gain _KMsc .

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 (front camera), 14 navigation device, 16 radar, 17 master cylinder pressure sensor, 18 accelerator opening sensor, 19 steering angle sensor, 22FL-22RR wheel speed sensor

Claims (9)

A lane departure tendency determination means for determining a vehicle departure tendency with respect to a traveling lane;
When the lane departure tendency determining means determines that the departure tendency is high, the yaw moment calculating means for calculating the yaw moment to be given to the vehicle as the lane departure prevention control according to the degree of the departure tendency;
Compensation value calculating means for calculating a compensation value for compensating the yaw moment calculated by the yaw moment calculating means based on the vehicle state;
Control means for performing lane departure prevention control so that the yaw moment compensated by the compensation value calculated by the compensation value calculating means is applied to the vehicle;
Variation degree estimating means for estimating the degree of dispersion of the compensation value calculated by the compensation value calculating means;
Limiting means for increasing the degree of limiting the compensation value calculated by the compensation value calculating means as the degree of variation estimated by the degree of variation estimating means increases.
A lane departure prevention apparatus comprising:   2. The lane departure prevention apparatus according to claim 1, wherein the control unit increases the yaw moment application time to the vehicle as the degree of restriction of the compensation amount by the limiting unit increases.   The lane departure prevention apparatus according to claim 1 or 2, wherein the limiting means limits an upper limit value of the compensation value.   The lane departure prevention apparatus according to any one of claims 1 to 3, wherein the limiting means limits the compensation value by reducing a gain of the compensation value.   The lane departure prevention apparatus according to any one of claims 1 to 4, wherein the restriction means restricts a change rate of the compensation value.   6. The apparatus according to claim 1, further comprising offset correction means for performing offset correction on the compensation value during operation of the lane departure prevention control based on an offset value obtained before the operation of the lane departure prevention control. The lane departure prevention apparatus according to any one of the preceding claims. 6. variation degree of compensation values the compensation value calculating means before the operation of the prior SL lane departure prevention control is calculated in the case of less than a predetermined threshold value, and obtains a value for the offset The lane departure prevention device according to claim 1.
  8. The variation degree estimation unit estimates a degree of dispersion of a compensation value based on at least one of a running state of a vehicle and a state of an external environment where the vehicle is placed. The lane departure prevention apparatus according to any one of the preceding claims.   The variation degree estimation means estimates the degree of variation of the compensation value based on at least one of the following values: vehicle lateral acceleration, steering angle, yaw rate, travel path curvature, yaw jerk, travel altitude, and outside air temperature. The lane departure prevention apparatus according to claim 1, wherein the lane departure prevention apparatus is a lane departure prevention apparatus.

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