JP3353576B2 - Vehicle behavior control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a behavior control device that suppresses and reduces undesirable behavior such as spin during turning of a vehicle such as an automobile.

[0002]

2. Description of the Related Art As one of behavior control devices for controlling the behavior of a vehicle such as an automobile at the time of turning, for example, Japanese Unexamined Patent Publication No.
As disclosed in Japanese Patent Application Laid-Open No. 500868, behavior control configured to detect skidding of a vehicle and to strongly brake (lock) the front wheels to prevent the vehicle from spinning when skidding of the vehicle is detected. Devices are conventionally known. According to this behavior control device, when the vehicle skids and spins, the front wheels are strongly braked and the lateral force of the front wheels is reduced, thereby suppressing the spinning. As a result, the turning behavior of the vehicle can be stabilized.

[0003]

As a method for detecting the skidding of a vehicle, the lateral acceleration and the yaw rate of the vehicle are detected, the yaw rate is multiplied by the vehicle speed, the lateral acceleration and the yaw rate are made the same dimension, and the deviation is integrated. It is conceivable to obtain the skid speed of the vehicle by using the following formula.

However, the detected lateral acceleration of the vehicle includes noise components due to disturbances from the road surface, such as unevenness of the road surface and cants, and it is not always possible to accurately detect the lateral acceleration itself of the vehicle. Therefore, in the above-described method, it is erroneously determined that the vehicle is skidding even though the vehicle does not actually skid, and as a result, unnecessary braking force control is performed, which may impair the behavior of the vehicle. There is.

[0005] The present invention is based on lateral acceleration and yaw rate.
Estimated skid condition of the vehicle
Sometimes it has been made in view of the in above-mentioned problems with the conventional behavior control device for executing a sideslip state suppression control, the main object of the present invention, a vehicle is added to the determination of whether the skid state To see if the vehicle is in grip
The vehicle is determined to be in a skidding condition and the vehicle is
Side skid only when determined to be in grip
By executing the suppression control, it is to prevent the unnecessary side slip state suppression control from being performed due to the erroneous determination of the side slip state of the vehicle.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a main object of the present invention is to provide an apparatus for estimating a skid state of a vehicle based on the detected lateral acceleration and yaw rate. In a behavior control device for a vehicle having a behavior control means for performing a side slip state suppression control when estimated, a means for detecting a steering angle, and a means for calculating a friction coefficient of a road surface based on at least the lateral acceleration, means for obtaining a first parameter corresponding to a deviation between the slip angle of the rear wheels and the front wheel slip angle based on the steering angle and the yaw rate, before Symbol vehicle based on the friction coefficient of the first parameter and the road surface with respect to the road surface Grip state determination means for determining whether or not the vehicle is in a grip state; and skid state suppression control by the behavior control means when the vehicle is determined to be in a non-grip state. Allow to, vehicle is achieved by the vehicle behavior control device having a means for inhibiting skid state suppression control by the behavior control means when it is determined to be in the grip condition.

When the vehicle turns normally without skidding, the deviation between the slip angle of the front wheels and the slip angle of the rear wheels is determined by at least the road surface friction obtained based on the lateral acceleration of the vehicle. The higher the coefficient, the larger the value. Also, when the vehicle skids, the deviation between the slip angle of the front wheel and the slip angle of the rear wheel increases as the skid increases. Therefore , for example, the difference between the slip angle of the front wheel and the slip angle of the rear wheel is determined by the deviation between the slip angle of the front wheel and the slip angle of the rear wheel and the coefficient of friction of the road surface .
Determine whether the increase in deviation is due to an increase in the coefficient of friction of the road surface.
By differentiating, it can be determined whether the vehicle is in a non-grip state and skidding , and later detailed
As explained, the slip angle of the front wheel and the slip angle of the rear wheel
By the grip judgment based on the deviation of the road and the coefficient of friction of the road surface
If the noise component included in the detected lateral acceleration is
Included in lateral acceleration because it is grasped as a change in friction coefficient
Ru can eliminate the influence of noise components.

[0008] According to the configuration of the first aspect, at least
The friction coefficient of the road surface is determined based on the lateral acceleration, the first parameter corresponding to the deviation between the slip angle of the front wheel and the slip angle of the rear wheel is determined based on the steering angle and the yaw rate, and the first parameter and the road surface whether the vehicle based on the friction coefficient is in the grip condition to the road surface is determined, the car
Skids when the vehicle is determined to be out of grip
Although the state suppression control is permitted, when the vehicle is determined to be in the grip state, the side slip state suppression control by the behavior control means is prohibited. Therefore, even if the side slip state of the vehicle is estimated based on the lateral acceleration and the yaw rate, the side slip occurs. The state suppression control is not executed, so that unnecessary braking force control is performed due to the noise component included in the detected lateral acceleration of the vehicle, and the possibility that the behavior of the vehicle is rather impaired is reduced.

According to the present invention, in order to effectively achieve the above-mentioned main object, the steering angle and the value obtained by dividing the lateral acceleration by the vehicle speed in the structure of the first aspect. A second parameter corresponding to a deviation between the slip angle of the front wheel and the slip angle of the rear wheel based on the friction between the first parameter, the second parameter, and the road surface. It is configured to determine whether or not the vehicle is gripping the road surface based on the coefficient.
Configuration).

According to this configuration, the determination as to whether or not the vehicle is in a tire grip state is made not only based on the first parameter and the friction coefficient of the road surface, but also based on the steering angle and the lateral acceleration based on the vehicle speed. The second parameter corresponding to the deviation between the slip angle of the front wheel and the slip angle of the rear wheel is obtained based on the divided value, and the second parameter is determined by the second parameter and the friction coefficient of the road surface. Is more accurately determined whether or not the vehicle is gripping the road surface.

[0011]

[0012]

According to the present invention, in order to effectively achieve the above-mentioned main object, in the configuration of the present invention, the grip state determining means may determine the first parameter and the friction coefficient of the road surface. First determining means for determining whether or not the vehicle is in a grip state based on the second parameter, and second determining means for determining whether or not the vehicle is in a grip state based on the second parameter and the friction coefficient of the road surface. DOO has adapted vehicle when both of said first discriminating means and the second discriminating means determines that the non-gripping state is determined to be in a non-gripping state (the third aspect) .

