JP3104575B2 - 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 for suppressing and reducing undesired behaviors such as drift-out and spin during turning of a vehicle such as an automobile.

[0002]

2. Description of the Related Art As one of devices for controlling the behavior of a vehicle such as an automobile at the time of turning, for example, JP-A-2-1097
No. 11, the slip angle β of the vehicle body
A behavior control device for estimating the turning behavior of a vehicle based on the linear sum of the slip angular velocity βd of the vehicle body and stabilizing the turning behavior by controlling the roll rigidity of the vehicle when the spin is estimated has been known.

According to such a behavior control device, when the spin is estimated, the roll rigidity of the vehicle is controlled.
It is possible to stabilize the turning behavior compared to a conventional general vehicle in which the turning behavior is not estimated and the roll stiffness is not controlled, and thereby, undesired turning behavior such as spinning and drift-out of the vehicle can be suppressed. Generation can be prevented.

[0004]

However, in the conventional behavior control apparatus described in the above publication, when the linear sum of the slip angle β and the slip angular velocity βd exceeds a threshold value, that is, when the slip angle β and the slip angle When the angular velocity βd enters a predetermined region (spin region) in the coordinate system, the vehicle is determined to be in a spin state. However, the region in which the vehicle is in the spin state is a traveling state such as the weight of the vehicle. Since the state differs depending on the state, the spin state cannot be accurately estimated depending on the running state of the vehicle.

In a situation where a sudden spin occurs, such as in the case of a delay in turning back the steering wheel during countersteering, the behavior control by the roll stiffness control is performed when the spin state is determined as described above. Even if you start,
The turning behavior cannot always be effectively controlled due to a response delay of the actuator or the like or a limit of the behavior control ability. Therefore, the slip angle β and the slip angular velocity βd
In these coordinate systems, it is in an area other than the spin area.
However, for example, when the magnitude of the slip angular velocity βd is large,
If it is in the range, control the behavior and
Preferably, it is stabilized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the conventional behavior control device, and a main object of the present invention is to provide a vehicle body slip angle β and a vehicle body slip angle β.
The physical quantity βd corresponding to the speed is the speed in β-βd coordinates.
Area, for example, the magnitude of the physical quantity βd
Convergence to the origin of β-βd coordinates
Area where the convergence is poor (in this specification,
Behavior control even when in the “quasi-spin region”).
This is to control the turning behavior of the vehicle optimally and effectively according to the running state of the vehicle.

[0007]

[0008]

[0009]

Means for Solving the Problems] major challenges such as described above, according to the present invention, a means for obtaining a vehicle body slip angle beta, and means for determining the physical quantity βd corresponding to the vehicle body slip angular velocity, the slip angle β and the physical quantity βd are β−
first determining means for determining whether or not the spin area is in the spin area on the βd coordinate, and the slip angle β and the physical quantity βd are areas other than the spin area on the β-βd coordinate, and
Second discriminating means for discriminating whether the physical quantity βd is in a large quasi-spin region and the first discriminating means determine that the slip angle β and the physical quantity βd are in the spin region. The vehicle behavior is controlled so that the magnitude of the slip angle β is reduced when the slip angle β and the physical quantity βd are determined to be in the quasi-spin region by the second determination means. the size is achieved by the behavior control device of a vehicle, characterized in that it has a behavior control means for controlling the behavior of the vehicle to be smaller (the first aspect) of the.

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[Action] When the general physical quantity βd corresponding to the vehicle body slip angle β and the vehicle body slip angular velocity is in the quasi-spin region hatched At a FIG. 24 (A) turning behavior of the vehicle is actively controlled Even if they do not exist, β and βd converge to the origin, but it takes time to converge, so that the turning behavior of the vehicle cannot be quickly stabilized.

According to the configuration of the first aspect , it is determined whether or not the physical quantity βd corresponding to the slip angle β of the vehicle body and the slip angular velocity of the vehicle body is in the spin range of the β-βd coordinate, and It is determined whether or not the physical quantity βd can be converged to the origin of the β-βd coordinate and is in a quasi-spin region where the convergence is poor, and the slip angle β and the physical quantity β
When it is determined that d is within the spin range, the behavior of the vehicle is controlled so that the magnitude of the slip angle β is reduced,
When it is determined that the slip angle β and the physical quantity βd are in the quasi-spin region, the behavior of the vehicle is controlled so that the magnitude of the physical quantity βd becomes small. However, the turning behavior of the vehicle can be quickly stabilized.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, the spin rate in the .beta .-. Beta.
The four-wheel steering system uses a yaw rate feedback system
In the case of the four-wheel steering device shown in FIG.
This is the area where the steering was performed, and the four-wheel steering system
In the case of an example of a four-wheel steering system, in FIG.
This is a hatched area. But four-wheel steering
When a failure occurs, the boundary indicating the spin region is shown in FIG.
And indicated by a broken line from the position indicated by a solid line in FIG.
Changes to the specified position. In addition, the spin in β-βd coordinates
Area is the standard area where the total weight of the vehicle corresponds to the standard payload.
When it is weight, hatching is applied in FIG.
Area, but spins when the total weight of the vehicle increases.
The boundary representing the area is the position indicated by the solid line in FIG.
The position changes to the position indicated by the broken line. Furthermore, β-βd locus
In the spin area at the target, the load distribution of the front and rear wheels is, for example, 5
When the standard distribution is 7:43, in FIG.
The hatched area, but the load distribution of the front and rear wheels
Is 60:40, 55:45, for example, spin
The boundary representing the region is indicated by a broken line and a boundary in FIG.
The position changes to the position indicated by the dashed line. Therefore, the present invention
According to one embodiment, in the configuration of claim 1 described above,
It is detected whether the four-wheel steering system has failed and
When a failure of the rudder is detected, the
Spin region and quasi-spin region are changed,
Gross weight is detected and β-βd coordinates based on the total weight of the vehicle
Spin region and quasi-spin region at
Indicates that the load distribution of the front and rear wheels is detected, and
Domain and quasi-spin domain in β-βd coordinates
Is changed. Further , according to one embodiment of the present invention, the spin value SV, which is an evaluation value for determining the turning behavior of the vehicle, is calculated as Ka * β + Kb * using Ka and Kb as coefficients.
It is calculated by βd, and it is determined whether or not the vehicle is in a spin state based on whether or not the magnitude of the spin value is equal to or larger than a reference value. Then, the coefficients Ka and Kb are corrected according to whether the four-wheel steering system is out of order, the total weight of the vehicle, and the load distribution of the front and rear wheels of the vehicle, and as a result, β-βd
The spin region in coordinates is changed.

