JPH06286598A - Antiskid brake device for vehicle - Google Patents

Abstract

PURPOSE:To insure optimum braking force although running condition is changed in any way by providing a means dividing wheels into groups, making different target slip ratio between the groups, and changing the target slip ratio according to the detected running condition by the use of a changing means. CONSTITUTION:For controlling slip ratio, various data, namely, wheel speed from wheel speed sensors 27-30, a lateral G signal from a lateral G sensor 32, longitudinal G signal from a longitudinal G sensor 33, air pressure of each tire from four air pressure sensors 34, and a yaw rate signal from a yaw rate sensor 35 are taken in. Next, friction coefficient of the road surface and body speed are estimated. The lock condition of a wheel is judged based on them, a threshold value variable is set against the wheel, and corrected. At first, a partially charged load of each wheel is estimated by the air pressure of the tire of each wheel, next each threshold value variable B is set, and corrected according to the load W applied on the wheel. Next, correction by the lateral G and the longitudinal G is performed, and hence the threshold value variable is finally decided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention monitors an anti-skid brake device that suppresses an excessive braking force when a vehicle is being braked. In particular, the present invention provides optimal control even when the moment acting on the vehicle changes during cornering, for example. The present invention relates to an anti-skid brake device for a vehicle that can obtain power.

[0002]

2. Description of the Related Art In a generally used anti-skid brake device, the acceleration / deceleration of a wheel (or slip ratio = ratio between wheel speed and vehicle body speed) is obtained based on the wheel speed detected by a wheel speed sensor or the like. The braking force is controlled so that the measured acceleration / deceleration (or slip ratio) of the wheel becomes the target acceleration / deceleration (or target slip ratio). Here, controlling to increase the braking force means that the slip ratio increases.

By the way, it is known that the load on each wheel changes during turning, and for this reason, a lateral acceleration of a predetermined magnitude is generated, for example, as in JP-A-61-1564. In this case, the braking pressure of the rear wheels is reduced to stabilize the braking to the limit region. This is because the load on the rear wheels is reduced during turning, which facilitates locking and reduces the lateral grip force of the rear wheels on the ground.

[0004]

However, in actuality, the frictional force generated in each tire during turning is such that a stable braking force can be secured simply by lowering the braking pressure on the rear wheel side. Not simple. It is assumed that the vehicle is now turning left as shown in FIG. If braking is applied during this turn, the outer front wheel will be most heavily loaded and the inner rear wheel will be least heavily loaded.
If the vertical load is W and the friction coefficient is μ, the friction force is μW
Becomes As shown in FIG. 2, this frictional force μW is decomposed into a braking force T and a lateral force CF (that is, cornering force). At this time, the relationship between the actual braking force Ti and the lateral force CFi is μW ≧ (CFi ² + Ti ² ) ^1/2 . Therefore, the braking force Ti is Ti = (μ ² W ² -CFi ² ) ^1/2 . The relationships among the frictional force μW, the braking force T, and the lateral force CF are illustrated in FIGS. 3 and 4.

When the braking operation (FIG. 1) is performed during turning, the load applied to each wheel is shown by a so-called "friction circle".
become that way. The larger the radius of the circle, the greater the frictional force and the greater the lateral force. Therefore, as in the past,
If control is performed with the same target slip ratio for all four wheels, the lateral force generated at the front becomes relatively large and becomes small at the rear wheels. Therefore, the vehicle is heading in the oversteer direction.

Therefore, it is preferable that the front wheels are controlled so that the braking force is emphasized, the rear wheels are controlled so that the lateral force is emphasized, and the outer wheels are controlled so that the inner wheels are emphasized for the braking force. In other words,
This means that it is difficult to suppress the yawing moment during turning braking by merely reducing the braking pressure of the rear wheels as in the conventional anti-skid brake device.

Therefore, the present invention has been proposed in order to solve the above-mentioned drawbacks of the prior art, and its purpose is to provide an optimum braking force suitable for the running condition no matter how the running condition changes. This is to propose an anti-skid brake device that can be secured.