According to this configuration, it is determined that the vehicle is in the non-grip state based on the first parameter and the road surface friction coefficient, and the vehicle is in the non-grip state based on the second parameter and the road surface friction coefficient. since the vehicle when it is determined that there is determined to be in the non-gripping state, the
Vehicle based on only one parameter and the coefficient of road friction
Compared to when it is determined whether or not it is in the grip state,
The non-grip state of the vehicle is more accurately determined.

According to the present invention, in order to effectively achieve the above-mentioned main object, in the configuration of claim 3 , the grip state determining means once determines the first grip state when the grip state is determined to be the non-grip state. until determination means determines that the gripping state is configured to determine that the non-gripping state (claim 4
Configuration).

According to this configuration, once the grip state is determined, the grip state is determined by the first determination means until the grip state is determined.
Until it becomes clear that the vehicle is in the grip state, the skid state suppression control is performed, whereby the behavior of the vehicle is reliably stabilized.

Further, according to the present invention, in order to effectively achieve the above-mentioned main object, in any one of claims 1 to 4 , the grip state determining means should issue an alarm when the grip state is detected. and means for determining whether the extent of the grip state, alarm means for issuing an alarm is provided when the determination indicating that the extent of the grip state be emitted an alarm is performed (the fifth aspect) .

According to this configuration, when it is determined that the grip state is such a grip state that an alarm should be issued, an alarm is issued, so that the driver of the vehicle can recognize that the vehicle is in an unstable state such as spin. It becomes possible to take necessary measures, such as braking, on the basis of the warning before the alarm occurs.

According to the present invention, in order to effectively achieve the above-mentioned main object, in any one of claims 1 to 4 , it is determined that the alarm means is in a non-grip state. It is configured to generate an alarm when it is performed (claim
6 ).

According to this configuration, an alarm is issued when it is determined that the vehicle is in the non-grip state. Therefore, the driver of the vehicle is likely to be in an unstable state such as spin due to the alarm. And take necessary measures such as braking.

[0021] According to the present invention, to the aspect of the effective, At a any one of the claims 1 to 4, wherein the gripping state judgment unit after the slip angle of the front wheel It determines that the gripping state when the magnitude of the deviation between the slip angle of the wheel is less than the reference value, the friction coefficient of the road surface is configured to set large the reference value higher (claim 7 Constitution).

According to this configuration, the grip state is determined when the magnitude of the deviation between the front wheel slip angle and the rear wheel slip angle is equal to or smaller than the reference value, and the higher the road surface friction coefficient, the higher the reference value. Is set large, it is accurately determined whether or not the vehicle is in a grip state regardless of the friction coefficient of the road surface.

[0023]

According to a preferred aspect of the present invention, in the configuration of the first aspect, the means for determining the first parameter includes a front wheel slip angle based on a steering angle and a yaw rate. And a steering angle deviation ΔSγ corresponding to a deviation between the slip angle of the rear wheels and the slip angle of the rear wheel, and the grip state determination means calculates a dead zone setting value μgm based on a road surface friction coefficient.
Is calculated, and whether or not the vehicle is gripping the road surface is determined based on the magnitude of ΔSγ−μgm.

According to another preferred embodiment of the present invention, the means for determining the second parameter is obtained by dividing the steering angle and the lateral acceleration by the vehicle speed.
The steering angle deviation ΔSgy corresponding to the deviation between the slip angle of the front wheels and the slip angle of the rear wheels is calculated based on the calculated values, and the grip state determination means determines the dead zone setting value μ based on the road surface friction coefficient.
gm is calculated, and it is determined whether or not the vehicle is gripping the road surface based on the magnitude of ΔSgy−μgm.

[0025]

Prior to the description of the embodiment of the present invention, the principle of grip state determination in the present invention will be described.

In a situation where a lateral force is generated in a state where the tire is in the linear region, the steering angle θf of the front wheels and the lateral acceleration Gy and the yaw rate γ are not affected even when the road surface is canted. There is a relationship represented by the following Equation 1. In Equation 1, δr is the actual steering angle of the rear wheel, N is the steering gear ratio, L is the wheelbase, Kh is the stability factor, Tv is the steering response time constant, Vx is the longitudinal speed of the vehicle, and s is the Laplace operator.

[Equation 1] {θf / (N * L) -δr / L-Kh * Gy}
/ (1 + Tv * s) = γ / Vx

[0027] When the comparison between the number 1 of the left and right sides discriminating grip state is not affected by the quasi-stationary lateral acceleration noise cant of the road surface or the like, the grip
Since the determination of the state is performed in real time , the influence of transient noise such as disturbance input from the road surface during running on a rough road is inevitable. Also , by comparing the left side and the right side of Equation 1 above,
The determination depends on the sensor output, which is generally detected in an analog manner, such as lateral acceleration and yaw rate, and these sensor systems may break down in a floating manner. Nevertheless, there is a possibility that the grip state is determined.

When the above equation (1) is transposed and developed, the steering angle θ
f, the actual steering angle δr of the rear wheel, and the value obtained by dividing the yaw rate γ by the front-rear speed Vx are the difference between the slip angle αf of the front wheel and the slip angle αr of the rear wheel. Proportional. That is, the following equation 2 is established.

[Equation 2] {θf / (N * L) -δr / L-γ / Vx} =
αf −αr ∝Kh * Gy

When the relationship of the above equation (2) is roughly grasped, it is understood that if the road surface friction coefficient is high and the lateral acceleration Gy is large, the deviation αf-αr of the slip angle can be increased accordingly. Therefore, the skid state based on Gy-V * γ
Apart from the judgment system, the deviation αf−αr of the slip angle of the front and rear wheels is calculated in real time from the steering angle θf, the actual steering angle δr of the rear wheel, and the yaw rate γ, and the friction coefficient μg of the road surface is calculated based on the lateral acceleration Gy. estimated performs based-out grip determining the magnitude of the deviation of the slip angle of the front and rear wheels is represented by the following numbers 3, grip determination system increases or decreases according to the reference value of the determination to the friction coefficient μg of road According to this determination system, even if transient noise is superimposed on the lateral acceleration Gy, the noise component of the lateral acceleration is grasped as a change in the friction coefficient of the road surface, so that the erroneous determination factor can be determined. Can be absorbed.

