JPH10315943A - Behavior controller of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a drift out condition effectively when a vehicle runs at a low or middle speed so as to prevent the occurrence of spin due to the drift out suppression control when the vehicle runs at a high speed without fail. SOLUTION: A spin condition amount SS and a drift out condition amount DS are calculated (steps 100, 150), and total yaw moment control variable Mt and total deceleration control variable Gt are calculated (step 200). Target yaw moment control variable Mreq and target deceleration control variable Greq are calculated (steps 250, 300), a control variable Dsj of each wheel is calculated (step 350), and braking pressure of each wheel is controlled in accordance with the control variable Dsj to decelerate a vehicle at the time of drift out and give auxiliary turn yaw moment to the vehicle (steps 450 to 550). In particular, a control variable Dsrin of a rear wheel on an inner side of turn is compensated in accordance with a car speed in such a manner that the higher a car speed V is, the less the control variable Dsrin becomes in a high car speed region (400).

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 drift-out during turning of a vehicle such as an automobile.

[0002]

2. Description of the Related Art For example, Japanese Patent Application No. 8-61911 filed by the applicant of the present invention discloses a device for controlling the behavior of a vehicle such as an automobile when the vehicle is turning. Means for estimating the amount of drift-out state as the degree of instability, means for estimating the slip angle of the rear wheel, and, when the amount of drift-out exceeds its reference value, the lateral angle of the rear wheel based on the slip angle of the rear wheel. Means for increasing or decreasing the target slip rate of each wheel so that the force is substantially maximum; and braking force control means for controlling the braking force so that the slip rate of each wheel becomes the target slip rate. There has already been proposed a vehicle behavior control device configured to control only the braking force of the rear inner wheel during a predetermined time after the amount exceeds the reference value.

According to such a behavior control device, during a predetermined time from the time when the drift-out state quantity exceeds the reference value, in other words, at the beginning of the drift-out suppression control, the braking force is applied only to the rear inner wheel. As a result, the lateral force of the front wheels is prevented from lowering, and a slight deceleration is achieved. After a lapse of a predetermined time after the start of the drift-out suppression control, a sufficient inward yaw moment is applied to the vehicle. In addition, since the vehicle is sufficiently decelerated, the turning assist yaw moment can be optimized according to the condition of the vehicle to assist the turning of the vehicle without excess and deficiency, thereby preventing occurrence of spin. Drift out can be suppressed as effectively as possible.

[0004]

Generally, when the vehicle is traveling at high speed such as when traveling on a highway, the steering angle does not become a high value, so that the vehicle rarely becomes excessively understeered. However, in the conventional behavior control device such as the behavior control device according to the above-mentioned proposal, the ratio of the magnitude of the turning assist yaw moment to the drift-out state amount is constant regardless of the vehicle speed. If it is attempted to effectively suppress the drift-out state during traveling, there is a problem that the turning assist yaw moment tends to be excessively large when the vehicle is traveling at high speed.

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 drift-out suppression control amount according to the vehicle speed when the vehicle is running at high speed. Assists the turning of the vehicle without excess and deficiency by optimizing the drift, effectively suppressing the drift-out condition at low and medium speed running and generating the spin due to the drift-out suppression control at high speed running Is to be surely prevented.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a main object of the present invention is to reduce the speed of a vehicle by lowering the wheel speed of at least the rear inner wheel when the vehicle turns. Alternatively, in a vehicle behavior control device that performs turning assist control that gives a turning assist yaw moment to the vehicle, a vehicle speed detecting unit, and a control amount correction unit that reduces the control amount of the turning assist control as the vehicle speed increases. This is achieved by a vehicle behavior control device having the same.

According to the first aspect of the present invention, the control amount of the turning assist control is reduced by the control amount correction means as the vehicle speed increases, so that the drift-out state at the time of low to medium speed running is effectively suppressed. At the same time, the occurrence of spin caused by the drift-out suppression control during high-speed running is reliably prevented.

[0008]

According to a preferred aspect of the present invention, in the above-mentioned configuration of the first aspect, the control amount correcting means turns only when the vehicle speed is higher than the reference value as the vehicle speed increases. The control amount of the auxiliary control is configured to be reduced (preferred mode 1).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned preferred embodiment 1, the control amount correcting means includes a control unit for controlling the vehicle speed to be equal to or higher than the reference value and the magnitude of the steering angular speed to be equal to or higher than the reference value. In some cases, the control amount of the turn assist control is configured to be reduced (preferred mode 2).