[0008]

SUMMARY OF THE INVENTION The present invention for achieving the above object provides an anti-skid brake system for changing a target slip ratio of a wheel according to a running state of a vehicle.
A grouping means for changing the grouping of the wheels according to the detected running state, and a changing means for changing the slip target ratio of the wheels among the groups and changing the target slip ratio according to the detected running state. It is characterized by

The braking force control should be performed for each wheel group. The wheel group changes according to a certain rule depending on the running state. Therefore, it is possible to estimate the change of the wheel group according to the traveling state and perform the optimum control for each wheel group for each wheel.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. <System Configuration> FIG. 6 shows an anti-skid brake system as an embodiment. As shown in the figure, in the vehicle according to this embodiment, the left and right front wheels 1 and 2 are driven wheels and the left and right rear wheels 3 and 4 are drive wheels, and the output torque of the engine 5 is from the automatic transmission 6 to the propeller. It is adapted to be transmitted to the left and right rear wheels 3 and 4 via the shaft 7, the differential device 8 and the left and right drive shafts 9 and 10.

The wheels 1 to 4 have disks 11a to 14a which rotate integrally with the wheels 1 to 4, respectively.
And receiving the braking pressure, these discs 11a ...
Brake devices 11 to 14 configured by calipers 11b to 14b that brake the rotation of 14a are provided, and a brake control system 15 that performs a braking operation of these brake devices 11 to 14 is provided.

The brake control system 15 includes a booster device 17 for increasing the stepping force on the brake pedal 16 by the driver, and a master cylinder 18 for generating a braking pressure according to the stepping force increased by the booster device 17. Have and. Then, the front wheel braking pressure supply line 19 guided from the master cylinder 18 is branched into two paths,
These front wheel branch braking pressure lines 19a and 19b are connected to the calipers 11a and 12a of the brake devices 11 and 12 of the left and right front wheels 1 and 2, respectively, and one front wheel branch that leads to the brake device 11 of the left front wheel 1 is connected. A first valve unit 20 including an electromagnetic on-off valve 20a and an electromagnetic relief valve 20b is installed in the braking pressure line 19a, and the other front wheel branch braking leading to the brake device 12 of the right front wheel 2 is provided. Similarly to the first valve unit 20, the pressure line 19b also has an electromagnetic opening / closing type 21.
and a second relief valve 21b, which is also an electromagnetic type,
A valve unit 21 is installed.

On the other hand, the rear wheel braking pressure supply line 22 guided from the master cylinder 18 is divided into two systems and sent to the third valve unit 31 and the fourth valve unit 23. Third valve unit 31, fourth valve unit 2
Similar to the first and second valve units 20 and 21, the solenoid 3 is provided with electromagnetic opening / closing valves 31a and 23a and also electromagnetic relief valves 31b and 23b. The left rear wheel branch braking pressure line 22a is connected to the caliper 13b of the brake device 13 on the left rear wheel 3 via the third valve unit 31, and the right rear wheel branch braking is connected via the fourth valve unit 23. The pressure lines 22b are respectively connected to the calipers 14b of the brake device 14 on the right rear wheel 4. That is, the brake control system 15 in this embodiment includes the first channel that variably controls the braking pressure of the brake device 11 on the left front wheel 1 by the operation of the first valve unit 20, and the second valve unit 2.
A second channel that variably controls the braking pressure of the brake device 12 on the right front wheel 2 by the operation of 1 and a third channel that variably controls the braking pressure of the brake device 13 on the left rear wheel 3 by the operation of the third valve unit 31. , 4th
A fourth channel that variably controls the braking pressure of the brake device 14 on the right rear wheel 4 by the operation of the valve unit 23 is provided, and these first to fourth channels are controlled independently of each other. .