Further, a value obtained by dividing the lateral acceleration Gy by the longitudinal speed Vx (vehicle speed) as shown in the following equation 4 is used as an alternative value of the yaw rate γ in the judgment system based on the value of the above equation 3. It is possible.

[Number 4] | θf / N-δr - ( Gy / Vx 2) * L | = | αf -αr |

In a quasi-static grip state where there is no cant on the road surface, the substitute value by the lateral acceleration Gy is equivalent to the yaw rate γ. Using this characteristic, a first determination system based on the steering angle θf, the actual steering angle δr of the rear wheel, and the yaw rate γ, and the steering angle θf, the actual steering angle δr of the rear wheel, and the lateral acceleration Gy are divided by the vehicle speed Vx . A double grip determination system with the second determination system based on the determined values is established, and the vehicle is in a grip state unless both values of these determination systems exceed a reference value that is increased or decreased according to the friction coefficient μg. By determining that there is a vehicle, it becomes possible to form a redundant grip determination system for the determination system of the side slip state based on the lateral acceleration Gy and the yaw rate γ, and the vehicle can be gripped more than the case where only the first determination system is used. It is possible to more accurately determine whether or not the vehicle is in the state.

[0032]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention;

FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electric control device of one embodiment of a behavior control device according to the present invention.

In FIG. 1, a braking device 10 includes a master cylinder 14 for pumping brake oil from first and second ports in response to a depression operation of a brake pedal 12 by a driver, and an oil pressure in the master cylinder. And a hydraulic booster 16 for increasing the brake oil to a pressure (regulator pressure) corresponding to the pressure. Master cylinder 1
The first port 4 is a brake hydraulic control conduit 18 for the front wheels.
The brake hydraulic control devices 20 and 22 for the left and right front wheels
The second port is connected to a three-port two-position switching type electromagnetic control valve 28 for the right and left rear wheels by a rear wheel brake hydraulic control conduit 26 having a proportional valve 24 on the way. The control valve 28 is connected by a conduit 30 to a brake hydraulic control device 32 for the left rear wheel and a brake hydraulic control device 34 for the right rear wheel.

The brake device 10 has an oil pump 40 that draws up brake oil stored in the reservoir 36 and supplies it to the high-pressure conduit 38 as high-pressure oil. The high-pressure conduit 38 is connected to the hydro booster 16 and to the switching valve 44, and an accumulator 46 for accumulating high-pressure oil discharged from the oil pump 40 as an accumulator pressure is connected in the middle of the high-pressure conduit 38. I have. As shown, the switching valve 44 is also a three-port two-position switching type electromagnetic switching valve, and is connected to the hydro booster 16 by a regulator pressure supply conduit 47 for four wheels.

The brake hydraulic control devices 20 and 22 for the front left and right wheels respectively include wheel cylinders 48FL and 48FR for controlling the braking force on the corresponding wheels, three-port two-position switching type electromagnetic control valves 50FL and 50FR, and a reservoir. Low pressure conduit 5 as return passage connected to 36
Normally open electromagnetic open / close valves 54FL and 54FR and a normally closed electromagnetic open / close valve 56FL provided in the middle of the regulator pressure supply conduit 53 for the left and right front wheels connected between the control valve 2 and the switching valve 44. And 56FR. On-off valve 5 each
The regulator pressure supply conduit 53 for the left and right front wheels between the 4FL, 54FR and the on-off valves 56FL, 56FR is connected to the connection conduits 58FL, 5FL.
The control valves 50FL and 50FR are connected by 8FR.

Brake hydraulic pressure control devices 32 for left and right rear wheels,
Reference numeral 34 denotes a normally-open electromagnetic on-off valve 60RL, 60 provided between the control valve 28 and the low-pressure conduit 52 in the middle of the conduit 30.
RR and normally closed solenoid-operated on-off valves 62RL, 62RR, and wheel cylinders 64RL, 64RR for controlling braking force on the corresponding wheels, respectively.
RL and 64RR are connected to the conduit 30 between the on-off valves 60RL and 60RR and the on-off valves 62RL and 62RR by connecting conduits 66RL and 66RR, respectively.

The control valves 50FL and 50FR are respectively a brake hydraulic control conduit 18 for the front wheels and a wheel cylinder 48FL.
And 48FR and wheel cylinder 48FL
, 48FR and the connection conduits 58FL and 58FR, the first position shown in the figure, the brake hydraulic control conduit 18 and the wheel cylinders 48FL and 48FR are disconnected, and the wheel cylinders 48FL and 48FR are connected to the connection conduit 58FL.
, And 58FR.

A regulator pressure supply conduit 68 for the left and right rear wheels is connected between the switching valve 44 and the control valve 28 for the left and right rear wheels, and the control valves 28 are connected to the brake hydraulic control conduits 26 for the rear wheels, respectively. The on-off valves 60RL and 60RR are connected in communication with each other, and the on-off valves 60RL and 60RR and the regulator pressure supply conduit 68
The communication between the brake oil pressure control conduit 26 and the on-off valves 60RL, 60RR is interrupted, and the on-off valves 60RL, 60RR and the regulator pressure supply conduit 6 are disconnected.
8 is switched to a second position for communicating with the second position.

The control valves 50FL, 50FR and 28 function as master cylinder pressure shut-off valves, and when these control valves are at the first position shown in the figure, the wheel cylinders 48FL and 48FR
FR, 64RL, 64RR are connected in communication with conduits 18, 26,
By supplying the master cylinder pressure to each wheel cylinder, the braking force of each wheel is controlled according to the amount of depression of the brake pedal 12 by the driver, and the control valves 50FL, 50FL
When 0FR, 28 is in the second position, each wheel cylinder is shut off from the master cylinder pressure.

The switching valve 44 has a wheel cylinder 48F.
L, 48FR, 64RL, 64RR serve to switch the hydraulic pressure supplied between the accumulator pressure and the regulator pressure, the control valves 50FL, 50FR, 28 are switched to the second position and the on-off valves 54FL, 54FR. , 60RL, 60RR and the opening / closing valves 56FL, 56FR, 62RL, 62RR are in the positions shown in the figure, and when the switching valve 44 is maintained at the first position shown in the figure, the wheel cylinders 48FL, 48FR, 64R
When the regulator pressure is supplied to L and 64RR, the pressure in each wheel cylinder is controlled by the regulator pressure, so that the braking pressure of the wheel is controlled by the amount of depression of the brake pedal 12 regardless of the braking pressure of the other wheels. It is controlled in the pressure increasing mode by the corresponding regulator pressure.

