JPH08310364A - Turn controller for vehicle - Google Patents

Abstract

PURPOSE: To prevent operation of undesirable anti-skid brake control and to surely stabilize a turning behavior of a vehicle by arranging a regulating means regulating increase of a controlling force in a selected wheel when an actual slip ratio for a wheel exceeds an allowable slip ratio. CONSTITUTION: In a setting unit 95, a pressure increase prohibiting flag Fk2 (i)=1 is outputted from an AND circuit 98 to a switch 92 when all the inputs in the AND circuit 98 are turned on, in other words, when a slip ratio Sl (i) for a wheel in a pressure increasing mode exceeds an allowable slip ratio Slmax (i), and consequently, the switch 92 is switched, so that a pulse width Wpls (i) is forcibly changed to 0. Following execution of yaw moment control, the braking force for the wheel in the pressure increasing mode is increased, so that the braking force for the wheel is not increased any more when its slip ratio exceeds the allowable value, and no excessive slip is generated in the wheel, and as a result, operation of ABS control is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking turn of a vehicle,
The present invention relates to a vehicle turning control device that controls a turning of a vehicle by generating a yaw moment in the vehicle by giving a braking force difference between wheels.

[0002]

2. Description of the Related Art A turning control device for a vehicle of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-185562. This known turning control device, when turning, gives a difference in braking force between the left and right wheels according to the turning state, generates a desired yaw moment in the vehicle by this braking force difference, and changes the turning behavior of the vehicle. It has a first braking force control function for controlling to a target characteristic and a second braking force control function for controlling the braking force of the wheel so that the slip of the wheel falls within a predetermined range.

In the known turning control device, the wheel braking force is controlled to increase or decrease according to the smaller one of the control amounts set in the first and second braking force controls. In a situation in which the increasing / decreasing direction due to those control amounts is reversed, the second braking force control has priority over the first braking force control function, and the wheel of the wheel is controlled according to the control amount set by the second braking force control. The braking force is controlled to increase or decrease.

[0004]

Therefore, in the known turning control device, when the vehicle makes a braking turn on a low μ road, the wheel slip easily exceeds a predetermined range. The braking force control, that is, the anti-skid brake control will be given priority. However,
When the slip of the wheel falls within a predetermined range as a result of the activation of the anti-skid brake control, the first braking force control may function effectively and the braking force of the wheel may be increased again. In such a case, the slip of the wheel exceeds the predetermined range, and the anti-skid brake control works again. That is, the control for the wheels is the first
Since the braking force control and the anti-skid brake control are alternately switched, the wheel speed vibrates and the riding comfort is deteriorated.

The present invention has been made based on the above-mentioned circumstances, and an object thereof is to provide a vehicle turning control device for stabilizing the turning behavior of a vehicle without undesirably operating the anti-skid brake control. To provide.

[0006]

The above-mentioned object is achieved by the turning control device for a vehicle according to the present invention.
According to the invention, a calculation means for calculating a required control amount of a yaw moment to be applied to the vehicle according to a motion state and a driving operation state of the vehicle, and the required control amount for the braking force between the selected wheels when the vehicle is turning. Is applied to a turning control device for a vehicle that controls the turning of the vehicle by generating a yaw moment on the vehicle body by the braking force difference, and the turning control device according to claim 1 is applied to the turning control device of the vehicle. Slip ratio detecting means for detecting the slip ratio, setting means for setting the allowable slip ratio of the wheel based on the required control amount, and when the actual slip ratio of the wheel exceeds the allowable slip ratio, the braking force of the selected wheel It further comprises a regulation means for regulating the increase.

In the turning control device according to the second aspect of the present invention, the setting means increases the allowable slip ratio by a predetermined ratio as the required control amount increases, and the allowable slip ratio is increased when the required control amount is a predetermined value or more. It is to be maintained at the upper limit. The turning control device according to claim 3 is applied to a vehicle in which an anti-skid brake control device is incorporated, and in this case, the setting means has an allowable slip ratio according to the slip ratio of the wheel when the anti-skid brake control device operates. And a changing means for changing the increase ratio based on the changed upper limit.

In the turning control device according to claim 4, the calculating means is based on a means for setting a target yaw rate of the vehicle, a yaw rate deviation between the target yaw rate and an actual yaw rate of the vehicle, and a differential value of the yaw rate deviation. And means for setting the required control amount. In the turning control device according to claim 5, the generating means for generating a yaw moment in the vehicle body has an outer front wheel and an inner rear wheel as target wheels when viewed in a turning direction of the vehicle, and increases a braking force of one of the target wheels. And reduce the braking force of the other.

[0009]

According to the turning control device of the first aspect, when the slip ratio of the wheels exceeds the allowable slip ratio, the increase of the braking force is restricted even in the situation where the braking force of the selected wheel should be increased. According to the turning control device of the second aspect, the allowable slip ratio of the wheel changes based on the required control amount for the yaw moment of the vehicle.

According to the turning control device of the third aspect, when the anti-skid brake control device operates, the upper limit value and the increase ratio of the allowable slip ratio are changed based on the slip ratio of the wheel at the time of the operation. According to the turning control device of the fourth aspect, the required control amount is set based on the yaw rate deviation that accurately indicates the turning state of the vehicle and its differential value.

According to the turning control device of the fifth aspect, when a yaw moment is generated in the vehicle during turning, the braking force of the outer front wheel and the inner rear wheel is increased / decreased when viewed in the turning direction.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a vehicle braking system is schematically illustrated. This brake system is equipped with a tandem type master cylinder 1, and the master cylinder 1 is connected to a brake pedal 3 via a vacuum brake booster 2. The pair of pressure chambers of the master cylinder 1 are respectively connected to the reservoir 4, while the main brake pipe lines 5 and 6 extend from these pressure chambers.

The main brake lines 5 and 6 extend in the hydraulic unit (HU) 7, and the main brake lines 5 and 6 are branched into a pair of branch brake lines. The branch brake pipelines 8 and 9 from the main brake pipeline 5 are connected to the wheel brakes (not shown) of the left front wheel FWL and the right rear wheel RWR, respectively, and the branch brake pipeline 10 from the main brake pipeline 6 is Reference numeral 11 is connected to the wheel brakes (not shown) of the right front wheel FWR and the left rear wheel RWL, respectively. Therefore, the wheel brakes of the respective wheels are connected to the tandem master cylinder 1 in a cross piping type.

An electromagnetic valve is inserted in each of the branch brake pipe lines 8, 9, 10, and 11, and each electromagnetic valve is composed of an inlet valve 12 and an outlet valve 13. A proportional valve (PV) is inserted between the rear wheel brake and the corresponding solenoid valve, that is, the inlet valve 12. On the side of the branch brake pipes 8 and 9, the outlet valve 13 of the pair of solenoid valves is connected to the reservoir 4 via the return route 14, and also on the side of the branch brake pipes 10 and 11,
An outlet valve 13 of the pair of solenoid valves is connected to the reservoir 4 via a return path 15. Therefore, the brake pressure of each wheel is controlled by supplying and discharging the pressure in the wheel brake by opening and closing the inlet valve and the outlet valve.

Discharge ports of pumps 16 and 17 are connected to the main brake pipes 5 and 6 respectively along the way through check valves. The pumps 16 and 17 are connected to a common motor 18. There is. On the other hand, the suction ports of the pumps 16 and 17 are connected to the return paths 14 and 15 via the check valves, respectively. Further, cut-off valves 19 and 20 composed of electromagnetic valves are inserted in the main brake pipe lines 5 and 6 at a portion upstream from a connection point with the pumps 16 and 17, and the cut-off valves 19 and 20 are also provided. Relief valves 21 are arranged so as to bypass 20. Here, the cutoff valves 19 and 20 form a cutoff valve unit (CVU) 22.

The above-mentioned inlet and outlet valves 12 and 13, cut-off valves 19 and 20, and the motor 18 are electrically connected to an electronic control unit (ECU) 23. More specifically, the ECU 23 includes a microprocessor, a storage device such as a RAM and a ROM, and an input / output interface.
3, 19, 20 and the motor 18 are connected to the output interface.

On the other hand, a wheel speed sensor 24 provided for each wheel and a rotation speed sensor 25 for detecting the rotation speed of the motor 18 are electrically connected to the input interface of the ECU 23. In addition, in FIG. 1, for convenience of drawing,
The connection between the motor 18 and the ECU 23 and the connection between the rotation speed sensor 25 and the ECU 23 are omitted. Further, as shown in FIG. 2, the input interface of the ECU 23 includes a wheel speed sensor 24 and a rotation speed sensor 25.
Besides, the steering wheel angle sensor 26, the pedal stroke sensor 27, the longitudinal G sensor 28, the lateral G sensor 29, and the yaw rate sensor 30 are electrically connected.

The steering wheel angle sensor 26 detects the steering amount of the steering wheel of the vehicle, that is, the steering wheel angle, and the pedal stroke sensor 27 detects the depression amount of the brake pedal 3, that is, the pedal stroke. The longitudinal G and lateral G sensors 28 and 29 detect longitudinal acceleration and lateral acceleration acting in the longitudinal direction and lateral direction of the vehicle, respectively, and the yaw rate sensor 30 detects each velocity around the vertical direction of the vehicle, that is, yaw angular velocity. .

The ECU 23 follows the various vehicle motion control based on the sensor signals of the various sensors described above, and executes the HU 7 and the CV.
Control the operation of C20. The vehicle motion control is shown in FIG.
As shown in the block of the ECU 23, there are yaw moment control, traction control (TCL) control, anti-skid brake (ABS) control, front and rear wheel braking force distribution control, etc. when the vehicle is turning. .

Referring to FIG. 3, a function related to the yaw moment control among the functions of the ECU 23 is shown in more detail, and FIG. 4 shows a main routine for executing the function related to the yaw moment control. Has been done. The control cycle T of the main loop is set to 8 msec, for example. First, when the sensor signals from the various sensors described above are supplied to the ECU 23, the ECU 23 filters the sensor signals (block 32 in FIG. 3). A recursive first-order low-pass filter is used for the filtering process here. Unless otherwise specified, the recursive first-order low-pass filter is also used in the following filter processing.

The filtered sensor signals, ie, wheel speed Vw (i), steering wheel angle θ, pedal stroke St, longitudinal acceleration Gx (longitudinal Gx), lateral acceleration Gy (lateral Gy) and yaw rate γ are shown in FIG. The information read in step S1 is calculated based on these sensor signals, and the information indicating the motion state of the vehicle and the information for determining the driving operation of the driver are calculated (step S2).

In step S1, the wheel speed Vw
(I) is for collectively indicating the wheel speed of each wheel, and i is an integer from 1 to 4 that identifies the wheel. For example, i = 1 is the left front wheel, i = 2 is the right front wheel, i
= 3 represents the left rear wheel, and i = 4 represents the right rear wheel. It should be noted that i attached to the following reference numerals is also used in the same meaning. As seen in FIG. 3, the execution of step S2 is performed by the calculation units 34 and 36.
The wheel speed Vw is calculated by the calculation unit 34.
(i), the front-rear Gx, the lateral Gy, and the yaw rate γ, the motion state of the vehicle is calculated, and the operation unit 36 determines the operation status of the steering wheel or the brake pedal by the driver based on the steering wheel angle Th and the pedal stroke St. To be judged.

Vehicle motion state: Reference wheel speed: First, reference wheel speed V is selected from among wheel speeds Vw (i).
s is selected, but here, the reference wheel speed Vs is one of the wheels that are not easily affected by the slip of the wheels due to the drive control, specifically, among the non-driving wheels when the vehicle is not braking. It is set to the faster wheel speed Vw, and is set to the fastest wheel speed Vw in the wheel speed Vw (i) during braking. It should be noted that whether or not the vehicle is in non-braking state is determined by a brake flag Fb set by pedal operation of the brake pedal 3 described later.

Vehicle speed: Next, with respect to the reference wheel speed Vs,
When the vehicle is turning, the center-of-gravity speed at the center-of-gravity position of the vehicle is calculated in consideration of the speed difference between the inner and outer wheels and the speed ratio between the front and rear wheels, and the vehicle body speed is determined based on this center-of-gravity speed. To do. First, yaw rate γ, front tread Tf,
If Tr is used, the inner and outer wheel speed differences ΔVif and ΔVir between the front wheels and the rear wheels are represented by the following equations.

ΔVif = γ × Tf ΔVir = γ × Tr Therefore, the average inner / outer wheel speed difference ΔVia between the front wheels and the rear wheels is represented by the following equation. ΔVia = γ × (Tf + Tr) / 2 Regarding the speed ratio between the front and rear wheels, if it is assumed that the turning center of the vehicle is on the extension line of the rear axle and the vehicle is turning right, Speed ratio Rvr between front and rear wheels,
Rvl is represented by the following equation.

Rvr = cos (δ) Rvl≈cos (δ) Therefore, the front-rear wheel speed ratio Rv can be represented by cos (δ) regardless of the left and right. In the above equation, δ represents the front wheel steering angle (steering wheel angle / steering gear ratio).

However, the above equation is valid only when the vehicle is at low speed (more accurately, when the lateral Gy is small).
The correction of the center-of-gravity velocity based on the front-rear wheel speed ratio Rv is limited to low speed only as shown below. Vbm ≧ 30 km / h, Rv = 1 Vbm <30 km / h, Rv = cos (δ) Here, Vbm represents the vehicle speed calculated in the previous routine, and this vehicle speed Vb The calculation will be described later.

If the vehicle is a front-wheel drive vehicle (FF vehicle), the reference wheel speed Vs follows the wheel speed of the rear outer wheel of the vehicle during turning without braking.
By adding 1/2 of the average inner / outer wheel speed difference ΔVia to s and the speed difference between the speed at the rear axle and the speed at the center of gravity,
Center-of-gravity velocity is obtained. However, in order to avoid complication of the calculation formula, if the center-of-gravity velocity is an intermediate value between the speeds of the front and rear axles, the center-of-gravity velocity Vcgo before filtering should be calculated by the following formula. You can

Vcgo = (Vs−ΔVia / 2) × (1+ (1 / Rv) / 2 On the other hand, when the vehicle is turning during braking, the reference wheel speed Vs follows the wheel speed of the front outer wheel of the vehicle. Therefore, in this case, the average inner / outer wheel speed difference Δ is added to the reference wheel speed Vs.
By correcting the speed difference between 1/2 of Via and the speed at the front axle and the speed at the center of gravity, the center-of-gravity speed Vcg0 before filtering can be obtained from the following equation.