According to another preferred aspect of the present invention, in the configuration of the above-mentioned claim 1, there are provided means for estimating a spin state amount of the vehicle, and means for estimating a drift-out state amount of the vehicle. Means for calculating a target yaw moment control amount and a target deceleration control amount based on the spin state amount and the drift out state amount, and means for calculating a control amount for each wheel based on the target yaw moment control amount and the target deceleration control amount. (Preferred embodiment 3).

[0011]

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 driver's depressing operation of a brake pedal 12, 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 braking device 10 has an oil pump 40 that pumps 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 is also connected to a front-wheel switching valve 42 and a rear-wheel switching valve 44.
An accumulator 46 that accumulates high-pressure oil discharged from the accumulator as an accumulator pressure is connected. As shown, the switching valves 42 and 44 are also three-port two-position switching type electromagnetic switching valves.

The brake hydraulic control devices 20 and 22 for the front left and right wheels respectively include wheel cylinders 48FL and 48FR for controlling braking force on the corresponding wheels, electromagnetic control valves 50FL and 50FR of a three-port two-position switching type, and a reservoir. Low pressure conduit 5 as return passage connected to 36
The normally open solenoid-operated on-off valves 54FL and 54FR and the normally-closed electromagnetic on-off valves 56FL and 56FL provided in the middle of the regulator pressure supply conduit 53 connected between the hydraulic pump 2 and the discharge port of the hydro booster 16. 56FR. The regulator pressure supply conduit 53 between the on-off valves 54FL, 54FR and the on-off valves 56FL, 56FR respectively has connection conduits 58FL, 58
FR is connected to control valves 50FL and 50FR.

A brake hydraulic control device 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 regulator pressure supply conduit 53 and the left and right rear wheel control valves 28, and the control valves 28 are respectively brake oil pressure control conduits for the rear wheels. 26 and on-off valve 60RL, 60RR
, And the first position shown in the drawing for interrupting the communication between the on-off valves 60RL, 60RR and the regulator pressure supply conduit 68, the brake hydraulic control conduit 26 and the on-off valves 60RL, 60RR.
And the switching to the second position where the on-off valves 60RL, 60RR and the regulator pressure supply conduit 68 are connected.

The control valves 50FL, 50FR, and 28 function as master cylinder pressure shutoff valves, and when these control valves are at the first position shown in the figure, the wheel cylinders 48FL, 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 valves 42 and 44 have a function of switching the hydraulic pressure supplied to the wheel cylinders 48FL, 48FR, 64RL and 64RR between the accumulator pressure and the regulator pressure. Is switched to the second position and the on-off valves 54FL, 54FR, 60RL, 60
When the switching valves 42 and 44 are maintained at the illustrated first positions while the RR and the on-off valves 56FL, 56FR, 62RL, and 62RR are at the illustrated positions, the wheel cylinder 48FL,
By supplying the regulator pressure to the 48FR, 64RL, and 64RR, the pressure in each wheel cylinder is controlled by the regulator pressure, whereby the braking of that wheel is performed regardless of the amount of depression of the brake pedal 12 and the braking pressure of the other wheels. The pressure is controlled in a pressure increase mode by a 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.

The control valves 50FL, 50FR, 28 are switched to the second position, and the on-off valves 54FL, 54FR, 60RL,
When the switching valves 42 and 44 are switched to the second position with the 60RR and the opening / closing valves 56FL, 56FR, 62RL, and 62RR in the illustrated positions, the wheel cylinders 48FL, 48F
By supplying the accumulator pressure to R, 64RL, and 64RR, the pressure in each wheel cylinder is controlled at an accumulator pressure higher than the regulator pressure, thereby affecting the amount of depression of the brake pedal 12 and the braking pressure of other wheels. Instead, the braking pressure of the wheel is controlled in the pressure increasing mode by the accumulator pressure.

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 state shown in the figure, the pressure in each wheel cylinder is maintained regardless of the positions of the switching valves 42 and 44, and the control valves 50FL, 50FR, 28
Are switched to the second position and the on-off valves 54FL, 5FL
4FR, 60RL, 60RR and open / close valve 56FL, 56FR, 62
When RL and 62RR are switched to the second position, the switching valve 42
The pressure in each wheel cylinder is reduced irrespective of the positions of and 44, whereby the braking pressure of the wheel is controlled in the reduced pressure mode regardless of the amount of depression of the brake pedal 12 and the braking pressure of the other wheels.

