JP2007230525A - Traveling controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the cooperation of both lane deviation prevention control and speed control such as follow-up traveling control in such a scene that the both control should operate, and to achieve accurate lane deviation prevention while performing deceleration control under speed control. <P>SOLUTION: Before it is decided that lane deviation may occur, an estimated lateral displacement (absolute value) Xs becomes equal to or above a threshold value Kk for deciding second deviation tendency, and when a second deviation judgement flag F<SB>Kout</SB>is set so as to be ON (step S31), a target inter-vehicle distance L* to be used for follow-up traveling control is increase-corrected (step S32). Thus, it is possible to perform inter-vehicle distance control under follow-up traveling control based on the increase-corrected target inter-vehicle distance L*. As a result, deceleration control is operated at a deceleration which is larger than a value in the case of normal control under the previous follow-up traveling control in which the lane deviation prevention control is operating. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides vehicle speed control for controlling the vehicle speed of the host vehicle and lane departure prevention control for preventing the host vehicle from deviating from the traveling lane when the host vehicle tends to deviate from the traveling lane. The present invention relates to a travel control device.

As conventional lane departure prevention control, when there is a possibility that the host vehicle departs from the driving lane, a braking force difference is applied to the left and right wheels, and a yaw moment is applied to the host vehicle so that the host vehicle moves from the driving lane. There is one that prevents deviation (see, for example, Patent Document 1).
JP 2000-33860 A

By the way, when the conventional lane departure prevention control and vehicle speed control such as follow-up running control (cruise control) are used in combination, when the scenes to be operated are overlapped, each control has its original function. You may not be able to do it. For example, if lane departure prevention control is mixed and operated during deceleration by vehicle speed control, both controls are common in terms of braking control, which complicates braking control, resulting in lane departure prevention. It may be difficult to output the yaw moment required for the operation. It is also possible to give priority to either the vehicle speed control or the lane departure prevention control, but in a scene where the distance between the vehicle and the vehicle ahead is short and there is a possibility of lane departure, the normal control details If the vehicle speed control is simply prioritized, the driver himself / herself performs a driving operation so that the vehicle does not deviate from the driving lane. On the other hand, if priority is given to the lane departure prevention control, There is a possibility that the driver may feel a sense of discomfort by approaching suddenly.
An object of the present invention is to coordinate both controls in a scene in which lane departure prevention control and vehicle speed control such as follow-up running control are to be operated, and while performing deceleration control by vehicle speed control, a reliable lane It is to realize deviation prevention.

The travel control device for a vehicle according to the first aspect of the present invention obtains position information of the own vehicle indicating the degree of deviation tendency of the own vehicle with respect to the traveling lane, and deviates when the position information exceeds a predetermined threshold value. A lane departure prevention control that prevents the own vehicle from deviating from the travel lane when the departure tendency determination unit determines that the vehicle is in a tendency and the departure tendency determination unit determines that the host vehicle is in a departure tendency. Lane departure prevention control means, and vehicle speed control means for performing vehicle speed control for controlling the vehicle speed of the host vehicle.
In this vehicle travel control device, the vehicle speed control means corrects the control parameter so that the deceleration in the vehicle speed control increases based on the position information before the position information exceeds the predetermined threshold value. To do.

  According to the vehicle travel control apparatus of the first aspect of the present invention, when the lane departure prevention control is likely to be activated, the deceleration of the vehicle speed control can be increased in advance, whereby the lane departure prevention control is performed. It can be done reliably.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
(Constitution)
The embodiment is a rear-wheel drive vehicle equipped with a vehicle travel control device according to the present invention. This rear-wheel drive vehicle is equipped with an automatic transmission and a conventional differential gear, and a braking device capable of independently controlling the braking force of the left and right wheels for both the front and rear wheels.

FIG. 1 is a schematic configuration diagram illustrating an 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. Usually, the brake fluid pressure increased by the master cylinder 3 according to the amount of depression of the brake pedal 1 by the driver. Is supplied to the wheel cylinders 6FL to 6RR of the wheels 5FL to 5RR. Further, a braking fluid pressure control unit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL-6RR, and the braking fluid pressure control unit 7 controls the braking fluid pressure of each wheel cylinder 6FL-6RR. Individual control is also possible.

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

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

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

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

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 has a front obstacle and a front obstacle by sweeping laser light forward and receiving reflected light from a preceding obstacle for follow-up running control (cruise control) constituting the vehicle speed control device. A radar 16 is provided for measuring the distance between the object and the like. A specific configuration for realizing the following traveling control will be described in detail later.

  Further, in this vehicle, a master cylinder pressure sensor 17 that detects an output pressure of the master cylinder 3, that is, master cylinder hydraulic pressures Pmf and Pmr, and an accelerator opening sensor 18 that detects an accelerator pedal depression amount, that is, an accelerator opening θt. , A steering angle sensor 19 for detecting a steering angle (steering angle) δ of the steering 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. Wheel speed sensors 22FL to 22RR for detecting (i = 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.

When the detected vehicle traveling state data has left and right directions, the right direction is the positive direction in all cases. That is, the yaw rate φ ′, the lateral acceleration Xg, and the yaw angle φ are positive values when turning right, and the lateral displacement X is a positive value when deviating from the center of the traveling lane to the right. The longitudinal acceleration Yg takes a positive value during acceleration and takes a negative value during deceleration.
Various data is input to the braking / driving force control unit 8 as described above, and follow-up traveling control and lane departure prevention control are performed based on the input data.

(Following traveling control processing details, etc.)
The configuration and processing contents of the follow-up running control are as follows.
FIG. 2 shows a configuration for performing the follow-up running control in the braking / driving force control unit 8. As shown in FIG. 2, the braking / driving force control unit 8 includes a vehicle speed signal processing unit 31 that calculates the vehicle speed based on data obtained by the wheel speed sensors 22FL to 22RR as a configuration for performing the follow-up running control. And measuring the time from receiving the reflected light from the preceding vehicle (front obstacle) existing ahead of the host vehicle on the traveling lane of the host vehicle after the laser beam is scanned by the radar 16, The distance measurement signal processing unit 34 that calculates the inter-vehicle distance L between the host vehicle, the host vehicle speed Vsp calculated by the vehicle speed signal processing unit 31, and the inter-vehicle distance L between the preceding vehicle calculated by the distance measurement signal processing unit 34 based on, sets the target inter-vehicle distance L ^*, a travel control unit 40 for calculating a target vehicle speed V ^* for maintaining the inter-vehicle distance L to the target inter-vehicle distance L ^*, target vehicle speed calculated in the travel control unit 40 V ^* to And Zui, so to match the vehicle speed Vsp on the target vehicle speed V ^*, the braking fluid pressure control unit 7, the vehicle speed control unit 33 for controlling the automatic transmission such that drive torque controller 12 and not shown, further, the imaging unit 13 And an image processing unit 32 for processing imaging information from.
In actual control, a value obtained by dividing the inter-vehicle distance by the own vehicle speed, that is, the head time is used as the “inter-vehicle distance”. Therefore, the target inter-vehicle distance L ^* also has a dimension value corresponding to such a vehicle head time.