Vcg0 = (Vs−ΔVia / 2) × (1 + Rv) / 2 After that, the center-of-gravity velocity Vcg0 is continuously processed twice by the filter process (fc = 6 Hz) to obtain the center-of-gravity velocity Vcg (= LPF (LPF (LPF (LPF ( Vc
g0)) is obtained. In calculating the center-of-gravity velocity Vcg, it is determined based on the above-mentioned brake flag Fb whether or not the vehicle is in the non-braking state.

Normally, the center-of-gravity velocity Vcg coincides with the vehicle body velocity Vb, so that the center-of-gravity velocity Vcg is set as the vehicle body velocity Vb.
That is, the vehicle body speed Vb is usually calculated by the following equation. Vb = Vcg However, in the situation where the selected wheel having the reference wheel speed Vs falls into the lock tendency and the ABS control is started also for the selected wheel, the reference wheel speed Vs follows the slip of the selected wheel. Will sink and the speed will drop significantly below the actual vehicle speed.

Therefore, when such a situation is reached, the vehicle body speed Vs is based on the longitudinal Gx, and the center of gravity speed V is calculated under the following separation conditions.
It is estimated to separate from cg and decrease with the following slope. When the separation judgment value is Gxs, dVcg / d
The condition of t ≦ Gxs continues for 50 msec, or dVcg
When the condition of /dt≦-1.4 g is satisfied, the vehicle body speed Vs is estimated separately from the center of gravity speed Vcg.

Here, the separation determination value Gxs is set by the following equation. Gxs =-(| Gx | +0.2) However, -1.4g≤Gxs≤ -0.
35g When the above-mentioned separation condition is satisfied, the vehicle body speed Vs is estimated based on the following equation. Vb = Vbm-ΔG Vbm represents the vehicle speed before the separation condition is satisfied, and ΔG represents the gradient set under the following conditions.

ΔG = (| Gx | +0.15) where -1.2 g
≤ΔG≤ -0.3g When the vehicle body speed Vb is estimated separately from the center-of-gravity velocity Vcg, the condition for returning to the center-of-gravity velocity Vcg, that is, the separation end condition is as follows. Vcg> Vbm Slip rate: Next, the above-mentioned average inner / outer wheel speed difference Via and the front / rear wheel speed ratio Rv are added to the calculated vehicle speed Vb, and the reference wheel position speed V at each wheel position is calculated based on the following equation.
Calculate r (i).

Vr (i) = Vb × 2 / (1 + Rv) + (or−) Via / 2 Here, regarding the positive / negative sign of the second term in the above formula, when the vehicle turns right, the outer front and rear wheels The reference wheel position speed corresponding to (1) is (+), and the reference wheel position speed corresponding to the front and rear wheels of the inside is (-). On the other hand, when the vehicle turns left, the positive and negative signs are opposite.

The slip ratio Sl (i) of each wheel is calculated by the following equation, and the calculated value is filtered (fc = 1).
0Hz). Sl0 (i) = (Vr (i) -Vw (i)) / Vr (i) Sl (i) = LPF (Sl0 (i)) Note that Sl0 (i) represents the slip ratio before filtering. .

Center-of-gravity slip angular velocity: The relationship between the center-of-gravity slip angular velocity dβ and the yaw rate γ is represented by the following equation, where ω is the angular velocity with respect to the turning center of the vehicle (revolution speed of the vehicle). γ = dβ (= βg) + ωβg; center-of-gravity slip angle Here, assuming that the center-of-gravity slip angle βg is small and the vehicle speed is V, the following formula is established.

Gy = V × ω Vb = V × cos (βg) = V If ω and V are eliminated from the above three equations, the center-of-gravity slip angular velocity dβ0 before filtering can be obtained from the following equation. dβ0 = γ-Gy / Vb Again, the center of gravity slip angular velocity dβ0 is filtered (f
c = 2 Hz), the center-of-gravity slip angular velocity dβ is obtained as shown in the following equation.

Dβ = LPF (dβ0) Regardless of the turning direction of the vehicle, the positive and negative of the center-of-gravity slip angular velocity dβ are positive on the understeer (US) side and negative on the oversteer (OS) side. , The calculated gravity center slip angular velocity dβ is multiplied by (−), and the positive / negative sign is inverted.

When the vehicle is running at a low speed, that is, Vb <10 km / h
When the condition of is satisfied, the calculation of the center-of-gravity slip angular velocity dβ is prohibited in order to prevent calculation overflow.
The center-of-gravity slip angular velocity dβ is set to zero. : Judgment of driving operation: Steering wheel angular velocity; Now, assume that the steering wheel angle θ changes as shown in FIG.

Here, the steering wheel angular velocity θa when the steering wheel angle θ changes can be obtained by dividing the change amount of the steering wheel angle θ by the time required for the change. For example, as shown in FIG.
Assuming that the steering wheel angle θ changes by Δθ (n + 4) at n + 4, the steering wheel angular velocity θa0 (n + 4) at time n + 4 is calculated by the following equation.

Θa0 (n + 4) = Δθ (n + 4) / (4 × T) Note that T is the control cycle of the main routine as described above. On the other hand, when the steering wheel angle θ does not change, the steering wheel angular velocity θa is in the same direction as the steering wheel angle θ when the steering wheel angle θ was last changed, and the steering wheel angle θ has the minimum change amount Δθmi.
It is obtained by dividing the minimum change amount Δθmin by the time required for the change, assuming that the change amount is n. For example, time n + 2
The steering wheel angular velocity θa0 (n + 2) at is calculated by the following equation.

Θa0 (n + 2) = Δθmin / (2 × T) Again, the steering wheel angular velocity θa0 is filtered (fc = 2H
z), the steering wheel angular velocity θa is calculated from the following equation. θa = LPF (θa0) Steering wheel angular velocity effective value: Steering wheel angular velocity effective value θae is
It is obtained by filtering the absolute value of the steering wheel angular velocity θa as shown in the following equation.

Θae = LPF (| θa |) In the filtering process here, whether the value of fc (cutoff frequency) is on the increasing side or the decreasing side of the steering wheel angle θa, that is, the value of It depends on the positive / negative, for example, fc = 20Hz in the direction in which the steering wheel angle θa increases,
On the contrary, fc = 0.32 Hz is set in the direction in which the steering wheel angle θa decreases.

Brake pedal pedal stroke speed:
For the pedal stroke speed Vst, the difference between the pedal strokes St is filtered (fc = 1H as shown in the following equation.
z) is obtained. Vst = LPF (St (n) -St (n-1)) where St (n-1) is the pedal stroke read in the previous routine, and St (n) is read in this routine. Brake pedal brake flag indicating pedal stroke: The above-mentioned brake flag Fb is set as follows based on the pedal stroke St or the pedal stroke speed Vst.

When the condition of St> Ste or Vst> 50 mm / s is satisfied, Fb = 1, and other than the above conditions, Fb = 0, where Ste is in the master cylinder 2 when the brake pedal 3 is depressed. It is the amount of depression that the pressure actually rises. The brake flag Fb is used when selecting the reference wheel speed Vs and calculating the center-of-gravity speed Vcg as described above.

Brake pedal additional depression flag: The additional depression flag Fpp is set as follows based on the pedal stroke speed Vst. In the case of Vst> 50 mm / s, Fpp = 1, in the case of Vst <20 mm / s, Fpp = 0. The routine for setting the above-described step-on additional flag Fpp is shown in FIG. In this setting routine, when the pedal stroke speed Vst is read (step S201), the step-on additional flag Fpp is set based on the determination results of steps S202 and S204 (steps S203 and S205).

Turn determination: When various information indicating the motion state of the vehicle and various information for determining the driver's driving operation are obtained as described above, as shown in FIG. 4, in the next step S3, the vehicle is determined. The turning determination is performed. In the case of FIG. 3, the determination of the turning direction is performed by the calculation unit 38, the details of which are shown in FIG. 7. The details of step S3 are shown in the determination routine of FIG.

Here, the turning direction of the vehicle and the counter steer are determined based on the steering wheel angle θ and the yaw rate γ. First, the turning angle flag Fds based on the steering wheel angle is determined from the map Mθ shown in the block in FIG. 7 based on the steering wheel angle θ. Specifically, the steering wheel angle θ is 10
When deg is exceeded in the positive direction, the turning direction flag Fds is set to 1, and in this case, the turning direction flag Fds indicates that the vehicle is turning right. On the other hand, the steering wheel angle θ
When -10 deg exceeds -10 deg in the negative direction, 0 is set in the turning direction flag Fds, and the turning direction flag Fds indicates that the vehicle is turning left.

The setting of the turning angle flag Fds based on the steering wheel angle here is shown in steps S301 to S304 in FIG. When the steering wheel angle θ is in the range of −10 deg ≦ θ ≦ 10 deg, the turning direction flag Fds is maintained at the value set in the previous routine. On the other hand, based on the yaw rate γ, the yaw rate based turning direction flag Fdy is determined from the map Mγ shown in the block in FIG. Specifically, when the yaw rate γ exceeds 2 deg in the positive direction,
The turning direction flag Fdy is set to 1, and in this case, the turning direction flag Fdy indicates that the vehicle is turning right. On the other hand, when the yaw rate γ exceeds -2 deg in the negative direction, the turning direction flag Fdy is set to 0, and the turning direction flag Fdy indicates that the vehicle is turning left.

The setting of the yaw rate-based turning direction flag Fdy here is shown in steps S305 to S308 in FIG. 8, and when the yaw rate γ is in the range of −2 deg ≦ θ ≦ 2 deg, the turning direction flag is set. It goes without saying that Fdy is maintained at the value set in the previous routine. When the turning direction flags Fds and Fdy are set as described above, one of them is selected as the turning flag Fd by the switch SWf in FIG. Switch SWf
Are switched by a switching signal output from the determination unit 40 in FIG.

That is, when the condition that the ABS control is operating for at least one front wheel and the brake flag Fb is set to 1 is satisfied, the determination section 40 causes the switch SW to switch.
A switching signal for switching f to the upper side is output as indicated by a dashed arrow in FIG. 7, and in this case, the turning flag Fd is the turning direction flag Fds based on the steering wheel angle as shown in the following equation.
Is selected.

Fd = Fds However, if the above condition is not satisfied, the switch SWf is switched as shown by the solid arrow, and in this case, the turning flag Fd is set to the yaw rate base as shown in the following equation. The turning direction flag Fdy is selected. Fd = Fdy The turning flag Fd here is set in step S309 to FIG.
This is shown in S311.

Further, after the turning flag Fd is set, in step S312 in FIG. 8, it is judged whether or not the values of the turning direction flag Fds and the turning direction flag Fdy match, and the result of the judgment here. Is true (Yes), that is, when the yawing direction of the vehicle body does not match the operating direction of the steering wheel, the canter steer flag Fcs is set to 1 (step S314).

On the other hand, if either of the determination results of steps S312 and S313 is false (No), the counter steer flag Fcs is set to 0 (step S315). : Calculation of target yaw rate: Next, in the routine of FIG. 4, steps S3 to S
4, the target yaw rate of the vehicle is calculated by the calculation unit 39 in FIG. 3, the details of which are shown in the block diagram of FIG.

First, the vehicle speed Vb and the front wheel steering angle δ are supplied to the calculating unit 42, where a steady gain is obtained, and then the steady gain is subjected to a two-step filter process as indicated by blocks 44 and 46. Thus, the target yaw rate γt is calculated. Here, the front wheel steering angle δ is expressed by the following equation, where the steering gear ratio is ρ as described above.

Δ = θ / ρ The steady-state gain indicates the steady-state value of the yaw rate response to the steering of the vehicle, which can be derived from the linear two-wheel model of the vehicle. A low-pass filter (LPF1) is used, and a low-pass filter (LPF2) for first-order lag response is used for the second stage filter processing.

Therefore, the target yaw rate γt is calculated from the following equation. γt = LPF2 ((LPF1 (Vb / (1 + A × Vb ² ) × (δ /
L)) In the above formula, A is the stability factor and L is the wheel base. Calculating the required yaw moment; When the target yaw rate γt is calculated in the previous step S4, the required yaw moment is calculated in step S5 in the routine of FIG. 3 and in the routine of FIG. The details of step S5 and step S5 are shown in the block diagram of FIG. 10 and the flowchart of FIG. 11, respectively.

First, as shown in FIG. 10, the subtractor 48 calculates the yaw rate deviation Δγ between the target yaw rate γt and the detected yaw rate γ. This is shown in steps S501 and S502 in FIG. Here, in step S502, the positive / negative of the yaw rate deviation Δγ is unified as positive on the understeer (US) side and negative on the oversteer (OS) side. Therefore, the yaw rate deviation Δγ is left when the vehicle turns left.
Reverses the sign of. The turning direction of the vehicle can be determined based on the value of the turning flag Fd described above.

Further, in step S502, the maximum yaw rate deviation Δγmax is calculated as shown in the following expression by filtering the absolute value of the calculated yaw rate deviation Δγ. Δγmax = LPF (| Δγ |) In the filtering process here, the value of fc differs depending on whether the yaw rate deviation Δγ is increasing or decreasing. For example, fc = 10Hz on the increasing side and its decreasing On the side, fc = 0.08Hz is set.

When the yaw moment control is completed (the yaw moment control start / end flag Fym which will be described later is set to 0).
In this case, the maximum yaw rate deviation Δγmax is set to the absolute value of the yaw rate deviation Δγ as shown in the following equation. Δγmax = | Δγ | Next, the yaw rate deviation Δγ is calculated by the differentiating section 50 of FIG. 10 as shown in the following equation, and after its differential value, that is, the difference is calculated, it is filtered (fc = 5 Hz) and the yaw rate deviation is differentiated. The value Δγs is obtained.