Switching valves 42 and 44, control valves 50FL, 50
FR, 28, on-off valves 54FL, 54FR, 60RL, 60RR and on-off valves 56FL, 56FR, 62RL, 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. The microcomputer 72 includes, for example, a central processing unit (CPU), a read-only memory (ROM), not shown in detail in FIG. , A random access memory (RAM), and an input / output port device, which may be connected to each other by a bidirectional common bus.

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 provided substantially 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 θ from the steering angle sensor 82, a signal indicating the longitudinal acceleration Gx of the vehicle body from a longitudinal acceleration sensor 84 provided substantially at the center of gravity of the vehicle body, the wheel speed sensors 86FL From 86RR, the wheel speeds (peripheral speeds) Vwi (i = fl, fr, r
l, rr). 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 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. The turning behavior is determined, the target braking force of each wheel for stabilizing the turning behavior of the vehicle is calculated, and the braking force of each wheel is controlled based on the calculation result.

Next, an outline of the behavior control of the vehicle will be described with reference to the 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, in step 50, the vehicle speed sensor 7
6, a signal indicating the vehicle speed V detected is read, and in step 100, the spin state amount SS indicating the degree of spin of the vehicle is calculated according to the flowchart shown in FIG. Then, a drift-out state quantity DS indicating the degree of drift-out of the vehicle is calculated according to the flowchart shown in FIG.

In step 200, the total yaw moment control amount Mt and the total deceleration control amount Gt are calculated in accordance with the flowchart shown in FIG. 5, and in step 250, the target is calculated in accordance with the flowchart shown in FIG. The yaw moment control amount Mreq is calculated, and in step 300, the target deceleration control amount Greq is calculated according to the flowchart shown in FIG.

In step 350, the control amounts Dsj (j = fin,
fout, rin, rout) are calculated, and in step 400, the control amount Dsrin of the turning inside rear wheel is corrected according to the flowchart shown in FIG. 9, and in step 450, according to the flowchart shown in FIG. The target wheel speed Vwti of each wheel is calculated.

In step 500, the duty ratio Dri (i = fl, fr, rl, rr) of each wheel is calculated according to the following equation (1). In the following equation 1, Kp and Kd are proportional constants of a proportional term and a differential term in the wheel speed feedback control.

Dri = Kp * (Vwi-Vwti) + Kd * d (V
wi-Vwti) / dt

In step 550, the switching valves 42, 4
4 and the control valves 28, 50FL, and 50FR are controlled to be switched to the second position by outputting control signals to the control valves 28, 50FL, and 50FR. Is output, the supply and discharge of the accumulator pressure to and from the wheel cylinders 48FL, 48FR, 66RL, 66RR are controlled, thereby controlling the braking pressure of each wheel.

In this case, when the duty ratio Dri is a value 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.

In step 102 of the spin amount SS calculation routine shown in FIG. 3, the lateral acceleration Gy and the vehicle speed V are calculated.
The deviation of the lateral acceleration, that is, the lateral slip acceleration Vyd of the vehicle is calculated as the deviation Gy-V * γ from the product V * γ of the yaw rate γ, and in step 104, the lateral slip acceleration Vyd is calculated.
Is integrated to calculate the vehicle body slip speed Vy, and the vehicle body slip angle β 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 106, the spin value SV is calculated as the linear sum K1 * β + K2 * Vyd of the slip angle β and the skid acceleration Vyd of the vehicle body using K1 and K2 as positive constants, respectively. In step 108, the yaw rate γ The turning direction of the vehicle is determined based on the sign of
The spin state amount SS is calculated as SV when the vehicle is turning left, and is calculated as -SV when the vehicle is turning right. When the calculation result is a negative value, the spin state amount is set to 0.
The spin value SV may be calculated as a linear sum of the slip angle β of the vehicle body and its differential value βd.

In step 152 of the routine DS for calculating the amount of drift-out state shown in FIG. 4, Kh is used as a stability factor, H is used as a wheel base, and R is used as R.
The target yaw rate γc is calculated according to the following equation 2 using g as a steering gear ratio, and T is set as a time constant and s
Is used as a Laplace operator to calculate a reference yaw rate γt according to the following equation (3). Incidentally, the target yaw rate γc may be calculated in consideration of the lateral acceleration Gy of the vehicle in consideration of a dynamic yaw rate.