The brake control system 15 is equipped with a control unit 24 for controlling the first to fourth channels.
Detects a brake signal from a brake switch 25 that detects ON / OFF of the brake pedal 16, a steering angle signal from a steering angle sensor 26 that detects a steering wheel operation angle of the vehicle, and a rotation speed of each wheel. The wheel speed signals from the wheel speed sensors 27 to 30 are input, and braking pressure control signals corresponding to these signals are input to the first to fourth valve units 2.
By outputting to 0, 21, 31, 23 respectively,
Braking control for slips of the left and right front wheels 1 and 2 and rear wheels 3 and 4, that is, ABS control, is performed in parallel for each of the first to fourth channels. That is, the control unit 24 uses the wheel speed sensors 27-3.
Based on the wheel speed indicated by the wheel speed signal from 0,
The on-off valves 20a, 21a, 31a, 23a and the relief valve 20 in the fourth valve unit 20, 21, 31, 23.
By controlling opening / closing of b, 21b, 31b, and 23b by duty control, braking force is applied to the front wheels 1 and 2 and the rear wheels 3 and 4 with a braking pressure according to a slip state. In addition, each relief valve 2 in the 1st-4th valve units 20, 21, 31, 23.
The brake oil discharged from 0b, 21b, 31b, 23b is returned to the reservoir tank 18a of the master cylinder 18 via a drain line (not shown).

In the ABS non-controlled state, the braking pressure control signal is not output from the control unit 24, so that the relief valves 20 in the first to fourth valve units 20, 21, 31, 23 as shown in the figure.
b, 20b, 31b, and 23b are closed and held, and the on-off valves 20a and 20a of the units 20, 21, 31, and 23 are
21a, 31a, and 23a are respectively held open, and the braking pressure generated in the master cylinder 18 according to the depression force of the brake pedal 16 is applied to the front wheel braking pressure supply line 19 and the rear wheel braking pressure supply line. The brake devices 11 to 14 on the left and right front wheels 1, 2 and the rear wheels 3, 4 are supplied via 22 to the front wheels 1, 2 and the rear wheels 3, 4 by a braking force corresponding to the braking pressure. Will be given directly.

Further, in this vehicle, a lateral G sensor 32 for detecting lateral acceleration of the vehicle body (hereinafter abbreviated as "lateral G").
A longitudinal G sensor 33 that detects longitudinal acceleration of the vehicle body (hereinafter, abbreviated as “front and rear G”) during deceleration, and two air pressure sensors 34 that detect air pressure of each wheel are provided. Furthermore, a yaw rate sensor 35 for detecting the yaw motion of the vehicle body is also provided. Later G, as described below
The signal and the longitudinal G signal are used to correct the threshold value of the slip ratio control, and the outputs of the four air pressure sensors are used to estimate the shared load on the wheels. The yaw rate signal is also used to detect the sideslip angle of the wheels.

An outline of slip ratio control in the anti-skid brake device of this embodiment will be described. The slip ratio control of the present embodiment is provided with five control modes as shown in FIG. Mode 0 is a mode in which slip ratio control is not performed, and slip ratio control is performed in modes 1 to 5. In mode 1, the brake pressure supplied to each brake device (11, 12, 13, 14) is controlled to increase at predetermined time intervals. Therefore, in this mode 1, the wheels are locked. In the mode 2, the brake pressure is maintained at the pressure when the mode 2 is entered. That is, the mode 2 is a mode that has been changed from the mode 1, and is a holding state after the pressure is increased. In mode 3, each braking device (1
1, 12, 13, 14) is controlled so as to reduce the brake pressure at predetermined time intervals. Therefore, in this mode 3, the braking force applied to the wheels is reduced. In mode 4, the pressure is reduced more rapidly than in mode 3. In the mode 5, the brake pressure is maintained at the pressure when the mode 5 was entered. That is,
Mode 5 is a mode that has changed from mode 3 or 4, and is a holding state after the pressure is reduced.

The slip ratio of the wheel is defined by the following equation. Sx = (Vwx-Vref) / Vwx (1) Here, Vwx means a wheel speed, and x is a subscript representing each wheel. Vref is a pseudo vehicle body speed. Figure 7
In, B12 indicates a slip ratio threshold value when the mode 1 transits to the mode 2. In addition, BSG switches from mode 2 to mode 3, B
Reference numeral 35 denotes a threshold value for returning from mode 3 to 5, and BSZ denotes a threshold value for returning from mode 5 to 1.