Even if each valve is switched to the pressure increasing mode by the regulator pressure, when the pressure in the wheel cylinder is higher than the regulator pressure, the oil in the wheel cylinder flows backward, and the control mode is the pressure increasing mode. Nevertheless, the actual braking pressure decreases.

Also, the control valves 50FL, 50FR, 28 are switched to the second position and the on-off valves 54FL, 54FR, 60RL,
When the switching valve 44 is switched to the second position in a state where the 60RR and the opening / closing valves 56FL, 56FR, 62RL, 62RR are at the positions shown in the figure, the wheel cylinders 48FL, 48FR, 64R
By supplying the accumulator pressure to the L and 64RR, the pressure in each wheel cylinder is controlled at an accumulator pressure higher than the regulator pressure, so that regardless of the amount of depression of the brake pedal 12 and the braking pressure of the other wheels, The braking pressure of the wheels is controlled in an accumulator pressure increasing mode.

Further, with the control valves 50FL, 50FR, 28 switched to the second position, the on-off valves 54FL, 54FR, 6
0RL and 60RR are switched to the second position, and the on-off valve 56F
When L, 56FR, 62RL, and 62RR are controlled to the illustrated state, the pressure in each wheel cylinder is maintained regardless of the position of the switching valve 44, and the control valves 50FL, 50FR, and 28 are switched to the second position. Open / close valve 54FL, 54FR, 6
0RL, 60RR and open / close valve 56FL, 56FR, 62RL, 62
When the RR is switched to the second position, the pressure in each wheel cylinder is reduced irrespective of the position of the switching valve 44, whereby the wheel is irrespective of the amount of depression of the brake pedal 12 and the braking pressure of the other wheels. The braking pressure is controlled in the pressure reduction mode.

Switching valve 44, control valves 50FL, 50FR, 2
8. The on-off valves 54FL, 54FR, 60RL, and 60RR and the on-off valves 56FL, 56FR, 62RL, and 62RR are controlled by an electric control device 70 as described later in detail. The electric control device 70 includes a microcomputer 72 and a drive circuit 74.
Although the microcomputer 72 is not shown in detail in FIG. 1, for example, the central processing unit (C)
PU), a read only memory (ROM), a random access memory (RAM), and an input / output port device, which are generally connected to each other by a bidirectional common bus. Good.

A signal indicating the vehicle speed V from the vehicle speed sensor 76, a signal indicating the lateral acceleration Gy of the vehicle body from a lateral acceleration sensor 78 substantially provided at the center of gravity of the vehicle body, a yaw rate sensor 80 A signal indicating the yaw rate γ of the vehicle body, a signal indicating the steering angle θf of the front wheels from the steering angle sensor 82, and a longitudinal acceleration G of the vehicle body based on a longitudinal acceleration sensor 84 provided substantially at the center of gravity of the vehicle body.
A signal indicating x and wheel speeds (peripheral speeds) Vwfl, Vwf of the left and right front wheels and the left and right rear wheels from the wheel speed sensors 86FL to 86RR, respectively.
Signals indicating r, Vwrl, Vwrr, and a signal indicating the actual steering angle δr of the rear wheels from the steering angle sensor 88 are input. The lateral acceleration sensor 78, the yaw rate sensor 80, and the like detect lateral acceleration and the like with the left turning direction of the vehicle as positive, and the longitudinal acceleration sensor 84 detects longitudinal acceleration with the acceleration direction of the vehicle as positive.

The ROM of the microcomputer 72 stores the control flows of FIGS. 2 to 6 and the control flows of FIGS.
The CPU performs various calculations as described below based on the parameters detected by the above-described various sensors to obtain a spin state amount SS for determining the turning behavior of the vehicle, and obtains a grip state. The index values Gγ and Ggy are obtained, the skid state of the vehicle is determined based on the spin state amount SS, and the slip state is determined based on the grip state index values Gγ and Ggy.
Determines whether the vehicle is in a grip state, and
Vehicle is in a grip state and the vehicle is in a non-grip state.
Then, the turning force is controlled by controlling the braking force of each wheel, and the alarm device 90 is operated as necessary.

Next, a vehicle turning behavior control routine will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is started by closing an ignition switch (not shown) and is repeatedly executed at predetermined time intervals. Also, in the flowchart shown in FIG. 2, the flag F relates to whether or not the vehicle is in a non-grip state, and 1 indicates that the vehicle is in a non-grip state.

First, in step 10, the vehicle speed sensor 7
6, a signal indicating the vehicle speed V detected is read, and in step 20, the deviation Gy of the lateral acceleration Gy and the product V * γ of the vehicle speed V and the yaw rate γ is calculated as Gy−V * γ. That is, the skid acceleration Vyd of the vehicle is calculated, and in step 30, the skid acceleration Vyd is integrated to calculate the skid speed Vy of the vehicle body.
The slip angle β of the vehicle body is calculated as the ratio Vy / Vx of the vehicle body slip speed Vy to the vehicle body front-rear speed Vx (= vehicle speed V).

In step 40, the spin amount SV is calculated as the linear sum K1 * β + K2 * Vyd of the vehicle body slip angle β and the skid acceleration Vyd using K1 and K2 as positive constants, respectively. In step 50, the yaw rate is calculated. The turning direction of the vehicle is determined based on the sign of γ, and the spin state amount SS is calculated as SV when the vehicle is turning left and −SV when the vehicle is turning right. When the calculation result is a negative value, the spin state amount SS is calculated. The amount is set to zero. The spin amount SV may be calculated as a linear sum of the slip angle β of the vehicle body and its differential value βd.

In step 60, it is determined whether or not the flag F is 1, that is, whether or not the vehicle is in a non-grip state. If an affirmative determination is made, then in step 70 A spin control amount Rsspin, which is a target slip rate of the entire vehicle, is calculated from a map corresponding to the graph shown in FIG. 10 based on the spin state amount SS, and if a negative determination is made, the spin control amount Rsspin is determined in step 80. Is set to 0.