The travel control unit 40 is input from the vehicle speed signal processing unit 31 and the relative speed calculation unit 41 that calculates the relative speed ΔV between the host vehicle and the preceding vehicle based on the inter-vehicle distance L calculated by the ranging signal processing unit 34. The target vehicle distance L ^* is set based on the own vehicle speed Vsp and the relative speed ΔV calculated by the relative speed calculation unit 41 or the inter-vehicle distance setting value Ls set by the driver by an operation with a manual switch (not shown), The target inter-vehicle distance setting unit 42 that corrects the target inter-vehicle distance L ^* based on the travel environment information from the navigation device 14 and the like, and the relative speed ΔV calculated by the relative speed calculation unit 41 and the inter-vehicle distance calculated by the ranging signal processing unit 34 based on the running environment information from the distance L and the navigation device 14, to match the inter-vehicle distance L to the target inter-vehicle distance setting section 42 target inter-vehicle distance calculated at L ^* And a distance control unit 43 for calculating a target vehicle speed V ^*.

Then, the vehicle speed control unit 33 calculates the target acceleration / deceleration Yg ^* from the difference value between the target vehicle speed V ^* and the host vehicle speed Vsp by, for example, a known procedure by PID (proportional-integral-derivative) control. ^{When *} is a negative value, the braking fluid pressure control unit 7 is controlled to generate a braking force so that the target acceleration / deceleration Yg ^* can be realized. Conversely, the target acceleration / deceleration Yg ^* is a positive value. In this case, the drive torque control unit 12 and an automatic transmission (not shown) are controlled so that the target acceleration / deceleration can be realized.

Next, the ranging signal processing unit 34 and the travel control unit 40 will be described in detail.
First, a method for calculating the relative speed ΔV will be described. As shown in FIGS. 3 and 4, the relative speed ΔV is approximately obtained using the band-pass filter or the high-pass filter with the inter-vehicle distance L to the preceding vehicle calculated by the ranging signal processing unit 34 as an input. Can do. For example, the bandpass filter can be realized by a transfer function expressed by the following equation (1).
F (s) = ωc ² · s / (s ² + 2ζ · ωc · s + ωc ² ) (1)
In equation (1), ωc = 2π · fc, s is a Laplace operator, and ζ is an attenuation coefficient. The cut-off frequency fc of the filter function is determined by the magnitude of the noise component included in the inter-vehicle distance L and the allowable value of the short-cycle vehicle body longitudinal acceleration fluctuation.

Next, a control law for traveling while keeping the inter-vehicle distance L at the target inter-vehicle distance L ^* will be described. As shown in FIG. 2, the basic control system has a configuration in which a travel control unit 40 and a vehicle speed control unit 33 are provided independently. Note that the output of the travel control unit 40 is a target vehicle speed (vehicle speed command value) V ^* and is not configured to directly control the inter-vehicle distance L.

The inter-vehicle distance control unit 43 of the travel control unit 40 calculates a target vehicle speed V ^* for traveling while maintaining the inter-vehicle distance L at the target inter-vehicle distance L ^* based on the inter-vehicle distance L and the relative speed ΔV. Specifically, as shown in FIG. 5, a value obtained by multiplying the difference (L ^* −L) between the target inter-vehicle distance L ^* and the actual inter-vehicle distance L by the control gain fd as shown in the following equation (2). And ΔV ^* , which is the sum of the relative speed ΔV and the control gain fv, is calculated, and a value obtained by subtracting this from the vehicle speed Vt of the preceding vehicle is set as the target vehicle speed V ^* .
V ^* = Vt−ΔV ^*
ΔV ^* = fd · (L ^* −L) + fv · ΔV
... (2)
The control gains fd and fv are parameters that determine the travel control capability. Here, since it is a 1-input 2-output system that controls two target values (inter-vehicle distance and relative speed) with one input (target vehicle speed), the control system uses state feedback (regulator) as a control method. Is designing.

Next, the design procedure of the control system will be described.
First, system state variables x ₁ and x ₂ are defined by the following equation (3).
x ₁ = Vt−V
x ₂ = ^L * -L
... (3)
Further, the control input (controller output) ΔV ^* is defined by the following equation (4).
ΔV ^* = Vt−V ^* (4)
Here, the inter-vehicle distance L can be expressed as the following equation (5).
L = ∫ (Vt−V) dt + L ₀ (5)
Incidentally, L ₀ in (5) is the target following distance when stopping the adaptive cruise control.

Further, the vehicle speed servo system can approximately represent the actual vehicle speed V with a first-order lag with respect to the target vehicle speed V ^* by a linear transfer function, for example, as shown in the following equation (6).
V = 1 / (1 + τv · s)
dV / dt = 1 / τv (V ^* −V)
... (6)
Therefore, when the vehicle speed Vt of the preceding vehicle is constant, the equation (3) and (4) and (6), the state variable x ₁ can be expressed by the following equation (7).
dx ₁ / dt = −1 / τv · x ₁ + 1 / τv · ΔV ^* (7)
Further, when the target inter-vehicle distance L ^* is constant, than the (3) and (5), the state variable x ₂ can be expressed by the following equation (8).
x ₂ = − (Vt−V) = − x ₁ (8)
Therefore, the state equation of the system can be expressed by the following equation (9) from the equations (7) and (8).

