JP2009035214A - Vehicle behavior control apparatus and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control vehicle behavior while preventing a driver from feeling uncomfortableness even when vehicle behavior is controlled by combining steering control and braking force control. <P>SOLUTION: A vehicle behavior control device calculates target steering torque which is made to be generated on a steering wheel grasped by the driver based on a cruising state (step S10), controls the steering torque to be added to the steering wheel based on the target steering torque, while estimates a secondary yaw moment to be generated to the vehicle as a result of change of steering wheel which is mechanically linked to the steering wheel by controlling the steering torque (step S11), then a braking and driving force for making the yaw moment generated on the vehicle based on target yaw moment and a secondary yaw moment is controlled based on the target yaw moment and the secondary yaw moment which are generated to the vehicle which is calculated based on the cruising state (step S12 to step S15). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle behavior control apparatus and method, and more particularly to a vehicle behavior control apparatus and method for suppressing lateral behavior of a vehicle.

Conventionally, when it is determined that the vehicle deviates from the driving lane, the vehicle behavior is controlled by combining the steering assist force control (steering control) and the braking force control, so that the vehicle is returned to the driving lane and the vehicle deviates from the lane. There is a system that prevents this (Patent Document 1).
JP 2005-178743 A

In such a conventional system, the steering assist force control and the braking force control are combined to change the control sharing between the steering assist force control and the braking force control according to the driving scene that can effectively exhibit the performance. It has become. However, such a system that changes the control sharing between the steering assist force control and the braking force control may give the driver an uncomfortable feeling. For example, if only braking force control is activated to prevent lane departure, depending on the driving scene, the driver may not be able to recognize the control that is implementing lane departure prevention. It may be difficult to determine whether it is in the correct operating state. Furthermore, the system that changes the control sharing between the steering assist force control and the braking force control is intended to be able to effectively demonstrate the performance with respect to the vehicle behavior to the last. In some cases, the corners become large, and the driver feels uncomfortable.
An object of the present invention is to perform control while preventing the driver from feeling uncomfortable even when the vehicle behavior is controlled by combining steering control and braking force control.

In order to solve the above-mentioned problems, the present invention provides a target to be generated on a steering wheel gripped by a driver based on a traveling state detected by a traveling state detection unit and detected by the traveling state detection unit. Steering torque is calculated by the target steering torque calculating means, and based on the target steering torque calculated by the target steering torque calculating means, the steering torque applied to the steering wheel is controlled by the steering torque control means, and the steering torque is controlled. The traveling state detected by the traveling state detecting means is estimated by the subsidiary yaw moment estimating means by the subsidiary yaw moment estimating means as a result of turning the steering wheel mechanically connected to the steering wheel. Based on the above, the target yaw moment to be generated in the vehicle is calculated by the target yaw moment calculating means. Based on the target yaw moment calculated by the target yaw moment calculating means and the secondary yaw moment estimated by the secondary yaw moment estimating means, the braking / driving force for generating the yaw moment in the vehicle is controlled by the braking / driving force control means. .
Thus, the steering control allows the driver to recognize the traveling state via a change in torque of the steering wheel, while the vehicle is given a yaw moment according to the traveling state by the braking / driving force control. It becomes like this.

  According to the present invention, as a result of steering control of the steering wheel gripped by the driver based on the traveling state of the vehicle, the steering wheel mechanically connected to the steering wheel is steered by the steering control. The vehicle braking / driving force control is performed so that the yaw moment obtained by adding the secondary yaw moment to the yaw moment generated in the vehicle is estimated based on the running state of the vehicle. Therefore, the driver can recognize the current traveling state via the steering wheel by the steering control, and even if the steered wheels are steered due to the influence of the steering control, based on the traveling state of the vehicle, Yaw moment can be applied to the vehicle without excess or deficiency.

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 vehicle behavior control apparatus which concerns on this invention. This 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.
In the vehicle behavior control apparatus according to the first embodiment, the steering wheel is controlled by steering control so that the driver recognizes that the vehicle deviates from the traveling lane, and the vehicle travels by driving force control. Lane departure prevention control is performed to prevent departure from the lane.

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

  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 (Trq) 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. When a drive torque command value is input from the braking / driving force control unit 8, the drive torque command unit 12 The drive wheel torque is controlled according to the 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. The imaging unit 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 the travel range where the vehicle should travel and determine the travel lane. For example, when there is no white line on the runway and both sides of the road are separated, the asphalt portion of the runway is determined as the travel lane. Moreover, what is necessary is just to determine a driving lane in consideration of the information, when there is a guardrail, a curb, etc.

Further, the traveling lane curvature β may be calculated based on a steering angle δ of the steering wheel 21 described later.
The vehicle is provided with a navigation device 14. The navigation device 14 detects the longitudinal acceleration Yg or the lateral acceleration Xg generated in the host vehicle, or the yaw rate φ ′ (= dφ / dt) generated in the host vehicle. The navigation device 14 outputs the detected longitudinal acceleration Yg, lateral acceleration Xg, and yaw rate φ ′ to the braking / driving force control unit 8 together with the road information. Here, as the road information, there is road type information indicating a road type such as the number of lanes, 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.

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 steering angle) δ of the steering wheel 21, a direction indicating switch 20 for detecting an operation of a direction indicator (turn signal switch) by a driver, and rotation of each wheel 5FL to 5RR. Wheel speed sensors 22FL to 22RR for detecting a speed, so-called wheel speed Vwi (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.

FIG. 2 shows further details of the configuration of the steering device that performs the steering control.
As shown in FIG. 2, in this vehicle, front wheels 5FL and 5FR are mechanically connected to a steering wheel 21 via a steering rack 31, a hydraulic power steering device 32, and a steering shaft 33. A direction indicator 34 is attached to the steering wheel 21, and a steering angle sensor 19, a steering actuator 35, and a torque sensor 36 are attached to the steering shaft 33 from the steering wheel 21 toward the hydraulic power steering device 32. Each is attached.

  The vehicle is equipped with a steering control unit 37 that controls the steering actuator 35, and the steering control unit 37 controls the steering actuator 35 based on a target steering torque command from the braking / driving force control unit 8. is doing. As a result, torque corresponding to the target steering torque is transmitted to the steering wheel 21 via the steering shaft 33. At this time, it is also transmitted to the front wheels 5FL and 5FR via the steering shaft 33, the hydraulic power steering device 32 and the steering rack 31. Further, the steering control unit 37 receives the torque detected by the torque sensor 36 and outputs this torque to the braking / driving force control unit 8. Furthermore, data from the vehicle speed sensor 38 and the imaging unit 13 are input to the steering control unit 37.

Next, calculation processing performed by the braking / driving force control unit 8 will be described.
FIG. 3 shows a calculation processing procedure performed by the braking / driving force control unit 8. 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. 3, information obtained by the calculation process is updated and stored in the storage device as needed, and necessary information is read out from the storage device as needed.

  As shown in FIG. 3, when the process is started, first, in step S1, various data are read from each sensor, controller, and control unit. Specifically, the longitudinal acceleration Yg, 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 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 formula (1) based on the wheel speed Vwi read in step S1.
For front wheel drive V = (Vwr1 + Vwrr) / 2
For rear wheel drive V = (Vwfl + Vwfr) / 2
... (1)
Here, Vwfl and Vwfr are the wheel speeds of the left and right front wheels, and Vwrl and Vwrr are the wheel speeds of the left and right rear wheels. That is, in the equation (1), the vehicle speed V is calculated as an average value of the wheel speeds of the driven wheels. In this embodiment, since the vehicle is a rear-wheel drive vehicle, the vehicle speed V is calculated from the latter equation, that is, the wheel speed of the front 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. In addition, a value used for navigation information in the navigation device 14 may be used as the vehicle speed V.
Subsequently, in step S3, an estimated lateral displacement Xs of the vehicle center of gravity lateral position after a predetermined time T is calculated. Specifically, using the yaw angle φ obtained in step S1, the traveling 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 expressed by the following equation (2). Xs is calculated.
Xs = Tt · V · (φ + Tt · V · β) + X0 (2)

  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. This estimated lateral displacement Xs is a deviation estimated value indicating a deviation tendency of the vehicle with respect to the traveling lane. According to equation (2), for example, when focusing on the yaw angle φ, the estimated lateral displacement Xs increases as the yaw angle φ increases.

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.
If the direction indicated by the direction switch signal (the blinker lighting side) matches the lane departure direction (positive or negative sign) indicated by the estimated lateral displacement Xs obtained in step S3, the driver has intentionally changed the lane. And the lane change determination flag _Flc is set to ON. If the direction indicated by the direction switch signal (the blinker lighting side) does not match the lane departure direction indicated by the estimated lateral displacement Xs, it is determined that there is a high possibility of lane departure, and the lane change determination flag F _lc is set. Set to OFF.