When the slip ratio Sx of a wheel x becomes higher than a predetermined threshold value, that is, when Sx ≧ α 0 (2), it is determined that the wheel x is in the locked state.
Once it is determined that the lock state is set, the mode changes from 0 to 1. As described above, while in the mode 1, the brake pressure gradually increases with time at a constant rate. For this reason, the slip ratio may decrease and Sx ≦ B12 (3) may be satisfied. At this time, the mode changes from 1 to 2. Further, when Sx ≦ BSG (4), the mode shifts from 2 to 3, and in mode 3, the brake pressure is controlled to gradually decrease with the passage of time. If the slip ratio further decreases and Sx≤B35 (5), the mode shifts to 5 and the brake pressure is held constant to watch the change in the slip ratio. If the slip ratio is again the increasing step S amount, the mode returns from 5 to 1 and the brake pressure is increased.

When Sx ≦ β 0 (6), the mode becomes 0 and the slip ratio control is stopped. When slip ratio control is performed by such mode control, it is possible to change to a lock tendency or a relaxation tendency of slip rate control by changing the threshold value. For example, changing the threshold value B12 that changes from mode 1 to 2 to a small value causes the increase control of the brake pressure to continue for a longer time until the slip ratio reaches the small threshold value B12. That is, the slip ratio is controlled according to the lock tendency. In other words, if the threshold value (for example, B12, BSG) at the time of shifting from the higher brake pressure mode to the lower brake pressure mode is changed to a smaller value, the lock tendency becomes stronger. Similarly, if the threshold value (for example, B35, BSZ) at the time of shifting from the mode in which the brake pressure is lower to the mode in which the brake pressure is higher is changed to a larger value, the lock tendency becomes stronger.

FIG. 8 shows an example of the above four threshold values. The threshold values are arranged in a table, and nine sets of values from HM1 to LM3 are set. As shown in FIG. 9, each of these nine sets of values sets the road surface into three friction coefficient states (high μ state, medium μ state, low μ state) and three vehicle speed states (high speed, medium speed, low speed). Use it properly according to your needs. In FIG. 8, the unit of the threshold value G indicates the deceleration of the wheel speed, and the unit of% indicates the slip ratio.

FIG. 10 shows an example of mode transition and brake pressure change when the vehicle body speed and the wheel speed are variously changed. The slip ratio control of the embodiment utilizes the property that changing the threshold value B changes the lock tendency. The features of the slip ratio control of the embodiment are listed as follows: Independent setting of threshold variable The threshold variable B for mode transition control is independently set for each wheel. For example, B12 on the right front wheel is set to B12FR. Therefore, since there are 36 threshold values for one wheel as shown in FIG. 8, 36 × 4 = 144 threshold variable B are set for four wheels. : Correction according to the shared load of the threshold variable The shared load of each wheel changes due to changes in the running state, such as turning. Therefore, in this embodiment, the value of the threshold variable is corrected according to the shared load. For example, as shown in FIG. 5, when turning, the load on the outer front wheel is the largest and the load on the inner rear wheel is the smallest. Since the frictional force increases by a large amount when the load is large, the braking force is emphasized for the outer front wheels, in other words, the slip ratio control can be corrected to the lock tendency. According to this correction, if the correction coefficient that changes according to the shared load W is k (w), the corrected threshold variable B becomes k (w) · B (7). In the present embodiment, a coefficient k having a characteristic such that it becomes larger than 1 as the load W increases as shown in FIG.
Use (w). If the lock system height becomes excessive, the slip ratio control becomes uncertain, so as shown in FIG. 11, when the load W is between W1 and W2, k (w) = k0 · W (8) and W ≧ W2 Then, k (w) = k0.W2 (9).