Further, the state equation of the entire system subjected to state feedback can be expressed by the following equation (10).
dX / dt = (A + BF) X (10)
However, control input u = FX, F = [fv fd].
Therefore, from the equation (10), the characteristic equation of the entire system can be expressed by the following equation (11).
| SI−A ′ | = s ² + (1−fv) / τv · s + fd / τv = 0
A ′ = A + BF (11)

Here, the vehicle speed servo system of the vehicle speed control unit 33 can be approximately expressed by a linear transfer function. Based on this transfer characteristic, the inter-vehicle distance L converges to the target inter-vehicle distance L ^* and the relative speed ΔV converges to 0, respectively. The control gains fd and fv are set according to the following equation (12) so that the convergence characteristics to be achieved are the characteristics (damping coefficient ζ, natural frequency ωn) intended by the designer.
fv = 1-2ζ · ωn · τv
fd = ωn ² · τv
(12)

Here, as shown in FIG. 6, since the relative speed ΔV is a difference in vehicle speed between the preceding vehicle and the host vehicle, the vehicle speed Vt of the preceding vehicle is expressed by the following equation (13) based on the host vehicle speed V and the relative speed ΔV. It can be calculated from
Vt = V + ΔV (13)
Therefore, the target vehicle speed V ^* can be expressed by the following equation (14) from the equations (2) and (13).
V ^* = V−fd (L ^* −L) + (1−fv) ΔV (14)

The target inter-vehicle distance L ^* may be set using the concept of inter-vehicle time used for approach warnings, etc., but here the function of the vehicle speed Vt of the preceding vehicle from the viewpoint of not affecting the convergence of control at all. And Using the vehicle speed Vt of the preceding vehicle defined by the equation (13), the target inter-vehicle distance L ^* is set as shown by the following equation (15).
L ^* = a · Vt + L ₀ = a · (V + ΔV) + L ₀ (15)

As shown in equation (15), when the target inter-vehicle distance L ^* is set using the vehicle speed Vt of the preceding vehicle calculated from the host vehicle speed V and the relative speed ΔV, the noise superimposed on the relative speed detection value Therefore, the target inter-vehicle distance L ^* represented by the following equation (16) may be set as a function of the host vehicle speed V, as shown in FIG.
L ^* = a · V + L ₀ (16)

In the inter-vehicle distance control unit 43, when the target inter-vehicle distance L ^* set in this way is less than the inter-vehicle distance set value Ls set by a manual switch (not shown), the inter-vehicle distance set value Ls is set to the target inter-vehicle distance set value Ls. It is set as the inter-vehicle distance L ^* .
There is also a vehicle speed setting switch that allows the driver to set the vehicle speed. As a result, when the preceding vehicle disappears from the state in which the host vehicle is following the preceding vehicle (lost), the target vehicle speed V ^* is set to the set vehicle speed set by the vehicle speed setting switch. The vehicle is accelerated to reach the set vehicle speed (target vehicle speed).
The above is the control law for driving the host vehicle while keeping the inter-vehicle distance L at the target inter-vehicle distance L ^* .

(Processing details of lane departure prevention control)
Next, processing contents of the lane departure prevention control (lane departure prevention apparatus) will be described.
FIG. 8 shows a processing procedure of lane departure prevention control performed by the braking / driving force control unit 8. The processing shown in FIG. 8 is executed by a timer interruption every predetermined sampling time ΔT every 10 msec., For example. Although no communication process is provided in the process shown in FIG. 8, 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, the lateral acceleration Xg, the yaw rate φ ′ and the road information obtained by the navigation device 14, the wheel speeds Vwi, the steering angle δ, the accelerator opening θt, the master cylinder hydraulic pressure detected by the sensors. Pmf, Pmr, direction switch signal, drive torque Tw from the drive torque control unit 12, and yaw angle φ, lateral displacement X, and travel lane curvature β are read from the imaging unit 13.

Subsequently, in step S2, the vehicle speed V is calculated. Specifically, the vehicle speed V is calculated by the following equation (17) 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
... (17)
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 (17), 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.
In addition, you may use the own vehicle speed which the vehicle speed signal process part 31 computed for follow-up driving control.

Subsequently, in step S3, a lane departure tendency is determined. Specifically, the processing procedure of this determination processing is as shown in FIG. FIG. 10 illustrates the definition of values used in this process.
First, in step S21, the estimated lateral displacement Xs of the lateral position of the vehicle center of gravity after a predetermined time is calculated. Specifically, using the yaw angle φ obtained in step S1, the travel lane curvature β and the lateral displacement X0 of the current vehicle, and the vehicle speed V obtained in step S2, the estimated lateral displacement is given by the following equation (18). Xs is calculated.
Xs = Tt · V · (φ + Tt · V · β) + X0 (18)

Here, Tt is the vehicle head time for calculating the forward gaze distance, and when this vehicle head time Tt is multiplied by the own vehicle speed V, it becomes the front gaze distance. 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 the equation (18), the estimated lateral displacement Xs increases as the yaw angle φ increases, for example, when focusing on the yaw angle φ.

Subsequently, in step S22, departure determination is performed. Specifically, comparing the estimated lateral displacement Xs with a predetermined departure-tendency threshold value X _L.
Here, the departure tendency determination threshold value (or departure determination threshold value, hereinafter referred to as the first departure tendency determination threshold value) _XL is a value that can be generally grasped when the vehicle has a lane departure tendency. And obtained through experiments. For example, the first departure tendency determination threshold value _XL is a value indicating the position of the boundary line of the travel path, and is calculated by the following equation (19).
X _L = (D−H) / 2 (19)

Here, D is the lane width and H is the width of the vehicle. The lane width D is obtained by processing the captured image by the imaging unit 13. You can also obtain the position of the vehicle from the navigation system 14, wherein the map data of the navigation device 14 may be or give a lane width D, departure-tendency threshold value X _L is is set in lane Alternatively, it may be set outside the lane. When setting out lane, actually own vehicle may be set so as to be determined that a lane departure tendency after departure from the lane, the departure-tendency threshold value X _L is arbitrarily set is there.

In this step S22, when the estimated lateral displacement (absolute value) Xs is equal to or higher than the first departure-tendency threshold value _{X L (| Xs | ≧ X} L), there lane departure tendency (are or lane deviation) determining that, the process proceeds to step S23, when the estimated lateral displacement Xs is smaller than the first departure-tendency threshold value _{X L (| Xs | <X} L), the process proceeds to step S25.
In step S23, the first departure determination flag F _Lout is _turned ON (F _Lout = ON). Then, the process proceeds to step S24.