When the lane change determination flag F _lc is set to ON, even when the direction indicator switch 20 is subsequently released (even in a scene where the lane change determination flag F _lc is supposed to be turned OFF) The lane change determination flag _Flc is kept on for a certain period (for example, 4 seconds) after the release. Depending on the driver or driving operation, the direction indicator switch 20 may be released during the lane change. In such a case, the lane change determination flag _Flc is changed to OFF, and the lane change is made during the lane change. This is to prevent the departure prevention control from operating.

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. It is determined that the lane has been changed, and the lane change determination flag _Flc is set to ON. The driver's intention may be determined based on the steering torque.

As described above, the lane change determination flag F _lc is set, and the alarm and the lane departure prevention control are activated according to the set state of the lane change determination flag F _lc as described later. That is, the warning and the lane departure prevention control depend on the operation state of the driver's direction indicating switch 20 and operate only according to the departure tendency without being influenced by other operations.
Here, the warning is to notify the driver that the own vehicle has deviated from the traveling lane by voice or image display. Specifically, the lane departure prevention control is performed by braking / driving force control. By generating a braking force difference between the left and right wheels, a yaw moment is applied to the vehicle to prevent the vehicle from deviating from the traveling lane.

Subsequently, in step S5, as a lane departure prevention control, an alarm is activated to notify the driver that the host vehicle has deviated from the lane. Specifically, the estimated lateral displacement Xs calculated in step S3 is compared with the warning determination threshold value Xw for determination. Here, the warning determination threshold value Xw is calculated by the following equation (3) using the lateral displacement limit value Xc that is the departure determination threshold value.
Xw = Xc−Xm (3)
Here, Xm is a margin (constant) until the lane departure prevention control by the braking / driving force is activated after the alarm is activated.

When the lane change determination flag F _lc is OFF (F _lc = OFF), the estimated lateral displacement Xs (positive value) is larger than the alarm determination threshold value Xw (Xs> Xw), or the estimated lateral displacement Xs When (negative value) is smaller than the alarm determination threshold value −Xw (Xs <−Xw), the alarm is activated. That is, when the lane change determination flag F _lc is OFF (F _lc = OFF), the alarm is activated when the absolute value of the estimated lateral displacement Xs is larger than the absolute value of the alarm determination threshold value Xw.

  When the alarm is activated once, the estimated lateral displacement Xs (positive value) is thereafter equal to or less than the value obtained by subtracting the predetermined value Xh from the alarm determination threshold value Xw (Xs ≦ Xw−Xh), or The alarm drive is maintained until the estimated lateral displacement Xs (negative value) is equal to or greater than the value obtained by adding the predetermined value Xh to the alarm determination threshold value −Xw (Xs ≧ −Xw + Xh). Here, the predetermined value Xh is a hysteresis (constant) for avoiding alarm hunting.

Subsequently, in step S6, a lane departure determination is performed. Specifically, the determination is made by comparing the estimated lateral displacement Xs and the lateral displacement limit value Xc. Here, when the estimated lateral displacement Xs (positive value) is equal to or greater than the lateral displacement limit value Xc (Xs ≧ Xc), it is determined that the vehicle deviates to the left side of the traveling lane, and the departure determination flag F _ld is set to 1 ( F _ld = 1), and when the estimated lateral displacement Xs (negative value) is the lateral displacement limit value −Xc ≦ (Xs ≦ −Xc), it is determined that the vehicle deviates to the right side of the traveling lane, and the departure determination flag F _ld is set. Set to −1 (F _ld = −1). In other cases, that is, when the absolute value of the estimated lateral displacement Xs is less than the absolute value of the lateral displacement limit value Xc, it is determined that the vehicle has not deviated from the lane, and the departure determination flag _Fld is set to zero. (F _ld = 0).

Here, the lateral displacement limit value Xc is a constant. In Japan, the lateral displacement limit value Xc is set to, for example, 0.8 m from the vehicle width of 3.35 m on the highway. Further, the lateral displacement limit value Xc may be a variable. In this case, the lateral displacement limit value is calculated based on the lane width L of the travel path calculated by processing a camera image or obtained from the map data of the navigation information. Xc can also be changed. For example, the lateral displacement limit value Xc is calculated by the following equation (4).
Xc = MIN (L / 2−Lc / 2, 0.8 [m]) (4)
Here, Lc is the vehicle width of the vehicle (host vehicle) on which the present apparatus is mounted. The function MIN (A, B) is a function for selecting the minimum value of A and B, that is, a function for performing a so-called select row. By this, the function MIN of the above equation (4) allows (L / 2-Lc / 2) and the minimum value of 0.8 [m] are selected.

Further, when the lane width can be obtained by communication with the road infrastructure side, so-called road-to-vehicle communication, the lane width can also be used. Moreover, when the distance (L / 2-Xs) to the lane marking in the departure direction can be obtained based on information from an infrastructure (for example, a marker embedded in a road), the information can also be used.
Subsequently, in step S7, the determination result of the lane departure determination (the departure determination flag F obtained in step S6) according to the determination result of the driver's intention to change lane (the lane change determination flag F _lc obtained in step S4). _ld ) is reset. Specifically, when the lane change determination flag F _lc is ON (F _lc = ON), the lane departure prevention control is not performed, and the departure determination flag F _ld (even if it is set to a value other than zero) Is changed to zero.

In addition, lane departure prevention control will not be performed even if it can be judged that the tire is in the limit range by ABS (Anti-lock Brake System), TCS (Traction Control System), VDC (VehicleDynamics Control), etc. The departure determination flag F _ld may be forcibly changed to zero.
Subsequently, in step S8, the start determination of the lane departure prevention control is performed. Here, based on the history of the estimated lateral displacement Xs calculated in step S3, the vehicle deviates from the lane as a result of the estimated lateral displacement Xs changing discontinuously from the state where the vehicle has not deviated from the lane. Is determined (Xs ≧ Xc or Xs ≦ −Xc) to determine whether to start the lane departure prevention control. Specifically, the following determination is performed.

(1) In the case of F _ld ≠ 0 (F _ld = 1 or -1) In this case, when the following expression (5) is satisfied, the prohibition flag F _cancel of the lane departure prevention control is set to ON (F _cancel = ON).
| Xsb−Xs | ≧ Lxs (5)
Here, Xs is the current value, Xsb is the previous value of the estimated lateral displacement Xs, and Lxs is a threshold value for determining the discontinuity of the estimated lateral displacement Xs. . According to the equation (5), if the current value of the estimated lateral displacement Xs greatly changes beyond the threshold value Lxs with respect to the previous value, the estimated lateral displacement Xs changes discontinuously. In order to prohibit the lane departure prevention control, the control prohibition flag F _cancel is set to ON.

(2) When departure determination flag F _ld = 0 In this case, it is not necessary to prohibit the lane departure prevention control, and the control prohibition flag F _cancel is set to OFF (F _cancel = OFF). Thus, when the control prohibition flag F _cancel is once set to ON, the control prohibition flag F is determined until it is determined that the vehicle has not deviated from the lane (until the departure determination flag F _ld = 0). _cancel is maintained in the ON state.

Then, in step S9, calculates target yaw moment Ms ₀ applied to the vehicle through the lane departure prevention control. Specifically, the estimated lateral displacement Xs calculated in Step S3, the lateral displacement limit value Xc used in the lane departure determination in Step S6, and the departure determination flag F set in Step S6 (Step S7) and Step S8. _{Based on 1d} and the control prohibition flag F _cancel , the target yaw moment Ms ₀ is calculated by the following formulas (6) to (8). Here, target yaw moment Ms ₀ to left turning of the vehicle (turning counterclockwise) is a positive value, the target yaw moment Ms ₀ to the right turning of the vehicle (turning clockwise) is negative value .
(1) When F _ld = 1 and F _cancel = OFF Ms ₀ = −K1 · K2 · (Xs−Xc) (6)
(2) When F _ld = −1 and F _cancel = OFF Ms ₀ = −K1 · K2 · (Xs + Xc) (7)
(3) In other cases (for example, F _ld = 0 or F _cancel = ON)
Ms ₀ = 0 (8)
Here, K1 is a constant determined by vehicle specifications, and K2 is a gain that varies according to the vehicle speed.

FIG. 4 shows an example of the gain K2. As shown in FIG. 4, in the low speed range, the gain K2 becomes a certain large value. When the vehicle speed V becomes larger than a certain value, the vehicle speed V increases while the gain K2 decreases and the vehicle speed V increases thereafter. When V is reached, the gain K2 becomes a certain small value. With reference to such a characteristic diagram, a gain K2 corresponding to the vehicle speed V is obtained.
According to the equations (6) and (7), the target yaw moment Ms ₀ is the difference value (Xs−Xc) between the estimated lateral displacement Xs and the lateral displacement limit value Xc, that is, the lane departure amount (lane departure tendency). ). Specifically, the absolute value of the target yaw moment Ms ₀ increases as the lane departure amount increases (the degree of lane departure tendency increases).