The shared load for each wheel is changed by the air pressure of each tire measured by the four air pressure sensors 34 provided on the tire of each wheel. : Correction of Threshold Variable According to Lateral Acceleration The above correction threshold variable is further corrected according to lateral G. This "lateral G correction" is performed by setting independent correction coefficients for the right wheel and the left wheel. That is, regardless of whether it is a front wheel or a rear wheel,
A correction coefficient CTR having the characteristics shown in FIG. 12 is set for the right wheel group (right front wheel and right rear wheel), and a correction coefficient CTL is set for the left wheel group (left front wheel and left rear wheel). That is, CTR · k (w) · B (10) for the right wheel and CTL · k (w) · B (11) for the left wheel. According to the characteristics of FIG. 12, the lateral movement of the vehicle body in which a large amount of load is applied to the right wheel (the positive direction on the horizontal axis of FIG. 12) is corrected so that the right wheel is “locked” and the left wheel is The lateral movement of the vehicle body (the negative direction on the horizontal axis in FIG. 12) to which a large amount of load is applied is corrected to the direction in which the left wheel is “locked”. This is because, as described with reference to FIG. 5, it is preferable to control the outer wheels so that the braking force is more important than the inner wheels when turning. : Correction of Threshold Variable According to Front-to-Back Direction Acceleration The threshold variable of the equation (10) or (11) is further corrected by the front-rear G. This correction is different between the front and rear wheel groups. That is, when the correction coefficient of the front-rear G correction is represented by CL, the correction coefficient of the front wheel group is CLF, and the correction coefficient of the rear wheel group is represented by CLR. The characteristics of the front wheel correction coefficient CLF and the rear wheel correction coefficient CLR are shown in FIG. In the characteristic of FIG. 13, the braking force of the rear wheels is simultaneously applied to the direction in which the front wheels are “locked” with respect to the longitudinal G movement of the vehicle body (the positive direction on the horizontal axis in FIG. 13) in which a large load is applied to the front wheels. The slip ratio is corrected in the direction of relaxation. However, in order to prevent the vehicle body from oversteering, the CLR that corrects the rear wheels does not correct the rear wheels to the lock tendency more than the front wheels. That is, CLR ≦ CLF. Thus, for the right front wheel, CLF ・ CTR ・ k (w) ・ B (12), for the left front wheel, CLF ・ CTL ・ k (w) ・ B (13), for the right rear wheel. Becomes CLR ・ CTR ・ k (w) ・ B (14), and for the left rear wheel becomes CLR ・ CTL ・ k (w) ・ B (15).

FIG. 14 shows the control procedure of the slip ratio control of this embodiment. A description will be given based on this flowchart.
In step S100, various data are captured. This data includes the wheel speeds from the wheel speed sensors 27 to 30, the lateral G signal from the lateral G sensor 32, and the front-rear G sensor 3
3 includes the front and rear G signals, the air pressure for each tire from the four air pressure sensors 34, and the yaw rate signal from the yaw rate sensor 35.

In step S200, the road surface friction coefficient μ
To estimate. In the present embodiment, the frictional state has three stages of high, medium and low. For example, the acceleration AW of the wheel speed is 20G
Higher than (AW> 20G), a high friction road, the acceleration AW of the wheel speed is 10G <AW ≦ 20G or AW ≦ 2.
It is presumed to be a medium friction road when 0 G and deceleration DW ≧ −20 G, and a low friction road when deceleration DW <−20 G and AW ≦ 10 G. The friction state is used when referring to the table in FIG.

The stocker device 300 estimates the vehicle speed Vref. This vehicle speed Vref is basically determined based on the speed of the wheel having the highest wheel speed. However, the maximum wheel speed can be erroneously detected because the wheel slips on a low μ road surface. Therefore, in order to improve the estimation accuracy, the wheel speed change amount ΔWmax of the wheel with the highest wheel speed is calculated (step S302 in FIG. 15).
Then, the amount of change ΔWmax is compared with a predetermined threshold value CVR set according to the frictional state (step S306). This threshold value CVR is shown in FIG. In the procedure of steps S308 to S314, even if the change amount ΔWmax is large (NO in step S308), the previous vehicle body speed Vref
If the maximum wheel speed Wmax of this time does not change so much, the maximum wheel speed Wmax is set as the vehicle body speed Vref (step S
314). On the other hand, whether the change in wheel speed ΔWmx is smaller than CVR (YES in step S308), or ΔWmx
> Even if CVR, if the maximum wheel speed Wmx this time is much lower than the previous vehicle body speed Vref, Wmx
Instead of the previous vehicle speed Vref, the current vehicle speed Vref
(Step S310).