Δγs = LPF (Δγ−Δγm) In the above equation, Δγm is the yaw rate deviation calculated in the previous routine. Also here, for the same reason as in the case of the yaw rate deviation Δγ, the positive / negative of the yaw rate deviation differential value Δγs is inverted when the vehicle turns left. The step of calculating the yaw rate deviation differential value Δγs described above is shown in step S503 of FIG.

Thereafter, as shown in FIG. 10, the yaw rate deviation differential value Δγs is multiplied by the feedback gain, that is, the proportional gain Kp in the multiplication section 52, and the yaw rate deviation Δγ is calculated in the multiplication section 54. Are multiplied by the integral gain Ki, and these multiplication values are added by the adder 56.
Will be added at. Furthermore, the required yaw moment γd is obtained by multiplying the added value output from the adder 56 by the correction value Cpi in the multiplier 58.

Here, the correction value Cpi takes different values depending on whether the vehicle is braking or not, and is set as follows, for example. When braking (Fb = 1), Cpi = 1.0 When not braking (Fb = 0), Cpi = 1.5 The above-described calculation of the required yaw moment γd is performed in steps S504 and S505 in the routine of FIG. It

Step S504 is a step of calculating the above-mentioned proportional and integral gains Kp and Ki, and the calculation procedure of the proportional gain Kp is shown in the block diagram of FIG. The proportional gain Kp is a reference value Kpu (for example, 4 kgm / s / (deg / s ² )) which is different between the time of turning in the US and the time of turning in the OS,
Kpo (for example, 5 kgm / s / (deg / s ² )), and use of these reference values Kpu and Kpo is selected by the switch SWp.

The switch SWp is switched by a judgment signal from the judgment unit 60, and this judgment unit 60 makes a judgment signal for switching the switch SWp to the reference value Kpu side when the yaw rate deviation differential value Δγs becomes 0 or more. Output. The reference value output from the switch SWp has a multiplication unit 6
The correction coefficients Kp1, Kp2, and Kp3 are sequentially multiplied at 2, 64, and 66, whereby the proportional gain Kp is calculated.

Therefore, the proportional gain Kp is calculated by the following equation. US: Kp = Kpu × Kp1 × Kp2 × Kp3 OS: Kp = Kpo × Kp1 × Kp2 × Kp3 When the yaw moment control for the vehicle body is activated before the vehicle reaches the limit travel area, the driver is informed. The correction coefficient Kp1 is for correcting the proportional gain Kp so that the proportional gain Kp works effectively only when the yaw rate deviation Δγ or the lateral Gy of the vehicle body becomes large. It is calculated according to the calculation routine of FIG.

In the calculation routine of FIG. 13, it is first judged whether or not the maximum yaw rate deviation Δγmax exceeds 10 deg / s (step S506). If the judgment result here is true, the correction coefficient Kp1 is set to 1.0. (Step S50
7). On the other hand, if the determination result in step S506 is false, the absolute value of the lateral Gy of the vehicle body is filtered as shown by the following equation, and the average lateral Gya thereof is calculated (step S508).

Gya = LPF (| Gy |) Here, fc of the filtering process is set to fc = 20 Hz when the lateral Gy is on the increasing side and fc = 0.23 Hz when it is on the decreasing side. After that, the reference lateral Gyr is calculated based on the vehicle body speed Vb (step S509). Specifically, a map as shown in FIG. 14 is prepared in advance in the storage device of the ECU 23, and the reference lateral Gy is calculated from this map based on the vehicle speed Vb.
r is read. As you can see from the map, the vehicle speed Vb
When the vehicle is in the high speed region, the running is likely to be uncertain, and therefore the reference lateral Gyr with respect to the vehicle body speed Vb is set low.

When the average lateral Gya and the reference lateral Gyr are calculated as described above, it is judged whether or not the average lateral Gya is larger than the reference lateral Gyr (step S510), and the judgment result here is true. In this case, the correction coefficient Kp1 is set to 1.0 (step S507). On the other hand, when the determination result is false, the correction coefficient Kp1 is set to 0.05 (step S511).

The correction coefficient Kp2 is used to correct the proportional gain Kp for the following reason. That is, when the yaw rate γ is simply made to follow the target yaw rate, when the road surface is a low μ road, the lateral force of the vehicle body reaches its limit value as shown in FIG. As a result of the increase in the angle β, the vehicle body may spin, and the correction coefficient Kp2 is set to prevent this. In other words, when the correction coefficient Kp2 is set appropriately,
It is considered that the center-of-gravity slip angle β of the vehicle body is kept small as shown in FIG. 5 (b), which can prevent the vehicle body from spinning. Note that (c) in FIG. 15 shows the case of the high μ road.

Specifically, the correction coefficient Kp2 is determined by the setting routine shown in FIG. First, the center-of-gravity slip angular velocity dβ is read (step S512), and the reference correction coefficient Kcb is read from the map shown in FIG. 17 based on the center-of-gravity slip angular velocity dβ (step S51).
3). As is apparent from FIG. 17, the reference correction coefficient Kcb is, for example, when the center-of-gravity slip angular velocity dβ becomes 2 deg / s or more.
It gradually decreases from the maximum value of 1.0, and above 5 deg / s
Maintained at a minimum of 0.1.

In the next step S514, the yaw rate deviation Δ
γ is read, and based on whether the yaw rate deviation Δγ is positive or negative as described above, it is determined whether or not the turn is US during the turn (step S515). If the determination result here is true, the reference correction coefficient K is added to the correction coefficient Kp2.
cb is set (step S516), and if the determination result is false, 1.0 is set to the correction coefficient Kp2 (step S5).
17). That is, when the vehicle turns in the US, the correction coefficient Kp2 is set based on the center-of-gravity slip angular velocity dβ. However, when the vehicle is OS, the correction coefficient Kp2 is set to the constant 1.0.

The steps after step S519 in FIG. 16 will be described later. On the other hand, the correction coefficient Kp3 is used to correct the proportional gain Kp for the following reasons. That is, when the vehicle is traveling on a bad road and a vibration component is added to the output of the yaw rate sensor 30, the effect of the vibration component is significantly exerted on the yaw rate deviation differential value Δγs, which may cause malfunction of control and deterioration of controllability. become. Therefore,
The correction coefficient Kp3 reduces the proportional gain Kp to prevent the above-mentioned problems.

Specifically, the procedure for calculating the correction coefficient Kp3 is shown in the block diagram and setting routine of FIG.
As shown in FIG. 18, the yaw rate γo that is the raw output from the yaw rate sensor 30 and the yaw rate γom obtained in the previous routine are supplied to the subtraction section 68 (step S522), and this subtraction section 68 is supplied. Then, the deviation between the yaw rate γo and the yaw rate γom, that is, the differential value Δγo thereof is calculated.

Next, the differential value Δγo is subjected to the first filter processing (fc = 12 Hz) and the second filter processing (fc = 10 Hz), and then the deviation of the filtered differential values is sent to the subtracting section 70. Calculated. That is, the bandpass filter process is applied to the differential value Δγo of the yaw rate γo. Then, the absolute value of the deviation output from the subtraction unit 70 is calculated by the calculation unit 72, and the deviation is output as the yaw rate vibration component γv through the third filter process (fc = 0.23 Hz) (step S523).

Therefore, the yaw rate vibration component γv is calculated by the following equation. Δγo = γo−γom γv = LPF3 (| LPF1 (Δγo) -LPF2 (Δγo) |) When the yaw rate vibration component γv is calculated in this way, in step S524 of FIG. 19, based on the yaw rate vibration component γv , The correction coefficient Kp3 is calculated. Specifically, here also, the map shown in FIG. 20 is prepared in advance, and the correction coefficient Kp3 is read from this map based on the yaw rate vibration component γv. As is apparent from FIG. 20, the correction coefficient Kp3 is, for example, the yaw rate vibration component γv.
Is 10 deg / s or more, it decreases from 1.0, and 15 deg / s or more
Maintained at a constant value of 0.2.

Next, referring to FIG. 21, there is shown a block diagram of a procedure for calculating the integral gain Ki described above.
Here, as in the case of the proportional gain Kp, the reference integral gain Ki0 (for example, 10 kgm / s / (deg / s)) is used, and this reference integral gain Ki0 is sequentially corrected by the multiplying units 74 and 76 in the correction coefficients Ki1 and The integral gain Ki is calculated by multiplying Ki2. Therefore, the integral gain Ki is calculated from the following equation.

Ki = Ki0 × Ki1 × Ki2 The correction coefficient Ki1 is used to reduce the integral gain Ki for the following reasons. That is, when the steering angle of the front wheels increases, the error of the target yaw rate γt may further expand the error of the yaw rate deviation Δγ, which may cause a malfunction of the control. Therefore, in such a situation, the integral gain is set by the correction coefficient Ki0. Decrease Ki.

Specifically, the correction coefficient Ki1 is set based on the steering wheel angle θ from the map shown in FIG. Figure 2
As is clear from 2, when the absolute value of the steering wheel angle θ is at a large steering angle of 400 deg or more, as the steering wheel angle θ increases,
The correction coefficient Ki1 gradually decreases from its maximum value, and is maintained at the minimum value of 0.5 when the steering wheel angle θ becomes 600 deg or more.

On the other hand, the correction coefficient Ki2 is the integral gain Ki for the same reason as the correction coefficient Kp2 of the proportional gain Kp described above.
, And therefore its calculation procedure is shown together with the routine of FIG. 16 as well as the calculation procedure of the correction coefficient Kp2. In step S518 of FIG. 16, the yaw rate deviation differential value Δγs is read, and based on whether the yaw rate deviation differential value Δγs is positive or negative, it is determined whether or not the vehicle is turning (US).
9). If the determination result here is true, the above-described reference correction coefficient Kcb is set in the correction coefficient Ki2 (step S52).
0), and if the determination result is false, the correction coefficient Ki2 is set to the maximum value of 1.0.

Yaw Moment Control: When the required yaw moment γd is calculated as described above, the main routine of FIG. 4 carries out the next step S6, and in FIG. Details of the calculation unit 78 are shown in FIG. First,
In the yaw moment control of FIG. 23, the control start / end determination section 80 determines the control start / end flag Fymc based on the required yaw moment γd.

Specifically, the control start / end flag Fymc
Is determined by the determination circuit of FIG. The determination circuit includes an OR circuit 81, and an ON / OFF signal corresponding to the required yaw moment γd is input to two input terminals of the OR circuit 81. Specifically, an ON signal is input to one input terminal of the OR circuit 81 when the required moment γd is smaller than a threshold value γos (eg, -100 kgm / s) on the OS side, and the other input terminal receives a request. When the moment γd is larger than the threshold γus on the US side (for example, 200 kgm / s), the ON signal is input. Therefore, when the required yaw moment γd exceeds one of the threshold values, an ON signal is output from the output terminal of the OR circuit 81, and this ON signal is input to the set terminal S of the flip-flop 82. As a result, the control start / end flag Fymc is output from the output terminal Q of the flip-flop 82, and in this case, Fymc = 1 indicating the start of control.
Is output.

Here, the absolute value of the threshold value γos on the OS side (100 k
gm / s) is smaller than the absolute value (200 kgm / s) of the threshold value γus on the US side, so that the control start / end flag F is set on the OS side.
The output timing of ymc = 1, that is, the yaw moment control start timing is earlier than that on the US side. On the other hand, the reset terminal R of the flip-flop 82
Is supplied with a reset signal for determining the reset timing of the control start / end flag Fymc, that is, the output timing of Fymc = 0 from the flip-flop 82.

The circuit for generating the reset signal is provided with a switch 83 as shown in FIG. 24, and the switch 83 has two input terminals. Switch 8
The first end determination time tst1 (for example, 152 msec) is supplied to one of the input terminals of No. 3 and the second end is supplied to the other of the input terminals.
The end determination time tst2 (for example, 504 msec) is supplied.

The switch 83 is adapted to be switched in response to a switching signal from the judging section 84. Here, the judging section 84 determines that the behavior of the vehicle body is stable, that is, all of the following conditions are satisfied. If so, a first switching signal for outputting the first end determination time tst1 as the end determination time tst is output from the output terminal of the switch 83. If even one of the above conditions is not satisfied, the switch 83 A second switching signal for outputting the second end determination time tst2 as the end determination time tst is output from the output terminal.

Conditions: Target yaw rate γt <10 deg / s, yaw rate γ <10 deg / s, and steering wheel angular velocity effective value θa
e <200 deg / s Next, the output of the end determination time tst is supplied to the determination unit 85, which holds or does not control the brake pressure control signal (control mode M (i) described later (In the holding or non-control mode) continues for the end determination time tst or longer, the end instruction flag Fst
(i) = 1 is output, and if the condition is not satisfied, the end instruction flag Fst (i) = 0 is output. The i of the end instruction flag Fst represents the corresponding wheel. The brake pressure control signal will be described later.

The end instruction flag Fst (i) is set in the AND circuit 86.
Of the AND circuit 86, and the output terminal of the AND circuit 86 is connected to one input terminal of the OR circuit 87, while the vehicle speed Vb is 10 km / h at the other input terminal.
The ON signal is input at a later time. The output terminal of the OR circuit 87 is connected to the reset terminal R of the flip-flop 82 described above.

The AND circuit 86 outputs the end instruction flag Fst.
When the values of (i) are all 1, the ON signal is sent to the OR circuit 87.
The OR circuit 87 supplies the ON signal to the reset terminal R of the flip-flop 82 when the ON signal is supplied to any of its input sides. In other words, the vehicle speed Vb is 10k
When it becomes slower than m / h or when the above-mentioned conditions regarding the control signal of the brake pressure are satisfied in all of the wheels,
The reset signal is supplied to the flip-flop 82.

When the flip-flop 82 receives the reset signal, the flip-flop 82 outputs a control start end flag Fymc = 0 indicating the end of control. As shown in FIG. 23, the output of the control start / end determination unit 80, that is, the control start / end flag Fymc is supplied to the hydraulic pressure control mode determination unit 88, and this determination unit 88 sets the control start / end flag Fymc. When the value is 1, the brake pressure control mode of each wheel is determined based on the required yaw moment γd and the turning flag Fd described above.