Subsequently, in step S10, a target steering torque (steering torque control amount) is calculated.
Specifically, first, the step S6 (step S7) and the departure flag while depending on the _{F ld} and control inhibition flag _{F cancel} set in step S8, the same estimated lateral displacement Xs and lateral displacement limit value and step S9 Using Xc, basic target steering torque (reference value of basic target steering torque, hereinafter referred to as basic target steering torque reference value) TS _ldp0 is calculated by the following equations (9) to (11). Here, the basic target steering torque reference value TS _ldp0 for turning the vehicle to the left (turning counterclockwise) is a positive value, and the basic target steering torque reference value for turning the vehicle to the right (turning clockwise) is Negative value.
(1) When F _ld = 1 and F _cancel = OFF TS _ldp0 = −K3 · K4 · (Xs−Xc) (9)
(2) When F _ld = −1 and F _cancel = OFF TS _ldp0 = −K3 · K4 · (Xs + Xc) (10)
(3) In other cases (for example, F _ld = 0 or F _cancel = ON)
TS _ldp0 = 0 (11)
Here, K3 is a constant determined by vehicle specifications, and K4 is a gain that varies according to the vehicle speed.

FIG. 5 shows an example of the gain K4. As shown in FIG. 5, in the low speed range, the gain K4 becomes a certain large value, and when the vehicle speed V becomes larger than a certain value, the vehicle speed V increases while the gain K4 decreases, and thereafter a certain vehicle speed. When V is reached, the gain K4 becomes a certain small value. With reference to such a characteristic diagram, a gain K4 corresponding to the vehicle speed V is obtained.
According to the equations (9) and (10), the basic target steering torque reference value TS _ldp0 is the difference value (Xs−Xc) between the estimated lateral displacement Xs and the lateral displacement limit value Xc, that is, the lane departure amount ( The value depends on the lane departure tendency. Specifically, the absolute value of the basic target steering torque reference value TS _{ldp0 increases} as the lane departure amount increases (the degree of lane departure tendency increases).

Next, the basic target steering torque reference value TS _ldp0 calculated as described above is used to calculate a lower limit value (minimum additional steering torque TSl _limit ) and an upper limit value (maximum additional steering torque TSu _limit ) according to the following equation (12). The final basic target steering torque (limited basic target steering torque, hereinafter referred to as final basic target steering torque final value) TS _ldp is calculated by using (correcting) and correcting (limiting).
TS _ldp = MID (TSl _limit , TS _ldp0 , TSu _limit ) (12)
Here, the function MID (A, B, C) is a function that selects an intermediate value of A, B, and C. Further, the minimum additional steering torque TSl _limit is a value smaller than the maximum additional steering torque TSu _limit (TSl _limit <TSu _limit ).

6 and 7 show examples of the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit . As shown in FIG. 6, in the region where the lateral acceleration Yg that is an indicator of the turning state is small, the minimum additional steering torque TSl _limit is a certain small value, and when the lateral acceleration Yg is larger than a certain value, the minimum additional steering is performed. The torque TSl _limit increases with the lateral acceleration Yg, and when the lateral acceleration Yg reaches a certain value thereafter, the minimum additional steering torque TSl _limit becomes a certain large value. The maximum additional steering torque _{tSU limit} Similarly, as shown in FIG. 7, the lateral acceleration Yg is smaller areas, the maximum additional steering torque _{tSU limit} becomes a constant small value in, than there is lateral acceleration Yg value When it increases, the maximum additional steering torque TSu _limit increases with the lateral acceleration Yg, and when the lateral acceleration Yg reaches a certain value thereafter, the maximum additional steering torque TSu _limit becomes a certain large value. With reference to these characteristic diagrams, the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit corresponding to the lateral acceleration Yg (turning state) are obtained.

Then, using the basic target steering torque final value TS _ldp calculated as described above and the steering assist torque Tps normally used in power steering, the target steering torque TS _ref is calculated by the following equation (13).
TS _ref = Tps + TS _ldp (13)
Here, the steering assist torque Tps is a value that varies depending on the steering angle and the vehicle speed, and is the target steering torque itself in the original steering assist control. That is, the basic target steering torque final value TS _ldp constitutes the fluctuation amount of the target steering torque in the original steering assist control, and is the steering torque for making the driver recognize the traveling state.

As described above, the basic target steering torque reference value TS _ldp0 is calculated based on the lane departure amount (lane departure tendency), and the calculated basic target steering torque reference value TS _ldp0 is set _according to the turning state (eg, lateral acceleration Yg). Is corrected to be equal to or higher than the minimum additional steering torque TSl _limit and lower than the maximum additional steering torque TSu _limit set according to the turning state, and the corrected basic target steering torque final value TS _ldp is steering assist. The target steering torque TS _ref is calculated by adding to the torque Tps.
The steering control unit 37 receives the target steering torque TS _ref calculated by the braking / driving force control unit 8 as described above, and controls the steering actuator 35. Thus, torque corresponding to the target steering torque is transmitted to the steering wheel 21 by steering control.

Subsequently, in step S11, a secondary yaw moment ΔMs _trf is calculated. Here, when the steering torque of the steering wheel 21 is actually controlled, the front wheels 5FL and 5FR are also steered because the steering wheel 21 and the front wheels 5FL and 5FR that are the steering wheels are mechanically coupled. The yaw moment is generated in the vehicle, and the secondary yaw moment ΔMs _trf is generated in the vehicle according to the basic target steering torque final value TS _ldp when the steering torque control is actually performed as described above. Equivalent to the yaw moment. Specifically, the front wheels 5FL and 5FR mechanically connected to the steering wheel 21 are moved (steered) by the basic target steering torque final value TS _ldp that is a fluctuation amount of the steering assist torque. When the yaw moment generated in the vehicle due to the change in the actual steering angle is calculated in advance corresponding to the turning state, and the secondary yaw moment ΔMs _{trf is} to be calculated, the basic target at that time The secondary yaw moment ΔMs _trf is calculated from the steering torque final value TS _ldp and the turning state.

FIG. 8 shows the relationship between the lateral acceleration Yg (turning state), the steering torque fluctuation amount Ts _ldp, and the secondary yaw moment ΔMs _trf .
As shown in FIG. 8, the lateral acceleration Yg increases, secondary yaw moment _{DerutaMs trf} decreases, on the other hand, the larger the steering torque fluctuation _{Ts ldp,} secondary yaw moment _{DerutaMs trf} increases. Such a characteristic diagram is prepared in advance, and when obtaining the secondary yaw moment ΔMs _trf , referring to this characteristic diagram, the lateral acceleration Yg (turning state) and the steering torque fluctuation Ts _ldp are determined. Further, the secondary yaw moment ΔMs _trf is obtained.

It is not intended to be limited to obtaining secondary yaw moment DerutaMs _trf Such characteristic diagram, it is also possible to obtain a secondary yaw moment DerutaMs _trf by other methods. For example, a vehicle model is provided in the controller, and the influence of the steering torque fluctuation on the vehicle behavior is estimated using the vehicle model to obtain the secondary yaw moment ΔMs _trf .
Subsequently, in step S12, the braking / driving force control yaw moment Ms is calculated. Specifically, the braking / driving force control yaw moment Ms is calculated by the following equation (14) using the target yaw moment Ms ₀ calculated in step S9 and the secondary yaw moment ΔMs _trf obtained in step S11. To do.
Ms = Ms ₀ −Ms _trf (14)

As described above, by adding the basic target steering torque final value TS _ldp to the steering assist torque, it is estimated that the secondary yaw moment ΔMs _trf is generated in the vehicle during the steering torque control. Then, the secondary yaw moment ΔMs _trf that is expected to be generated is subtracted in advance to set the braking / driving force control yaw moment Ms to an appropriate value. That is, when the yaw moment is applied to the vehicle on the basis of the braking-driving force control yaw moment Ms, is actually a process as yaw moment generated in the vehicle reaches a target yaw moment Ms _0.

Subsequently, in step S13, a target brake hydraulic pressure for each wheel is calculated. Specifically, the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated using the braking / driving force control yaw moment Ms and the master cylinder hydraulic pressure Pm calculated in step S12. As described below, the calculation is based on the deviation determination flag _Fld and the control prohibition flag _Fcancel .
(1) When F _ld = 0 or F _cancel = ON Psfl = Psfr = Pm (15)
Psrl = Psrr = Pmr (16)
Here, Pmr is the rear wheel master cylinder hydraulic pressure in consideration of the front-rear distribution calculated from the master cylinder hydraulic pressure Pm.

(2) In other cases (F _ld = 1 or −1 and F _cancel = OFF)
In this case, if the braking / driving force control yaw moment Ms is less than the set value Ms1 (> 0) (| Ms | <Ms1), a braking force difference is generated between the left and right wheels of the rear wheel, and the braking / driving force control yaw moment is controlled. When Ms is equal to or greater than the set value Ms1 (| Ms | ≧ Ms1), a braking force difference is generated between the front and rear wheels.