Further, according to the present invention, in the embodiment corresponding to the first aspect, whether the four-wheel steering device is out of order also in the quasi-spin region by changing the spin region as described above . Is changed according to the gross weight of the vehicle and the load distribution of the front and rear wheels of the vehicle, whereby the determination as to whether β and βd are in the quasi-spin region is performed more accurately according to the running state of the vehicle.

Further, the spin region in the β-βd coordinate is
When the steering angle is 0, the region is hatched in FIG. 25 (A).
When d, the boundary representing the spin region is shown in FIG.
At the position indicated by the broken line. Therefore the claim
In the embodiment corresponding to the first configuration, the spin area is changed according to whether the four- wheel steering device is out of order, the total weight of the vehicle, and the load distribution between the front and rear wheels of the vehicle, and also according to the steering angle. Is done.

The quasi-spin region in the β-βd coordinate is a region hatched in FIG. 24A when the steering angle is 0, but the steering angle is 0.0, for example.
At 8 rad, the boundary representing the quasi-spin region is shown in FIG.
In (A), the position changes to the position indicated by the broken line, and the quasi-spin region also changes. Accordingly, in the embodiment corresponding to the first aspect , the quasi-spin region is also changed according to the steering angle.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 1 is a schematic diagram showing a vehicle braking device to which a behavior control device according to the present invention is applied and an electric control device thereof.

In FIG. 1, a braking device 10 has a master cylinder 14 for pumping brake oil from first and second ports in response to a driver's depressing operation of a brake pedal 12, and a first port. Is connected to brake hydraulic control devices 18 and 20 for the front left and right wheels by a brake hydraulic control conduit 16 for the front wheels, and the second port is connected to the rear left and right wheels by a brake hydraulic control conduit 24 for the rear wheels having a proportional valve 22 in the middle. Hydraulic control device 2 for
6 and 28. Further, the braking device 10 pumps the brake oil stored in the reservoir 30 and supplies it to the high-pressure conduit 32 as high-pressure oil.
have. The high-pressure conduit 32 is connected to each of the brake hydraulic control devices 18, 20, 26, 28, and an accumulator 36 is connected in the middle thereof.

Each of the brake hydraulic control devices 18, 20, 2
6, 28 are wheel cylinders 38FL, 38FR, 38RL, 38RR for controlling the braking force on the corresponding wheels, respectively.
And a 3-port 2-position switching type electromagnetic control valve 40FL,
The normally open electromagnetic on-off valves 44FL, 44FR, 44RL, 44RR provided between the 40FR, 40RL, 40RR and the low pressure conduit 42 and the high pressure conduit 32 connected to the reservoir 30 and the normally closed electromagnetic valve On-off valves 46FL, 46FR, 46RL, 46
RR. On-off valves 44FL, 44FR, 4 respectively
4RL, 44RR and open / close valve 46FL, 46FR, 46RL, 46RR
High-pressure conduit 32 between the connection conduits 48FL, 48FR, 48
Control valve 40FL, 40FR, 40RL, 40 by RL, 48RR
Connected to RR.

The control valves 40FL and 40FR are respectively a brake hydraulic control conduit 16 for the front wheels and a wheel cylinder 38FL.
And 38FR and wheel cylinder 38FL
, 38FR and the connection conduits 48FL and 48FR, the first position shown in the figure, the brake hydraulic control conduit 16 and the wheel cylinders 38FL and 38FR, and the wheel cylinders 38FL and 38FR and the connection conduit 48FL.
, And a second position for communicating and connecting with the 48FR. Similarly, 40RL and 40RR are respectively a brake hydraulic control conduit 24 for the rear wheel and a wheel cylinder 3
8RL and 38RR, and wheel cylinder 3
8RL and 38RR and the first position shown to cut off the communication between the connecting conduits 48RL and 48RR, and the brake hydraulic control conduit 2
4 to cut off the communication between the wheel cylinders 38RL and 38RR and connect the wheel cylinders 38RL and 38RR to the connecting conduit 4.
The position is switched to a second position for communicating and connecting 8RL and 48RR.

When the control valves 40FL, 40FR, 40RL, and 40RR are in the second position, the on-off valves 44FL, 44FR,
4RL, 44RR and open / close valve 46FL, 46FR, 46RL, 46
When RR is controlled to the state shown in FIG.
FL, 38FR, 38RL, 38RR are control valves 40FL, 40FR,
40RL, 40RR and connecting conduits 48FL, 48FR, 48RL,
The pressure in the wheel cylinder is increased by communicating with the high pressure conduit 32 through 48RR. Conversely, when the control valve is in the second position, the on-off valves 44FL, 44FR,
44RL, 44RR are closed and the on-off valves 46FL, 46FR, 46
When the valves RL and 46RR are opened, the wheel cylinder is connected to the low-pressure conduit 42 via the control valve and the connection conduit, so that the pressure in the wheel cylinder is reduced. Further, when the control valve is in the second position, the on-off valve 44FL,
4FR, 44RL, 44RR and open / close valve 46FL, 46FR, 46
When the valves RL and 46RR are closed, the wheel cylinder is disconnected from both the high-pressure conduit 32 and the low-pressure conduit 42, so that the pressure in the wheel cylinder is maintained.

Thus, the braking device 10 includes the control valve 40FL,
When the 40FR, 40RL, 40RR is in the first position, the wheel cylinders 38FL, 38FR, 38RL, 38RR generate a braking force according to the amount of depression of the brake pedal 12 by the driver, and the control valves 40FL, 40FR, 40RL, 40RR.
When any of RR is in the second position, the on-off valves 44FL, 44FR, 44RL, 44RR and on-off valves 46FL,
By controlling the opening and closing of the wheels 46FR, 46RL and 46RR, the braking force of the wheel can be controlled irrespective of the amount of depression of the brake pedal 12 and the braking force of the other wheels.