In step 90, the spin control amount Rss
It is determined whether or not the pin is 0, that is, whether or not the behavior of the vehicle is stable and the behavior control is not required. When the affirmative determination is made, each valve is determined in step 100. After the control is returned to the normal position shown in FIG. 1, the process returns to step 10, and when a negative determination is made, in step 110, the turning front front wheel, turning inside front wheel,
The target slip ratio Rsfo of the turning outer rear wheel and the turning inner rear wheel,
Rsfi, Rsro, and Rsri are calculated.

## EQU5 ## Rsfo = Rsspin Rsfi = 0 Rsro = -Rsspin / 2 Rsri = -Rsspin / 2

In step 120, the turning inner and outer wheels are specified by determining the turning direction of the vehicle based on the sign of the yaw rate γ, and the final target slip ratio Rsi (i = fr, i = fr, fl, rr, rl) are calculated. That is, when the final target slip ratio Rsi is a left turn and a right turn of the vehicle, the following equations 6 and 7 are respectively given.
Is required in accordance with

[0054]

Rsfr = Rsfo Rsfl = Rsfi Rsrr = Rsro Rsrl = Rsri

Rsfr = Rsfi Rsfl = Rsfo Rsrr = Rsri Rsrl = Rsro

In step 130, the target wheel speed Vwti of each wheel is calculated in accordance with the following equation 8 using Vb as a reference wheel speed (for example, the wheel speed of the inside front wheel).

Vwti = Vb * (100-Rsi) / 100

In step 140, Vwid is the wheel acceleration (differential value of Vwi) of each wheel, and Ks is a positive constant coefficient.
i is calculated, and in step 150, the duty ratio D of each wheel is obtained from the map corresponding to the graph shown in FIG.
ri is calculated.

## EQU9 ## SPi = Vwi-Vwti + Ks * (Vwid-Gx)

Further, in step 160, the switching valve 44
Is switched to the second position, the accumulator pressure is introduced, and a control signal is output to the control valves 28, 50FR to 50RL of the respective wheels corresponding to the wheels for which the final target slip Rsi is not zero. The control valve is set to switch to the second position. By outputting a control signal corresponding to the duty ratio Dri to the open / close valve of each wheel, the supply and discharge of the accumulator pressure to and from the wheel cylinders 48FR to 48RL are controlled, thereby controlling the braking pressure of each wheel.

In this case, when the duty ratio Dri is between the negative reference value and the positive reference value, the upstream open / close valve is switched to the second position and the downstream open / close valve is set to the first position. By holding the position, the pressure in the corresponding wheel cylinder is held, and when the duty ratio is equal to or more than the positive reference value, the upstream and downstream open / close valves are controlled to the positions shown in FIG. By supplying the accumulator pressure to the corresponding wheel cylinder, the pressure in the wheel cylinder is increased. When the duty ratio is equal to or less than the negative reference value, the upstream and downstream open / close valves are in the second position. , The brake oil in the corresponding wheel cylinder is supplied to the low-pressure conduit 52.
To reduce the pressure in the wheel cylinder.

Next, a routine for calculating the estimated value μg of the friction coefficient of the road surface will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 3 is executed by interruption every predetermined time.

First, at step 210, a signal indicating the lateral acceleration Gy of the vehicle detected by the lateral acceleration sensor 78 is read, and at step 220, the estimated value μg of the road surface friction coefficient is calculated. Is calculated according to the following equation (10).

Gxy = (Gx ² + Gy ² ) ^1/2

In step 230, the horizontal acceleration Gxy
Is determined to be greater than or equal to the horizontal acceleration Gxy (n-1) one cycle before. If an affirmative determination is made, the coefficient K is set to 1 in step 240, and a negative determination is made. In step 250, the coefficient K is set to 0.
Set to 01. In step 260, the estimated value μg of the road surface friction coefficient is calculated according to the following equation (11).

Μg = (1−K) * μg (n−1) + K * Gxy

In the illustrated embodiment, the coefficient of friction of the road surface is calculated as the square root of the sum of squares of Gx and Gy, but may be estimated from the absolute value of the lateral acceleration Gy of the vehicle. A lateral acceleration component Gyfy at the front wheel position and the rear wheel position generated by yawing of the vehicle,
Gyry is calculated, and these components and the lateral acceleration G of the vehicle are calculated.
The lateral acceleration components Gyf and Gyr at the front wheel position and the rear wheel position are calculated as the sum of y, the larger value of Gyf and Gyr is calculated as the lateral acceleration Gys, and calculated as the square root of the sum of squares of Gx and Gys. Is also good.

Next, the routine for setting the flag F, that is, the routine for determining the grip state of the vehicle will be described with reference to the flowcharts shown in FIGS. 4 and 5
Is also executed by interruption every predetermined time.

In step 310 of this routine, a signal indicating the steering angle θf is read, and step 3 is executed.
At 20 and 330, the front-rear speed Vx (= V) of the vehicle
The low-speed processing coefficients Ka and Kb are calculated from the maps corresponding to the graphs shown in FIGS.

In step 340, a first parameter corresponding to the deviation between the front wheel slip angle and the rear wheel slip angle, that is, the steering angle deviation ΔSγ based on the yaw rate γ is calculated according to the following equation (12).

ΔSγ = ｛θf−δr * N− (N * L / Vx
) * Γ｝ * Ka

In step 350, a second parameter corresponding to the deviation between the front wheel slip angle and the rear wheel slip angle, that is, the steering angle deviation ΔSgy based on the lateral acceleration Gy is calculated according to the following equation (13).

ΔSgy = ｛θf−δr * N− (N * L / Vx
² ) * Gy｝ * Kb

In step 360, the friction coefficient μg of the road surface calculated according to the flowchart shown in FIG.
The dead zone set value μgm is calculated from the map corresponding to the graph shown in FIG. 14 based on the following equation. In step 370, the grip state index value Gγ based on the first parameter according to the following equation 14 with Kc as a positive constant: Is calculated. In step 380, the grip state index value Gγ
Is determined whether or not is negative. If a negative determination is made, the process proceeds directly to step 400, and if an affirmative determination is made, the grip state index value Gγ is set to 0 in step 390.

Gγ = (| ΔSγ | -μgm) * Kc

In step 400, the grip state index value Ggy based on the second parameter is calculated according to the following equation 15 with Kd as a positive constant. In step 400, whether the index value Ggy is negative or not is calculated. Is determined,
When a negative determination is made, the process proceeds directly to step 430, and when an affirmative determination is made, the index value Ggy is set to 0 in step 420. In addition, dead zone setting value μ
Since gm increases as the road surface friction coefficient μg increases, the grip state index values Gγ and Ggy decrease as the road surface friction coefficient increases.