  In step S24, 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). 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). Then, the process shown in FIG. 9 (the process of step S3) ends.

On the other hand, in step S25, the first departure determination flag F _Lout is turned off (F _Lout = OFF). Then, the process proceeds to step S26.
In step S26, the estimated lateral displacement (absolute value) Xs and first departure-tendency threshold value X _L separately from the set departure-tendency threshold value (or the estimated departure threshold, below the second departure tendency that determining threshold value.) compares the _{X K.} Here, the second departure tendency determination threshold value _XK is smaller than the first departure tendency determination threshold value X _L (X _K < _XL ).

In this step S26, when the estimated lateral displacement Xs is equal to or higher than the second departure-tendency threshold value _{X K (| Xs | ≧ X} K), determines that there is lane departure tendency (likely to lane deviation) the process proceeds to step S27, when the estimated lateral displacement Xs is smaller than the second departure-tendency threshold value _{X L (| Xs | <X} K), the process proceeds to step S28.
In step S27, the second departure determination flag F _Kout is _turned ON (F _Kout = ON). Then, the process proceeds to step S24.
In step S28, it is determined that there is no lane departure tendency, and the second departure determination flag F _Kout is turned OFF (F _Kout = OFF). Then, the process shown in FIG. 9 (the process of step S3) ends.

As described above, the lane departure tendency is determined in step S3. According to the determination of the lane departure tendency, the estimated lateral displacement (absolute value) when Xs is equal to or higher than the first departure-tendency threshold value X _L, sets the first departure determination flag F _Lout to ON (in step S22 If the determination is “Yes”, step S23). Also, the estimated lateral displacement (absolute value) if Xs is less than the threshold value _{X L} for determining the first departure tendency, when the first departure determination flag _{F Lout} is set to OFF (the determination in step S22 "No", step S25), and this time, if the estimated lateral displacement (absolute value) Xs is a second departure-tendency threshold value _{X K} or more, the second departure determination flag _{F Kout} set to oN (the determination in step S26 for "Yes", step S27), if the estimated lateral displacement (absolute value) Xs is smaller than the second departure-tendency threshold value _{X K,} to set the second departure determination flag _{F Kout} to OFF (step S22 If the determination is “No”, step S28). Accordingly, even when the result is judged that there is no first departure-tendency threshold value _{X L} in the lane departure tendency _{(| Xs | <X L,} F Lout = OFF), the second departure-tendency threshold value X _{With L} , it is determined that there is a tendency to depart from the lane (there is a possibility of lane departure) (| Xs | ≧ X _K , F _Kout = ON).

Subsequently, in step S4, the driver's intention to change lanes is determined. Specifically, the driver's intention to change the lane is determined as follows based on the direction switch signal and the steering angle δ obtained in step S1.
When the direction indicated by the direction switch signal (the blinker lighting side) is the same as the direction indicated by the departure direction Dout obtained in step S3, it is determined that the driver has intentionally changed the lane, and the first departure The judgment flag F _Lout is changed to OFF (F _Lout = OFF). That is, it is changed to the determination result that there is no lane departure tendency.

Further, the direction indicated by the directional switch signal (blinker ON side), if the direction indicated by departure direction Dout obtained in step S3 is different, and maintaining the first departure determination flag _{F Lout,} first departure determination flag _{F Lout Is} left ON (F _Lout = ON). That is, the determination result that there is a tendency to depart from the lane is maintained.
When the direction indicating switch 20 is not operated, the driver's intention to change the lane is determined based on the steering angle δ. That is, when the driver is steering in the departure direction, the driver is conscious when both the steering angle δ and the change amount of the steering angle (change amount per unit time) Δδ are equal to or greater than the set value. And the first departure determination flag F _Lout is changed to OFF (F _Lout = OFF).

The driver's intention may be determined based on the steering torque.
As described above, when the first departure determination flag _FLout is ON and the driver has not intentionally changed the lane, the first departure determination flag _FLout is maintained ON.
The second departure determination flag F _Kout is also maintained in the state based on the direction indicated by the direction switch signal (the driver's intention to change lanes) in the same manner as the first departure determination flag F _Lout described above. It may be changed.

Subsequently, in step S5, the control content of the lane departure prevention control (including the control content of the follow-up traveling control) is determined. The processing procedure for determining the control content is specifically shown in FIG.
First, in step S31, it is determined whether or not the second departure determination flag F _Kout set in step S3 (or step S4) is ON. If the second departure determination flag F _Kout is ON (F _Kout = ON), the process proceeds to step S32. If the second departure determination flag F _Kout is not ON (F _Kout = OFF), the process proceeds to step S33.

In step S32, as a process for determining the control content (control parameter) of the follow-up running control, the target inter-vehicle distance L ^* of the follow-up running control is multiplied by the departure sensitive gain Ig which is a gain that changes according to the lane departure tendency. Change (update) the target inter-vehicle distance L ^* (L ^* = L ^* · Ig).
FIG. 12 shows the relationship between the absolute value | Xs | of the estimated lateral displacement and the deviation sensitive gain Ig. As shown in FIG. 12, the deviation sensitive gain Ig is increased in proportion to the absolute value | Xs | of the estimated lateral displacement, with 1 as an initial value. Accordingly, the target inter-vehicle distance L ^* increases as the absolute value | Xs | of the estimated lateral displacement increases. Then, the process proceeds to step S33.

In FIG. 12, the absolute value of the estimated lateral displacement | Xs |, and the absolute value of the estimated lateral displacement Xs | Xs | difference value between the second departure-tendency threshold value _{X K} (| Xs | -X _K ). As a result, the departure sensitivity gain Ig is increased in proportion to the difference value (| Xs | −X _K ) with 1 as an initial value.
In step S33, a target inter-vehicle distance L ^* for the following traveling control is set as a process for determining the control content of the following traveling control. That is, when the second departure determination flag F _Kout is ON in the step S31, the follow-up running control is performed using the target inter-vehicle distance L ^* changed in the step S32. When the second departure determination flag F _Kout is OFF in S31, the follow-up traveling control is performed using the target inter-vehicle distance L ^* that has not been changed.