Control valves 40FL, 40FR, 40RL, 40RR,
On-off valves 44FL, 44FR, 44RL, 44RR and on-off valves 46
FL, 46FR, 46RL, 46RR are controlled by an electric control device 50 as described in detail later. The electric control device 50 includes a microcomputer 52 and a drive circuit 54. The microcomputer 52 is not shown in detail in FIG. 1, but is, for example, a central processing unit (CPU).
, A read only memory (ROM), a random access memory (RAM), and an input / output port device, which may be of a general configuration connected to each other by a bidirectional common bus.

A signal indicating the vehicle speed V from the vehicle speed sensor 56, a signal indicating the lateral acceleration Gy of the vehicle from a lateral acceleration sensor 58 provided substantially at the center of gravity of the vehicle, and a yaw rate sensor 60 A signal indicating the yaw rate γ of the vehicle body, a signal indicating the steering angle θ from the steering angle sensor 62, a signal indicating the wheel speeds VFL and VFR of the left and right front wheels from the wheel speed sensors 64FL and 64FR, respectively.
A longitudinal acceleration sensor 66 provided substantially at the center of gravity of the vehicle body
A signal indicating the longitudinal acceleration Gx of the vehicle body, a vehicle height sensor 68
Height H of left and right front wheels and left and right rear wheels from FL-68RR
A signal indicating FL to HRR and a signal indicating whether or not it is out of order are input from a four-wheel steering device (4WS) 70. The lateral acceleration sensor 58 and the like detect lateral acceleration and the like with the left turning direction of the vehicle as positive.

The ROM of the microcomputer 52 stores various control flows and maps as described later, and the CPU performs various calculations as described later based on the parameters detected by the various sensors described above to execute the control of the vehicle. A spin value SV for determining the turning behavior is obtained, a turning amount of the vehicle is estimated based on the spin value, and a control amount for stabilizing the turning behavior of the vehicle is calculated.
The braking force of the left front wheel or the right front wheel is controlled based on the calculation result to stabilize the turning behavior of the vehicle.

Next, an outline of the turning behavior control of the vehicle according to the embodiment will be described with reference to a general 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.

First, at step 50, the vehicle speed sensor 56
A signal indicating the vehicle speed V detected by the above is read, and in step 100, it is determined whether or not the vehicle speed V is 0, that is, whether or not the vehicle is stopped is performed.
When a negative determination is made, the routine proceeds to step 200, and when an affirmative determination is made, in step 150 , the average vehicle height HT of all the wheels and the average of the left and right front wheels based on the vehicle heights HFL, HFR, HRL and HRR of each wheel. The vehicle height HF and the average vehicle height HR of the right and left rear wheels are calculated, the total weight M of the vehicle is calculated based on the average vehicle height HT of all wheels, and the average vehicle height HF of the left and right front wheels and the average vehicle of the right and left rear wheels are calculated. Front wheel load distribution ratio R based on high HR
MF is calculated.

In step 200, the lateral acceleration G of the vehicle body
A cant correction value C for y, that is, a correction value for correcting the lateral force caused by the cant on the road surface is calculated according to the flowchart shown in FIG. 3, and in step 300, the vehicle body in step 500 described below is calculated. The integration time Ti in the calculation of the skid speed Vy is determined according to the flowchart shown in FIG. In step 400, the actual lateral acceleration Gya (= G
y−C) and the deviation Vyd between the vehicle lateral acceleration V * γ determined by the vehicle speed V and the yaw rate γ are calculated according to the flowchart shown in FIG. 5, and in step 500, the slip angle β of the vehicle body is calculated in FIG. In step 600, the slip angular velocity βd of the vehicle body is calculated as a differential value of the slip angle β.

In step 700, the spin value SV (SVp and SVm) is calculated according to the flowchart shown in FIG. 7, and in step 800, the spin value is corrected according to the flowchart shown in FIG. At 900, the behavior of the vehicle is determined according to the flowchart shown in FIG. 9 based on the spin value SV. At step 1000, the vehicle behavior is determined based on the determination result of the behavior and the spin value SV according to the flowchart shown in FIG. A control amount for controlling the braking force of the front wheel or the right front wheel is calculated, and the braking amount of the left front wheel or the right front wheel is controlled by the control amount.
Return to 0.

Next, each routine of steps 200 to 500 and 700 to 900 will be described in detail with reference to flowcharts of each routine shown in FIGS. 3 to 10 and corresponding graphs from FIG.

The calculation routine for the cant correction value C in step 200
(FIG. 3) In steps 202 to 208 of this routine, it is determined whether or not the flags Fsp, Fsm, Fdp, and Fdm are 1, that is, the turning behavior of the vehicle in step 900 one cycle before is determined. It is determined whether the estimation result is a spin or a quasi-spin. When a negative determination is made in these steps, the time constant Tc is calculated in step 210 from the map corresponding to the graph shown in FIG. 11, and the deviation of the lateral acceleration of the vehicle body is calculated according to the following equation (1). Gy
The low-frequency component of the deviation of the lateral acceleration is calculated as a cant correction value C by performing a low-pass filter process on -V * γ, and if an affirmative determination is made in any step, the cant correction is performed in step 215. The magnitude of the cant correction value C is attenuated in each cycle by, for example, decreasing the magnitude of the value C in an equal or differential manner. Number 1
Where S is a Laplace operator, which is the same for other mathematical expressions described later.

C = (Gy−V * γ) / (1 + Tc * S)

In step 220, the rate of change of the cant correction value C, that is, the absolute value of the deviation ΔC between the cant correction value C of the current cycle and the cant correction value of a predetermined cycle before is set to the limit value C1.
It is determined whether or not the value is (positive constant) or more. If the determination is affirmative, in step 225 the cant correction is performed so that the absolute value of the rate of change ΔC of the cant correction value is limited to the limit value C1. The value C is set.

In step 230, it is determined whether or not the absolute value of the cant correction value C is greater than or equal to a limit value C2 (positive constant).
At 5 the upper and lower cant correction values are C2 and -C2, respectively.
Clipped to Step 2 in Step 240
The sign of the cant correction value C calculated in 10 or 225 or 235 is the sign that increases the absolute value of the vehicle body slip angle β calculated in step 500, that is, calculated in step 500 one cycle before. Lateral velocity Vy
A determination is made as to whether or not the code is the same as that of the above. If an affirmative determination is made, the cant correction value C is reset to 0 in step 245.