In step S400, the wheel lock state is determined based on the friction state, the vehicle body speed Vref, and the like. This determination is made for each wheel. For this determination, for example, when the vehicle body speed Vref <5 Km / H and the wheel speed Vx <7.5 Km / H, it is not necessary to perform the control for the anti-skid brake. That is, the lock control flag FLKx = 0
And When the vehicle body speed Vref ≧ 5 Km / H and the wheel speed Vx <7.5 Km / H, it is determined that the wheel x is in the locked state, and the lock flag is set for the wheel.

FLKx = 1 When it is determined in step S500 that the wheel is in the locked state, a threshold variable is set for the wheel in the locked state and the correction is performed in steps S600 to S1000. That is, in step S600, first, the shared load for each wheel is estimated. As described above, the shared load is estimated by the tire air pressure of each wheel. Step S
At 700, the 36 threshold variables B shown in FIG. 8 are set for each wheel in the locked state. In step S800, correction is performed according to the load W applied to the wheels in the locked state estimated in step S700. That is, the threshold variable B is corrected based on the above equation (7).

The meaning of the correction of the equation (7) described with reference to FIG. 11 will be further described with reference to FIG. 17, and the correction coefficient k (w) set according to the load W has been described with reference to FIG. Thus, it has a substantially linear property in the range of W1 ≦ W ≦ W2,
> In W2, practice to a fixed value. This is to prevent the locking tendency from becoming excessive. In the area of W <W1, k (w) = 1. By doing so, the correction of the threshold value is concentrated on the well-balanced area (range A to B in the figure) of the braking force curve and the lateral force curve, as shown in FIG.

In step S800, equations (10), (1
Lateral G correction is performed based on 1). In step S100, front-back G correction is further performed according to equations (12) to (15). In this way, the threshold variable is finally determined. In step S1100, the current slip ratio is compared with the value of the threshold variable thus determined, and it is determined whether the mode needs to be changed. If it needs to be changed, the mode is changed in step S1200.

According to the embodiment described above, the following effects can be obtained. : In the above embodiment, since the threshold variable is independently set for each wheel, independent lock control can be performed for each wheel. As a result, it is possible to realize the optimum braking force control for each wheel group. In the above-mentioned embodiment, the same wheel dynamically belongs to the front wheel group, sometimes to the rear wheel group, sometimes to the right wheel group, and sometimes to the left wheel group. . The braking force control of the wheels should be changed and controlled according to which group the wheels currently belong to, but in the present embodiment, since lock control is performed for each wheel, even if the same wheel is used. Even if the wheel group changes in accordance with the change in the running state, it is possible to follow the change and continue the optimum control. Specifically, −1: in the above embodiment, the threshold variable B according to the shared load
The value of is corrected. The shared load varies greatly depending on the wheel group. Since the frictional force increases by a large amount when the load is large, it is allowed to emphasize the braking force on such wheels, in other words, to correct the slip ratio control to the lock tendency. -2: In the example, the threshold variable was further corrected according to the lateral acceleration. This "lateral G correction" is performed by setting independent correction coefficients for the right wheel and the left wheel. As a result, the optimum lock control can be performed by following the change in the load between the wheel groups that changes according to the change in the lateral G. : In the example, the threshold variable was further corrected according to the longitudinal acceleration. As a result, the optimum lock control can be performed by following the change in the load between the wheel groups that changes according to the change in the front-rear G.

The invention is not limited to the embodiments described above. For example, in the above embodiment, the braking force between the wheels is
The threshold is set according to the load applied to the wheel. However, the threshold variable B may be corrected according to the sideslip angle instead of the load. In this case, the sideslip angle is determined as follows. Ψ is the yaw rate signal,
Letting Lf be the distance from the center of gravity of the vehicle to the front wheel drive shaft, Lr be the distance from the center of gravity of the vehicle to the rear wheel drive shaft, and θ be the steering angle, the skid angle of the front wheels γf = θ−Ψ ・ (Lf / Vref) The sideslip angle of the wheel is γr = Ψ · (Lr / Vref). For these γf and γr, k (w)
It suffices to set the coefficient k (γ) in place of

In particular, if the lock control is controlled so as to be changed according to the sideslip angle, the following effects can be obtained.
That is, in the above-described modified example, the larger the slip angle, the stronger the locking tendency. Therefore, the lateral force can be changed to the braking force in the front-rear direction by forcibly locking the tire during turning. It is also possible to modify the above embodiment as follows.