In step 34, it is determined whether or not the first departure determination flag (current first departure determination flag) _FLout is ON. If the first departure determination flag F _Lout is ON (F _Lout = ON), the process proceeds to step S35. If the first departure determination flag F _Lout is not ON (F _Lout = OFF), the processing shown in FIG. (Process of step S5) is terminated.
Subsequently, in step S35, it is determined whether or not the second departure determination flag F _Kout (F _{Kout_z1} ) of the previous time (the previous process in the calculation process of FIG. 11) is ON. If the previous second departure determination flag F _Kout is ON (F _Kout = ON), the process proceeds to step S36, and if the previous second departure determination flag F _Kout is not ON (F _Kout = OFF), 11 (the process of step S5) is terminated.

In step S36, it is determined whether or not the target acceleration / deceleration Yg ^* (Yg ^* _z1) is less than zero. If the target acceleration / deceleration Yg ^* is less than 0 (Yg ^* <0), that is, if the follow-up running control is performing deceleration control, the process proceeds to step S37, and the target acceleration / deceleration Yg ^* is 0 or more (Yg ^* ≧ 0) In other words, when the follow-up running control is performing acceleration control, the processing shown in FIG. 11 (processing in step S5) is terminated.

In step S37, the control shift flag Fs is set to ON (Fs = ON). That is, when the first departure determination flag F _Lout is ON, the previous second departure determination flag F _Kout is ON, and the previous target acceleration / deceleration Yg ^* is less than 0, the control transition flag Fs is turned ON. Set. Then, the process shown in FIG. 11 (the process of step S5) ends.
As described above, the control content is determined in step S5.

Subsequently, in step S6, if the first departure determination flag _FLout is ON as a result of the processing in step S4, sound output or display output is performed as an alarm for preventing lane departure.
As will be described later, when the first departure determination flag _FLout is ON, the application of the yaw moment to the host vehicle is started as the lane departure prevention control. Is done. 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 S7, a target yaw moment Ms to be given to the vehicle as lane departure prevention control is calculated. Specifically, the target yaw moment Ms is calculated by the following equation (20) based on estimated lateral displacement Xs and lateral displacement limit distance obtained in step S3 to the (first departure-tendency threshold value) X _L .
Ms = K1 · K2 · (| Xs | −X _L ) (20)
Here, K1 is a proportional gain determined from vehicle specifications, and K2 is a gain that varies according to the vehicle speed V. FIG. 13 shows an example of the gain K2. As shown in FIG. 13, for example, the gain K2 has a large value in the low speed range, and when the vehicle speed V reaches a certain value, it has a decreasing relationship with respect to the increase in the vehicle speed V. It becomes a constant value.

According to the (20) equation, the larger the difference between estimated lateral displacement Xs and lateral displacement limit distance X _L is, target yaw moment Ms becomes larger.
The target yaw moment Ms is calculated when the first departure determination flag _FLout is ON, and the target yaw moment Ms is set to 0 when the first departure determination flag _FLout is OFF.
Subsequently, in step S8, a target brake hydraulic pressure for each wheel is calculated. That is, the final braking fluid pressure is calculated based on the presence or absence of braking control for preventing lane departure. Specifically, it is calculated as follows.

When the first departure determination flag _FLout is OFF, that is, when the determination result that there is no lane departure tendency is obtained, as shown in the following equations (21) and (22), the target braking hydraulic pressure Psi of each wheel (I = fl, fr, rl, rr) is set to the brake fluid pressures Pmf, Pmr.
Psfl = Psfr = Pmf (21)
Psrl = Psrr = Pmr (22)
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 performing a brake operation, the brake fluid pressures Pmf and Pmr are values corresponding to the operation amount of the brake operation.

On the other hand, when the first departure determination flag _FLout is ON, that is, when the determination result that there is a lane departure tendency is obtained, based on the target yaw moment Ms calculated in step S7, the front wheel target braking hydraulic pressure difference ΔPsf and A rear wheel target braking hydraulic pressure difference ΔPsr is calculated. Specifically, the target braking hydraulic pressure differences ΔPsf and ΔPsr are calculated by the following equations (23) to (26).
If | Ms | <Ms1, ΔPsf = 0 (23)
ΔPsr = Kbr · Ms / T (24)
When | Ms | ≧ Ms1 ΔPsf = Kbf · (| Ms | −Ms1) / T (25)
ΔPsr = Kbr · Ms1 / T (26)
Here, Ms1 represents a setting threshold value. T represents a tread. This tread T is set to the same value before and after for simplicity. Kbf and Kbr are conversion coefficients for the front wheels and the rear wheels when the braking force is converted into the braking hydraulic pressure, and are determined by the brake specifications.

  Thus, the braking force generated by the wheels is distributed according to the magnitude of the target yaw moment Ms. When the target yaw moment Ms is less than the setting threshold value Ms1, the front wheel target braking hydraulic pressure difference ΔPsf is set to 0, a predetermined value is given to the rear wheel target braking hydraulic pressure difference ΔPsr, and a braking force difference is generated between the left and right rear wheels. Further, when the target yaw moment Ms is equal to or larger than the setting threshold value Ms1, a predetermined value is given to each target braking hydraulic pressure difference ΔPsr, ΔPsr, and a braking force difference is generated between the front, rear, left and right wheels.

When the first departure determination flag _FLout is ON, the final target braking fluid pressure Psi of each wheel is calculated based on the departure direction Dout using the calculated target braking fluid pressure difference ΔPsf, ΔPsr. (I = fl, fr, rl, rr) is calculated. That is, when the departure direction Dout is left (Dout = left), that is, when there is a lane departure tendency with respect to the left lane, the target braking fluid pressure Psi (i = fl, fr, rl) of each wheel according to the following equation (27) , Rr).
Psfl = Pmf
Psfr = Pmf + ΔPsf
Psrl = Pmr
Psrr = Pmr + ΔPsr
... (27)

When the departure direction Dout is right (Dout = right), that is, when there is a lane departure tendency with respect to the right lane, the target braking fluid pressure Psi (i = fl, fr, rl) of each wheel is calculated according to the following equation (28). , Rr).
Psfl = Pmf + ΔPsf
Psfr = Pmf
Psrl = Pmr + ΔPsr
Psrr = Pmr
... (28)
According to the equations (27) and (28), 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, as shown in the equations (27) and (28), the brake operation by the driver, that is, the target brake fluid pressure Psi (i = fl, fr, rl) of each wheel in consideration of the brake fluid pressures Pmf, Pmr. , Rr). Then, the braking / driving force control unit 8 uses the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) calculated for each wheel thus calculated as a braking fluid pressure command value to the braking fluid pressure control unit 7. Output. The brake fluid pressure control unit 7 controls the brake fluid pressure based on the input target brake fluid pressure Psi (i = fl, fr, rl, rr) to generate a braking force on each wheel.