(2-1) Specifically, first, the target braking hydraulic pressure difference ΔPsf, ΔPsr for generating the yaw moment by the braking force difference between the left and right wheels is expressed as follows using the braking / driving force control yaw moment Ms: It calculates by (17) Formula-(20) Formula.
(2-1-1) | Ms | <Ms1 ΔPsf = 0 (17)
ΔPsr = 2 · Kbr · | Ms | / T (18)
(2-1-2) | Ms | ≧ Ms1 ΔPsf = 2 · Kbf · (| Ms | −Ms1) / T (19)
ΔPsr = 2 · Kbr · Ms1 / T (20)
Here, T is a tread. Here, for example, the front and rear treads have the same value. Kbf and Kbr are conversion coefficients for converting braking force into braking hydraulic pressure, and are determined by brake specifications.
Note that the yaw moment may be generated only on the front wheels. In this case, for example, the target brake hydraulic pressure difference ΔPsf on the front wheel side is calculated by the following equation (21).
ΔPsf = 2 · Kbf · | Ms | / T (21)

(2-2) Then, in consideration of the master cylinder hydraulic pressure Pm which is a braking operation by the driver, the target brake hydraulic pressure Psi of each wheel is calculated according to the lane departure direction.
(2-2-1) When the departure direction is left (when Ms is negative)
Psfl = Pm
Psfr = Pm + ΔPsf
Psrl = Pmr
Psrr = Pmr + ΔPsr
(22)
(2-2-2) When the departure direction is rightward (when Ms is positive)
Psfl = Pm + ΔPsf
Psfr = Pm
Psrl = Pmr + ΔPsr
Psrr = Pmr
... (23)

Subsequently, in step S14, the driving force of the driving wheel is calculated. Specifically, based on the step S6 (step S7) and the departure flag _{F ld} and control inhibition flag _{F cancel} set in step S8, by the following equation (24) and (25), driving of the drive wheels A target drive torque Trq as a force is calculated.
(1) When F _ld ≠ 0 and F _cancel = OFF Trq = f (Ac) −g (Ps) (24)
(2) In other cases (when F _ld = 0 or F _cancel = ON)
Trq = f (Ac) (25)
Here, Ps is the total braking fluid pressure value of the front wheel target braking fluid pressure difference ΔPsf and the rear wheel target braking fluid pressure difference ΔPsr generated by the lane departure prevention control (Ps = ΔPsf + ΔPsr). The function f (Ac) is a function for calculating the target driving torque according to the accelerator operation amount of the driver, that is, the accelerator degree Ac, and the function g (Ps) is generated by the braking hydraulic pressure value Ps. Is a function for calculating the expected braking torque.

As a result, when the lane departure prevention control is operating (when F _ld ≠ 0 and F _cancel = OFF), the target value is determined based on the accelerator opening degree Ac and the braking hydraulic pressure value Ps that is the control amount of the lane departure prevention control. The drive torque Trq is calculated (the above formula (24)), and the target drive torque Trq is calculated according to the accelerator opening Ac when the lane departure prevention control is not operating (when F _ld = 0 or F _cancel = ON). (Equation (25)).

  Subsequently, in step S15, a drive signal is sent to the brake fluid pressure control unit (pressure control unit) 7 and the drive torque control unit 12 in accordance with the target brake fluid pressure Psi and the target drive torque Trq calculated in steps S13 and S14. Output. As a result, while the lane departure prevention control is in operation, a yaw moment is applied to the vehicle as the braking force control, and the driving torque is generated by subtracting the amount of braking torque generated during the driving force control. Even if the driver performs an accelerator operation, the engine output is reduced and acceleration cannot be performed. On the other hand, when the lane departure prevention control is not operating, no yaw moment is applied to the vehicle, and the engine output is controlled according to the driver's accelerator operation.

(Operation)
The operation is as follows.
While the vehicle is running, various data are read (step S1), the vehicle speed V and the estimated lateral displacement Xs are calculated, and the driver's intention to change lanes is determined (steps S2 to S4). Then, based on the estimated lateral displacement Xs and the determination result of the driver's intention to change lane (lane change determination flag F _lc ), a warning is activated and a lane departure is determined (steps S5 to S7). At this time, the start determination of the lane departure prevention control is performed based on the history of the estimated lateral displacement Xs (step S8).

Subsequently, while calculating the target yaw moment Ms ₀ based on the estimated lateral displacement Xs, the basic target steering torque final value TS _ldp is calculated (steps S9 and S10). Then, based on the calculated basic target steering torque final value TS _ldp and the turning state (lateral acceleration Yg), a secondary yaw moment ΔMs _trf is calculated (step S11), and the calculated secondary yaw moment ΔMs _trf is calculated as the target yaw. The yaw moment Ms for braking / driving force control is calculated by subtracting from the moment Ms ₀ (step S12).

Then, based on the states of the departure determination flag F _ld and the control prohibition flag F _cancel , the target braking fluid pressure Psi (i = fl, fr, rl, rr) of each wheel is determined based on the braking / driving force control yaw moment Ms. In addition to calculating the target driving torque Trq, the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) and the target driving torque Trq are calculated and the braking fluid pressure control unit (pressure control unit) 7 and the driving torque. Output to the control unit 12 (steps S13 to S15). As a result, torque is applied to the steering wheel 21 according to the lane departure tendency of the vehicle as steering control, and a yaw moment according to the lane departure tendency is applied to the vehicle as lane departure prevention control, during which the driver Even if there is an accelerator operation by, acceleration will not be possible.

(Function and effect)
The operation and effect are as follows.
As described above, at the time of lane departure, the basic target steering torque reference value TS _ldp0 is calculated, and the basic target steering torque final value TS _ldp obtained based on the calculated basic target steering torque reference value TS _ldp0 is _normally obtained by power steering. The target steering torque TS _ref is obtained by adding to the steering assist torque Tps to be used (step S10). As a result, when the vehicle departs from the lane, a torque corresponding to the basic target steering torque final value TS _ldp is transmitted to the steering wheel 21 separately from the steering assist torque Tps normally used in power steering. The torque transmitted to the wheel 21 makes it possible to recognize that the host vehicle has deviated from the lane.

Further, the basic target steering torque reference value TS _ldp0 is calculated according to the lane departure amount (lane departure tendency). Specifically, the basic target steering torque reference value TS _ldp0 is increased as the lane departure amount increases. (Formula (9), formula (10)). Thus, if the basic target steering torque reference value TS _ldp0 is a value between the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit , the basic target steering torque final value TS _ldp also increases with the lane departure amount. growing. As a result, torque corresponding to the lane departure amount is transmitted to the steering wheel 21, so that the driver can recognize the degree of lane departure of the host vehicle by the torque transmitted to the steering wheel 21. It becomes like this.

Here, when torque is applied to the steering wheel 21 in accordance with the basic target steering torque final value TS _ldp , the steering wheel 21 and the front wheels 5FL, 5FR are mechanically connected, so the basic target steering torque final value TS. _The front wheels 5FL and 5FR are steered according to _ldp . In this case, a yaw moment is generated in the vehicle.

Correspondingly, in the present embodiment, as described above, the secondary yaw moment ΔMs _trf is calculated based on the basic target steering torque final value TS _ldp (step S11), and the calculated secondary yaw The braking / driving force control yaw moment Ms is calculated by subtracting the moment ΔMs _trf from the target yaw moment Ms ₀ (step S9) calculated based on the lane departure amount, and the calculated braking / driving force control yaw moment is calculated. Based on Ms, yaw moment is applied to the vehicle as lane departure prevention control (step S12). In this manner, by subtracting the secondary yaw moment ΔMs _trf calculated based on the basic target steering torque final value TS _ldp in advance, the front wheels 5FL and 5FR are steered according to the basic target steering torque final value TS _ldp. Even if the yaw moment is applied to the vehicle due to the above, the yaw moment actually generated in the vehicle by the lane departure prevention control corresponds to the target yaw moment Ms ₀ calculated based on the lane departure amount. That is, by subtracting the secondary yaw moment ΔMs _trf calculated based on the basic target steering torque final value TS _ldp in advance, the yaw moment applied to the vehicle is canceled according to the basic target steering torque final value TS _ldp. In addition, a yaw moment corresponding to the target yaw moment Ms ₀ calculated based on the lane departure amount is generated in the vehicle. As a result, the vehicle can accurately prevent lane departure without being excessive or deficient.

  As a result, steering control (recognition control, haptic control) performed for the purpose of allowing the driver to recognize that the host vehicle is in a lane departure state and braking / driving force control performed for the purpose of preventing the vehicle from departing from the lane are performed. , It can be carried out at the same time without interference. That is, in terms of configuration, the steering control and the braking / driving force control interfere with each other, but apparently, the steering control and the braking / driving force control can be performed independently.