First, from the map shown in FIG. 25, based on the required moment γd, the control execution flags Fcus and Fcos for the brake pressure control at the time of each of US and OS are based on the magnitude relationship with their threshold values as follows. Is set. US time: γd> γdus1 (= 100kgm / s), Fcus = 1 γd <γdus0 (= 80kgm / s), Fcus = 0 OS time: γd <γdos1 (= -80kgm / s), Fcos = 1 γd> γdos0 (= -60 kgm / s), Fcos = 0 Next, control execution flags Fcus, Fcos and turning flag Fd
26, the control mode M (i) of the brake pressure control for each wheel is selected based on the combination of FIG.
Is shown in.

In the control mode selection routine of FIG. 26, first, it is judged if the value of the turning flag Fd is 1 (step S601). If the judgment result here is true,
That is, when the vehicle is turning right, the control execution flag F
It is determined whether or not the value of cus is 1 (step S60).
2). The situation where the determination result here is true means that the US tendency of the vehicle at the time of turning is strong, the required moment γd is a large value of the threshold γdus1 or more, and the vehicle requests the turning moment. ing. In this case, the control mode M (1) of the left front wheel FWL is set to the pressure reducing mode, while the control mode M (4) of the right rear wheel RWR is set to the pressure increasing mode, and the right front wheel FWR and the left wheel The control modes M (2) and M (3) of the rear wheel RWL are set to the non-control mode (step S603).

If the determination result of step S602 is false,
It is determined whether or not the value of the control execution flag Fcos is 1 (step S604). The situation where the determination result here is true means that the OS tendency of the vehicle at the time of turning is strong, the required moment γd is a small value equal to or larger than the threshold γdos1, and the vehicle requests the restoration moment. ing. In this case, the control mode M (1) of the left front wheel FWL is set to the pressure increasing mode, while the control mode M (4) of the right rear wheel RWR is set to the pressure reducing mode, and the right front wheel F
The control modes M (2) and M (3) of WR and the left rear wheel RWL are set to the non-control mode (step S605).

The situation in which the determination results of steps S602 and S604 are both false is that neither the US tendency nor the OS tendency of the vehicle body is strong at the time of turning, so in this case, the left front wheel FWL and the right rear wheel RWR are The control modes M (1) and M (4) are both set to the holding mode, and the control modes M (2) and M (3) of the right front wheel FWR and the left rear wheel RWL are set to the non-control mode ( Step S606).

On the other hand, if the determination result of step S601 is false and the vehicle is turning left, it is determined whether the value of the control execution flag Fcus is 1 (step S6).
07). In the situation where the determination result here is true, it means that the vehicle requests the turning moment as in the case of the right turn described above. In this case, contrary to the case of the right turn, , The control mode M (2) of the right front wheel FWR is set to the pressure reducing mode, while the control mode M (3) of the left rear wheel RWL is set to the pressure increasing mode, and the left front wheel FWL and the right rear wheel R
The WR control modes M (1) and M (4) are set to the non-control mode (step S608).

If the determination result of step S607 is false,
It is determined whether or not the value of the control execution flag Fcos is 1 (step S609). If the determination result here is true, the vehicle is requesting a restoring moment, so the right front wheel FWR
The control mode M (2) of the left rear wheel RWL is set to the pressure increasing mode, while the control mode M (3) of the left rear wheel RWL is set to the pressure reducing mode, and the control mode of the left front wheel FWL and the right rear wheel RWR is set. M (1) and M (4) are set to the non-control mode (step S610).

When the determination results of steps S607 and S609 are both false, as in the case of the right turn described above, the control modes M (2) and M (3) of the right front wheel FWRL and the left rear wheel RWL are determined.
Are both set to the holding mode, and the control modes M (1) and M (4) of the left front wheel FWL and the right rear wheel RWR are set to the non-control mode (step S611). The selection of the control mode M (i) described above is summarized in Table 1 below.

[0098]

[Table 1]

When the control mode M (i) for each wheel is selected as described above, the next valve control signal calculator 89 calculates each wheel based on the control mode M (i) and the required yaw moment γd. The control signals for the solenoid valves, i.e. the inlet and outlet valves 12, 13 for controlling the brake pressure of the wheel brakes of the above are calculated. Specifically, first, the hydraulic pressure in the wheel cylinder to obtain the required yaw moment,
That is, the pressure increasing / decreasing rate (gradient of pressure increasing / decreasing) with respect to the brake pressure is calculated. Then, in accordance with the calculated pressure increasing / decreasing rate, the actual brake pressure is increased by a constant amount of pressure increasing / decreasing Δ.
In order to change with P, the drive pulse of the inlet or outlet valves 12 and 13 for realizing the pressure increase / decrease amount ΔP, that is, the pulse period Tpls and the pulse width Wpls (i) of the valve control signal are calculated. The pressure increase / decrease amount ΔP is set to, for example, ± 5 kg / cm ² , but the pressure increase / decrease amount ΔP is set to ± 10 kg / cm ² only for the first time in order to ensure responsiveness. In this regard, referring to FIG. 27, there is shown a state in which the brake pressure in the wheel cylinder is increased or decreased for each increase / decrease amount ΔP.

The inlet and outlet valves 12 and 13 are driven by receiving the valve control signal, that is, the pressure increasing pulse signal or the pressure reducing pulse signal, based on the holding mode. Is instructed every control cycle T (8 msec) of the main routine, so that the drive mode Mpls is set so that the actual driving is performed every pulse cycle Tpls.
Set (i).

The above-mentioned pulse period Tpls, pulse width Wpls (i) and drive mode Mpls (i) will be described in detail below. First, when the brake pressure in the wheel brakes of the front wheels changes by ΔPwc, the change amount ΔMz of the yaw moment of the vehicle body can be expressed by the following formula, ignoring the lateral force of the vehicle body.

ΔMz = ΔPwc × BF × TF / 2 where BF is the front brake coefficient (kg / cm ² → kg),
TF indicates the front tread. Therefore, the rate of pressure increase / decrease Rpwc (kg / cm ² / s) of the brake pressure when the required yaw moment γd is given can be expressed by the following equation.

Rpwc = 2 × γd / BF / TF On the other hand, when the pressure increase / decrease amount ΔP (5 kg / cm ² or 10 kg / cm ² ) once is fixed, the relationship between the pressure increase / decrease rate Rpwc and the pulse period Tpls. The following equation is derived from | Rpwc | = ΔP / (Tpls × T (= 8 msec)) From the above two equations, the pulse period Tpls is represented by the following equation.

Tpls = ΔP × BF × TF / (2 × T × | γd |) where 2 ≦ Tpls ≦ 12 Note that the pulse cycle Tpls on the front wheel side is used as the pulse cycle for the inlet and outlet valves on the rear wheel side. . Next, pulse width Wpls
Regarding (i), it has been set in advance by an experiment, and in this experiment, the master cylinder pressure and the wheel brake pressure (brake pressure) are used as reference pressures, and in this state, the valve is driven and then the wheel brake pressure is increased or decreased. Amount ΔP
The time when a change of (5 kg / cm ² or 10 kg / cm ² ) appears is measured, and the pulse width Wpls (i) is set based on this time. Since the discharge pressure from the pump 16 or 17 described above is used for increasing the wheel brake pressure, the pulse width Wpls (i) is set in consideration of the response delay of the pump 16 or 17. Is desirable.

The drive mode Mpls (i) described above is based on the control mode M (i) and the pulse period Tpls described above.
It is set according to the setting routine shown in. In this setting routine, first, the control mode M (i) is determined (step S612). If the control mode M (i) is not controlled, the pressure increase cycle counter CNTi (i) and the pressure decrease cycle counter are determined. Both CNTd (i) are set to 0, and the non-control mode is set to the drive mode Mpls (i) (step S613).

When the control mode M (i) is the holding mode, the driving mode Mpls (i) is set to the holding mode (step S614). When the control mode M (i) is the pressure increasing mode, only the pressure increasing period counter CNTi (i) operates (step S615), and the pressure increasing period counter CNTi.
It is determined whether or not the value of (i) has reached the pulse period Tpls (step S616). Since the determination result is false at this time, it is next determined whether or not the value of the pressure increase cycle counter CNTi (i) is 0 (step S617), and the determination result here is true. Therefore, the pressure increasing mode is set to the drive mode Mpls (i) (step S618).

When the subsequent routine is repeatedly executed, the determination result of step S617 is maintained to be false.
The holding mode is set to the drive mode Mpls (i) (step S619). However, with the passage of time, the determination result of step S616 becomes true, and the pressure increase cycle counter CN
When the value of Ti (i) is reset to 0 (step S62)
0) In this case, the determination result of step S617 becomes true, and the pressure increasing mode is set to the drive mode Mpls (i) (step S618). Therefore, when the control mode M (i) is the pressure increasing mode, the drive mode Mpls (i) is set to the pressure increasing mode every pulse period Tpls.

On the other hand, when the control mode M (i) is the pressure reducing mode, the steps S621 to S629 in FIG. 28 are executed in the same manner as in the pressure increasing mode, so that the drive mode Mpls. (i) is set to the pressure reduction mode for each pulse period Tpls. When the drive mode Mpls (i) and the pulse width Wpls (i) are calculated as described above, the next pressure increase / decrease prohibition correction unit 90 (see FIG. 23) indicates that the driver is performing countersteering or excessive slip. Further, the pulse width Wpls (i) is corrected so as to prohibit the increase and decrease of the brake pressure in consideration of the control overshoot, and the details thereof are shown in the block diagram of FIG.

The pulse width Wpls (i) supplied to the pressure increase / decrease inhibition correction unit 90 is output as the pulse width Wpls1 (i) by passing through the three switches 91, 92, 93. Is the setting unit 94, 95, 96
The output is Wpls1 according to the value of the flag set in
(i) = Wpls (i) or Wpls1 (i) = 0 can be switched. In the pressure increase / decrease prohibition correction unit 90, the supplied drive mode Mpls (i) is output as it is.

First, the setting section 94 sets the pressure increase prohibition flag Fk1 (i) during counter steering. In particular,
The setting unit 94 includes an AND circuit 97, and the AND circuit 97
The output of the circuit 97 is supplied to the switch 91,
An ON signal is supplied to each of the inputs when the corresponding condition is satisfied. Here, the input condition of each ON signal includes the case where the own wheel is the rear wheel, the case where the counter steer flag Fcs is 1, and the case where the control mode M (i) is the pressure increasing mode. There is.

Therefore, when all of the inputs of the AND circuit 97 are ON signals, the pressure increase prohibition flag Fk1 (i) = 1.
Is output. In other cases, the pressure increase prohibition flag Fk1 (i) is output.
= 0 will be output. When the switch 91 receives the pressure increase prohibition flag Fk1 (i) = 1, it is switched from the state shown in the figure, and thereby the pulse width Wpls1 (i) is set to zero. In this case, the pulse width Wpls (i) may be decreased instead of 0.

FIG. 30 shows a routine for setting the pressure increase prohibition flag Fk1 (i). In this routine, the pressure increase prohibition flag Fk1 (i) is set only when all the determination results in steps S627 to S631 are true. ) Is set to 1. In step S630, i represents the numerical value for distinguishing the wheels as described above, and when i is 3 or 4, the wheel is a rear wheel.

In the setting section 95, the pressure increase prohibition flag Fk2 (i) at the time of excessive slip is set. Here again, the setting unit 95
Includes an AND circuit 98, the output of the AND circuit 98 is supplied to the switch 92, and an ON signal is supplied to each input of the switch 92 when a corresponding condition is satisfied. . The input condition of the ON signal here is that the slip ratio Sl (i) is the allowable slip ratio Slmax.
It is larger than (i) and the control mode M (i) is the pressure increasing mode.

The AND circuit 98 outputs the pressure increase prohibition flag Fk2 (i) = 1 when all of its inputs are ON signals, and outputs the pressure increase prohibition flag Fk2 (i) = 0 otherwise. Will be output. The switch 92 has a pressure increase prohibition flag F.
When k2 (i) = 1 is received, the state shown in the figure is switched, and in this case as well, the pulse width Wpls1 (i) is set to zero. In this case, the pulse width Wpls (i) may be decreased instead of 0.

Referring to FIG. 31, the pressure increase prohibition flag Fk2
Detailed routine showing the setting procedure of (i) is shown,
In this setting routine, first, it is determined whether or not the value of the control start / end flag Fymc is 1, that is, whether or not the yaw moment control is being performed (step S634),
If the determination result here is true, it is determined whether or not the ABS control is operating for the wheel (pressure-increasing wheel) whose control mode M (i) is in the pressure-increasing mode (step S63).
Five). A flag Fabs (i), which will be described later, is used for the determination here, and therefore the flag Fabs (i) is set in the setting unit 95 of FIG.
Is also supplied.

If the determination result in step S635 is true, the determination slip ratio of the pressure-increasing wheel at the time when the ABS control is started is held as Slst (i) (step S636), and then the next Step S638 is executed. On the other hand, if the determination result of step S635 is false, step S638 is executed without executing step S636. The ABS control will be described later.

On the other hand, if the determination result in step S634 is false, that is, if the yaw moment control is not being performed, the determination slip ratio Slst is reset to 0 (step S637), and then step S638 is executed. . Step S
At 638, it is judged if the judgment slip ratio Slst (i) is 0, and if the judgment result here is false, that is, if the ABS control is not operating for the pressure-increasing wheels, The allowable slip rate Slmax (i) is calculated (step S63).
9). Specifically, the allowable slip ratio Slmax (i) is calculated as shown in FIG.
The yaw moment γd is read from the map as shown in FIG. Here, the allowable slip ratio Slmax (i)
32, the required yaw moment γd
Has the characteristic of increasing at a predetermined rate as
The maximum value is set to 20%.