Thus, in steps 205 to 235 of the cant correction value calculation routine, the lateral force caused by the cant on the road surface, that is, the deviation G of the lateral acceleration of the vehicle body as the cant correction value C.
The low frequency component of y−V * γ is calculated, and the lateral acceleration Gy of the vehicle body is corrected by the cant correction value C in step 490 of a lateral acceleration deviation calculation routine (FIG. 5) described later, so that the lateral acceleration is calculated. The deviation Vyd is accurately calculated irrespective of the presence or absence of the cant and its magnitude, whereby the slip angle β of the vehicle body is accurately calculated.

In particular, in this case, in the calculation of the cant correction value C in step 210, the time constant Tc of the low-pass filter makes the turning behavior of the vehicle unstable from the map corresponding to the graph shown in FIG. As the turning behavior of the vehicle is stable, it is reliably prevented that the estimation of the turning behavior of the vehicle and the behavior control are not accurately performed due to the cant, and the turning behavior of the vehicle is reduced. When it becomes unstable, the cant correction value C is calculated to be small, whereby a state in which necessary behavior control is started early is ensured. Further, when the vehicle falls into the spin state or the quasi-spin state, an affirmative determination is made in any of steps 202 to 208 and the cant correction value C is attenuated in step 215, so that the lateral acceleration Gy is changed to the cant correction value. Due to the correction at C, interruption of the behavior control is reliably prevented, and necessary behavior control is reliably and continuously executed until the turning behavior of the vehicle is stabilized.

In steps 220 to 235, when the rate of change of the cant correction value | ΔC | or the absolute value of the cant correction value | C | is equal to or greater than a predetermined value, the rate of change of the cant correction value and the magnitude of the cant correction value are respectively determined. Is limited to a predetermined value, the cant correction value C is calculated to be an abnormal value that does not correspond to the actual cant due to disturbance from the road surface or the like,
As a result, the deviation Vyd of the lateral acceleration of the vehicle body and the slip angle β of the vehicle body are reliably prevented from being calculated to abnormal values.

In steps 240 and 245, when the sign of the cant correction value C is the same as the sign of the vehicle slip velocity Vy, the cant correction value is forcibly reset to zero. Therefore, for example, when the vehicle turns on a curved running road in which the height of the road surface of the turning outer wheel is lower than the height of the road surface of the turning inner wheel, the lateral acceleration Gy can be reduced even though the vehicle does not actually generate spin. It is surely prevented that the spin is incorrectly estimated due to the correction with the correction value C.

Routine for determining the integration time Ti in step 300
(FIG. 4) In step 310 of this routine, it is determined whether or not the vehicle speed V is equal to or lower than a predetermined value Vo, for example, 10 km / h. If a negative determination is made, the process proceeds to step 320. It is determined whether the sign of the spin value SV is the same as the sign of the yaw rate γ. When a negative determination is made in step 320, the time constant in the integration calculation of the lateral acceleration deviation Vyd of the vehicle body in step 510 of the vehicle body slip angle β calculation routine (FIG. 6) described later in step 330 Ti is calculated from the map corresponding to the graph shown in FIG. 12 according to the absolute value of the spin value SV, and if a positive determination is made in step 310 or step 320, the time constant Ti is calculated in step 340.
Is set to its minimum value Timin.

Thus, in step 330, the time constant Ti is set to be large so that the integral value becomes longer as the absolute value of the spin value SV becomes larger, that is, the more unstable the behavior of the vehicle, the more stable the turning behavior of the vehicle. When, the accumulation of errors due to integration is reduced, which prevents the turning behavior of the vehicle from being erroneously estimated due to the accumulation of errors, and the turning behavior of the vehicle is unstable and the accumulation of errors is reduced. When it is necessary to stabilize the turning behavior of the vehicle promptly without any problem, the integration time Ti is set to be long so that the skid speed Vy of the vehicle can be reliably calculated, whereby the unstable turning behavior of the vehicle can be ensured. And is effectively corrected.

Step 400: lateral acceleration deviation calculation routine
(FIG. 5) In step 410 of this routine, it is determined whether or not the absolute value of the lateral acceleration Gy is smaller than the absolute value of the product V * γ of the vehicle speed V and the yaw rate γ. If so, it is determined in step 420 whether or not the magnitude of the lateral acceleration Gy has decreased. If an affirmative determination is made, the lateral acceleration Gy is low-pass filtered in step 430. In step 440, it is determined whether the rate of change of the lateral acceleration Gy, that is, the absolute value of the deviation ΔGy between the lateral acceleration in the current cycle and the lateral acceleration before a predetermined cycle exceeds the reference value Gyo (positive constant). Is determined, and when an affirmative determination is made, in step 450, the lateral acceleration Gy is corrected so that the magnitude of the rate of change ΔGy of the lateral acceleration is limited to the reference value Gyo, and the flag Fg is set to 1. When a negative determination is made, the lateral acceleration Gy is held at the previous value in step 480.

At step 460, it is determined whether or not the flag Fg is 1, and when an affirmative determination is made, at step 470, the absolute value of the deviation Gy-V * γ is set to the reference value Gye ( It is determined whether or not the value exceeds a positive constant. If the determination is affirmative, the lateral acceleration Gy is held at the previous value in step 480, and if the determination is negative, the determination is made in step 485. The flag Fg is reset to zero. In step 490, a deviation (side slip acceleration) Vyd of the lateral acceleration of the vehicle body is calculated according to the following equation (2).

## EQU2 ## Vyd = Gy-CV * γ

FIG. 19A shows a case where the magnitude of the lateral acceleration Gy suddenly decreases and becomes smaller than the magnitude of the estimated lateral acceleration V * γ of the vehicle body, which is caused by disturbance such as unevenness of the road surface. Is what you do. In this case, a positive determination is made in steps 410 and 420, and the lateral acceleration G
If the rate of decrease in the magnitude of y is large, an affirmative determination is made in step 440, and the rate of decrease in the magnitude of the lateral acceleration Gy is corrected to be reduced in step 450 to reduce the magnitude of the lateral acceleration Gy. When the rate is small, and when the magnitude of the difference between the lateral acceleration Gy and the product V * γ exceeds the reference value Gye even if the magnitude of the lateral acceleration starts to increase, the lateral acceleration is held at the previous value, and Thus, the possibility that the turning behavior of the vehicle is erroneously estimated due to road surface disturbance is reduced.