Ggy = (| ΔSgy | -μgm) * Kd

In step 430, it is determined whether or not the grip state index value Gγ exceeds the reference value Gγ1 (positive constant), that is, whether or not the determination based on the first parameter is a non-grip state. When a positive determination is made, the flag F1 is set to 1 in step 440, and when a negative determination is made, step 45 is performed.
At 0, the flag F1 is reset to 0.

In step 460, it is determined whether or not the grip state index value Ggy exceeds a reference value Ggy1 (positive constant), that is, whether or not the determination based on the second parameter is a non-grip state. When a positive determination is made, the flag F2 is set to 1 in step 470, and when a negative determination is made, step 48 is executed.
At 0, the flag F2 is reset to 0.

In step 490, the flag F1 is set to 1
And whether the flag F2 is 1 or not, that is, whether both the determination based on the first parameter and the determination based on the second parameter are in the non-grip state is performed, and a negative determination is made. Is performed, the routine proceeds to step 530, and if a positive determination is made, the count value C1 of the counter is incremented by one in step 500.

At step 510, the count value C1
Is greater than a reference value t1 (positive constant),
That is, it is determined whether or not the state in which the determination of the non-grip state is made has been continued for a predetermined time or more by both the determination based on the first parameter and the determination based on the second parameter, and a negative determination is made. If the answer is YES, the routine is terminated, and if an affirmative determination is made, the flag F is set to 1 in step 520.

In step 530, the count value C1
Is reset to 0, and it is determined in step 540 whether or not the flag F is 1. When a negative determination is made, the process directly proceeds to step 570, and when an affirmative determination is made, the process proceeds to step 550. move on.

At step 550, the flag F1 is set to 0.
Is determined, and if an affirmative determination is made, in step 560, the count value C2 of the counter is determined.
Is incremented by one, and when a negative determination is made, the count value C2 is reset to 0 in step 570.

In step 580, the count value C2
Is greater than or equal to a reference value t2 (positive constant),
That is, after the determination based on the first and second parameters is performed to determine that the vehicle is in the non-grip state, the state in which the determination based on the first parameter is performed to determine that the vehicle is in the grip state is continued for a predetermined time or more. This routine is terminated if a negative determination is made and the routine is terminated if an affirmative determination is made.
The flag F is reset to 0.

Next, the alarm processing routine will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 6 is also executed by interruption every predetermined time.

In step 710 of this routine, it is determined whether or not the flag F is 1, that is, whether or not the vehicle is in a non-grip state. When the routine is terminated and a positive determination is made, the process proceeds to step 720.

In step 720, it is determined whether or not the vehicle speed V exceeds the reference value Vo, that is, whether or not the vehicle is running at a speed higher than a predetermined vehicle speed, and a negative determination is made. This routine is sometimes terminated as it is, and when an affirmative determination is made, the alarm device 90 is activated in step 730 to issue an alarm to the driver that the vehicle is in a non-grip state.

Thus, in the illustrated embodiment, the vehicle slip acceleration Vyd is calculated in step 20, the vehicle body slip angle β is calculated in step 30, and the linear sum thereof is calculated in step 40. Is calculated at step 50. In step 50, the spin amount SV is calculated.
Is calculated as an absolute value.

Then, in step 60, it is determined whether or not the vehicle is in the non-grip state. When the vehicle is in the non-grip state, the spin state amount SS is determined in step 70.
The spin control amount Rsspin is calculated from the map corresponding to the graph shown in FIG. 10 based on the above, and if a negative determination is made, the spin control amount Rsspin is set to 0 in step 80. Further, in step 90, it is determined whether or not the turning behavior of the vehicle is stable based on the spin control amount Rsspin.

When the turning behavior of the vehicle is in a stable state, an affirmative determination is made in step 90 to control each valve to the normal position shown in FIG. Therefore, in this case, the behavior control in steps 110 to 160 is not executed, and accordingly, the braking force of each wheel is controlled according to the amount of depression of the brake pedal 12 by the driver.

When the turning behavior of the vehicle is in the spin state, a negative determination is made in step 90, and the final target slip ratio Rsi of each wheel is calculated in steps 110 and 120, and in step 130. The target wheel speed Vwti of each wheel is calculated, and the braking force is controlled in steps 140 to 160 so that the wheel speed of each wheel becomes the target wheel speed Vwti.

In particular, according to the illustrated embodiment, step 3
At steps 20 and 340, a steering angle deviation ΔSγ is calculated as a first parameter corresponding to a deviation between the slip angle of the front wheel and the slip angle of the rear wheel based on the steering angle θf and the yaw rate γ. Steering angle deviation Δ
A grip state index value Gγ is calculated based on Sγ and the road surface friction coefficient μg, and it is determined in steps 430 to 450 whether or not the vehicle is in a non-grip state based on the grip state index value Gγ. At some point, the flag F1 is set to one.

[0084] also step 330 and the steering angle at the 350 .theta.f, the lateral acceleration Gy as a second parameter corresponding to a deviation between the slip angle of the slip angle and the rear wheel of the front wheels based on a value obtained by dividing by the vehicle speed V The steering angle deviation ΔSgy is calculated, and in steps 360 and 400 to 420, the grip state index value Ggy based on the steering angle deviation ΔSgy and the road surface friction coefficient μg is calculated.
At 480, it is determined whether or not the vehicle is in the non-grip state based on the grip index value Ggy. When the vehicle is in the non-grip state, the flag F2 is set to 1.

Then, in step 490, the judgment based on the grip state index value Gγ and the grip state index value Ggy
It is determined whether or not any of the determinations based on is in the non-grip state. If the determination of these two non-grip states continues for a predetermined time or more, an affirmative determination is made in step 510 and the flag F is set to 1 Set. In other words, the magnitude of the steering angle deviation ΔSγ based on the steering angle and the yaw rate,
Is a non-gripping state when larger than deviation both the magnitude of the steering angle deviation ΔSgy based a steering angle and lateral acceleration and a value obtained by dividing by the vehicle speed is commensurate with the friction coefficient of the road surface state continues for a predetermined time or longer Is determined.