In the next step S641, the slip ratio Sl
It is determined whether or not (i) is larger than the allowable slip ratio Slmax (i). If the determination result here is true, the pressure increase prohibition flag Fk2 (i) is set to 1 (step S642), and If the determination result is false, 0 is set to the pressure increase prohibition flag Fk2 (i) (step S643). On the other hand, if the determination result of step S638 is true, that is, if the ABS control is operating for the pressure-increasing wheels, the allowable slip ratio S
The map used to read lmax (i) is modified (step S640). Specifically, in step S640, the map shown in FIG. 32 is replaced with the map shown in FIG.
In this case, as is clear from FIG. 33, the maximum value of the permissible slip rate Slmax (i) is the determined slip rate Slst (i).
(Or 95% of Slst (i)), and the increasing gradient is also changed according to the determination slip rate Slst (i).

Therefore, when the ABS control is operating for the pressure-increasing wheels, the allowable slip ratio Slmax (i)
Is set to the determination slip ratio Slst (i), the determination result in step S641 becomes true, and the pressure increase prohibition flag Fk2 (i) is maintained at 1. Setting unit 9
6 (refer to FIG. 29, when the condition that the absolute value of the required yaw moment γd tends to decrease by a predetermined value or more is satisfied, a prevention flag Fk3 = that prevents control overshoot
1 is output to the switch 93, and when the condition is not satisfied, the prevention flag Fk3 = 0 is output to the switch 93.
Also here, when the prevention flag Fk3 = 1 is supplied to the switch 93, the switch 93 is switched and the pulse width Wpl
Set 0 to s1 (i).

Referring to FIG. 34, there is shown a detailed routine showing a procedure for setting the prevention flag Fk3. In this setting routine, first, the required yaw moment γd is read (step S644), and the required yaw moment is then read. A value Dγd obtained by differentiating the absolute value of γd is calculated (step S645). Further, the differential value Dγd is filtered (fc = 2 Hz) (step S646).

The processing in steps S645 and S646 can be expressed by the following equation. Dγd = LPF (| γd | − | γdm |) γdm: Previous value Next, the differential value Dγd is the overshoot determination value Dγov
(For example, -125 kgm / s ² ) is determined (step S647), and if the determination result here is true, the prevention flag Fk3 is set to 1 (step S648), and vice versa. If the result is false, 0 is set to the prevention flag Fk3 (step S649).

Referring again to FIG. 23, the block diagram of the yaw moment control includes the preload control determination unit 100. In this determination unit 100, prior to the start of the yaw moment control, the pumps 16, 17 and the inlets are controlled. The preload flags Fpre1 and Fpre2 for controlling the operation of the outlet valves 12 and 13 and the cutoff valves 19 and 20 are set.
Specifically, when the absolute value of the required yaw moment becomes larger than a predetermined value or the maximum yaw rate deviation Δγmax becomes larger than a predetermined value and the yaw moment control is started, the preload flag Fpre1 = 1 or Fpr
When e2 = 1 is set for a fixed duration (for example, 96 msec), and the yaw moment control is started during the duration, the preload flag Fpre1 or Fpre2 is reset to 0 at the start time. The preload flag Fpre1 = 1 is set when the vehicle turns right, while the preload flag Fpre2 is set when the vehicle turns left.

Further, FIG. 23 includes a control signal compulsory changing unit 111, and the details of the compulsory changing unit 111 are shown in FIG. The compulsory changing unit 111 can compulsorily change the pulse width Wpls (i) and the driving mode Mpls (i) according to various situations, and the pulse width Wpls (i) and the driving mode Mpls (i) are compulsorily changed. After passing through the changing unit 111, the pulse width Wy (i) and the driving mode My (i) are output.

As is clear from FIG. 35, the drive mode Mpl
s (i) passes through the switches 112 to 117 to drive mode My.
(i), the switches 112 to 117 are supplied with a flag and are switched according to the value of the flag.
That is, the switch 112 is the non-control diagonal hold determination unit 1
It is switched by a flag Fhld (i) output from 18, and the determination unit 118 determines that the vehicle is not being braked (Fb =
0) and the pumps 16 and 17 are operating (when the motor drive flag Fmtr = 1 described later), the flag Fhld (i) corresponding to the wheel in the non-control mode is set to 1. Therefore, in this case, the switch 112 outputs the drive mode Mpls1 (i) in which the wheels in the non-control mode in the drive mode Mpls (i) are forcibly switched to the holding mode, while the flag Fhld (i) is output. = 0, drive mode Mpls (i)
Is output as is. In the drive mode Wpls1 (i), the uncontrolled wheel is forcibly switched to the holding mode, so that the discharge pressure from the pumps 16 and 17 is not supplied to the wheel brake of that wheel. .

The switch 113 has a termination control determination section 119.
It is switched by an end flag Ffin (i) output from the determination unit 119, and in the determination unit 119, a predetermined period (for example, 40 msec) is maintained for a fixed period (for example, 340 msec) after the end of yaw moment control (Fymc = 0). Therefore, the end flag Ffin (i) is set to 1 for a predetermined time (for example, 16 msec). The end flag Ffin (i) is also used for opening / closing control of the cutoff valves 19 and 20 as described later.

When the end flag Ffin (i) = 1 is supplied,
The switch 113 is a drive mode Mpls2 that switches the wheels that were the control target to the holding mode during the drive mode Mpls (i).
(i) is output. On the other hand, when the flag Ffin = 0, the drive mode Mpls (i) is output as it is. Thus, after the end of the yaw moment control, when the drive mode of the wheel that was the control target is periodically switched to the holding mode, the brake pressure of the control target wheel does not change suddenly,
The behavior of the vehicle can be stabilized.

The switch 114 is switched by the preload flags Fpre1 and Fpre2 output from the preload control determination unit 100 described above, and these preload flags Fpre1 = 1 or Fpr.
When e2 = 1 is received, the switch 114 switches the drive mode Mpl.
During s (i), the drive mode Mpls3 (i) in which the wheel to be controlled is forcibly switched to the holding mode is output, and Fpre1 = Fpre
When 2 = 0, the drive mode Mpls (i) is output as it is. Here, in the above description relating to FIG. 23, the control mode M (i) and the drive mode Mpls (i) are received in response to the output of the control start / end flag Fymc = 1 from the control start / end determination unit 80.
However, the control mode M (i) and the drive mode Mpls (i) are set regardless of the control start / end flag Fymc. Therefore, even if the drive mode Mpls (i) is set to the drive mode Mpls3 (i) and the above-mentioned preload control is started, the brake pressure of the wheel to be controlled is adversely affected before the yaw moment control is started. There is no such thing.

The switch 115 is used for the pedal release determining section 12
It is switched by the release flag Frp output from 0,
The determination unit 120 sets the release flag Frp to 1 for a predetermined time (for example, 64 msec) when the brake pedal 3 is released during the yaw moment control during braking. Release flag Frp
= 1 is received, the switch 115 drives the drive mode Mpls.
In (i), the drive mode Mpls4 (i) for forcibly reducing the brake pressure of the wheel in the pressure reduction mode is output, and the release flag Frp is output.
When = 0, the drive mode Mpls (i) is output as it is.

The release flag Frp is also supplied to the switch 121. When Frp = 1, the switch 121 forcibly changes the value of the pulse width Wpls (i) to the control cycle T (= 8 msec). (i) is output, and when Frp = 0, the pulse width Wpls (i) is output as it is as the pulse width Wy (i). The switch 116 is switched by the additional pedal flag Fpp output from the pedal additional pedal determination unit 122,
The step-up flag Fpp is set as described above according to the routine of FIG. When Fpp = 1 is received, the switch 116 forces the drive mode M to switch all the wheels to the non-control mode instead of the drive mode Mpls (i).
If pls5 (i) is output and Fpp = 0, drive mode Mpls
Output (i) as it is. When the drive mode is set to Mpls5 (i), the brake pedal operation by the driver can be reflected in the brake pressure of each wheel.

The switch 117 is switched by the reverse flag Frev output from the reverse judging unit 123, and the judging unit 123 sets the reverse flag Frev to 1 when the reverse gear is selected in the transmission of the vehicle, In other cases, the backward movement flag Frev is set to 0. Flag Fr
Upon receiving ev = 1, the switch 117 switches the drive mode M
Instead of pls (i), the drive mode My (i) for forcibly switching all the wheels to the non-control mode is output, and when Frev = 0, the drive mode Mpls (i) is set to the drive mode My (i). Output as.

As shown in FIG. 23, the output from the control signal compulsory change unit 111, that is, the drive mode My (i) and the flag from the preload control determination unit 100 are the drive determination unit 1
24, and details of the drive determination unit 124 are shown in FIGS. 36 to 39. First, in the determination circuit 125 shown in FIG. 36, flags requesting drive of the cutoff valves 19 and 20 and the motor 18 are set for each wheel cylinder of each wheel.

The determination circuit 125 includes two AND circuits 12
6, 127, one of the AND circuits 126 has its input at the brake flag Fb = 1 and the drive mode My (i).
Is in the pressure increasing mode, the pressure increasing mode i is output to the OR circuit 128. When the input of the other AND circuit 127 is the brake flag Fb = 0 and the drive mode My (i) is in the non-control mode, i which is not in the non-control mode is set to O.
Output to the R circuit 128. That is, the drive mode side input of the AND circuit 127 is supplied via the NOT circuit 129.

The OR circuit 128 is composed of AND circuits 126, 1
When the output from 27 is received, the value of the request flag Fmon (i) corresponding to the received i among the request flags Fmon (i) requesting the driving of the motor 18 is set to 1 and output. Also,
The output of the OR circuit 128 is also supplied to the set terminal of the flip-flop 130, and the reset terminal receives a reset signal for each i when the drive mode My (i) is uncontrolled. ing.

When the request flag Fmon (i) = 1 is supplied to the set terminal of the flip-flop 130, the flip-flop 130 requests the request flag Fcov (i) requesting the drive of the cutoff valves 19 and 20. Flag Fmon (i) =
The value of the request flag Fcov (i) corresponding to i of 1 is continuously output as 1 and when the reset signal is received, the values of all the request flags Fcov (i) are reset to 0.

Next, the judgment circuit 131 of FIG. 37 is provided with an OR circuit 132, and this OR circuit 132 is a request flag Fcov (1) relating to the cutoff valve 19 on the left front wheel FWL and right rear wheel RWR which is the input thereof. ), Fcov (4), the end flags Ffin (1), Ffin (4), and the preload flag Fpre1 are set to 1, the value of the cut drive flag Fvd1 for driving the cutoff valve 19 is set to Output as 1.

Cut drive flag F from the OR circuit 132
vd1 is further output via the switches 133 and 134,
Here, the switch 133 is switched by the step-up flag Fpp, and the switch 134 is switched by the reverse flag Frev. That is, even if the output of the OR circuit 132 is Fvd1 = 1, the cut drive flag Fvd1 is reset to 0 (non-control mode) when one of the step-up flag Fpp and the backward movement flag Frev is set to 1. .

The determination circuit 135 of FIG. 38 has the same configuration and function as the determination circuit 131 of FIG. 37, but the OR circuit 136 thereof has a cutoff valve 20 on the right front wheel FWR and left rear wheel FWL side. Request flags for Fcov (2), Fco
v (3), end flag Ffin (2), Ffin (3), preload flag Fpre2
In this case, the OR circuit 136 outputs the cut drive flag Fvd2 for driving the cutoff valve 20 via the switches 137 and 138, unlike the determination circuit 131 in that the input is input.

The determination circuit of FIG. 39, that is, the OR circuit 139.
When the value of the request flag Fmon (i) for each wheel requesting the drive of the motor 18 or the value of the preload flag Fpre1 or Fpre2 indicating that the preload control is in operation is 1, , And sets the value of the motor drive flag Fmtr to 1 and outputs. : ABS coordinate control: In the yaw moment control described above, the drive mode My
When (i), the pulse width Wy (i), the cut drive flags Fvd1 and Fvd2, and the motor drive flag Fmtr are set, cooperative control with the ABS control is performed (the determination unit 78a in FIG. 3 and the steps in FIG. 4). (See S7).

If the ABS control is activated, the ABS
Since the yaw moment control is executed in coordination with the control,
In the BS coordinated control, the drive mode Mabs (i) and the pulse width Wabs (i) of each wheel in consideration of the ABS control are set. Here, detailed description on the setting of the drive mode Mabs (i) and the pulse width Wabs (i) is omitted, but the drive mode Mabs (i) and the pulse width Wabs (i) are also increased / decreased as described above. It should be noted that the functions of the pressure inhibition correction unit 90 (see FIG. 29) and the control signal forced change unit 111 (see FIG. 35) are reflected.

However, to explain one function in the ABS coordinated control, when the vehicle is in a situation of requesting a recovery or restoration moment when turning during ABS control, the AB
In S coordinated control, drive mode Mabs (i) and pulse width Wabs
(i) is set as follows. That is, ABS in FIG.
As shown in the cooperation routine, in step S701, it is determined whether the ABS control is operating. It should be noted that the determination here is made based on whether or not the flag Fabs (i) indicating each wheel during the operation of the ABS control is 1.
The flag Fabs (i) is set in an ABS control routine (not shown) based on the changing tendency of the slip ratio of the wheel as is known.

If the determination result of step S701 is true,
It is determined whether or not the control execution flag Fcus or Fcos is 1 (step S702), and if the determination result here is true, that is, the vehicle requests the recovery or restoration moment when turning. In such a situation, in the next step S703, the drive mode Mabs (i) and the pulse width Wabs (i)
Is set as follows.

When the yaw moment control is executed for the diagonal wheels: 1) To further obtain the recovery moment, the front wheel FW, which is the inner side in the turning direction, is set to the decompression mode, and its pulse width is the outer side. It is set to be the same as the pulse width of the front wheels FW. 2) To further obtain the restoration mode, the rear wheel RW, which is the outer side in the turning direction, is set to the decompression mode, and its pulse width is set to be the same as the pulse width of the inner rear wheel.

The yaw moment control can be executed not only for the diagonal wheels but also between the front and rear wheels. That is, when the yaw moment control is executed based on the braking force difference between the left and right wheels, the braking force of the outer wheels is set to the pressure increasing mode and the braking force of the inner wheels is set to the depressurizing mode to generate a restoring moment in the vehicle. On the other hand, if the braking force of the outer wheels is set to the pressure reducing mode and the braking force of the inner wheels is set to the pressure increasing mode, a recovery moment can be generated in the vehicle.