FIG. 19B shows a case where the magnitude of the yaw rate γ suddenly increases and becomes larger than the magnitude of the lateral acceleration Gy of the vehicle body, which is caused by the spin of the vehicle. In this case, an affirmative determination is made in step 410, but a negative determination is made in steps 420 and 460, and the vehicle body is determined in step 490 without correcting the reduction rate of the magnitude of the lateral acceleration Gy. Is calculated, whereby the turning behavior of the vehicle is accurately estimated and appropriately controlled.

FIG. 19C shows a case where the magnitude of the lateral acceleration Gy suddenly increases and becomes larger than the magnitude of the estimated lateral acceleration Vγ of the vehicle body. This is also caused by disturbance such as unevenness of the road surface. However, since it is not necessary to control the turning behavior of the vehicle in this case, the lateral acceleration Gy
Is not corrected for reduction.

In the illustrated embodiment, step 440 is performed.
If an affirmative determination is made in step (i), that is, if the rate of decrease in the magnitude of the lateral acceleration Gy is large, then in step 450, the rate of decrease in the magnitude of the lateral acceleration Gy is limited to ΔGy. However, when an affirmative determination is made in step 440, the time constant of the low-pass filter processing in step 430 is set to a large value, whereby the lateral acceleration Gy is set.
May be prevented from being smaller than the magnitude of the product V * γ by a predetermined value or more.

Calculation of vehicle body slip angle β in step 500
Routine (FIG. 6) In step 510 of this routine, the deviation Vyd of the lateral acceleration is integrated with the time constant Ti calculated in step 330 according to the following equation (3), so that the slip velocity Vy of the vehicle body is calculated. In step 520, it is determined whether or not the vehicle speed V is equal to or less than a predetermined value Vo, such as 10 km / h.
At 30, the sign of the vehicle body's side slip velocity Vy is the lateral acceleration G.
A determination is made as to whether it is the same as the sign of y.

## EQU3 ## Vy = Vyd / (1 / Ti + S)

When an affirmative determination is made in step 520 or 530, Δt is defined as the cycle time of the general flowchart shown in FIG.
Is reset by gradually reducing the skid speed Vy of the vehicle body in each cycle. Note that ΔV
y is a small positive constant when the slip velocity Vy is positive, and a negative small constant when Vy is negative.

[0053]

## EQU4 ## Vy ← Vy (1-Δt / Ti)

Vy ← Vy−ΔVy

In step 550, the longitudinal speed V of the vehicle
The ratio V of the vehicle body slip speed Vy to x (= vehicle speed V)
The slip angle β of the vehicle body is calculated as y / Vx, it is determined in step 560 whether or not the absolute value of the slip angle β exceeds 1, and if a positive determination is made, the process proceeds to step 570. Is set to 1 when the slip angle β is positive, and set to -1 when the slip angle β is negative.

Thus, in step 530 of the vehicle body slip angle β calculation routine, it is determined that the direction of the skid speed Vy is inconsistent with the direction of the lateral acceleration Gy of the vehicle body as another state quantity of the vehicle in terms of kinematics. That is, when the lateral slip velocity Vy includes a large error due to the error and the integration included in the lateral acceleration Gy of the vehicle body, the magnitude of the lateral slip velocity Vy is corrected to be reduced in step 540. This prevents the turning behavior of the vehicle from being erroneously estimated due to the large error included in the speed Vy.

Spin value SV calculation in step 700
Routine (FIG. 7) In step 710 of this routine, the correction coefficients Kspp, Kspm, Ksdp, and Ksdm are calculated based on the steering angle θ from a map corresponding to the graph shown in FIG. In step 720, it is determined whether or not the four-wheel steering device 70 is out of order. When an affirmative determination is made, in step 730, the correction coefficients Kfpp, Kfpm, and Kfdp,
Kfdm is calculated from the map corresponding to the graph shown in FIG. 14, and when a negative determination is made, step 740 is executed.
When the correction coefficients Kfpp, Kfpm and Kfdp, Kfdm are 1
Is set to

When the four-wheel steering system is a four-wheel steering system of the yaw rate feedback type, the correction coefficient calculated in step 730 is calculated from a map corresponding to the graph shown in FIG. When the four-wheel steering device is a four-wheel steering device of a steering angle proportional type, the calculation is performed from a map corresponding to the graph shown in FIG.

In step 750, correction coefficients Kwp and Kwd are calculated from the map corresponding to the graph shown in FIG. 15 based on the total weight M of the vehicle, and in step 760, the load distribution ratio RMF of the front wheels is calculated. The correction coefficient Krd based on FIG.
Is calculated from the map corresponding to the graph shown in FIG. In step 770, Kap and Kam are used as coefficients of the vehicle body slip angle β, and Kbp and Kbm are used as the vehicle body slip angular velocity β.
The spin values SVp and SVm are calculated according to the following equations (6) and (7), using the coefficients of d as Ksp and Ksd as constant coefficients.

[0059]

SVp = Kap * β + Kbp * βd = Kspp * Kfpp * Kwp * Ksp * β + Ksdp * Kfdp * Kwd * Krd * Ksd * βd

SVm = Kam * β + Kbm * βd = Kspm * Kfpm * Kwp * Ksp * β + Ksdm * Kfdm * Kwd * Krd * Ksd * βd

Thus, in steps 710, 720 to 740, 750, and 760 of the spin value calculation routine, the steering angle θ, whether the four-wheel steering device 70 is out of order, the total weight M of the vehicle, and the load on the front wheels, respectively. A corresponding correction coefficient is calculated according to the distribution ratio RMF, whereby the spin values SVp and SVm are corrected according to the running state of the vehicle such as whether or not the four-wheel steering device is out of order.

Spin value SV correction in step 800
Routine (FIG. 8) In step 810 of this routine, an estimated yaw rate γhat is calculated according to the following equation 8 based on the wheel speeds VFL and VFR of the left and right front wheels and the tread Lt, and step 820
In this case, the front-rear accelerations GFL and GFR of the left and right front wheels are calculated by differentiating the wheel speeds VFL and VFR of the left and right front wheels, and the estimated front-rear acceleration Gxhat is calculated as an average value of these front-rear accelerations according to the following equation 9. Is done.