Therefore, in this case, an affirmative determination is made in step 60, and in step 70, the spin control amount Rsspin is calculated from the map corresponding to the graph shown in FIG. Spin control amount Rss
If pin is not 0, an affirmative determination is made in step 90, whereby the spin suppression control in steps 110 to 160 is performed. On the other hand, when the flag F is 0
In other words, the judgment or the grip based on the grip state index value Gγ
Judgment based on the lip state index value Ggy is the grip state.
When a negative judgment is made in step 60,
In step 80, the spin suppression control amount Rsspin becomes zero.
Is set, so that the spin of steps 110 to 160
The suppression control is prohibited.

Also, once the flag F is set to 1 and the flag F1 or F2 becomes 0, that is, when either the judgment based on the grip state index value Gγ or the judgment based on the grip state index value Ggy enters the grip state, Step 49
At step 540, a negative determination is made, and at step 540, an affirmative determination is made. At step 550, it is determined whether or not the flag F1 is 0. Step 590 if continued for more than hours
The flag F is reset to 0.

Therefore, once it is determined that the vehicle is in the non-grip state based on both the determinations based on the first and second parameters, the magnitude of the steering angle deviation ΔSγ based on the steering angle and the yaw rate changes the friction coefficient of the road surface. If the state smaller than the appropriate deviation has continued for a predetermined time or longer, it is determined that the grip state has been reached.

FIG. 7 is a flowchart showing the latter half of the vehicle grip state determination routine according to another embodiment, that is, a part corresponding to FIG. In FIG. 7, the steps corresponding to the steps shown in FIG. 5 are given the same step numbers as those given in FIG.

In this embodiment, step 520
And 590, it is determined whether or not the grip state index value Gγ exceeds a reference value Gγ0 (a positive constant smaller than Gγ1). If an affirmative determination is made, In step 610, the flag Fa is set to 1. When a negative determination is made, the flag Fa is reset to 0 in step 620.

In step 630, it is determined whether or not the grip state index value Ggy exceeds a reference value Ggy0 (a positive constant smaller than Ggy1). If an affirmative determination is made, the process proceeds to step 640. And the flag Fb is 1
Is set to, and when a negative determination is made, step 6
At 50, the flag Fb is reset to zero.

Therefore, according to this embodiment, the flag Fa
Alternatively, depending on whether the flag Fb is 1, it is possible to determine whether or not there is a high possibility of a large skid state by the determination based on the first parameter and the second parameter, respectively.

FIGS. 8 and 9 are flowcharts showing the alarm processing routine in the other embodiment described above, similar to FIG. In these figures, steps 820 and 92
0, steps 830 and 930 respectively correspond to steps 720 and 730 in FIG.

In the alarm processing routine shown in FIG. 8, it is determined in step 810 whether the flag Fa is 1 and the flag Fb is 1, and a negative determination is made. In some cases, this routine is terminated as it is, and if a positive determination is made, the process proceeds to step 820.

Therefore, according to this processing routine, in a situation where the vehicle is running at a vehicle speed equal to or higher than the predetermined value, the vehicle may be in a large skid state by both the determination based on the first and second parameters. The alarm device 90 is actuated when the determination that the probability is high is made.

In the alarm processing routine shown in FIG. 9, it is determined in step 910 whether the flag Fa is 1 or the flag Fb is 1, and a negative determination is made. If the answer is affirmative, the routine proceeds to step 920.

Therefore, according to this processing routine, in a situation where the vehicle is running at a vehicle speed equal to or higher than the predetermined value, the vehicle enters a large skid state by one of the determinations based on the first or second parameter. When it is determined that the possibility is high, the alarm device 90 is activated.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to the above embodiment, and various other embodiments are included within the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in each of the above embodiments, it is determined whether or not the vehicle is in the non-grip state based on both the steering angle deviation ΔSγ as the first parameter and the steering angle deviation ΔSgy as the second parameter. Although it is performed, the determination of the non-grip state based on the second parameter may be omitted if necessary. In this case, steps 330, 350, 400 to 420, and 460 to 480 are omitted. In step 490, it is determined whether or not the flag F1 is 1, and steps 540 to 580 are omitted.

[0100] Also, in each embodiment described above, the vehicle speed V at the alarm processing routine is whether <br/> not exceeds the reference value Vo determination and the like are performed, required Then, this determination step may be omitted. However, when the vehicle starts moving when the coefficient of friction of the road surface is very low, such as an icy road surface, the vehicle is likely to be in a non-grip state when the vehicle speed determination is omitted. In some cases, it is preferable to determine the vehicle speed as in the illustrated embodiments in order to solve such a problem.

[0101]

As is apparent from the above description, according to the configuration of the first aspect of the present invention , based on at least the lateral acceleration,
A friction coefficient of the road surface is determined, a first parameter corresponding to a deviation between the slip angle of the front wheel and the slip angle of the rear wheel is determined based on the steering angle and the yaw rate, and based on the first parameter and the friction coefficient of the road surface. It is determined whether the vehicle is gripping the road or not, and the vehicle is not gripped.
When it is determined that the vehicle is
However, when it is determined that the vehicle is in the grip state, the skid state suppression control by the behavior control means is prohibited, and the skid state suppression control is not executed even if the skid state of the vehicle is estimated based on the lateral acceleration and the yaw rate. Therefore, it is possible to prevent unnecessary braking force control from being performed due to the noise component included in the detected lateral acceleration of the vehicle, thereby impairing the behavior of the vehicle due to the unnecessary braking force control. It is possible to reduce the risk of occurrence.

According to the second aspect of the present invention, whether or not the vehicle is in the grip state of the tire is determined not only based on the first parameter and the friction coefficient of the road surface, but also based on the steering angle and the lateral acceleration. The second parameter corresponding to the deviation between the front wheel slip angle and the rear wheel slip angle is obtained based on the value obtained by dividing the vehicle speed by the vehicle speed , and the second parameter is also determined by the discrimination based on the road surface friction coefficient. Therefore, it is possible to more accurately determine whether the vehicle is gripping the road surface.