[0037]

Γ c = V * θ / (1 + Kh * V ² ) * H / Rg

Γt = γc / (1 + T * s)

In step 154, the drift value DV is calculated according to the following equation (4). The drift value DV may be calculated according to the following equation (5).

[0039]

## EQU4 ## DV = (γt−γ)

## EQU5 ## DV = H * (γt−γ) / V

In step 156, the turning direction of the vehicle is determined based on the sign of the yaw rate γ, and the drift-out state amount DS is calculated as DV when the vehicle is turning left, and as -DV when the vehicle is turning right. When the calculation result is a negative value, the drift-out state amount is set to zero.

In step 202 of the routine for calculating the total yaw moment control amount Mt and the total deceleration control amount Gt shown in FIG. 5, a map corresponding to the graph shown in FIG. Then, the yaw moment control amount Mts for spin is calculated, and in step 204, the deceleration control amount Gts for spin is calculated from the map corresponding to the graph shown in FIG. 12 based on the spin state amount SS.

Similarly, in step 206, the yaw moment control amount Mtd for the drift is calculated from the map corresponding to the graph shown in FIG. 13 on the basis of the drift-out state amount DS. The deceleration control amount Gtd for the drift is calculated from the map corresponding to the graph shown in FIG. 14 based on the amount DS.

In step 210, it is determined whether or not the yaw moment control amount Mts for spin is equal to or greater than the yaw moment control amount Mtd for drift. When an affirmative determination is made, the total amount in step 212 is determined. The yaw moment control amount Mt is set to the yaw moment control amount Mts for the spin, and if a negative determination is made, the total yaw moment control amount Mt is set to the yaw moment control amount Mtd for the drift in step 214.

Similarly, in step 216, the deceleration control amount Gts for the spin is changed to the deceleration control amount G for the drift.
It is determined whether or not it is equal to or greater than td. If an affirmative determination is made, the total deceleration control amount Gt is set to the deceleration control amount Gts for the spin in step 218, and if a negative determination is made, the process proceeds to step 218. At 220, the total deceleration control amount Gt
Set to td.

In step 252 of the routine for calculating the target yaw moment control amount Mreq shown in FIG. 6, the coefficient of friction μ of the road surface with respect to the wheel is estimated and calculated according to, for example, the following equation 6 using g as the gravitational acceleration. In the above, the upper limit value βrl is calculated from a map (not shown) based on the friction coefficient μ.

## EQU6 ## μ = (Gx2 + Gy2) ^1/2 / g

In step 256, the slip angle βf of the front wheels is determined by using Lf as the distance between the center of gravity of the vehicle and the front wheel axle.
Is calculated according to the following equation (7), the actual steering angular velocity δfd of the front wheel is calculated as a differential value of the actual steering angle δf (= θ / Rg) of the front wheel, and Ts is a time constant of the phase advance, and the following equation (8) is obtained. , A reference value βfs for calculating the target slip angle βrt of the rear wheels is calculated.

[0047]

## EQU7 ## βf = β + Lf * γ / V−θ / Rg

[Equation 8] βfs = βf + Ts * δfd

The reference value βfs may be calculated according to the following equation (9).

[Equation 9] βfs = DV + Ts * δfd

In step 258, a target slip angle βrt of the rear wheels is calculated from a map corresponding to the graph shown in FIG. 15 based on the reference value βfs. Note that the slope of the straight line portion of the graph shown in FIG. 15 is such that Cf is the cornering power of the front wheel, Cr is the cornering power of the rear wheel, and L
Let r be the distance between the center of gravity of the vehicle and the rear wheel vehicle (Cf
* Lf) / (Cr * Lr), and the upper and lower limits are βrl and −βrl, respectively.

The target slip angle βrt of the rear wheel is represented by C in FIG.
The slope (Cf * Lf) / (Cr * L) of the graph shown in FIG.
r) may be calculated according to Equation 10 below.

[Formula 10] βrt = βrl * tanh (βfs * C)

In step 260, the yaw moment control coefficient Km is calculated according to the following equation (11), and in step 262, the target yaw moment control amount Mreq is calculated according to the following equation (12).

[0052]

Km = βr−βrt + Vyd

## EQU12 ## Mreq = Km * Mt

In step 302 of the target deceleration control amount Greq calculation routine shown in FIG.
g is calculated in step 252 to calculate the friction coefficient μ of the road surface.
In step 304, the target deceleration control amount Greq is calculated in accordance with the following equation (13).