[0062]

## EQU8 ## γhat = (VFR−VFL) / Lt

Gxhat = (GFR + GFL) / 2

At step 830, the magnitude of the deviation of the estimated yaw rate Δγhat is calculated according to the following equation (10). At step 840, the magnitude of the deviation of the estimated yaw rate Δγhat is subjected to the high-pass filter processing. Is larger than the reference value Δγho (positive constant), Δγhat is clipped to Δγho. In step 850, the magnitude of the deviation ΔGxhat of the estimated longitudinal acceleration is calculated according to the following equation 11, and in step 860, the magnitude of the deviation of the estimated longitudinal acceleration Δ
Gxhat is subjected to the high-pass filter processing, and when the magnitude of the deviation ΔGxhat after the processing exceeds the reference value ΔGxho (positive constant), ΔGxhat is clipped to the reference value ΔGxho.

[0064]

[Equation 10] Δγhat = | γhat−γ |

１１Gxhat = | Gxhat-Gx |

In step 870, based on the vehicle speed V, the magnitude Δγhat of the estimated yaw rate deviation calculated in steps 830 and 840 and the magnitude ΔGxhat of the estimated longitudinal acceleration deviation calculated in steps 850 and 860. The road surface disturbance D is calculated according to the following equation (12).

D = VΔγhat + ΔGxhat

In step 880, it is determined whether or not the spin value SVp calculated in step 770 is positive. If a negative determination is made, the process proceeds to step 890, and an affirmative determination is made. Step 8
At 85, the spin value SVp becomes the disturbance correction value Kd * D.
Is corrected by subtraction. Step 89
At 0, it is determined whether or not the spin value SVm calculated at step 770 is negative. When a negative determination is made, the process proceeds to step 900, and when an affirmative determination is made, step 895 is performed. Is corrected by adding the spin value SVm with the disturbance correction value Kd * D.

Thus, in steps 810 to 870 of the spin value correction routine, the degree of road surface disturbance is calculated based on the wheel speeds VFL and VFR of the left and right front wheels, and in steps 880 to 895, the spin is calculated according to the degree of disturbance. Since the value SVp or SVm is corrected, the turning behavior of the vehicle can be accurately estimated even when the road surface has irregularities or the like and the lateral acceleration Gy or the like is affected by road surface disturbance.

Step 900 for determining the behavior of the vehicle
(FIG. 9) In step 905 of this routine, it is determined whether or not the spin value SVp is equal to or larger than a reference value SVcp (positive constant) for determining spin. In step 910, the spin value SV
It is determined whether or not the sign of p is different from the sign of the lateral acceleration Gy. If a negative determination is made, the process proceeds to step 955. If an affirmative determination is made, the spin flag Fsp is set to 1 in step 915. And the count value Cs of the counter is reset to zero.

In step 920, the spin value S
It is determined whether or not Vm is equal to or less than a reference value -SVcm (negative constant) for determining spin, and when a positive determination is made, the spin value SV is determined in step 925.
It is determined whether or not the sign of m is different from the sign of the lateral acceleration Gy. If a negative determination is made, the process proceeds to step 955. If an affirmative determination is made, the spin flag Fsm is set to 1 at step 930. And the count value Cs of the counter is reset to zero.

In step 935, Kbm * βd becomes -S
It is determined whether or not Vcm or less and β is positive. If a negative determination is made, the process proceeds to step 945. If an affirmative determination is made, the spin flag Fdm is set to 1 in step 940. At the same time, the count value Cd of the counter is reset to zero. Step 94
In step 5, it is determined whether Kbp * βp is greater than or equal to SVcp and β is negative. If a negative determination is made, the process proceeds to step 955, and if an affirmative determination is made, the process proceeds to step 950. At this time, the spin flag Fdp is set to 1 and the count value Cd of the counter is reset to 0.

In step 955, it is determined whether or not the flag Fsp = 1 or Fsm = 1. If a negative determination is made, the process proceeds to step 975. If a positive determination is made, the process proceeds to step 960. At this time, it is determined whether or not the count value Cs of the counter exceeds a reference value Cso (positive constant).
At 65, the spin flags Fsp and Fsm are reset to 0, and when a negative determination is made, the count value Cs of the counter is incremented by 1 at step 970.

In step 975, it is determined whether or not the flag Fdp = 1 or Fdm = 1. If a negative determination is made, the process proceeds to step 1000, and if a positive determination is made, the process proceeds to step 980. At step 985, it is determined whether or not the count value Cd of the counter exceeds a reference value Cdo (positive constant). When the determination is affirmative, at step 985, the spin flags Fdm and Fdp are reset to 0. When a negative determination is made, at step 990, the count value Cd of the counter is incremented by one.

Thus, in the vehicle behavior determination routine, if SVp does not exceed the reference value SVcp or SVm does not fall below the reference value -SVcm even if the magnitude of the spin value SV increases , in other words, the vehicle body Of the slip angle β and
When the slip angular velocity βd of the vehicle
Otherwise, the flags Fsp and Fsm are not set to 1, so that unnecessary behavior control is reliably prevented. Even if SVp is smaller than reference value SVcp or SVm is larger than reference value-SVcm, Kbm
* Βd is less than -SVcm and β is positive or Kbp * βp is more than SVcp and β is negative, in other words, the slip angle β of the vehicle body and the slip of the vehicle body
Angular velocity βd is not in the spin region at β-βd coordinate
Are also in the quasi-spin region, the flag Fdm,
Since Fdp is set to 1, the turning behavior of the vehicle is quickly stabilized.

The spin value SVp is equal to the reference value SVcp.
The flag Fsp and Fsm are maintained at 1 until the count value Cs of the counter exceeds the reference value Cso even if SVm exceeds the reference value -SVcm, and Ksdm * .beta.d becomes -SV.
cm or β becomes negative or Ksdp * βp
Is smaller than SVcp or if β becomes positive, the flags Fdm and Fdp are kept at 1 until the count value Cd of the counter exceeds the reference value Cdo, so that the turning behavior of the vehicle is completely stabilized. Behavior control is surely continued.