  As a result, even when the vehicle slowly deviates from the lane, the steering control changes the steering torque according to such a lane departure state, so that the driver can recognize the lane departure state, Further, in the case of a large lane departure, the steering control changes the steering torque in accordance with such a lane departure state. In the braking / driving force control for the purpose of the lane departure prevention control, the steering torque changes. The yaw moment that is optimal for preventing lane departure can be imparted to the vehicle, and the driver can be prevented from feeling uncomfortable.

  Here, as shown in FIG. 9, in a situation where it can be determined that the vehicle 100 has deviated from the lane on a curved road, in a configuration in which steering control and braking / driving force control are shared as in the past, When trying to prevent the lane departure by braking / driving force control, even if the lane departure amount (estimated departure amount) is large, as long as the target yaw moment is calculated according to the estimated departure amount (equivalent to estimated lateral displacement), It is possible to prevent the vehicle from deviating from the lane. However, since the steering wheel that is originally a control target of the steering control also varies greatly according to the target yaw moment (estimated deviation amount), the driver feels uncomfortable.

  On the other hand, when the present invention is applied, the steering wheel is steering-controlled with a steering torque necessary and sufficient to make the driver recognize that the vehicle is deviating from the lane, while the steering control is performed in the vehicle. Because the braking / driving force control is performed in consideration of the influence on the vehicle (change in yaw moment), the driver can recognize that the vehicle has deviated from the lane without giving the driver a sense of incongruity. Can be accurately prevented.

  Further, as shown in FIG. 10, in a situation where it can be determined that the vehicle 100 is slowly deviating from the lane on a straight road, the steering control and the braking / driving force control are shared as in the conventional case. When trying to prevent the lane departure, when the lane departure amount (estimated departure amount) is small, whether the lane departure prevention control is performed by the steering control or the lane departure prevention control is performed by the braking / driving force control, the lane departure Can be sufficiently prevented. However, depending on the lane departure amount (estimated departure amount), not only when the braking / driving force control is used alone, but also when the steering control is used, driving through the steering wheel to gradually deviate from the lane. It may not be possible for a person to fully recognize the traveling state (lane departure state).

  On the other hand, when the present invention is applied, the steering wheel is steering-controlled with a steering torque necessary and sufficient to make the driver recognize that the vehicle is deviating from the lane, while the steering control is performed in the vehicle. Since the braking / driving force control is performed in consideration of the influence on the vehicle (change in yaw moment), it is possible to accurately prevent the vehicle from departing from the lane while reliably allowing the driver to recognize that the vehicle has deviated from the lane.

Further, as described above, the upper and lower limit values of the basic target steering torque reference value TS _ldp0 calculated according to the lane departure amount (lane departure tendency) by using the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit. And the basic target steering torque final value TS _ldp is calculated (see the equation (12)). As a result, if the basic target steering torque reference value TS _ldp0 is too small (TS _ldp0 <TSl _limit ), the basic target steering torque final value TS _ldp is set to the minimum additional steering torque TSl _limit , and the basic target steering torque reference value is set. If TS _ldp0 is too large (TS _ldp0 > TSu _limit ), the basic target steering torque final value TS _ldp is set to the maximum additional steering torque TSu _limit .

Here, FIG. 11 shows the relationship between the estimated lateral displacement Xs (FIG. 11A), the target steering torque reference value TS _ldp0 (FIG. _11B ) and the target steering torque final value TS _ldp (FIG. 11C). Indicates.
As shown in FIG. 11, when the estimated lateral displacement Xs (absolute value) is larger than the lateral displacement limit value Xc (| Xs |> Xc), the basic target steering torque reference value TS _ldp0 is a difference value (| Xs | −Xc) (FIGS. 6A and 6B). Therefore, if the difference value (| Xs | −Xc) is small, the basic target steering torque reference value TS _ldp0 also decreases accordingly, and if the difference value (| Xs | −Xc) increases, the basic target steering torque reference value. TS _ldp0 also increases accordingly. Accordingly, the basic target steering torque is set using the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit without directly setting the basic target steering torque reference value TS _ldp0 as the basic target steering torque final value TS _ldp. By limiting and setting the upper and lower limit values of the reference value TS _ldp0 , even when the difference value (| Xs | −Xc) is small, that is, even when the lane departure amount is small, the lower limit of the basic target steering torque final value TS _ldp is set. maintaining a minimum additional steering torque _{TS1 limit,} on the other hand, the difference value if (| | Xs -Xc) is very large, i.e., when the lane deviation amount is very large, the basic target steering torque final value TS The upper limit of _ldp is maintained at the maximum additional steering torque TSu _limit .

As a result, when the amount of lane departure is small, for example, when the vehicle slowly deviates from the lane, or even in the initial stage of steering control for lane departure recognition, the lower limit of the basic target steering torque final value TS _ldp is set to the minimum additional steering torque TSl. _{When the limit} is maintained, the degree of recognition of the lane departure state by the driver is improved, and when the amount of lane departure becomes very large, the upper limit of the basic target steering torque final value TS _ldp is set to the maximum additional steering torque. By limiting with TSu _limit , it is possible to prevent the torque generated in the steering wheel from becoming excessive, and to reduce the uncomfortable feeling given to the driver.

As described above, as shown in FIG. 8, the secondary yaw moment ΔMs _trf is set to decrease as the lateral acceleration Yg increases, and the secondary yaw moment ΔMs increases as the steering torque fluctuation amount Ts _ldp increases. _{The trf} is set to be large. That is, even if the steering torque fluctuation Ts _ldp is the same value, if the lateral acceleration Yg is large, the secondary yaw moment ΔMs _trf is decreased. If the lateral acceleration Yg is large, the yaw moment is generated in the vehicle due to the turning state, and the secondary yaw moment ΔMs _trf obtained according to the steering torque fluctuation Ts _ldp is corrected to be small. . As a result, an appropriate secondary yaw moment can be calculated in consideration of the turning state, and recognition by steering control can be performed without causing the driver to feel uncomfortable.

The first embodiment of the present invention has been described above. However, the present invention can also be realized by the following configuration.
That is, in the first embodiment, the basic target steering torque reference value TS _ldp0 is calculated according to the lane departure amount (lane departure tendency). However, it is not limited to this. That is, for example, the basic target steering torque reference value TS _ldp0 or the basic target steering torque final value TS _ldp, which is a torque generated in the steering wheel, may be set to a predetermined pattern that changes in time series so that the driver can easily recognize. it can.

For example, as shown in FIG. 12, the basic target steering torque final value TS _ldp is used as a recognition support pattern. That is, as the recognition support pattern, the basic target steering torque final value TS _ldp is increased stepwise ((c) in the figure). For example, the basic target steering torque final value TS _ldp is stepwise in correspondence with the basic target steering torque reference value TS _ldp0 (FIGS. (A) and (b)) that changes according to the lane departure amount (lane departure tendency). (Fig. 3C).

Further, as shown in FIG. 13, the basic target steering torque final value TS _ldp is caused to vibrate as a recognition support pattern. For example, the basic target steering torque final value TS _ldp is vibrated and changed in correspondence with the basic target steering torque reference value TS _ldp0 (the same figure (a), (b)) that changes according to the lane departure amount (lane departure tendency). (Fig. 3C).
Further, as shown in FIGS. 12 and 13, as recognition support pattern, in some aspects the basic target steering torque final value TS _ldp increases, so changed stepwise or oscillating changed the basic target steering torque final value TS _ldp to, in some aspects the basic target steering torque final value TS _ldp decreases may be a value corresponding to the basic target steering torque final value TS _ldp the basic target steering torque reference value _TS ldp0.

As described above, the basic target steering torque reference value TS _ldp0 or the basic target steering torque final value TS _ldp, which is the torque generated in the steering wheel, is set to a predetermined pattern that changes in time series so that the driver can easily recognize it. Thus, the driver's cognition can be improved as compared with the case where the basic target steering torque reference value TS _ldp0 or the basic target steering torque final value TS _ldp changes according to the lane departure amount.

In the embodiment, it is assumed that the driver is made aware of the traveling state of the vehicle by adding the basic target steering torque final value TS _ldp to the steering assist torque Tps (formula (13)). As a result, the braking / driving force control yaw moment Ms is calculated by subtracting the secondary yaw moment ΔMs _trf from the target yaw moment Ms ₀ (formula (14)). However, the basic target steering torque final value TS _ldp may be subtracted from the steering assist torque Tps for the purpose of making the driver recognize the traveling state of the vehicle. In this case, the basic target steering torque final value TS _ldp The braking / driving force control yaw moment Ms can be calculated in consideration of the secondary yaw moment ΔMs _trf estimated to be generated in the vehicle in accordance with the change.