[Expression 13] Greq = Kg * Gt

In step 352 of the routine for calculating the control amount Dsj of each wheel shown in FIG. 8, turning is performed based on the target yaw moment control amount Mreq from the maps corresponding to the graphs shown in FIGS. 16 to 19, respectively. The yaw moment distribution ratio Rmj (j = fin, fout, rin, rout) of the inside front wheel, turning outside front wheel, turning inside rear wheel, and turning outside rear wheel is calculated, and in step 354, each wheel is calculated according to the following equation (14). Is calculated.

Dsmj = Rmj * Mreq

In step 356, the turning inside front wheel, turning outside front wheel, turning inside rear wheel, turning outside rear wheel are obtained from the maps corresponding to the graphs shown in FIGS. 20 to 23 based on the target yaw moment control amount Mreq. The deceleration distribution ratio Rdj (j = fin, fout, rin, rout) is calculated. In step 358, the deceleration control amount Dsdj for each wheel is calculated according to the following equation (15).

Dsdj = Rdj * Greq

In step 360, the control amount D for each wheel
sj is the yaw moment control amount Dsmj and the deceleration control amount Dsdj
Is calculated according to the following equation (16).

Dsj = Dsmj + Dsdj

The control amount Dsr of the turning inside rear wheel shown in FIG.
In step 402 of the in correction routine, it is determined whether or not the vehicle speed V is equal to or higher than a reference value Vc (a positive constant of about 80 km / h). If an affirmative determination is made, the process proceeds to step 406. If a negative determination is made, the correction coefficient Kv and the correction coefficient Ks are set to 1 in step 404.

In step 406, a correction coefficient Kv is calculated from the map corresponding to the graph shown in FIG. 24 based on the vehicle speed V. In step 408, the steering angular velocity θd is calculated as a time differential value of the steering angle θ. Is calculated, and a correction coefficient Ks is calculated from the map corresponding to the graph shown in FIG. 25 based on the absolute value of the steering angular velocity θd. The subsequent control amount Dsrin is calculated.

Dsrin = Kv * Ks * Dsrin

The target wheel speed Vti of each wheel shown in FIG.
In step 452 of the calculation routine, it is determined whether or not the product of the lateral acceleration Gy of the vehicle and the target yaw moment control amount Nreq is positive, that is, the target yaw moment control amount is the yaw moment control amount in the turning assist direction. Is determined, and if an affirmative determination is made, step 46 is reached.
0, and when a negative determination is made, step 454 is performed.
Proceed to.

In step 454, it is determined whether or not the yaw rate γ is positive, that is, whether or not the vehicle is turning left. When an affirmative determination is made, step 456 is performed. The target wheel speed Vwti of each wheel is calculated according to the following equation (18), and if a negative determination is made, the target wheel speed Vwti of each wheel is calculated at step 458 according to the following equation (19).

[0061]

Vwtfl = (1-Dsfin) Vwfr Vwtfr = Vwfr Vwtrl = (1-Dsrin) Vwfr Vwtrr = (1-Dsrout) Vwfr

Vwtfl = Vwfl Vwtfr = (1-Dsfin) Vwfl Vwtrl = (1-Dsrout) Vwfl Vwtrr = (1-Dsrin) Vwfl

Similarly, in step 460, it is determined whether or not the yaw rate γ is positive. When the determination is affirmative, in step 462, the target wheel speed Vwti of each wheel is calculated according to the following equation (20). Is calculated, and when a negative determination is made, the target wheel speed Vwti of each wheel is calculated in step 464 according to the following equation 21.

[0063]

Vwtfl = Vwfl Vwtfr = (1-Dsfout) Vwfl Vwtrl = (1-Dsrin) Vwfl Vwtrr = (1-Dsrout) Vwfl

Vwtfl = (1-Dsfout) Vwfr Vwtfr = Vwfr Vwtrl = (1-Dsrout) Vwfr Vwtrr = (1-Dsrin) Vwfr

Thus, according to the illustrated embodiment, in steps 100 and 150, the spin state SS
And the drift-out state quantity DS is calculated, and
In step 00, the total yaw moment control amount Mt and the total deceleration control amount Gt are calculated based on these state quantities, and in steps 250 and 300, the target yaw moment control amount Mreq and the target deceleration are calculated based on these control amounts. The control amount Greq is calculated.