Therefore, when the yaw moment control is executed between the left and right rear wheels, in order to further obtain the recovery moment, the outer front wheel is set to the pressure reduction mode and its pulse width is set to that of the outer rear wheel. Set the same as the pulse width. On the other hand, when yaw moment control is executed between the left and right front wheels, in order to further obtain the restoring moment, the inner rear wheel is set to the decompression mode, and its pulse width is set to the pulse width of the inner front wheel. Set the same as.

On the other hand, if the determination result in any of steps S701 and S702 is false, this routine is terminated without executing step S703. : Control signal selection: Coordination routine with ABS control, that is, when step S7 is exited in FIG. 4, the control signal selection routine is executed in the next step S8, and the selection circuit 140 for executing this routine is shown in FIG. It is shown. Note that in FIG. 41, a block 141 for executing the routine of FIG.
142 is also shown.

The selection circuit 140 includes four switches 143 ...
The switch 143 has a block 1
The drive mode Mabs (i) after passing 41 and the drive mode My (i) set by the yaw moment control described above are input, and the switch 144 passes through the block 142. The subsequent pulse width Wabs (i) and the pulse width Wy (i) set by the yaw moment control are input.

The cut drive flags Fvd1 and Fvd2 set by the yaw moment control and 0 for resetting these flags are input to the switch 145. The motor drive flag Fmtr set by the yaw moment control is set in the switch 146 by the OR circuit 14.
7, the motor drive flag Fmabs during ABS control is also input, and the motor drive flag Fmabs is also supplied to the other input terminal of the OR circuit 147. The motor drive flag F
mabs is a flag set by the ABS control itself, and is set to Fmabs = 1 when the ABS control is started.

The switches 143-146 described above are switched in response to the result of the flag output from the determination unit 148. That is, the determination unit 148 includes an OR circuit 149. The input of the OR circuit 149 is when the three or more wheels are in the ABS control or the drive mode My (i) in the yaw moment control is not the pressure reduction mode. AND the flag Fmy (i) = 1 corresponding to the wheel in the decompression mode
Output to the circuit 150. When three or more wheels are under ABS control, the flag Fabs3 = 1 is supplied to the switches 145 and 146.

Further, the drive mode Mabs (i) = 1 is input to the AND circuit 150 when the drive mode Mabs (i) in the ABS coordinated control is not the non-control mode, and the AND operation is performed.
From the circuit 150, its input flags Fmy (i) and Mabs
In (i), the flag Fm # a (i) having the same i number is set to 1 and output to the switches 143 and 144, respectively.

If three or more wheels of the vehicle are under ABS control,
Since the determination unit 148 supplies the flags Fabs3 = 1 to the switches 1454 and 146, respectively, the switch 1
Reference numeral 45 denotes cut drive flags Fvd1 and Fvd2, that is, Fv1 =
Fv2 = 1 is output, and the switch 146 outputs the motor drive flag Fmabs as Fm. On the other hand, switch 1
When the flag Fabs3 = 0 is supplied to 45 and 146, the switch 145 outputs the cut drive flags Fvd1 and Fvd2 as Fv1 and Fv2, respectively, and the switch 146 outputs the motor drive flag Fmtr as Fm. Here, the motor drive flag Fmabs is set to the switch 14 via the OR circuit 147.
6, the motor drive flag Fm = 1 is output from the switch 146 when any of the motor drive flags Fmabs and Fmtr is set to 1 regardless of the switching of the switch 146. become.

On the other hand, when the input condition of the AND circuit 150 is satisfied, the AND circuit 150 switches to the switch 143.
The flag Fm # a (i) = 1 is supplied to 144, and in this case, the switch 143 changes the drive mode Mabs (i) to the drive mode MM.
(i), and the switch 144 outputs the pulse width Wabs (i).
Is output as the pulse width WW (i). On the other hand, when the flag Fm # a (i) = 0 is supplied to the switches 134 and 144, the switch 143 outputs the drive mode My (i) as the drive mode MM (i), and the switch 144. The pulse width Wy (i) is output as the pulse width WW (i).

Drive signal initialization: When the drive mode MM (i) and the pulse width WW (i) are output from the control signal selection circuit 140, these are shown in FIG. 3 as the drive signal initialization unit 151 and FIG. Then, in step S9, the actual drive mode Mexe (i) and the actual pulse width Wexe (i) are set, and initial values are given to the actual drive mode Mexe (i) and the actual pulse width Wexe (i).

The step S9 is shown in detail in FIG. 42. Here, after the interrupt prohibition process is executed (step S901), the drive mode MM (i) is discriminated (step S902). If the determination result of step S902 is the non-control mode, the pressure increasing mode is set to the actual drive mode Mexe (i), and the control cycle T (= 8 msec) of the main routine is set to the actual pulse width Wexe (i). Is set (step S90
3) Then, after the interrupt permission process is executed (step S904), the routine here ends.

If the result of the determination in step S902 is the pressure increasing mode, it is determined whether or not the actual drive mode Mexe (i) is the pressure increasing mode (step S905). However, since the actual drive mode Mexe (i) has not yet been set at this point, the result is false, and in this case, the actual drive mode Mexe (i) is changed to the drive mode MM (i), that is, the pressure increase. After the mode is set and the actual pulse width Wexe (i) is set to the pulse width WW (i) (step S906), this routine ends after step S904.

If the determination result of step S902 is maintained in the pressure increasing mode even when the next routine is executed, in this case, the determination result of step S905 becomes true and the pulse width WW (i) is It is determined whether or not the actual pulse width Wexe (i) is smaller than that (step S907). Here, the pulse width WW (i) is newly set for each control cycle T, as is clear from the fact that the main routine is executed for each control cycle T, but the actual pulse width Wexe (i) will be described later. When the inlet or outlet valve is actually driven, the amount decreases with the driving. Therefore, according to the determination result in step S907, the newly set pulse width WW (i) is the remaining actual pulse width at this moment. If it is longer than Wexe (i), a new pulse width WW (i) is set to the actual pulse width Wexe (i) (step S908). However, when the determination result of step S907 is false, the remaining actual pulse width Wexe (i) is maintained without resetting the new pulse WW (i) to the actual pulse width Wexe (i). .

On the other hand, if the result of the determination in step S902 is the pressure reducing mode, steps S909 to S912 are executed, and the actual drive mode Mexe (i) and The actual pulse width Wexe (i) is set. Further, when the determination result of step S902 is the pressure reduction mode, the holding mode is set to the actual drive mode Mexe (i) (step S913).

Drive signal output: When the actual drive mode Mexe (i) and the actual pulse width W (i) are set as described above, these are changed from the drive signal initial setting unit 151 to the valve drive unit 152 in FIG. Is output to step S10 in the main routine of FIG. In step S10, in addition to the actual drive mode Mexe (i) and the actual pulse width W (i), based on the cut drive flags Fv1, Fv2 and the motor drive flag Fm set by the control signal selection routine, the cutoff valve is set. Drive signals for driving 19, 20 and the motor 18 are also output.

Here, the cut drive flag Fv1 is Fv1 = 1.
In the case of, a drive signal for closing the cutoff valve 19 is output, and when the cut drive flag Fv2 is Fv2 = 1, a drive signal for closing the cutoff valve 20 is output. On the other hand, when the cut drive flags Fv1 and Fv2 are reset to 0, the cutoff valves 19 and 20 are cut off.
Is kept open. On the other hand, the motor drive flag Fm
When Fm = 1, a drive signal for driving the motor 18 is output, and when Fm = 0, the motor 18 is not driven.

Driving the inlet and outlet valves: When the actual drive mode Mexe (i) and the actual pulse width W (i) are supplied to the valve drive unit 152 described above, the valve drive unit 152 drives as shown in FIG. The inlet and outlet valves 12, 13 are driven according to a routine. Here, the drive routine of FIG. 43 is executed independently of the main routine of FIG. 4, and its execution cycle is 1 msec.

In the drive routine, first, the actual drive mode Mexe (i) is discriminated (step S1001). If the actual drive mode Mexe (i) is the pressure increasing mode in this discrimination, It is determined whether or not the actual pulse width Wexe (i) is larger than 0 (step S1002). If the determination result here is true, the inlet and outlet valves 1 corresponding to the wheels 1
For 2 and 13, the inlet valve is opened while the outlet valve 13 is closed and the actual pulse width Wexe (i)
Is reduced by its execution cycle (step S1003). Therefore, when step S1003 is performed, the motor 18 is already driven and the corresponding cutoff valve 19
Alternatively, if 20 is closed, the wheel brake corresponding to the wheel will be boosted.

When the actual driving mode Mexe (i) is maintained in the pressure increasing mode, the driving routine is repeatedly executed, and when the determination result of step S1002 becomes false,
At this point, the corresponding inlet and outlet valve 1 for that wheel
For 2 and 13, both the inlet and outlet valves are closed, and the actual drive mode Mexe (i) is set to the hold mode (step S1004).

If it is determined in step S1001 that the actual drive mode Mexe (i) is the pressure reducing mode, it is again determined whether the actual pulse width Wexe (i) is greater than zero. (Step S1005). If the determination result here is true, the inlet and outlet valves 12, 13 corresponding to the wheels are
Regarding, regarding the inlet valve, the outlet valve 13 is opened while the outlet valve 13 is opened, and the actual pulse width Wexe (i) is decreased by its execution period (step S1006). Therefore, by executing step S1006, the wheel brakes corresponding to the wheels are depressurized.

Also in this case, when the drive routine is repeatedly executed in the state where the actual drive mode Mexe (i) is maintained in the pressure reduction mode, and the determination result of step S1005 becomes false, at this point, Regarding the inlet and outlet valves 12 and 13 corresponding to the wheel, both the inlet and outlet valves are closed, and the actual drive mode Mexe (i) is set to the holding mode (step S1007).

If it is determined in step S1001 that the actual drive mode Mexe (i) is the holding mode, both the inlet and outlet valves 12 and 13 corresponding to the wheel are closed (step S1008). . Referring to FIG. 44, a time chart shows the relationship between the drive mode MM (i), the pulse width WW (i), the actual drive mode Mexe (i), and the actual pulse width Wexe (i) described above.

Action of Yaw Moment Control: Diagonal Wheel Control: It is assumed that the vehicle is currently traveling and the main routine of FIG. 4 is repeatedly executed. In this state, in step S3 of the main routine, that is, in the turning determination routine of FIG. 8, if the turning flag Fd indicating turning of the vehicle from the steering wheel angle θ and the yaw rate γ is set to Fd = 1, in this case, The vehicle is making a right turn.

During right turn: After this, when the required yaw moment γd is obtained through steps S4 and S5 of the main routine, and the yaw moment control of step S6 is executed, the control is started in this yaw moment control. The control mode selection routine is executed on condition that the end flag Fymc (see the determination circuit in FIG. 24) is Fymc = 1, and the control mode M (i) for each wheel is set in accordance with the selection routine in FIG. It

Since it is assumed here that the vehicle is turning to the right, step S601 in the selection routine of FIG.
The determination result of is true, and steps after step S602 are performed. Right turn of US tendency: In this case, if the determination result of step S602 is true, that is, the control execution flag Fcus is Fcus = 1 and the vehicle has a strong US tendency, the left front wheel (outer front wheel) ) The control mode M (1) of the FWL is set to the pressure reducing mode, the control mode M (4) of the right rear wheel (inner rear wheel) RWR is set to the pressure increasing mode, and the control of the other two wheels is performed. The modes M (2) and M (3) are set to the non-control mode (see Table 1 and step S603).

Thereafter, the drive mode Mpls (i) is set as described above based on the control mode M (i) of each wheel and the required yaw moment γd (see the setting routine of FIG. 28), and each wheel is also set. Each pulse width Wpls (i) is set. Then, these drive modes Mpls (i) and pulse width W
pls (i) becomes the drive mode My (i) and the pulse width Wy (i) after passing through the pressure increase prohibition correction unit 90 and the control signal forced change unit 111 in FIG.

On the other hand, in the drive determination section 124 of FIG. 23, that is, the determination circuits of FIGS. 36 to 39, in the determination circuit 125 of FIG. 36, the brake flag Fb is Fb = 1 (during braking) and the drive mode My (i ) Is in the pressure increasing mode, a request flag Fmon (i) for each wheel requesting the drive of the motor 18 via the AND circuit 126 and the OR circuit 128, and a cutoff valve 19, via the flip-flop 130. Request flag Fcov for each wheel that requires 20 drives
(i) is set to 1, respectively.

Specifically, as described above, in the situation where the brake pedal 3 is depressed during the right turn having a strong US tendency, the output of the determination circuit 125 is Fmon (4) = Fcov.
(4) = 1, and the determination circuit 131 (O
The cut drive flag Fvd1 from the R circuit 132) is Fvd1 = 1.
And the decision circuit of FIG. 39, that is, OR
The motor drive flag Fmtr is output from the circuit 139 as Fmtr = 1. Here, the request flag Fcov (2) = Fcov
Since (3) = 0, Fvd2 = 0 for the cut drive flag Fvd2 output from the determination circuit 135 (OR circuit 136) in FIG.

Therefore, at the time of braking, only one cut drive flag, in this case, Fvd1 becomes 1. Thereafter, the cut drive flag Fvd1 = 1 and the motor drive flag Fmtr = 1 are set in the control signal selection unit 140 (FIG. 41) of FIG.
Then, through the switches 145, 14), Fv1 = 1, Fv2 =
0, Fm = 1, and these flags are supplied as drive signals to the cutoff valves 19 and 20 and the motor 18. That is, in this case, the front left wheel FWL and the rear right wheel R
Cut-off valve 1 paired with WR wheel brake
Only 9 is closed, the cut-off valve 20 paired with the wheel brakes of the right front wheel FWR and the left rear wheel RWL remains open, and the motor 18 is driven. By driving the motor 18, the pressure liquid is discharged from the pumps 16 and 17.