Here, when the subject vehicle shows a tendency to deviate while the subject vehicle is following the preceding vehicle by the follow-up running control (| Xs | ≧ X _L ), the operation of the follow-up running control (follow-up running control) ) Is stopped and lane departure prevention control is activated (switching to braking control by lane departure prevention control). That is, when the departure determination flag Fout is turned ON, the vehicle speed control by the follow-up running control (braking control by the follow-up running control) is stopped and the lane departure prevention control is activated (intervened) (by the lane departure prevention control). Switch to braking control). When the first departure determination flag _FLout is turned off, that is, after avoiding the lane departure by the lane departure prevention control, or after avoiding the lane departure by the driver's own driving operation in some cases, The following traveling control is activated (braking control by the following traveling control is activated).

  In addition, when the following traveling control (during deceleration control) is switched to lane departure prevention control (immediately after switching), that is, in step S5 (step S37), the control transition flag Fs is set to ON. In this case (immediately after the setting), in the lane departure prevention control, the braking fluid pressure of the wheel on the lane departure side is decreased and the target braking fluid pressure Psi of the wheel on the lane departure avoidance side is increased and corrected. At this time, the correction is performed so that the target braking hydraulic pressure Psi of the lane departure avoiding wheel is increased by at least the target braking hydraulic pressure difference ΔPsr, ΔPsr with respect to the target braking hydraulic pressure Psi of the lane departure side wheel. For example, as shown in FIG. 14, by multiplying the target braking hydraulic pressure Psi of the wheel on the lane departure avoidance side by a gain Gs that gradually decreases to 1 when a predetermined time Ts has elapsed (Psi = Psi · Gs). ) The target braking hydraulic pressure Psi of the wheel on the lane departure avoidance side is increased and corrected only for the predetermined time Ts. Here, the predetermined time Ts indicates that the braking hydraulic pressure controlled by the following traveling control for the wheel on the lane departure side when the following traveling control is switched from the following traveling control to the lane departure preventing control. This is the time taken to decrease to the required target brake hydraulic pressure Psi.

(Operation, action and effect)
With the processing as described above, the following series of operations are performed. Here, the operation and effect will also be described.
First, various data are read from each sensor or the like (step S1), and the vehicle speed V is calculated (step S2).
Subsequently, a lane departure tendency is determined based on the estimated lateral displacement Xs (step S3). That is, the estimated lateral displacement (absolute value) if Xs is greater than or equal to the threshold _{X L} for determining the first departure tendency, setting the first departure determination flag _{F Lout} to ON. Further, when the estimated lateral displacement (absolute value) Xs less than the threshold value _{X L} for determining the first departure tendency, the first departure determination flag _{F Lout} is set to OFF, this time, the estimated lateral displacement (absolute value) Xs if There is a second departure-tendency threshold value _{X K} or more, the second departure determination flag _{F Kout} set to oN, the estimated lateral displacement (absolute value) Xs second departure-tendency threshold value _{X K} If it is less, the second departure determination flag F _Kout is set to OFF. When the first departure determination flag _FLout is ON, the departure direction Dout is detected.

Further, even when the first departure determination flag F _Lout to ON, determines the intention of the driver to change lanes, if there is intention to change lanes to the driver, to change the first departure determination flag F _Lout to OFF If the driver does not intend to change lanes, the first departure determination flag _FLout is maintained ON (step S4). If the first departure determination flag _FLout is ON, a warning is output (step S6).

Further, the target yaw moment Ms to be given to the vehicle as the lane departure prevention control is calculated (step S7). When the first departure determination flag _FLout is ON, the target yaw moment is applied to the host vehicle as the lane departure prevention control. The brake fluid pressure is controlled based on the target brake fluid pressure Psi (i = fl, fr, rl, rr) so that Ms is applied, and a braking force is generated on the wheel (step S8). At this time, a braking force is generated on the wheel based on a predetermined control method (step S5).

That is, the estimated lateral displacement (absolute value) Xs is a second departure-tendency threshold value X _K or more, when the second departure determination flag F _Kout set to ON, the target inter-vehicle distance L to be used in the following distance control ^* Is increased and corrected ("Yes" in step S31, step S32). Accordingly, in deceleration control in follow-up running control, inter-vehicle distance control is performed based on the increased corrected target inter-vehicle distance L ^*. The As a result, the target acceleration / deceleration Yg ^* becomes small (because the target acceleration / deceleration Yg ^* becomes large at a negative value), so that the host vehicle decelerates more than during normal control.

Then, while the follow-up running control is performing the deceleration control with the target inter-vehicle distance L ^* thus corrected for increase, this time, the estimated lateral displacement (absolute value) Xs becomes the first departure tendency determination threshold value X. _When it becomes _L or more, that is, when it is determined that there is a lane departure tendency (in the case of “Yes” in the determination of Steps S34 to S36), the control transition flag Fs is set to ON (Step S37). , By switching the traveling control from the following traveling control (braking control by following traveling control) to the lane departure preventing control (braking control by lane departure preventing control), the braking fluid pressure of the wheel on the lane departure side is reduced and controlled. Then, the target braking hydraulic pressure Psi of the wheel on the lane departure avoidance side is increased and corrected. Specifically, as the braking control in the lane departure prevention control, the target braking fluid pressure Psi of the lane departure avoiding wheel is at least the target braking fluid pressure difference ΔPsr, compared to the target braking fluid pressure Psi of the lane departure avoiding wheel. Increase correction is performed so as to increase by ΔPsr.

  As described above, when the cruising control is switched to the lane departure prevention control, the braking fluid pressure of the lane departure side wheel is reduced and the braking fluid pressure of the lane departure side wheel is reduced by the deceleration of the following traveling control. By reducing the value under control to the value required under lane departure prevention control (target braking hydraulic pressure Psi), the difference in braking force between the left and right wheels is generated from the follow-up traveling control that performs deceleration control. It is possible to smoothly shift to the lane departure prevention control that gives the yaw moment to the vehicle.