[0103]

According to the third aspect of the present invention, the vehicle is determined to be in the non-grip state based on the first parameter and the road surface friction coefficient, and the vehicle is determined based on the second parameter and the road surface friction coefficient. When it is determined that the vehicle is in the non-grip state, it is determined that the vehicle is in the non-grip state. Therefore, the vehicle is determined based only on the first parameter and the road surface friction coefficient.
The vehicle is in a grip state
, The non-grip state of the vehicle can be determined more accurately.

According to the fourth aspect of the present invention, once it is determined that the vehicle is in the non-grip state, it is determined that the vehicle is in the non-grip state until the first determination means determines that the vehicle is in the grip state. The skid state suppression control is performed until it becomes clear that there is a certain condition, whereby the behavior of the vehicle can be reliably stabilized.

According to the fifth aspect of the present invention, a warning is issued when it is determined that the grip state is such a level that a warning should be issued, so that the driver of the vehicle can feel that the vehicle is spinning. Necessary measures, such as braking, can be taken based on the alarm before the condition becomes unstable.

According to the sixth aspect of the present invention, a warning is issued when it is determined that the vehicle is in the non-grip state, so that the driver of the vehicle is given an unstable state such as spin by the warning. It is possible to recognize that the possibility is high and to take necessary measures such as braking.

According to the configuration of claim 7 , when the magnitude of the deviation between the slip angle of the front wheel and the slip angle of the rear wheel is equal to or smaller than the reference value, it is determined that the vehicle is in the grip state, and the friction coefficient of the road surface is reduced. The higher the value, the larger the reference value is set, so that it is possible to accurately determine whether the vehicle is in a grip state regardless of the friction coefficient of the road surface.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electric control device of one embodiment of a behavior control device according to the present invention.

FIG. 2 is a flowchart illustrating a behavior control routine according to the embodiment.

FIG. 3 is an estimated value μg of a friction coefficient of a road surface in the embodiment.
6 is a flowchart showing a calculation routine of FIG.

FIG. 4 is a flowchart illustrating a first half of a vehicle grip state determination routine according to the embodiment.

FIG. 5 is a flowchart illustrating the latter half of a vehicle grip state determination routine according to the embodiment.

FIG. 6 is a flowchart illustrating an alarm processing routine according to the embodiment.

FIG. 7 is a flowchart illustrating a main part of a vehicle grip state determination routine according to another embodiment.

FIG. 8 is a flowchart illustrating an alarm processing routine according to another embodiment.

FIG. 9 is a flowchart illustrating an alarm processing routine according to still another embodiment.

FIG. 10 is a graph showing a relationship between a spin state amount SS and a spin control amount Rsspin.

FIG. 11 is a graph showing a relationship between a target slip amount SPi of each wheel and a duty ratio Dri.

FIG. 12 is a graph showing a relationship between a front-rear speed Vx and a low-speed processing coefficient Ka.

FIG. 13 is a graph showing a relationship between a front-rear speed Vx and a low-speed processing coefficient Kb.

FIG. 14 is a graph showing a relationship between a road surface friction coefficient μg and a dead zone set value μgm.

[Explanation of symbols]

 Reference Signs List 10 braking device 14 master cylinder 16 hydro booster 20, 22, 32, 34 brake hydraulic control device 28, 50FL, 50FR control valve 44 switching valve 48FL, 48FR, 64RL, 64RR wheel cylinder 70 electric type Control device 76 ... vehicle speed sensor 78 ... lateral acceleration sensor 80 ... yaw rate sensor 82 ... steering angle sensor 84 ... longitudinal acceleration sensor 86FL-86RR ... wheel speed sensor 88 ... steering angle sensor 90 ... alarm device

──────────────────────────────────────────────────の Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60T 8/24 B60T 8/58

Claims (7)

(57) [Claims] A vehicle behavior control device having behavior control means for estimating a side slip state of a vehicle based on the detected lateral acceleration and yaw rate, and executing a side slip state suppression control when the side slip state is estimated. A means for detecting a steering angle, a means for determining a friction coefficient of a road surface based on at least the lateral acceleration, and a first means corresponding to a deviation between a slip angle of a front wheel and a slip angle of a rear wheel based on a steering angle and a yaw rate. means for determining parameters, before Symbol gripping state judgment means vehicle based on the friction coefficient of the first parameter and the road surface is determined whether or not the gripping state to the road surface, the vehicle is in a non-gripping state judgment When it is performed, the side slip state suppression control by the behavior control means is permitted,
Means for inhibiting side skid state suppression control by the behavior control means when the vehicle is determined to be in a grip state. 2. A vehicle behavior control device according to claim 1,
Means for obtaining a second parameter corresponding to the deviation between the slip angle of the front wheel and the slip angle of the rear wheel based on a value obtained by dividing the steering angle and the lateral acceleration by the vehicle speed , and wherein the grip state determining means includes A behavior control device for a vehicle, comprising: determining whether or not the vehicle is gripping the road surface based on one parameter, the second parameter, and the friction coefficient of the road surface. 3. The vehicle behavior control device according to claim 2,
The grip state determination unit determines whether the vehicle is in a grip state based on the first parameter and the friction coefficient of the road surface, and the second parameter and the friction coefficient of the road surface. Second determination means for determining whether or not the vehicle is in a grip state based on the vehicle. When both the first determination means and the second determination means determine that the vehicle is in the non-grip state, the vehicle is in a non-grip state. A vehicle behavior control device for determining that the vehicle is in a grip state. 4. A vehicle behavior control device according to claim 3 ,
The behavior control device for a vehicle according to claim 1, wherein the grip state determination means determines the non-grip state once the first determination means determines the grip state once the grip state is determined to be the non-grip state. 5. In the behavior control apparatus of any vehicle of claim 1, wherein the gripping state judgment means a means for determining whether a gripping state of the extent gripping state be emitted an alarm A behavior control device for a vehicle, comprising: an alarm unit for issuing an alarm when it is determined that the grip state is such that an alarm should be issued. 6. In the behavior control apparatus of any vehicle of claims 1 to 4, wherein the alarm means of the vehicle, characterized in that issues an alarm when the determination indicating that the non-gripping state has been performed Behavior control device. 7. In the behavior control apparatus of any vehicle of claim 1, wherein the gripping state judgment means below the reference value the size of the deviation between the slip angle of the rear wheels and the slip angle of the front wheel The behavior control device for a vehicle, wherein the reference value is set to be larger as the friction coefficient of the road surface is higher when the vehicle is in the grip state.