In the description of the first embodiment, the process of step S3 of the braking / driving force control unit 8 realizes a traveling state detecting means for detecting the traveling state of the vehicle, and the step of the braking / driving force control unit 8 is performed. The process of S10 is a target steering torque calculation unit that calculates a target steering torque (basic target steering torque reference value TS _ldp0 ) to be generated by the steering wheel held by the driver based on the driving state detected by the driving state detection unit. The steering control unit 37 realizes steering torque control means for controlling the steering torque applied to the steering wheel based on the target steering torque calculated by the target steering torque calculation means, and performs braking / driving. The process of step S11 of the force control unit 8 is performed by the steering torque control means. By controlling the steering torque, a secondary yaw moment estimating means for estimating the secondary yaw moment generated in the vehicle as a result of turning of the steering wheel mechanically connected to the steering wheel is realized. The processing in step S9 of the braking / driving force control unit 8 realizes target yaw moment calculating means for calculating a target yaw moment to be generated in the vehicle based on the running state detected by the running state detecting means. The processing of step S12 to step S15 of the driving force control unit 8 is performed on the vehicle based on the target yaw moment calculated by the target yaw moment calculating means and the secondary yaw moment estimated by the secondary yaw moment estimating means. The braking / driving force control means for controlling the braking / driving force that generates the pressure is realized.

  Further, in the description of the first embodiment, the processes of step S6 and step S7 of the braking / driving force control unit 8 indicate the deviation tendency of the vehicle from the traveling lane based on the traveling state detected by the traveling state detecting means. Corresponding to this, the step S10 of the braking / driving force control unit 8 corresponds to the target steering torque corresponding to the vehicle deviation tendency detected by the departure tendency detection means. The target steering torque calculating means for calculating the target yaw moment is calculated in step S9 of the braking / driving force control unit 8 so as to suppress the deviation tendency of the vehicle detected by the deviation tendency detecting means. A target yaw moment calculating means for calculating is realized.

(Second Embodiment)
Next, a second embodiment will be described.
(Constitution)
In the first embodiment, the lane departure prevention control is performed to prevent the vehicle from departing from the traveling lane by the driving force control. On the other hand, in the second embodiment, vehicle behavior stability control (VDC: Vehicle Dynamics Control) is performed to suppress the vehicle behavior from becoming unstable by the driving force control.

FIG. 14 shows a processing procedure for vehicle behavior stability control in the second embodiment. For example, as in the first embodiment, the braking / driving force control unit 8 performs this process.
The basic part of the processing procedure in the second embodiment shown in FIG. 14 is the same as the processing procedure of the first embodiment shown in FIG. 3, but in the second embodiment, in particular, the step Steps S31 to S32 are provided instead of S3 to S8. In the following description, in the processing in the second embodiment, the same reference numerals as those in the processing in the first embodiment are the same unless otherwise specified.

As shown in FIG. 14, as in the first embodiment, first, in step S1, data acquisition is acquired, and then in step S2, the vehicle speed V is calculated.
In step S31 following step S2, unstable behavior is estimated (instability degree is estimated). Specifically, the side slip angle βe of the vehicle is estimated based on the vehicle speed V, the side acceleration Yg, and the yaw rate φ ′, and the estimated side slip angle (side slip angle estimated value) βe is used as an index of the unstable behavior. Use as an estimate. For example, Japanese Patent Application Laid-Open No. 2004-243787 discloses a technique related to vehicle stabilization control, and estimates a side slip angle βe of a vehicle based on a vehicle speed V, a lateral acceleration Yg, and a yaw rate φ ′. For example, the side slip angle βe of the vehicle is estimated using the technique disclosed in Japanese Patent Application Laid-Open No. 2004-243787.

Subsequently, in step S32, the unstable behavior is determined (determined whether it is unstable). Specifically, when the estimated side slip angle βe obtained in step S31 is equal to or larger than the reference side slip angle β ₀ (| βe | ≧ β ₀ ), it is determined that the behavior is unstable. Specifically, the vehicle behavior determination flag F _vdc is turned on (F _vdc = ON).
Here, the reference side slip angle β ₀ is a threshold value for determining unstable behavior that changes according to the vehicle speed V. The unstable behavior may be determined based on the amount of change in the difference between the estimated side slip angle βe and a predetermined threshold (for example, the reference side slip angle β ₀ ).

Subsequently, in Step S9, calculates target yaw moment Ms _0. In the second embodiment, the target yaw moment Ms ₀ to be given to the vehicle in order to stabilize the vehicle behavior in the vehicle behavior stabilization control is calculated. Specifically, the target yaw moment Ms ₀ is calculated by the following equations (26) to (28) based on the estimated slip angle βe and the reference slip angle β ₀ used in steps S31 and S32. Here, target yaw moment Ms ₀ to left turning of the vehicle (turning counterclockwise) is a positive value, the target yaw moment Ms ₀ to the right turning of the vehicle (turning clockwise) is negative value .
(1) When βe ≧ β ₀ (F _vdc = ON, indicating unstable behavior in the left direction)
Ms ₀ = −K1 · K6 · (βe−β ₀ ) (26)
(2) For _{βe ≦ -β 0 (F vdc =} ON, when showing the unstable behavior to the right)
Ms ₀ = −K1 · K6 · (βe + β ₀ ) (27)
(3) In other cases (F _vdc = OFF (when not unstable behavior))
Ms ₀ = 0 (28)
Here, K1 is a constant determined by vehicle specifications, and K6 is a gain that varies according to the vehicle speed.

FIG. 15 shows an example of the gain K6. As shown in FIG. 15, in the low speed range, the gain K6 becomes a certain large value. When the vehicle speed V becomes larger than a certain value, the vehicle speed V increases while the gain K6 decreases, and the vehicle speed V thereafter. When the value reaches, the gain K6 becomes a certain small value. With reference to such a characteristic diagram, a gain K6 corresponding to the vehicle speed V is obtained.
In step S10, a target steering torque (steering torque control amount) is calculated.

Specifically, first, based on the estimated side slip angle βe and the reference side slip angle β ₀ used in step S31 and step S32, the basic target steering torque reference value TS _{vdc0 is obtained} by the following equations (29) to (31). Is calculated. Here, the basic target steering torque reference value TS _vdc0 for turning the vehicle to the left (turning counterclockwise) is a positive value, and the basic target steering for turning the vehicle to the right (turning clockwise). The torque reference value TS _vdc0 is a negative value.
(1) When βe ≧ β ₀ (when unstable behavior is shown in the left direction)
TS _vdc0 = −K7 · K8 · (βe−β ₀ ) (29)
(2) For .beta.e ≦-beta ₀ (if shows unstable behavior to the right)
TS _vdc0 = −K7 · K8 · (βe + β ₀ ) (30)
(3) In other cases (when the behavior is not unstable)
TS _vdc0 = 0 (31)
Here, K7 is a constant determined by vehicle specifications, and K8 is a gain that varies according to the vehicle speed.

FIG. 16 shows an example of the gain K8. As shown in FIG. 16, in the low speed range, the gain K8 is a certain large value. When the vehicle speed V is greater than a certain value, the vehicle speed V increases while the gain K8 decreases and the vehicle speed thereafter increases. When V is reached, the gain K8 becomes a certain small value. With reference to such a characteristic diagram, a gain K8 corresponding to the vehicle speed V is obtained.
According to the equations (29) and (30), the basic target steering torque reference value TS _vdc0 is the difference value (βe + β ₀ ) between the estimated side slip angle βe and the reference side slip angle β ₀ , that is, unstable behavior ( The value depends on the degree of instability. Specifically, the basic target steering torque reference value TS _vdc0 increases as the unstable behavior (instability degree) increases.

Next, the basic target steering torque reference value TS _vdc0 calculated as described above is _converted into the lower limit value (minimum additional steering torque TSl _limit ) and the upper limit _limit by the following equation (31), as in the first embodiment. The basic target steering torque final value TS _vdc is calculated by correcting (limiting) the value (maximum additional steering torque TSu _limit ).
TS _vdc = MID (TSl _limit , TS _vdc0 , TSu _limit ) (32)
Here, as shown in FIGS. 6 and 7, the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit are based on the lateral acceleration Yg as an index of the turning state, as in the first embodiment. Calculated.
Next, in the same manner as in the first embodiment, using the basic target steering torque final value TS _vdc calculated as described above and the steering assist torque Tps normally used in power steering, A steering torque TS _ref is calculated.
TS _ref = TS _vdc + Tps (33)

As described above, the basic target steering torque reference value TS _vdc0 is calculated based on the unstable behavior (instability degree), and the calculated basic target steering torque reference value TS _vdc0 is set _according to the turning state (for example, the lateral acceleration Yg). Is corrected to be equal to or higher than the minimum additional steering torque TSl _limit and equal to or lower than the maximum additional steering torque TSu _limit set according to the turning state, and the corrected basic target steering torque final value TS _vdc and steering assist are corrected. The target steering torque TS _ref is calculated by adding the torque Tps.