  Here, as described above, the braking fluid pressure of the lane departure side wheel is decreased from the value under the deceleration control of the following traveling control to the value required under the lane departure prevention control (target braking fluid pressure Psi). If it tries to do so, it will take time to reach the value required under the lane departure prevention control. At this time, if the target braking fluid pressure Psi of the wheel on the lane departure avoiding side opposite to the wheel is kept at the value used in the normal lane departure preventing control, the braking fluid pressure of the wheel on the lane departure side becomes the lane. During the period until the value is reduced to the value required under the departure prevention control, the difference in braking force between the left and right wheels is not sufficient, and the yaw moment sufficient to prevent the lane departure cannot be applied to the host vehicle. Therefore, by increasing and correcting the target braking fluid pressure Psi of the lane departure avoiding side wheel for a predetermined time including such a decrease time of the braking fluid pressure, the braking force difference between the left and right wheels is reduced to the lane. The value can be sufficient to generate the yaw moment necessary to prevent deviation.

As a result, as shown in FIG. 15A, if the departure tendency becomes high during the operation of the follow-up running control (when predicted to deviate from the lane, | Xs | ≧ X _K ), the departure tendency becomes high. in the follow-up running control, thereby decelerating the host vehicle in deceleration is larger than the value of the normal control, then, when switched to the lane departure prevention control from the following distance control (| Xs | ≧ X _L In the lane departure prevention control, while the brake fluid pressure of the lane departure side wheel is controlled to decrease, the target brake fluid pressure Psi of the lane departure avoidance side wheel is made larger than the value during normal control for a predetermined time. Thus, a braking force difference is generated between the left and right wheels, and a yaw moment is applied to the host vehicle.

As a result, in the process until the lane departure prevention control is activated (the process immediately before the operation), the host vehicle is decelerated at a deceleration larger than that in the normal control by the following traveling control, and the subsequent lane departure prevention control A yaw moment sufficient to avoid lane departure will be applied.
On the other hand, even if it is determined that there is a tendency to deviate from the lane (in the case of “No” in the determination in Step S34), the deceleration of the follow-up travel control is not immediately corrected to increase (“No in the determination in Step S35”) ”), Or when the follow-up running control is operating immediately before, but the follow-up running control is performing acceleration control (in the case of“ No ”in the determination of step S36), the control transition flag Fs is OFF ( In the lane departure prevention control, the brake fluid pressure is controlled so as to be the target brake fluid pressure Psi that is not subjected to the increase correction as described above to control the left and right wheels. A power difference is generated and a yaw moment is applied to the host vehicle.

As described above, the braking control based on the lane departure prevention control and the braking control based on the following traveling control do not operate at the same time, so that the braking control based on the lane departure preventing control and the deceleration control of the following traveling control are required. The braking control is not complicated.
Furthermore, when the follow-up running control is decelerating immediately before it is predicted that the lane departure prevention control is activated, the deceleration control decelerates at a deceleration greater than normal, so the deceleration action causes a lane departure tendency. That is, the operation of the lane departure prevention control can be suppressed. Accordingly, it is possible to prevent the driver from being bothered by frequent operation of the lane departure prevention control. Further, even if the lane departure prevention control is activated, the deceleration effect by the immediately following traveling control is combined with the lane departure prevention control to increase the lane departure prevention effect.

Further, as the absolute value | Xs | of the estimated lateral displacement is increased, the target inter-vehicle distance L ^* is increased (see FIG. 12). Accordingly, the follow-up traveling control is increased as the lane departure tendency (| Xs |) is increased. Since the deceleration at is increased, it is possible to prevent the deceleration from being corrected more than necessary in the follow-up traveling control.
In the conventional example in which the lane departure tendency is present during the tracking control operation and the normal control content is simply switched from the tracking control to the lane departure prevention control, as shown in FIG. As described above, since the travel control does not make the correction to increase the deceleration, the lane departure prevention control that operates when the vehicle tends to deviate from the lane (| Xs | ≧ X _L ) has the effect of preventing the lane departure. It cannot be obtained as much as the effect of the invention.

The embodiments of the present invention have been described above. However, the present invention is not limited to being realized as the embodiment.
In the above-described embodiment, the case where the yaw moment is applied to the host vehicle to prevent the lane departure as the lane departure prevention control has been described. However, it is not limited to this. For example, as the lane departure prevention control, the host vehicle may be decelerated in the traveling direction (hereinafter referred to as lane departure prevention deceleration control) by generating the same braking force on the left and right wheels. In this case, for example, when the departure tendency becomes large due to an increase in the yaw angle with respect to the traveling road, the deceleration control for preventing lane departure is performed, and the timing to perform the control is just before the yaw moment is applied. Or at the same time that the yaw moment is applied. Even when such lane departure prevention deceleration control is performed, the braking control is performed in a scene where braking control by lane departure prevention deceleration control and braking control of follow-up traveling control are required, as in the previous embodiment. It won't be complicated.

Further, the lane departure prevention control is not limited to the one that gives a braking force difference between the left and right wheels, for example, one that changes the driving force distribution of the left and right wheels, one that performs steering control, or a combination thereof. good.
In the above-described embodiment, the description is given on the assumption that inter-vehicle distance control for controlling the vehicle speed of the host vehicle so as to follow the preceding vehicle by following traveling control is performed. However, it is not limited to this. For example, when the following traveling control is performing deceleration control by changing the driver's set vehicle speed in a traveling scene other than following the preceding vehicle (for example, when traveling at a constant vehicle speed), the following operation is performed. It may be a case where the travel control is switched to the lane departure prevention control.

In the above embodiment, the target acceleration / deceleration Yg ^* is decreased (negative value ⁾ as a result by increasing and correcting the target inter-vehicle distance L ^* used in the follow-up travel control when the second departure determination flag F _Kout is ON. The case where the correction is performed has been described (in the case of “Yes” in the determination of step S31, step S32). However, it is not limited to this. That is, when the second departure determination flag F _Kout is ON, the target acceleration / deceleration Yg ^* (or the control gain for calculating the target acceleration / deceleration Yg ^* ) may be corrected directly, and the target of the follow-up running control Since the acceleration / deceleration Yg ^* is originally used to set the target vehicle speed V ^* , the target vehicle speed V ^* may be corrected to decrease. Further, the correction of the target inter-vehicle distance L ^*, the correction of the target acceleration / deceleration Yg ^* , and the correction of the target vehicle speed V ^* may be combined.