Step 1000: Vehicle behavior control execution
Routine (FIG. 10) In step 1010 of this routine, the flag Fsp =
It is determined whether it is 1 or not. If a negative determination is made, the process proceeds to step 1020. If an affirmative determination is made, the right front wheel is set as a control wheel in step 1015. In step 1020, it is determined whether or not the flag Fsm = 1. If a negative determination is made, the process proceeds to step 1030. If an affirmative determination is made, in step 1025 the left front wheel is set to the control wheel. It is said.

In step 1030, the flag Fdp = 1
Is determined, and if a negative determination is made, the process proceeds to step 1040, and if an affirmative determination is made, the left front wheel is set as a control wheel in step 1035.
In step 1040, it is determined whether or not the flag Fdm = 1. If a negative determination is made, the process proceeds to step 1050. If an affirmative determination is made, in step 1045, the right front wheel is set to the control wheel. It is said.

In step 1050, the flag Fsp = 1
17, the target slip ratio Rs of the front outer wheel for reducing spin based on the spin value SVp when the flag Fsm = 1 and the spin value SVm when the flag Fsm = 1 is a map corresponding to the graph shown in FIG. It is calculated by Similarly, in step 1055, when the flag Fdp = 1, the front wheel side turning outer wheel for improving the convergence of the turning behavior is improved based on the spin value SVp when the flag Fdp = 1, and based on the spin value SVm when the flag Fdm = 1. The target slip ratio Rs is calculated from a map corresponding to the graph shown in FIG.

In step 1060, the target wheel speed Vwt is calculated using Kw as a coefficient in accordance with the following equation (13). In step 1065, the target wheel speed Vwt for the control wheels is calculated.
Wheel speed deviation ΔV as the difference between the wheel speed Vw (VFL or VFR) detected by the wheel speed sensor 64FL or 64FR.
w is calculated.

Vwt = KwV (1−Rs / 100)

In step 1070, the wheel speed deviation ΔV
It is determined whether or not the absolute value of w exceeds a reference value Vwo (positive constant). If a negative determination is made, the wheel speed deviation ΔVw is corrected to 0 in step 1075, and If an affirmative determination is made in 1070, the process proceeds to step 1280 without correcting the wheel speed deviation ΔVw to 0, and in this step, the braking force of the control wheel is controlled according to the wheel speed deviation ΔVw.

That is, the spin value is positive and the flag Fsp
Alternatively, when Fdp is 1, the control valve 40FR and the opening / closing valves 44FR and 46FR of the right front wheel, which is the turning outer wheel, cause the wheel speed deviation Δ
When the spin value is negative and the flag Fsm or Fdm is 1, the control valve 40FL and the opening / closing valve 44FL of the left front wheel, which is the turning outer wheel, are controlled by the duty ratio according to Vw.
46FL is controlled at a duty ratio corresponding to the wheel speed deviation ΔVw, whereby the braking device 10 is feedback-controlled so that the wheel speed deviation ΔVw falls within a range of −Vwo to Vwo, and the front outer and outer inner wheels are turned. The anti-spin moment is generated by the difference in the braking force between the two, thereby reducing the spin or improving the convergence of the turning behavior.

Thus, in the illustrated embodiment, in steps 200 to 800, the spin values SVp and SVm
Is calculated, and in step 900, it is determined whether or not the turning behavior of the vehicle is unstable based on the spin values SVp and SVm, that is, whether or not the behavior control is necessary. When the determination is made, the flag F
By resetting sp and Fsm to 0 and setting the target slip ratio Rs to 0, the process returns to step 50 without executing the turning behavior control, whereby the braking pressure of each wheel is reduced to the master cylinder pressure, and thus the brake pressure. It is controlled according to the amount of depression of the pedal 12.

On the other hand, in step 900, it is determined that the vehicle is in the spin state, that is, the slip angle β of the vehicle body and
When the slip angular velocity βd of the vehicle
When the flag Fsp or Fsm is set to 1, the target slip ratio Rs for reducing the spin is calculated in step 1050 based on the spin value SVp or SVm. In step 1060, the target wheel speed Vwt for achieving the target slip ratio is calculated, and in steps 1065 to 1080, the front wheel-side turning outer wheel is controlled so that the wheel speed of the front wheel-side turning outer wheel becomes the target wheel speed Vwt. By providing power or increasing the braking force, the turning behavior of the vehicle is stabilized, and spin and drift-out are reduced.

In step 900, it is determined that the vehicle is not in a spin state but is in a quasi-spin region, that is,
The vehicle body slip angle β and the vehicle body slip angular velocity βd are β
Quasi-spin region not in spin region at −βd coordinate
Is determined , and if the flag Fdp or Fdm is set to 1, a target slip ratio Rs for improving the convergence of the turning behavior is calculated in step 1055 based on the spin value SVp or SVm. , Step 10
At step 60, the target wheel speed Vwt for achieving the target slip ratio is calculated, and at steps 1065 to 1080, the front turning outer wheel is gentle so that the wheel speed of the front turning outer wheel becomes the target wheel speed Vwt. Is applied to or increased by the braking force , the slip angular velocity β of the vehicle body is increased.
By reducing the magnitude of d, the turning behavior of the vehicle is quickly stabilized, and the instability of the turning behavior is reduced.

In particular, according to the illustrated embodiment, a corresponding correction coefficient is calculated according to whether the four-wheel steering device 70 is out of order, the total weight M of the vehicle, the load distribution ratio RMF of the front wheels, and the steering angle θ. As a result, the spin values SVp and SVm are corrected, so that the boundaries indicating the spin region and the quasi-spin region are changed as shown by broken lines in FIGS. 20 (B) to 25 (B), respectively. The turning behavior of the vehicle is determined in a manner equivalent to this.

Therefore, whether the four-wheel steering device 70 is out of order, changes in the total weight M of the vehicle and changes in the load distribution RMF of the front and rear wheels,
The turning behavior of the vehicle can be accurately determined in accordance with the change in the spin area and the quasi-spin area due to the steering, whereby whether the four-wheel steering device is normal, the total weight of the vehicle and the front and rear wheels can be determined. The turning behavior of the vehicle can be optimally and effectively controlled irrespective of load distribution and steering.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments may be 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-described embodiments, when the vehicle is in the spin state or the quasi-spin region, the braking force of the front outer wheel is increased by the spin value SVp or SV.
m, the spin is reduced by the anti-spin moment due to the difference between the braking force of the front outer wheel and the braking force of the inner inner wheel. The braking force of the turning outer wheel may be controlled.