On the other hand, in the case of non-braking in which the brake pedal 3 is not depressed, the control mode M (1) of the left front wheel FWL and the control mode M (4) of the right rear wheel RWR are not in the control mode. Therefore, the AND circuit 12 of the determination circuit 125
7 and the OR circuit 128, the request flag Fmon (1) = F
mon (4) = 1 is output, and Fcov (1) = Fcov (4) = 1 is output from the flip-flop 130. Therefore, also in this case, the motor drive flag Fmt
When r = 1 and the motor 18, that is, the pumps 16 and 17 are driven, and only the cut drive flag Fvd1 is set to 1, as a result, only the cutoff valve 19 is closed.

However, in the case of non-braking, when the drive mode Mpls (i) described above is processed by the control signal compulsory changing unit 111 (FIG. 23), the non-control diagonal hold determining unit Flag F, which is the output of 118 (FIG. 35)
It should be noted that since hld is set to 1, switch 112 is toggled, forcing drive mode Mpls (i) in the uncontrolled mode to hold mode.

Further, in the case of non-braking (Fb = 0), regarding the calculation of the required yaw moment γd (see FIG. 10), the correction value Cpi is set to 1.5 which is larger than 1.0 in the case of braking. Therefore, the required yaw moment γd is raised. This padding is the drive mode Mpl
Since the pulse period Tpls for executing s (i), that is, My (i) is shortened, if the drive mode My (i) is the pressure increasing mode or the pressure decreasing mode, the increase / decrease is strongly executed. It should be noted that

After that, the drive mode My (i) and the pulse width W
As described above, y (i) is set as the drive mode MM (i) and the pulse width WW (i) via the control signal selection unit 140, and based on these, the actual drive mode Mexe (i) and the actual pulse width Wexe are set. As a result of setting (i), the corresponding inlet and outlet valves 12 and 13 are driven according to the actual drive mode Mexe (i) and the actual pulse width Wexe (i) (see the drive routine in FIG. 43).

Specifically, when the vehicle is turning to the right with a strong US tendency and is braking, the actual drive mode Mexc (1) of the wheel brake for the left front wheel FWL is the pressure reducing mode. As a result of closing the inlet valve 12 corresponding to (4) and opening the outlet valve 13 (step S1006 in FIG. 43), the brake pressure of the left front wheel FWL is reduced. On the other hand, in this case, since the actual drive mode Mexe (4) is the pressure increasing mode for the wheel brake of the right rear wheel RWR, the inlet valve 12 corresponding to the wheel brake is opened and the outlet valve 13 is closed. (Step S1003 in FIG. 43). Here, at this point, the cutoff valve 19 is closed as described above,
Since the pumps 16 and 17 are driven by the motor 18, the pressure in the branch brake pipe line 8 (see FIG. 1) leading to the wheel brake of the right rear wheel RWR is independent of the master cylinder pressure. Has already been launched,
As a result, the wheel brake of the right rear wheel RWR receives the supply of the pressure fluid from the branch brake line 8 through the inlet valve 12, and as a result, the brake pressure of the right rear wheel RWR is increased.

Referring to the braking force / cornering force characteristics with respect to the slip ratio shown in FIG. 45, the wheel brake pressure, that is, the braking force Fx, is in the slip ratio range when the vehicle is in a normal running state. It can be seen that the slip ratio decreases as the braking force Fy increases, whereas the slip ratio increases as the braking force Fy increases. On the other hand, decreasing the slip ratio increases the cornering force, while increasing the slip ratio increases the cornering force. It can be seen that the force is reduced.

Therefore, as shown in FIG. 46, when the braking force Fx of the left front wheel FWL is reduced from the white arrow to the black arrow, the cornering force Fy increases from the white arrow to the black arrow. On the other hand, when the braking force Fx of the right rear wheel RWR is increased from the white arrow to the black arrow, the cornering force Fy decreases from the white arrow to the black arrow. As a result, the braking force Fx of the front left wheel FWL is reduced and the cornering force Fy is reduced.
On the other hand, since the braking force Fx of the right rear wheel RWR increases and the cornering force Fy decreases, a turning moment M (+) is generated in the turning direction of the vehicle.

In FIG. 46, hatching arrows indicate changes in braking force Fx and cornering force Fy ± ΔFx, ± Δ.
It shows Fy. Here, in the left front wheel FWL and the right rear wheel RWR, which are diagonal wheels of the vehicle, the inlet and outlet valves 12 and 13 of those wheels are the actual drive mode Mexe (i) and the actual drive mode set based on the required yaw moment γd. Since the vehicle is opened / closed in accordance with the pulse cycle Wexe (i), the turning moment M (+) can be appropriately added to the vehicle, whereby the US tendency of the vehicle can be eliminated and its drift-out can be prevented.

Further, since the increase amount and the decrease amount of the brake pressure of the left front wheel FWL and the right rear wheel RWR are calculated based on the same required yaw moment γd, their absolute values are the same. Therefore, even if the brake pressures of the left front wheel FWL and the right rear wheel RWR are reduced or increased, the braking force of the entire vehicle does not fluctuate and the braking feeling of the vehicle does not deteriorate.

Further, the required yaw moment γd is calculated in consideration of the motion state and the driving operation state of the vehicle as described above (in the calculation routine of FIG. 11, step S
504, S505), and if the braking force of the diagonal wheels is increased or decreased based on the required yaw moment γd, fine yaw moment control according to the turning state of the vehicle becomes possible.

Moreover, since the required yaw moment γd is calculated with reference to the yaw rate deviation Δγ and the yaw rate deviation differential value Δγs, the required yaw moment γd.
Means that the vehicle at that time accurately shows the turning behavior. Therefore, when the braking force of the diagonal wheels is increased or decreased on the basis of the required yaw moment γd, the unstable turning behavior of the vehicle quickly recovers, and extremely stable turning of the vehicle becomes possible.

In calculating the required yaw moment γd, it is possible to use the lateral Gy or the open control according to the vehicle speed V and the steering angle δ, instead of the yaw rate feedback control described above. Further, since the turning direction of the vehicle is determined based on the output of the yaw rate sensor 30 when determining the diagonal wheel for which the braking force is to be controlled, the turning direction can be determined with high accuracy and the yaw moment control can be performed. The execution can be done accurately.

When the above yaw moment control is being executed and the vehicle is being braked, the actual drive mode Mexe (i) of the inlet and outlet valves 12 and 13 of the right front wheel FWR and the left rear wheel RWL is the non-control mode. Is set to
The cut-off valve 20 paired with the wheel brakes of the right front wheel FWR and the left rear wheel RWL is kept open. Therefore, since the wheel brakes of the right front wheel FWR and the left rear wheel RWL receive the master cylinder pressure, the brake pressures of the right front wheel FWR and the left rear wheel RWL are controlled by the driver's operation of the brake pedal 3, and those brake pressures are set. The driver's will can be reflected. As a result, sufficient fail-safe for yaw moment control can be ensured.

On the other hand, when the vehicle is in the non-braking state while the yaw moment control is being executed, the inlet and outlet valves 1 on the right front wheel FWR and left rear wheel RWL side as described above.
Since the actual driving modes Mexe (i) of the wheels 2 and 13 are forcibly changed to the holding mode, both the inlet and outlet valves 12 and 13 of the wheels are closed at this time (see FIG. 43). Step S1008 is executed in the drive routine). Therefore, the pump 16 is driven by the motor 18.
Even when the engine is driven, the discharge pressure of the pump 16 does not act on the wheel brakes of the right front wheel FWR and the left rear wheel RWL through the inlet valve 12, and as a result, the right front wheel FWR and the left rear wheel RWL of these wheels are driven. It is possible to prevent the brake pressure from undesirably increasing.

When the vehicle is not braking, the left front wheel FWL is
Since the brake pressure of No. has not risen, the pressure reducing control of the brake pressure is substantially unexecutable, which results in a shortage of the turning moment M (+). However, during non-braking, as described above, the required yaw moment γd is calculated by raising the required yaw moment γd. Therefore, in this case, the braking pressure of the right rear wheel RWR is higher than that during braking. Is further strengthened. Therefore, as the slip ratio of the wheel increases, the cornering force Fy further decreases, so that the cornering force of the left front wheel FWL acts relatively strongly, and the turning moment M (+) similar to that in the case of braking is applied to the vehicle. Can be given to.

Further, when the driver depresses the brake pedal 3 at a speed faster than a predetermined pedal stroke speed (50 mm / s) while the yaw moment control is being executed, as shown in FIG.
As described with respect to the setting routine of (1), 1 is set to the additional depression flag Fpp of the brake pedal 3. In this case, the step-up flag Fpp = 1 indicates that the control signal forced change unit 1
11 (see FIG. 23), the forced change unit 1
In 11, the switch 116 (see FIG. 35) is switched by receiving the additional press flag Fpp = 1, and as a result, the drive mode My (i) of all wheels is set to the non-control mode.

Therefore, both the request flag Fmon (i) and the request flag Fcov (i) are reset to 0 (see FIG. 36), and the cut drive flag Fvd1 (Fv1) and the motor drive flag Fmtr (Fm). Is also reset to 0 (see FIGS. 37 and 38), the cutoff valve 19 is opened while the motor 18 is stopped. Then, the inlet valve 12 of each wheel is opened and the outlet valve 13 thereof is closed. In this case, in the drive routine of FIG. 43, step S1003 on the pressure increasing mode side is executed, but at this time, since the wheel brakes of the respective wheels receive the supply of the master cylinder pressure, the driver operates the brake pedal 3 The brake pressure corresponding to the depression is raised in the wheel brake of each wheel, so that the braking force of the vehicle can be sufficiently secured.

26. Right turn of OS tendency: In the control mode selection routine of FIG. 26, the determination result of step S602 is false, the determination result of step S604 is true, that is, Fcos = 1, and the OS tendency of the vehicle is strong. If so, left front wheel F
This is different from the US tendency only in that the control mode M (1) of WL is set to the pressure increasing mode and the control mode M (4) of the right rear wheel RWR is set to the pressure reducing mode (Table 1 And step S605).

Here, when the vehicle is being braked, FIG.
As shown in Fig. 5, the braking force Fx of the left front wheel FWL increases while the cornering force Fy decreases, while the braking force Fx of the right rear wheel RWR decreases while the cornering force Fy increases. Therefore, in this case, the restoring moment M (-) is applied to the vehicle.
Occurs. This restoring moment M (-) cancels the OS tendency of the vehicle, whereby the spin of the vehicle due to the tuck-in can be surely avoided.

Even when the OS-oriented right turn is made, when the vehicle is not braked or when the additional pedal flag Fpp is set to 1, it is the same as the US-oriented right turn. It goes without saying that the above-mentioned effects can be obtained. Right turn with non-US tendency and non-OS tendency: In the control mode selection routine of FIG. 26, when the determination results of steps S602 and S604 are both false, that is, the turning tendency of the vehicle is neither US nor OS. In case, left front wheel FWL
The control modes M (1) and M (4) of the right rear wheel RWR are both set to the holding mode (see Table 1 and step S606).

In this case, the inlet and outlet valves 12, 13 on the left front wheel FWL and right rear wheel RWR side are closed. Therefore, the brake pressure of these wheels will be maintained,
Here, neither the turning moment M (+) nor the restoring moment M (-) is generated. Left turn: When the turn flag Fd and the control start / end flag Fymc described above become Fd = Fymc1 = 1 and the yaw moment control in the left turn is executed, again, as in the case of the right turn described above, When the US tendency of the vehicle is strong, the turning moment M (+) is generated, and
When the S tendency is strong, the brake pressures of the right front wheel FWR and the left rear wheel RWL are controlled to generate the restoring moment M (-), and as a result, the effect in the case of a right turn can be obtained (Table 1 And steps S607 to S611 of FIG. 26 and the drive routine of FIG. 43).

Counter steer: When the vehicle is not braked, FIG.
As shown in Fig. 2, the countersteer state in which the traveling direction of the vehicle (solid arrow: yawing direction) and the traveling direction intended by the driver (broken arrow: steering wheel operating direction) are different, that is, the driver When the vehicle itself also requires a restoring moment, the values of the turning direction flags Fdy and Fds do not match in the turning determination routine of FIG. 8, so in this case, the counter steer indicating the counter steer state. The flag Fcs is set to 1 (step S314).

In such a situation, as described above, even if the turning direction of the vehicle is determined based on the output from the yaw rate sensor 30, the turning direction is determined to be the left turn and the control execution flag Fcos is set. Since the value is 1 (see Table 1 and the selection routine of FIG. 26), in this case,
The braking force of the right front wheel FWL, which is the outer wheel in the turning direction, is increased. Therefore, as a result of the restoring moment M (−) being generated in the vehicle, the vehicle can stably turn.
It should be noted that the pressure reduction of the left rear wheel RWL is not executed here because the vehicle is not being braked.

However, at the time of braking turn, especially at the time of limit braking of the vehicle in which the ABS control is operated, the slip ratio of the right front wheel FWL is already large, so the slip ratio is increased with the increase of the brake pressure. However, the cornering force is further reduced (see FIG. 45), and it is not possible to generate an effective restoring moment in the vehicle.

Therefore, when the front wheels are in the limit braking range, the state shown in FIG.
As shown in the turning determination routine of step S30
Since the turning flag Fd is set based on the turning angle flag Fds based on the steering wheel angle, that is, the steering wheel angle θ based on the determination result of 9 (step S311), this case is shown in FIG. 49. As described above, even when the traveling direction of the vehicle (broken line arrow) is left, the turning direction is determined to be right (solid line arrow).

When the turning direction is changed in this way,
Since the sign of the yaw rate deviation Δγ is inverted as described in the calculation of the required yaw moment γd, the control execution flag Fcus is set to 1 instead of the execution control flag Fcos. Therefore, in this case, as is apparent from the selection routine of Table 1 and FIG. 26, the brake pressure of the left front wheel FWL is reduced and the slip ratio thereof is reduced. As a result, as shown in FIG. 49, the left front wheel FW
The cornering force Fy of L increases and a turning moment M (+) is generated in the vehicle. Since this turning moment M (+) acts in the same direction as the restoring moment M (-) in FIG. 48, the restoring moment effectively acts on the vehicle, thereby stabilizing the turning of the vehicle. it can.