Then, in step 350, the control amount Dsj of each wheel is calculated based on the target yaw moment control amount Mreq and the target deceleration control amount Greq. In step 450, the target wheel speed Vwti of each wheel is calculated. 500
In step 550, the duty ratio Dri of each wheel is calculated based on the control amount Dsj, and in step 550, the braking pressure of each wheel is controlled in accordance with the duty ratio Dri, so that the vehicle is decelerated and necessary for the vehicle. A yaw moment is provided.

For example, when the vehicle is in a spin state, the spin state amount SS becomes a high value, and in response to this, the target yaw moment control amount Mreq and the target deceleration control amount Greq in the anti-spin direction are calculated. By calculating the wheel control amount Dsj, a yaw moment in the anti-spin direction is given to the vehicle, and the vehicle is decelerated.
Thereby, a spin state is reduced.

When the vehicle drifts out,
The drift-out state amount DS becomes a high value, and the target yaw moment control amount Mreq and the target deceleration control amount Greq in the turning assist direction are calculated accordingly, and the control amount Dsj of each wheel is calculated based on these. As a result, the yaw moment in the turning assist direction is given to the vehicle, and the vehicle is decelerated, whereby the drift-out state is reduced.

In this case, in particular, the control amount Dsr of the turning inside rear wheel
in is corrected in step 400. That is, it is determined in step 402 whether or not the vehicle speed V is equal to or higher than the reference value Vc.
In step 06, the correction coefficient Kv is calculated so as to increase as the vehicle speed V increases, and in step 408, the steering angular velocity θ
The correction coefficient Ks is calculated so as to increase as the magnitude of d increases. In step 410, the product of the correction coefficient Kv and the correction coefficient Ks and the control amount Dsrin before correction of the turning inside rear wheel is calculated as the product of the turning inside rear wheel. The corrected control amount Dsrin is calculated.

Accordingly, in a high vehicle speed range in which the vehicle speed V is equal to or higher than the reference value Vc, the higher the vehicle speed, the smaller the control amount Dsrin of the turning inner rear wheel, and the higher the speed at which the vehicle is unlikely to understeer. In some cases, the braking force of the rear inner wheel due to the drift-out suppression control becomes excessive, which surely prevents the vehicle from spinning due to the drift-out suppression control. Insufficient braking force of the rear wheel on the inner side of the turn and deceleration of the vehicle and excessive shortage of the turning assist yaw moment are avoided.
Thereby, the drift-out state is effectively suppressed.

According to the illustrated embodiment, the correction coefficient K
Since s is calculated in step 408 so as to increase as the magnitude of the steering angular velocity θd increases, for example, in the case of emergency avoidance steering when the vehicle is running at a high speed, the braking force of the rear inner wheel is excessively increased. It is possible to prevent the vehicle speed from lowering and the vehicle turning deceleration and turning assist yaw moment from being excessively insufficient.

According to the illustrated embodiment, the control amount Dsrin of the turning inside rear wheel is corrected even when the vehicle is in the spin state, but the control amount of the turning inside rear wheel is corrected when the vehicle is in the spin state. Is not so high, whereas the control amount of the front outside wheel is high, so that the effect of the spin suppression control is not greatly reduced by correcting the control amount Dsrin of the rear inside wheel.

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 the illustrated embodiment, in step 408, the correction coefficient Ks is calculated so as to increase as the magnitude of the steering angular velocity θd increases.
As the magnitude of the steering angular velocity increases, the reduction correction amount of the control amount Dsrin of the turning inside rear wheel is reduced.
The correction of the control amount Dsrin of the turning inside rear wheel by the correction coefficient Ks may be omitted.

In the illustrated embodiment, the spin state amount SS and the drift-out state amount DS are calculated, and the total yaw moment control amount Mt and the total deceleration control amount Gt are calculated based on these state amounts. The target yaw moment control amount Mreq and the target deceleration control amount Greq are calculated based on these control amounts, and the control amount Dsj for each wheel is calculated based on these control amounts. The calculation may be performed in any manner as long as the control amount for suppressing the drift-out is calculated based on the drift-out state amount.

Further, in the illustrated embodiment, the deceleration for suppressing the drift-out and the application of the turning assist yaw moment direction are achieved by controlling the braking force of each wheel. Or the control of the braking force and the driving force of each wheel.