In the above embodiment, step 81
At 0 to 895, the spin value SVp or SVm is corrected in accordance with the disturbance level on the road surface, whereby the control amount of the behavior control is corrected. However, the spin value is corrected based on the disturbance level on the road surface. May be omitted.

[0089]

[0090]

As is clear from the above description, the present invention
According to the configuration of claim 1 , when the physical quantity βd corresponding to the slip angle β and the slip angular velocity is determined to be in the spin range, the behavior of the vehicle is controlled so that the magnitude of the slip angle β is reduced, Slip angle β and physical quantity β
When d is determined to be in the quasi-spin region, the physical quantity β
Since the behavior of the vehicle is controlled to reduce the magnitude of d, the physical quantity corresponding to the slip angle β and the slip angular velocity
vehicle only if βd is determined to be within the spin range
Compared with the conventional behavior control device where the behavior of
Thus, the turning behavior of the vehicle in a state where the slip angle β and the physical quantity βd are in the quasi-spin region can be quickly and reliably stabilized.

In particular, according to the configuration of the first aspect , the slip angle β and the physical quantity βd are determined to be in the quasi-spin region before being determined to be in the spin region, and the convergence of the turning behavior of the vehicle is improved. This reduces the spin behavior of the vehicle, so that β and βd are subsequently determined to be in the spin range, and even when braking force is applied to the turning outer wheel to reduce β, for example, the braking force is small. As a result, it is possible to suppress a decrease in the lateral force of the wheel and improve the course tracing property of the vehicle.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a vehicle braking device to which a behavior control device according to the present invention is applied and an electric control device thereof.

FIG. 2 is a general flowchart showing behavior control by an embodiment of the behavior control device according to the present invention.

3 is a flowchart showing a cant correction value calculation routine in step 200 of the general flowchart shown in FIG. 2;

FIG. 4 is a flowchart showing an integration time determination routine in step 300 of the general flowchart shown in FIG. 2;

FIG. 5 is a flowchart showing a lateral acceleration deviation calculation routine in step 400 of the general flowchart shown in FIG. 2;

6 is a flowchart showing a vehicle body slip angle calculation routine in step 500 of the general flowchart shown in FIG. 2;

FIG. 7 is a flowchart showing a spin value calculation routine in step 700 of the general flowchart shown in FIG. 2;

FIG. 8: Step 80 of the flowchart shown in FIG. 7
7 is a flowchart illustrating a spin value correction routine at 0.

FIG. 9 is a flowchart showing a vehicle behavior determination routine in step 900 of the general flowchart shown in FIG. 2;

FIG. 10 is a flowchart showing a vehicle behavior control execution routine in step 1000 of the general flowchart shown in FIG. 2;

FIG. 11 is a graph showing a relationship between an absolute value of spin value and a time constant Tc.

FIG. 12 is a graph showing a relationship between an absolute value of a spin value and a time constant Ti.

FIG. 13: Steering angle θ and correction coefficients Kspp, Kspm, Ksdp
, Ksdm.

FIG. 14 is a graph showing the relationship between the steering angle θ and the correction coefficients Kfpp, Kfpm, Kfdp, and Kfdm for the yaw rate feedback type 4WS (A) and the steering angle proportional type 4WS (B).

FIG. 15 is a graph showing the relationship between the total weight M of the vehicle and the correction coefficients Kwp and Kwd.

FIG. 16 is a graph showing a relationship between a front wheel load distribution ratio RMF and a correction coefficient Krd.

FIG. 17 is a graph showing a relationship between spin values SVp and SVm and a target slip ratio Rs for reducing spin.

FIG. 18 is a graph showing a relationship between spin values SVp and SVm and a target slip ratio Rs for improving convergence of turning behavior.

FIG. 19 is a graph showing an example of changes in the lateral acceleration Gy and the product V * γ.

FIG. 20 is a graph showing changes in a spin region and its boundary in β-βd coordinates when the four-wheel steering device is a four-wheel steering device of a yaw rate feedback type.

FIG. 21 is a graph showing a change in a spin region and its boundary in β-βd coordinates when the four-wheel steering device is a four-wheel steering device of a steering angle proportional type.

FIG. 22: β-βd when the total weight of vehicles is different
5 is a graph showing a change in a spin region and its boundary in coordinates.

FIG. 23 shows a case where the load distribution of the front and rear wheels is different.
6 is a graph showing a change in a spin region and its boundary at the βd coordinate.

FIG. 24 is a graph showing changes in a quasi-spin region and its boundary in β-βd coordinates when steering angles are different.

FIG. 25 is a graph showing changes in a spin region and its boundary in β-βd coordinates when the steering angle is different.

[Explanation of symbols]

 10 Brake device 14 Master cylinder 18, 20, 26, 28 Brake hydraulic pressure control device 38FL, 38FR, 38RL, 38RR Wheel wheel 40FL, 40FR, 40RL, 40RR Control valve 44FL, 44FR, 44RL, 44RR Open / close valve 46FL, 46FR, 46RL, 46RR Open / close valve 50 Electric control device 56 Vehicle speed sensor 58 Lateral acceleration sensor 60 Yaw rate sensor 62 Steering angle sensor 64FL, 64FR Wheel speed sensor 70 Four-wheel steering device

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-109711 (JP, A) JP-A-3-281482 (JP, A) JP-A-4-231207 (JP, A) JP-A-2- 74471 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 8/24 B60T 8/58

Claims (1)

(57) [Claims] 1. A means for determining a slip angle β of a vehicle body, a means for determining a physical quantity βd corresponding to a slip angular velocity of the vehicle body, and whether or not the slip angle β and the physical quantity βd are in a spin region of β-βd coordinates. First determining means for determining whether the slip angle β and the physical quantity βd are equal to the β-β
a region other than the spin region on the d-coordinate and the physical quantity
Second discriminating means for discriminating whether the magnitude of βd is in a large quasi-spin region and the first discriminating means determine that the slip angle β and the physical quantity βd are in the spin region. Sometimes, the behavior of the vehicle is controlled such that the magnitude of the slip angle β is reduced.
And a behavior control means for controlling the behavior of the vehicle so as to reduce the size of the vehicle.