According to the selection routine of Table 1 and FIG. 26, when the brake pressure of the left front wheel FWL is reduced,
The brake pressure on the right rear wheel RWR should be increased at the same time. However, in the counter steer state,
Regarding the right rear wheel RWR, the increase of the brake pressure is prohibited. That is, when the value of the counter steerer Fcs is set to 1 (Fcs = 1), the setting unit 94 of FIG.
In the pressure increase / decrease prohibition correction unit 90, the input condition of the AND circuit 97 is satisfied, and the pressure increase prohibition flag Fk1 (i) is supplied from the AND circuit 97 to the switch 91. Therefore, in this case, the right rear wheel RWR in the pressure increasing mode
The pulse width Wpls (4) of is forcedly changed to 0. As a result, even if the ABS control is activated, the pulse width Wpls (4) in the yaw moment control is preferentially output as the pulse width WW (4) via the control signal selection unit (see FIGS. 3 and 41). In this case, the brake pressure of the right rear wheel RWR is not increased.

Here, even if the slip ratio is increased with an increase in the braking force of the right rear wheel RWR, the cornering force is reduced. In this case, therefore, the increase of the slip ratio at the right rear wheel RWR is shown in FIG. However, in this case, since the braking pressure increase at the right rear wheel RWR is prohibited, the above-described increase in the turning moment M (+) of the vehicle is adversely affected. There is no defect.

Excessive slip: In the setting unit 95 (pressure increase / decrease prohibition correction unit 90) of FIG. 29, when the inputs of the AND circuits 98 are both turned on, that is, the slip ratio of the wheel in the pressure increase mode. Sl (i) is the allowable slip ratio S
When it becomes larger than lmax (i), the AND circuit 98 outputs the pressure increase prohibition flag Fk2 (i) = 1 to the switch 92. As a result, the switch 92 is switched and its pulse width Wpls.
(i) is forcibly changed to 0.

Therefore, as a result of the yaw moment control being executed, the braking force of the wheels in the pressure increasing mode is increased.
If the slip ratio increases above the allowable value, no more,
Since the braking force of the wheel is not increased, it does not cause an excessive slip on the wheel and does not cause the ABS control to operate. Here, the allowable slip ratio Slmax (i)
32 is set on the basis of the required yaw moment γd as shown in FIG. 32, the required yaw moment γd is large, and when the vehicle strongly requests the yaw moment control, the boosting pressure is increased. Since it becomes difficult to set the prohibition flag Fk2 (i) to 1, it is possible to effectively execute the yaw moment control without undesirably prohibiting the pressure increase from the wheel in the pressure increase mode.

On the other hand, with the execution of yaw moment control,
As a result of the wheel brake pressure being continuously controlled in boost mode,
If the ABS control is started for that wheel, in this case, the maximum value of the allowable slip ratio Slmax (i) becomes
The slip rate of the wheel at the time when the control is started, that is, the determination slip rate Slst (i) (or 95% of Slst (i)) is set, and the increase rate is also set based on the new maximum value. (See the setting routine of the pressure increase prohibition flag Fk2 (i) in FIG. 31).

Therefore, even if the wheel lock tendency is canceled by the ABS control and the control of the wheel returns from the ABS control to the yaw moment control, the wheel pressure increasing mode is prohibited in the yaw moment control thereafter. The wheel does not tend to lock again, and the control does not frequently switch between the ABS control and the yaw moment control.

ABS Coordination: The ABS control is activated and each wheel has the above-mentioned drive mode Mabs (i) and pulse width Wabs (i).
50, the diagonal wheels that are the control targets of the basic yaw moment control during the right turn US, that is, the left front wheel FWL and the right rear wheel RWR. In addition, the right front wheel FWR is also subject to control, and the right front wheel FWR is controlled in the pressure reduction mode.

When the ABS control is operated with respect to the right rear wheel RWR, an increase in the braking force Fx at the right rear wheel RWR, that is, a decrease in the cornering force Fy is not desired, but that much. , Front right wheel FWR
Since the cornering force Fy is increased as the braking force of the vehicle is decreased, in this case, the turning moment M (+) can be sufficiently generated mainly in the vehicle based on the difference in the cornering force Fy before and after the vehicle.

Further, as shown in FIG. 51, the right turn OS
Even at times, in addition to the left front wheel FWL and the right rear wheel RWR, which are the objects to be controlled by the yaw moment control, the left rear wheel RWL is controlled in the decompression mode.
Even if the reduction of the cornering force Fy at WL is not effectively exhibited, a sufficient restoring moment M (-) can be generated in the vehicle mainly based on the difference between the front and rear cornering forces Fy as in the case described above. it can.

Further, as described above, the yaw moment control is executed with the left and right rear wheels as the control target wheels.
As shown in 2, during the right turn US, the left front wheel FWL is controlled in the decompression mode in addition to the control target wheel, and as a result, the braking force at the right rear wheel RWR is increased by the ABS control. Even if does not function, the cornering force Fy of the left front wheel FWL can be increased by that amount to generate the turning moment M (+) in the vehicle, and as shown in FIG. 53, the vehicle makes a right turn. At the time of OS, the right rear wheel RWR is controlled in the decompression mode in addition to the control target wheel, so even if the pressure increase at the left front wheel FWL is impossible, the cornering at the right rear wheel RWR is correspondingly made. By increasing the force Fy, a restoring moment M (-) can be generated in the vehicle.

[0208]

As described above, according to the turning control device of the first aspect of the present invention, when the slip ratio of the wheels exceeds the allowable slip ratio, a yaw moment is generated in the vehicle. This is a situation where the braking force of the selected wheel should be increased, and the pressure increase is restricted. Therefore, in this case, the slip ratio of the selected wheel does not increase any more, and the wheel does not tend to lock.

According to the second aspect of the present invention, since the allowable slip ratio of the wheels changes based on the required control amount, when the yaw moment is generated in the vehicle, the increase of the braking force at the selected wheel is undesired. It is not restricted, and a yaw moment can be sufficiently generated. According to the apparatus of claim 3, when the anti-skid brake control is operated, the upper limit value and the increase ratio of the allowable slip ratio of the wheels are changed based on the slip ratio of the wheels at that time.
Since the increase of the braking force at the selected wheel is restricted even if the slip ratio is relatively small, the antiskid brake control is not repeatedly activated.

According to the apparatus of claim 4, the required control amount is accurately set according to the turning state of the vehicle, so that the turning behavior of the vehicle can be stably controlled. According to the apparatus of claim 5, the front wheel on the outer side and the rear wheel on the inner side are selected as the selected wheels in the turning direction, so that the yaw moment can be effectively generated in the vehicle.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a brake system that executes yaw moment control.

FIG. 2 is a diagram showing a connection relationship between various sensors and an HU (hydro unit) with respect to an ECU (electronic control unit) in the brake system of FIG.

FIG. 3 is a functional block diagram schematically illustrating a function of an ECU.

FIG. 4 is a flowchart showing a main routine executed by the ECU.

FIG. 5 is a steering wheel angle θ when the steering wheel is operated.
It is a graph showing the change over time.

FIG. 6 is a flowchart showing a brake pedal further depression flag setting routine which is a part of step S2 of FIG. 4;

7 is a block diagram showing details of a turning determination unit in FIG.

FIG. 8 is a flowchart showing details of a turning determination routine executed by a turning determination unit in FIG.

9 is a block diagram showing details of a target yaw rate calculation unit in FIG.

10 is a block diagram showing details of a required yaw moment calculation unit in FIG.

FIG. 11 is a flowchart showing a required yaw moment calculation routine.

FIG. 12 is a block diagram for obtaining a proportional gain Kp by calculating a required yaw moment.

FIG. 13 is a correction coefficient Kp1 for the proportional gain Kp.
5 is a flowchart showing a calculation routine of FIG.

FIG. 14 is a graph showing a relationship between a vehicle body speed Vb and a reference lateral Gyr.

FIG. 15 is a diagram for explaining the turning behavior of the vehicle body with respect to the center-of-gravity slip angle β when the vehicle turns.

FIG. 16 is a flowchart showing a routine for calculating correction coefficients Kp2 and Ki2 for the proportional gain Kp and the integral gain Ki.

FIG. 17: Center-of-gravity slip angular velocity dβ and reference correction coefficient Kcb
It is a graph showing the relationship with.

FIG. 18 is a block diagram for calculating a yaw rate vibration component γv.

FIG. 19 is a flowchart showing a routine for calculating a correction coefficient Kp3 for the proportional gain Kp.

FIG. 20 is a graph showing the relationship between the yaw rate vibration component γv and the correction coefficient Kp3.

FIG. 21 is a block diagram for obtaining the integral gain Ki in the calculation of the required yaw moment.

FIG. 22 is a graph showing the relationship between the absolute value of the steering wheel angle θ and the correction coefficient Ki1 of the integral gain Ki.

23 is a block diagram showing details of a yaw moment control unit in FIG. 3. FIG.

FIG. 24 is a block diagram showing details of a control start / end determining unit in FIG. 23;

FIG. 25 is a graph showing setting criteria of control execution flags Fcus and Fcos with respect to the magnitude of the required yaw moment.

FIG. 26 is a flowchart showing a control mode selection routine.

27 is a control mode M (i), a drive mode Mpls (i), and a pulse width Wpls (i) set in the selection routine of FIG. 26.
It is a time chart showing the relationship with.

FIG. 28 is a flowchart showing a setting routine of drive mode Mpls (i).

FIG. 29 is a block diagram showing details of a pressure increase / decrease prohibition correction unit in FIG. 23.

FIG. 30 is a pressure increase prohibition flag F regarding the pressure increase / decrease prohibition correction unit.
7 is a flowchart showing a setting routine for k1 (i).

FIG. 31 is a pressure increase prohibition flag F regarding the pressure increase / decrease prohibition correction unit.
6 is a flowchart showing a setting routine for k2 (i).

FIG. 32: Required yaw moment γd and allowable slip ratio Sl
It is a graph showing the relationship with max.

FIG. 33 is a graph showing the relationship between the required yaw moment γd and the allowable slip ratio Slmax after the ABS control is activated.

FIG. 34 is a flowchart showing a routine for setting a prevention flag Fk3.

FIG. 35 is a block diagram showing details of a control signal forcible change unit in FIG. 23.

FIG. 36 is a block diagram showing a part of a drive determination unit in FIG. 23.

FIG. 37 is a block diagram showing a part of the drive determination unit in FIG. 23.

FIG. 38 is a block diagram showing a part of the drive determination unit in FIG. 23.

FIG. 39 is a block diagram showing a part of the drive determination unit in FIG. 23.

FIG. 40 is a flowchart showing an ABS cooperation routine.

41 is a block diagram showing details of a control signal selection unit in FIG. 3. FIG.

FIG. 42 is a flowchart showing a drive signal initial setting routine.

FIG. 43 is a flowchart showing a drive routine.

FIG. 44 is a time chart showing the relationship between drive mode MM (i), pulse width WW (i) and actual drive mode Mexe (i), pulse width Wexe (i).

FIG. 45 is a graph showing braking force / cornering force characteristics with respect to slip ratio.

FIG. 46 is a diagram for explaining the execution result of yaw moment control during a right turn US during braking.

FIG. 47 is a diagram for explaining an execution result of yaw moment control during a right turn OS during braking.

FIG. 48 is a diagram for explaining the execution result of the yaw moment control in the counter steer state during non-braking.

FIG. 49 is a diagram for explaining an execution result of yaw moment control in a counter steer state at the time of limit braking.

FIG. 50 is a diagram for explaining the execution result of yaw moment control (diagonal wheel base) during ABS control and right turn US.

FIG. 51 is a diagram for explaining an execution result of yaw moment control (diagonal wheel base) during ABS control and right turn OS.

FIG. 52 is a diagram for explaining an execution result of yaw moment control (right and left rear wheel base) during ABS control and right turn US.

FIG. 53 is a diagram for explaining an execution result of yaw moment control (base of left and right front wheels) during ABS control and right turn OS.

[Explanation of symbols]

 2 Tandem master cylinder 3 Brake pedal 12 Inlet valve 13 Outlet valve 16,17 Pump 18 Motor 19,20 Cut-off valve 22 HU (Hydro unit) 23 ECU (Electronic control unit) 24 Wheel speed sensor 26 Handle angle sensor 27 Pedal stroke sensor 28 front and rear G sensor 29 lateral G sensor 30 yaw rate sensor

Claims (5)

[Claims] 1. A calculation means for calculating a required control amount of a yaw moment to be applied to the vehicle according to a motion state and a driving operation state of the vehicle, and the required control for a braking force between selected wheels when the vehicle turns. In the turning control device for a vehicle, which controls the turning of the vehicle by giving a braking force difference based on the amount and generating a yaw moment in the vehicle body by the braking force difference, slip ratio detecting means for detecting the actual slip ratio of the wheels, Based on the required control amount, setting means for setting an allowable slip ratio of the wheel, and regulating means for restricting an increase in the braking force at the selected wheel when the actual slip ratio of the wheel exceeds the allowable slip ratio. A turning control device for a vehicle, comprising: 2. The setting means increases the allowable slip ratio at a predetermined ratio as the required control amount increases, and maintains the allowable slip ratio at an upper limit value when the required control amount is a predetermined value or more. Claim 1 characterized by the above.
A turning control device for a vehicle according to item 1. 3. An anti-skid brake control device is incorporated in the vehicle, and the setting means sets an upper limit value of the allowable slip ratio according to a slip ratio of a wheel when the anti-skid brake control device operates. The turning control device for a vehicle according to claim 1, further comprising a changing unit that changes the increase ratio based on the changed upper limit value when the change is made. 4. The calculation means sets the required control amount based on a means for setting a target yaw rate of the vehicle and a yaw rate deviation between the target yaw rate and an actual yaw rate of the vehicle and a differential value of the yaw rate deviation. The turning control device for a vehicle according to claim 1, further comprising: 5. The generating means for generating a yaw moment in the vehicle body uses the outer front wheel and the inner rear wheel as target wheels when viewed in the turning direction of the vehicle, increases the braking force of one of the target wheels, and controls the other wheel. The turning control device for a vehicle according to claim 1, wherein power is reduced.