  In the description of the above-described embodiment, the processing of step S21 and step S22 of the braking / driving force control unit 8 obtains the position information of the own vehicle indicating the degree of departure tendency of the own vehicle from the traveling lane, and the position information A departure tendency determination unit that determines that the vehicle has a departure tendency when a predetermined threshold value is exceeded is realized. In the processing of steps S6 to S8 of the braking / driving force control unit 8, the departure tendency determination unit determines that the own vehicle When it is determined that the vehicle has a tendency to deviate, lane departure prevention control means for performing lane departure prevention control for preventing the host vehicle from deviating from the traveling lane is realized, and step S26 of the braking / driving force control unit 8 is performed. The processes of Step S27 and Steps S31 to S33 and the control of the follow-up running control according to these processes are performed by the vehicle of the host vehicle. The vehicle speed control means for performing the vehicle speed control for controlling the vehicle speed and the deceleration in the vehicle speed control increase based on the position information before the vehicle speed control means exceeds the predetermined threshold value. Thus, the control parameter is corrected.

It is a schematic block diagram which shows embodiment of the vehicle carrying the traveling control apparatus of the vehicle of this invention. It is a block diagram which shows the structure for implementing follow | following driving | running | working control which is a structure of the control unit of the travel control apparatus of the said vehicle. It is a block diagram for demonstrating the ranging signal process part of the said control unit. It is a block diagram for demonstrating the relative speed calculating part of the said control unit. It is a block diagram for demonstrating the inter-vehicle distance control part of the said control unit. It is a block diagram for demonstrating the inter-vehicle distance control part of the said control unit. It is a block diagram for demonstrating the target inter-vehicle distance setting part of the said control unit. It is a flowchart which shows the processing content of the control unit which comprises a lane departure prevention apparatus (lane departure prevention control) in the travel control apparatus of a vehicle. It is a flowchart which shows the processing content of determination of the lane departure tendency by the said control unit. It is a diagram used for explanation of the estimated lateral displacement Xs and the departure tendency determination threshold value X _L. It is a flowchart which shows the processing content which determines the control content of the lane departure prevention control by the said control unit. FIG. 6 is a characteristic diagram showing a relationship between an absolute value | Xs | of an estimated lateral displacement and a deviation sensitive gain Ig. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K2. FIG. 6 is a characteristic diagram showing a change with time in gain Gs from when the follow-up running control is switched to lane departure prevention control. It is a figure which shows the traveling control of the vehicle at the time of applying this invention, and the traveling control of the vehicle in the conventional case.

Explanation of symbols

  6FL to 6RR wheel cylinder, 7 brake fluid pressure control unit, 8 braking / driving force control unit, 9 engine, 12 drive torque control unit, 13 imaging unit, 14 navigation device, 16 radar, 17 master cylinder pressure sensor, 18 accelerator opening Sensor, 19 Steering angle sensor, 22FL-22RR Wheel speed sensor, 31 Vehicle speed signal processor, 32 Image processor, 33 Vehicle speed controller, 34 Ranging signal processor, 40 Travel controller

Claims (9)

A departure tendency determination means for obtaining position information of the own vehicle indicating a degree of departure tendency of the own vehicle with respect to the traveling lane, and determining that the position information is a departure tendency when the position information exceeds a predetermined threshold, and the departure tendency determination Lane departure prevention control means for performing lane departure prevention control for preventing the own vehicle from deviating from the traveling lane when the means determines that the own vehicle has a tendency to deviate, and vehicle speed control for controlling the vehicle speed of the own vehicle Vehicle speed control means for performing,
The vehicle speed control means corrects a control parameter so that a deceleration in the vehicle speed control is increased based on the position information before the position information exceeds the predetermined threshold value. Travel control device.   The vehicle travel control device according to claim 1, wherein the vehicle speed control unit corrects the control parameter so that the deceleration increases as the position information approaches the predetermined threshold value.   The vehicle speed control means uses a distance between the host vehicle and a preceding vehicle as a target inter-vehicle distance, and corrects to increase the target inter-vehicle distance as the position information approaches the predetermined threshold value. The travel control device for a vehicle according to claim 1 or 2.   4. The vehicle travel control device according to claim 1, wherein the vehicle speed control unit cancels the vehicle speed control when the departure tendency determination unit determines the departure tendency. 5.   The vehicle speed control means controls the deceleration by a control gain, and increases the deceleration by correcting the control gain. The vehicle travel control apparatus described.   The vehicle travel control device according to claim 5, wherein the vehicle speed control unit increases the correction amount of the control gain as the position information approaches the predetermined threshold value.   The lane departure prevention control applies a yaw moment to the host vehicle by increasing the braking force of the left and right wheels on the lane departure avoiding side of the left and right wheels more than the braking force of the left and right wheels. And the vehicle speed control is to apply braking force to the left and right wheels to perform deceleration control, and when the departure tendency determination means determines that the host vehicle is in a departure tendency, the vehicle speed control starts from the vehicle speed control to the lane. 7. The lane departure prevention control at the time of switching is switched to departure prevention control, and the braking force of the lane departure side wheel of the left and right wheels is reduced. The travel control device according to any one of the above.   In the lane departure prevention control, the braking force of the left and right wheels on the lane departure side is made larger than the braking force of the lane departure side wheels on the left and right wheels, and a yaw moment is applied to the host vehicle. And the vehicle speed control is to apply braking force to the left and right wheels to perform deceleration control, and when the departure tendency determination means determines that the host vehicle is in a departure tendency, the vehicle speed control starts from the vehicle speed control to the lane. Switch to departure prevention control, and perform a correction to increase the braking force of the lane departure avoidance side of the left and right wheels for a predetermined time after switching from the vehicle speed control to the lane departure prevention control. The travel control device according to any one of claims 1 to 7, wherein Vehicle travel that performs vehicle speed control for controlling the vehicle speed of the host vehicle and lane departure prevention control for preventing the host vehicle from deviating from the traveling lane when it is determined that the host vehicle is deviating from the traveling lane In the control device,
A vehicle travel control apparatus that corrects a control parameter so that a deceleration in the vehicle speed control is increased before the departure tendency is determined.

Images