The steering control unit 37 receives the target steering torque TS _ref calculated by the braking / driving force control unit 8 as described above, and controls the steering actuator 35. As a result, torque corresponding to the target steering torque is transmitted to the steering wheel 21 as steering control.
Subsequently, in step S11, the secondary yaw moment ΔMs _trf is calculated based on the basic target steering torque final value TS _vdc in the same manner as in the first embodiment. That is, with reference to the characteristic diagram as shown in FIG. 8, the secondary yaw moment ΔMs _trf corresponding to the lateral acceleration Yg (turning state) and the steering torque fluctuation Ts _vdc is obtained.

Subsequently, in step S12, the braking / driving force control yaw moment (final target yaw moment) Ms is calculated in the same manner as in the first embodiment. That is, by subtracting the secondary yaw moment _{DerutaMs trf} obtained in the step S11 from the target yaw moment Ms ₀ calculated in step S9, it calculates the braking driving force control yaw moment Ms (the (14) see formula) .

Subsequently, in step S13, the target brake hydraulic pressure of each wheel is calculated in the same manner as in the first embodiment. Specifically, the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel is calculated using the braking / driving force control yaw moment Ms and the master cylinder hydraulic pressure Pm calculated in step S12. As described below, the vehicle behavior determination flag F _vdc is calculated.
(1) When F _vdc = OFF Psfl = Psfr = Pm (34)
Psrl = Psrr = Pmr (35)
(2) Otherwise (F _vdc = ON)
In this case, if the braking / driving force control yaw moment Ms is less than the set value Ms1 (> 0) (| Ms | <Ms1), a braking force difference is generated between the left and right wheels of the rear wheel, and the braking / driving force control yaw moment is controlled. When Ms is equal to or greater than the set value Ms1 (| Ms | ≧ Ms1), a braking force difference is generated between the front and rear wheels.

(2-1) Specifically, first, the target braking hydraulic pressure difference ΔPsf, ΔPsr for generating the yaw moment by the braking force difference between the left and right wheels is expressed as follows using the braking / driving force control yaw moment Ms: Calculation is performed using equations (36) to (39).
(2-1-1) | Ms | <Ms1 ΔPsf = 0 (36)
ΔPsr = 2 · Kbr · | Ms | / T (37)
(2-1-2) | Ms | ≧ Ms1 ΔPsf = 2 · Kbf · (| Ms | −Ms1) / T (38)
ΔPsr = 2 · Kbr · Ms1 / T (39)

(2-2) Then, in consideration of the master cylinder hydraulic pressure Pm which is a braking operation by the driver, the target brake hydraulic pressure Psi of each wheel is calculated according to the lane departure direction.
(2-2-1) When the unstable direction is to the left (when Ms is negative)
Psfl = Pm
Psfr = Pm + ΔPsf
Psrl = Pmr
Psrr = Pmr + ΔPsr
... (40)
(2-2-2) When the unstable direction is rightward (when Ms is positive)
Psfl = Pm + ΔPsf
Psfr = Pm
Psrl = Pmr + ΔPsr
Psrr = Pmr
... (41)

Subsequently, in step S14, the driving force of the driving wheels is calculated in the same manner as in the first embodiment. Specifically, based on the vehicle behavior determination flag F _vdc set in step S32, the target drive torque Trq as the drive force of the drive wheels is calculated by the following formulas (42) and (43).
(1) When F _vdc = ON Trq = f (Ac) −g (Ps) (42)
(2) In other cases (when F _vdc = OFF)
Trq = f (Ac) (43)

  Subsequently, in step S15, as in the first embodiment, the brake fluid pressure control unit (pressure control unit) 7 and the drive torque control unit 12 are driven according to the target brake hydraulic pressure Psi and the target drive torque Trq. Output a signal. As a result, while the vehicle behavior stability control is in operation, the yaw moment is applied to the vehicle as the braking force control, and the driving torque is generated by subtracting the braking torque generated by the vehicle behavior stability control as the driving force control. At the same time, even if the driver performs an accelerator operation, the engine output is reduced so that acceleration cannot be performed. On the other hand, when the vehicle behavior stabilization control is not operating, no yaw moment is applied to the vehicle, and the engine output is controlled according to the driver's accelerator operation.

(Operation)
The operation is as follows.
While the vehicle is traveling, various data are read (step S1) and the vehicle speed V is calculated (step S2). Then, the side slip angle βe of the vehicle is calculated, and the unstable behavior is determined based on the calculated side slip angle βe of the vehicle (steps S3 and S4). Further, while calculating the target yaw moment Ms ₀ based on the side slip angle βe of the vehicle, the basic target steering torque final value TS _vdc is calculated (steps S9 and S10). Then, a secondary yaw moment ΔMs _trf is calculated based on the calculated basic target steering torque final value TS _vdc and the turning state (lateral acceleration Yg) (step S11), and the calculated secondary yaw moment ΔMs _trf is calculated as the target yaw moment ΔMs _trf. The yaw moment Ms for braking / driving force control is calculated by subtracting from the yaw moment Ms ₀ (step S12). Based on the state of the vehicle behavior determination flag _Fvdc , the target braking hydraulic pressure Psi (i = fl, fr, rl, rr) of each wheel based on the braking / driving force control yaw moment Ms is calculated and driven. A target drive torque Trq as a wheel drive force is calculated, and the calculated target brake hydraulic pressure Psi (i = fl, fr, rl, rr) and target drive torque Trq of each wheel are calculated as a brake fluid pressure control unit (pressure control unit). ) 7 and the drive torque control unit 12 (steps S13 to S15). As a result, torque is applied to the steering wheel 21 according to the degree of vehicle instability as steering control, and yaw moment according to the degree of instability of the host vehicle is applied to the vehicle as vehicle behavior stability control. Even if there is an accelerator operation by the driver, the output of the engine is throttled so that it cannot be accelerated.

(Function and effect)
The operation and effect are as follows.
As described above, when it is determined that the vehicle behavior is unstable, the basic target steering torque reference value TS _vdc0 is calculated and obtained based on the calculated basic target steering torque reference value TS _vdc0. The basic target steering torque final value TS _vdc is added to the steering assist torque Tps normally used in power steering to obtain the target steering torque TS _ref (step S10). As a result, when the vehicle exhibits an unstable behavior, a torque corresponding to the basic target steering torque final value TS _vdc is transmitted to the steering wheel 21 separately from the steering assist torque Tps normally used in power steering. Thus, the driver can recognize that the host vehicle is unstable due to the torque transmitted to the steering wheel 21.

The basic target steering torque reference value TS _vdc0 is calculated according to the degree of instability (stability) of the vehicle behavior. Specifically, the basic target steering torque reference value TS _ldp0 increases as the lane departure amount increases. (Formula (28), formula (29)). Thus, if the basic target steering torque reference value TS _vdc0 is a value between the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit , the basic target steering torque final value TS _vdc is also the degree of instability of the vehicle behavior. Grows with increasing. As a result, torque corresponding to the degree of instability of the vehicle behavior is transmitted to the steering wheel 21, so that the driver can determine the degree of instability of the host vehicle behavior by the torque transmitted to the steering wheel 21. Can be recognized.

Here, as in the first embodiment, when torque is applied to the steering wheel 21 in accordance with the basic target steering torque final value TS _vdc , the steering wheel 21 and the front wheels 5FL and 5FR are mechanically coupled. Therefore, the front wheels 5FL and 5FR are steered according to the basic target steering torque final value TS _vdc . In this case, a yaw moment is generated in the vehicle.

Correspondingly, in the present embodiment, as described above, the secondary yaw moment ΔMs _trf is calculated based on the basic target steering torque final value TS _vdc (step S11), and the calculated secondary yaw The braking / driving force control yaw moment Ms is calculated by subtracting the moment ΔMs _trf from the target yaw moment Ms ₀ (step S9) calculated based on the degree of instability of the vehicle behavior. Based on the yaw moment Ms, yaw moment is given to the vehicle as lane departure prevention control (step S12). In this way, by subtracting the secondary yaw moment ΔMs _trf calculated based on the basic target steering torque final value TS _vdc in advance, the front wheels 5FL and 5FR are steered according to the basic target steering torque final value TS _vdc. Even if the yaw moment is applied to the vehicle due to the vehicle, the yaw moment actually generated in the vehicle by the vehicle behavior stabilization control is in accordance with the target yaw moment Ms ₀ calculated based on the degree of instability of the vehicle behavior. . That is, by subtracting the secondary yaw moment ΔMs _trf calculated based on the basic target steering torque final value TS _vdc in advance, the front wheels 5FL and 5FR are steered according to the basic target steering torque final value TS _ldp. The yaw moment applied to the vehicle is offset, and the yaw moment corresponding to the target yaw moment Ms ₀ calculated based on the degree of instability of the vehicle behavior is generated in the vehicle. As a result, the vehicle can accurately stabilize the vehicle behavior without excess or deficiency.