In addition to air pressure, for example, if the vehicle is equipped with an active suspension, the load on the wheels can be changed by the cylinder pressure used for the active suspension. A strain gauge may be attached to the suspension instead of the lateral G sensor.

[0035]

As described above, according to the antiskid brake device for a vehicle of the present invention, the change of the wheel group is estimated according to the running state, and the optimum control for the wheel group is performed for each wheel. You can Therefore, it is possible to secure the optimum braking force while suppressing the change in the yawing moment.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a traveling state of a vehicle.

FIG. 2 is a diagram illustrating a force applied to a wheel.

FIG. 3 is a diagram illustrating a force applied to a wheel.

FIG. 4 is a diagram illustrating a force applied to a wheel.

FIG. 5 is a diagram for explaining how the force applied to the wheels during turning changes variously.

FIG. 6 is a diagram showing a configuration of a preferred embodiment of the present invention.

FIG. 7 is a diagram illustrating a transition between modes used in the control of the embodiment.

FIG. 8 is a diagram illustrating a threshold variable used for control of the embodiment.

FIG. 9 is a diagram illustrating a threshold variable used for control of the embodiment.

FIG. 10 is a diagram for explaining how modes are changed.

FIG. 11 is a graph illustrating the relationship between the load W and the correction coefficient k (w).

FIG. 12 is a graph illustrating characteristics of a correction coefficient for lateral G correction.

FIG. 13 is a graph illustrating characteristics of a correction coefficient for front-back G correction.

FIG. 14 is a flowchart illustrating a control procedure of the embodiment.

FIG. 15 is a flowchart illustrating a control procedure of the embodiment.

FIG. 16 is a graph illustrating the characteristic of the correction value CVR.

FIG. 17 is a diagram illustrating the control principle of the embodiment.

Claims (7)

[Claims] 1. An anti-skid brake device for changing a target slip ratio of a wheel according to a running state of a vehicle, a grouping means for changing a grouping of wheels according to a detected running state, and a slip target for the wheel. An anti-skid brake device for a vehicle, comprising: a changing unit that changes a rate between groups and changes the rate according to a detected running state. 2. The antiskid brake device for a vehicle according to claim 1, wherein a sideslip angle of a tire is detected, and the detected sideslip angle is output to the grouping means and the changing means as a signal indicating a running state of the vehicle. An anti-skid brake device for a vehicle, comprising: 3. The vehicle anti-skid brake device according to claim 1, wherein load sharing for each wheel is detected, and the detected shared load is output to the grouping means and the changing means as a signal indicating a running state of the vehicle. An anti-skid brake device for a vehicle, comprising: 4. The vehicle anti-skid brake device according to claim 1, wherein lateral acceleration of the vehicle body is detected, and the detected lateral acceleration is used as a signal indicating a running state of the vehicle by the grouping means and the changing means. The anti-skid brake device for a vehicle, further comprising a means for outputting, wherein the changing means changes the target slip ratio between the left and right wheels in accordance with the detected lateral acceleration. 5. The vehicle anti-skid brake system according to claim 1, wherein the longitudinal acceleration of the vehicle body is detected, and the detected longitudinal acceleration is used as a signal indicating a running state of the vehicle by the grouping means and the changing means. An anti-skid brake device for a vehicle, further comprising a means for outputting, wherein the changing means changes the target slip ratio between the front and rear wheels in accordance with the detected longitudinal acceleration. 6. The vehicle anti-skid brake device according to claim 2, further comprising means for detecting a braking operation during turning, and means for permitting execution of the grouping means and the changing means during turning braking. An anti-skid brake device for a vehicle, which is characterized in that 7. The vehicle anti-skid brake system according to claim 1, wherein the group is a front wheel group and a rear wheel group, an outer wheel group and an inner wheel group, or a right wheel group according to a detected running state. And an anti-skid brake device for a vehicle, which is divided into a left wheel group.