[0076]

As is apparent from the above description, according to the configuration of the first aspect of the present invention, the control amount of the turning assist control is reduced by the control amount correction means as the vehicle speed becomes higher.
It is possible to effectively suppress the drift-out state at the time of low-medium-speed running, and to surely prevent the occurrence of spin due to the drift-out suppression control at the time of high-speed running.

[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 general flowchart showing an outline of behavior control achieved by one embodiment of the behavior control device according to the present invention.

FIG. 3 is a flowchart illustrating a calculation routine of a spin state amount SS in the illustrated embodiment.

FIG. 4 is a flowchart showing a calculation routine of a drift-out state quantity DS in the illustrated embodiment.

FIG. 5 is a flowchart showing a routine for calculating a total yaw moment control amount Mt and a total deceleration control amount Gt in the illustrated embodiment.

FIG. 6 is a flowchart showing a calculation routine of a target yaw moment control amount Mreq in the illustrated embodiment.

FIG. 7 shows a target deceleration control amount Greq in the illustrated embodiment.
6 is a flowchart showing a calculation routine of FIG.

FIG. 8 is a flowchart illustrating a calculation routine of a control amount Dsj of each wheel in the illustrated embodiment.

FIG. 9 is a flowchart illustrating a correction routine of a control amount Dsrin of a rear inside wheel in the turning in the illustrated embodiment.

FIG. 10 shows a target wheel speed V of each wheel in the illustrated embodiment.
5 is a flowchart showing a calculation routine of wti.

FIG. 11 is a graph showing a relationship between a spin state amount SS and a spin yaw moment control amount Mts.

FIG. 12 shows a spin state amount SS and a spin deceleration control amount Gts.
6 is a graph showing the relationship between

FIG. 13 is a graph showing a relationship between a drift-out state amount DS and a drift yaw moment control amount Mtd.

FIG. 14 is a graph showing a relationship between a drift-out state quantity DS and a drift deceleration control amount Gtd.

FIG. 15 is a graph showing a relationship between a reference value βfs and a rear wheel target slip angle βrt.

FIG. 16 is a graph showing a relationship between a target yaw moment control amount Mreq and a yaw moment distribution ratio Rmfin of a turning inside front wheel.

FIG. 17 is a graph showing a relationship between a target yaw moment control amount Mreq and a yaw moment distribution ratio Rmfout of a front wheel on the outside of turning;

FIG. 18 is a graph showing a relationship between a target yaw moment control amount Mreq and a yaw moment distribution ratio Rmrin of a turning inside rear wheel.

FIG. 19 is a graph showing a relationship between a target yaw moment control amount Mreq and a yaw moment distribution ratio Rmrout of a turning outside rear wheel.

FIG. 20 is a graph showing a relationship between a target yaw moment control amount Mreq and a deceleration distribution ratio Rdfin of a turning inside front wheel.

FIG. 21 is a graph showing a relationship between a target yaw moment control amount Mreq and a deceleration distribution ratio Rdfout of a turning outside front wheel.

FIG. 22 is a graph showing a relationship between a target yaw moment control amount Mreq and a deceleration distribution ratio Rdrin of a turning inside rear wheel.

FIG. 23 is a graph showing a relationship between a target yaw moment control amount Mreq and a deceleration distribution ratio Rdrout of a turning outer rear wheel.

FIG. 24 is a graph showing a relationship between a vehicle speed V and a correction coefficient Kv for a control amount of a turning inside rear wheel.

FIG. 25 is a graph showing a relationship between an absolute value of a steering angular velocity θd and a correction coefficient Ks for a control amount of a rear wheel on the inside of the turn.

[Explanation of symbols]

 Reference Signs List 10 brake device 14 master cylinder 16 hydro booster 20, 22, 32, 34 brake hydraulic control device 28, 50FL, 50FR control valve 42, 44 switching valve 44FL, 44FR, 64RL, 64RR wheel cylinder 54FL 54FR, 60RL, 60RR ... open / close valve 56FL, 56FR, 62RL, 62RR ... open / close valve 70 ... electric 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

Claims (1)

[Claims] 1. A vehicle behavior control device for performing a turning assist control for reducing a speed of a vehicle by turning at least a wheel speed of a rear inner wheel at the time of turning of the vehicle or giving a turning assist yaw moment to the vehicle. And a control amount correction unit that reduces the control amount of the turning assist control as the vehicle speed increases.