  This interferes with steering control (recognition control, haptic control) performed for the purpose of allowing the driver to recognize that the host vehicle is unstable and braking / driving force control performed for the purpose of stabilizing the vehicle. Can be implemented at the same time. That is, in terms of configuration, the steering control and the braking / driving force control interfere with each other, but apparently, the steering control and the braking / driving force control can be performed independently.

  As a result, even when the vehicle slowly becomes unstable, the steering control changes the steering torque according to the unstable state, so that the driver can recognize the unstable state. When the vehicle suddenly becomes unstable, the steering control changes the steering torque according to the unstable state. However, in the braking / driving force control for the purpose of vehicle behavior stability control, the steering torque The influence of the change can be suppressed, and the optimum yaw moment for stabilizing the vehicle can be applied to the vehicle, thereby preventing the driver from feeling uncomfortable.

Further, as described above, by using the minimum additional steering torque TSl _limit and the maximum additional steering torque TSu _limit , the upper and lower limit values of the basic target steering torque reference value TS _vdc0 calculated according to the degree of instability of the vehicle are limited. Thus, the basic target steering torque final value TS _vdc is calculated (see the equation (31)). Thereby, when the basic target steering torque reference value TS _vdc0 is too small (TS _vdc0 <TSl _limit ), the basic target steering torque final value TS _vdc is set to the minimum additional steering torque TSl _limit , and the basic target steering torque reference value is set. When TS _vdc0 is too large (TS _vdc0 > TSu _limit ), the basic target steering torque final value TS _vdc is set to the maximum additional steering torque TSu _limit .

In this way, as in the first embodiment, when the degree of instability of the vehicle behavior is small, for example, when the vehicle slowly becomes unstable or when the steering control operation initial stage is recognized for vehicle behavior recognition. However, by maintaining the lower limit of the basic target steering torque final value TS _vdc at the minimum additional steering torque TSl _limit , the driver's recognition of the unstable state is improved, and the degree of vehicle instability increases rapidly. By limiting the upper limit of the basic target steering torque final value TS _vdc with the maximum additional steering torque TSu _limit , it is possible to prevent the torque generated in the steering wheel from becoming excessive and to give the driver a sense of discomfort. Can be reduced.

Heretofore, the second embodiment of the present invention has been described. However, the present invention can also be realized by the following configuration.
That is, in the second embodiment, the basic target steering torque reference value TS _vdc0 is calculated according to the lane departure amount (lane departure tendency). However, it is not limited to this. That is, for example, as described in the first embodiment, the driver can easily recognize the basic target steering torque reference value TS _vdc0 or the basic target steering torque final value TS _vdc, which is the torque generated by the steering wheel. In addition, a predetermined pattern that changes in time series can be used (see FIGS. 12 and 13).

In this way, by setting the basic target steering torque reference value TS _vdc0 or the basic target steering torque final value TS _vdc, which is the torque generated by the steering wheel, to a predetermined pattern that changes in time series, the degree of instability of the vehicle behavior is increased. Accordingly, compared with the case where the basic target steering torque reference value TS _vdc0 or the basic target steering torque final value TS _vdc changes, the driver's cognition can be improved.

  In the description of the second embodiment, the processes of step S31 and step S32 of the braking / driving force control unit 8 are performed to detect the stability of the vehicle behavior based on the traveling state detected by the traveling state detecting means. In step S10 of the braking / driving force control unit 8, the target steering torque calculating means for calculating the target steering torque according to the degree of stability of the vehicle behavior detected by the stability detecting means is realized. The processing of step S9 of the braking / driving force control unit 8 realized is a target yaw moment calculating means for calculating a target yaw moment for stabilizing the vehicle based on the degree of stability of the vehicle behavior detected by the stability detecting means. Is realized.

It is a schematic block diagram which shows embodiment of the vehicle carrying the vehicle behavior control apparatus of this invention. It is a figure which shows the structure which performs steering control of the said vehicle behavior control apparatus. It is a flowchart which shows the processing content of the control unit of the said vehicle behavior control apparatus. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K2. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K4. It is a characteristic view which shows the relationship between the lateral acceleration Yg and the minimum additional steering torque TSl _limit . It is a characteristic view which shows the relationship between the lateral acceleration Yg and the maximum additional steering torque TSu _limit . FIG. 6 is a characteristic diagram showing the relationship between lateral acceleration Yg (turning state), steering torque fluctuation Ts _ldp, and secondary yaw moment ΔMs _trf . It is the figure used for description of the effect | action and effect of this invention. It is the figure used for description of the effect | action and effect of this invention. FIG. 5 is a characteristic diagram showing a relationship _{among an} estimated lateral displacement Xs, a target steering torque reference value TS _ldp0, and a target steering torque final value TS _ldp . It is a characteristic view which shows the recognition assistance pattern which changes basic target steering torque final value TS _ldp in steps. It is a characteristic view showing a recognition support pattern for changing the vibration of the basic target steering torque final value TS _ldp . It is a flowchart which shows the processing content of the control unit in 2nd Embodiment. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K6. It is a characteristic view which shows the relationship between the vehicle speed V and the gain K8.

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, 35 Steering actuator, 37 Steering control unit

Claims (12)

Traveling state detecting means for detecting the traveling state of the vehicle;
Target steering torque calculating means for calculating a target steering torque to be generated by a steering wheel held by the driver based on the driving condition detected by the driving condition detecting means;
Steering torque control means for controlling the steering torque applied to the steering wheel based on the target steering torque calculated by the target steering torque calculation means;
By controlling the steering torque by the steering torque control means, the secondary yaw moment estimation for estimating the secondary yaw moment generated in the vehicle as a result of turning of the steering wheel mechanically connected to the steering wheel is performed. Means,
Target yaw moment calculating means for calculating a target yaw moment to be generated in the vehicle based on the running state detected by the running state detecting means;
Braking / driving force control means for controlling braking / driving force for generating a yaw moment on the vehicle based on the target yaw moment calculated by the target yaw moment calculating means and the secondary yaw moment estimated by the secondary yaw moment estimating means; ,
A vehicle behavior control device comprising:   Stability detecting means for detecting the stability of the vehicle behavior based on the running state detected by the running state detecting means is provided, and the target steering torque calculating means is the degree of stability of the vehicle behavior detected by the stability detecting means. And calculating the target yaw moment at which the vehicle is stabilized based on the degree of stability of the vehicle behavior detected by the stability detecting unit. The vehicle behavior control device according to claim 1.   The target steering torque calculation means increases the target steering torque as the degree of stability of the vehicle behavior detected by the stability detection means decreases, and calculates the target steering torque by limiting the target steering torque with an upper and lower limit value. The vehicle behavior control device according to claim 2, wherein   A departure tendency detection means for detecting a departure tendency of the vehicle with respect to the travel lane is provided based on the traveling state detected by the traveling state detection means, and the target steering torque calculation means is a deviation of the vehicle detected by the departure tendency detection means. The target steering torque according to a tendency is calculated, and the target yaw moment calculating means calculates the target yaw moment so as to suppress the vehicle departure tendency detected by the departure tendency detection means. The vehicle behavior control device according to claim 1.   The target steering torque calculation means calculates the target steering torque by increasing the target steering torque as the degree of vehicle departure tendency detected by the departure tendency detection means increases and limiting the target steering torque by upper and lower limit values. The vehicle behavior control apparatus according to claim 4.   The vehicle behavior control device according to any one of claims 1 to 5, wherein the target steering torque calculation means calculates a target steering torque having a predetermined pattern that changes in time series.   The vehicle behavior control device according to claim 6, wherein the predetermined pattern changes stepwise.   The vehicle behavior control apparatus according to claim 6, wherein the predetermined pattern changes in vibration.   The secondary yaw moment estimation means corrects the yaw moment generated in the vehicle as a result of the steering torque being controlled by the steering torque control means based on the turning state of the vehicle, and uses the correction value as the secondary yaw moment. The vehicle behavior control device according to claim 1, wherein the vehicle behavior control device is estimated.   The vehicle behavior control according to any one of claims 1 to 9, wherein the secondary yaw moment estimating means estimates that the secondary yaw moment increases as the target steering torque increases. apparatus.   11. The braking / driving force control unit controls the braking / driving force so that a yaw moment obtained by subtracting the secondary yaw moment from the target yaw moment is applied to the vehicle. The vehicle behavior control device according to claim 1.   As a result of steering control of a steering wheel gripped by a driver based on the running state of the vehicle, and steering wheels mechanically connected to the steering wheel by the steering control, a subsidiary wheel generated in the vehicle is generated. A vehicle behavior control method for controlling a driving force of a vehicle so that a yaw moment obtained by adding a secondary yaw moment to a yaw moment generated in the vehicle based on a running state of the vehicle is estimated.

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