JPH04135958A - Vehicle anti-skid brake - Google Patents

Abstract

PURPOSE:To stop quickly a vehicle at a short brake distance while making a good use of an anti-skid brake characteristic, by changing a control threshold value on the basis of a brake pedal stepping on condition detected by means of a brake pedal stepping on condition detecting means. CONSTITUTION:A control unit is equipped with a control means 3 which conducts the increase/decrease control of each vehicle wheel brake pressure by means of a valve unit according to a predetermined control threshold value on the basis of each vehicle wheel speed, and a control threshold value changing means 5, and a control threshold value change prohibiting means 6, and a control threshold value correcting means 7, and the means 7 changes a control threshold value in the direction in which vehicle wheel brake efficiency becomes high (tighter locking), when a brake pedal depressing speed obtained by means of a brake sensor is more than a predetermined value. Thus, when the brake pedal depressing speed is high, for example, when an operater is falling into a panicky condition, brakability is secured by controlling brake pressure so as to become on the side locking, and when it is not high, the operation safety of a vehicle can be secured by conducting an ordinary ABS control.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an anti-skid brake device for a vehicle.

(Prior Art) Anti-skid brake devices basically reduce wheel speed to a predetermined deceleration (control threshold), or reduce the wheel speed to a predetermined deceleration (control threshold), or reduce the wheel speed to a target slip rate (control threshold). By controlling the increase or decrease of the braking pressure applied to the wheels (hereinafter simply referred to as ABS control as necessary), it is possible to prevent the wheels from locking or skidding during braking, and improve directional stability. This system allows the vehicle to stop within a short braking distance without losing the braking distance.

There are various proposals regarding the control of the braking pressure. For example, Japanese Patent Laid-Open No. 62-253560 proposes achieving both braking effectiveness and maneuverability by changing the target slip ratio according to the rotation angle of the steering wheel. There is a disclosure of technology that aims to achieve this. In other words, when the rotation angle of the steering wheel is large, the braking pressure is controlled with the goal of a low slip ratio in order to improve maneuverability, and when the rotation angle of the steering wheel is small, the braking pressure is controlled with the goal of a high slip ratio. This control increases the braking effect.

(Problems to be Solved by the Invention) By the way, when driving a vehicle, the brakes may be applied to the wheels while the driver is temporarily in a state of panic. For example, when a road aircraft suddenly jumps out in front of the vehicle while the vehicle is in motion, the driver must press the brake pedal firmly to avoid danger.
You may find yourself instinctively turning the steering wheel quickly to the right or left.

In such a situation, if the anti-skid brake device operates in the same way as during normal braking, the anti-skid brake device itself will generate a predetermined lateral force (reaction force from the road surface), taking into account that turning will occur even during braking. Since the braking pressure is controlled to be increased or decreased so that the braking pressure is increased or decreased, the vehicle is not necessarily provided with the highest possible braking effect.

That is, an object of the present invention is to make it possible to quickly stop a vehicle in a short braking distance while taking advantage of the characteristics of the anti-skid brake device even in the above-mentioned panic state.

(Means for Solving the Problems) In order to solve such problems, the present invention detects the depression state of the brake pedal by the driver, and makes it possible to change the threshold value of braking pressure control according to this depression state. It is something.

That is, as shown in FIG. 1, specific means for this purpose include: wheel speed detection means for detecting the rotational speed of the wheels; braking pressure adjusting means 2 for adjusting the braking pressure of the wheels; The anti-skid braking system for a vehicle is assumed to be an anti-skid braking system for a vehicle, comprising a control means 3 for controlling the braking pressure adjusting means 2 to increase or decrease the braking pressure according to a predetermined control threshold based on the wheel speed detected by the detecting means 1, The brake pedal depression state detection means 4 detects the depression state of the pedal, and the control threshold value changing means 5 changes the control threshold based on the brake pedal depression state detected by the brake pedal depression state detection means 4. It is characterized by having

When the brake pedal depression state detection means 4 detects the depression speed of the brake pedal, the control threshold value changing means 5 changes the control threshold value in a direction that increases the braking efficiency of the wheels when the depression speed is equal to or higher than a predetermined value. It shall be.

In addition, when the brake pedal depression state detection means 4 is configured to detect the amount of depression of the brake pedal, the control threshold value changing means 5 detects the amount of depression detected when the amount of depression is equal to or greater than a predetermined limit. It is assumed that the control threshold value is changed so that the braking efficiency of the end wheel for which the value obtained by subtracting the limit amount of depression from the front wheel is increased becomes higher.

When detecting the brake pedal depression speed, a steering amount detection means for detecting the amount of steering is provided, and when the amount of steering detected by the steering amount detection means exceeds a predetermined steering limit, the detection is performed. The control threshold value can be changed so that the braking efficiency of the dovetail wheel is increased when the value obtained by subtracting the limit steering amount from the steered amount is large.

Further, a vehicle speed detection means for detecting the vehicle speed may be provided, and when the brake pedal depression speed is less than a predetermined value t, the control threshold value may be changed such that the higher the vehicle speed, the higher the braking efficiency of the wheels.

Further, when changing the control threshold based on the amount of depression of the brake pedal, a control threshold correction means 7 is provided which corrects the amount of change in the control threshold by the control threshold change means 5 in a direction that increases the braking efficiency of the wheels as the vehicle speed increases. You can.

Further, even if the brake pedal depression speed is above a predetermined value, when the steering amount is below a predetermined value, or when the brake pedal depression amount is below a predetermined value, the control threshold value changing means 5 does not change the control threshold value. It is also possible to provide a control threshold value changing means 6 for changing the threshold value.

(Function) The above-mentioned anti-skid brake device is equipped with means for changing the threshold value for braking pressure control based on the depression state of the brake pedal. When pressing the brake pedal suddenly), by changing the control threshold so that the braking pressure acts on the wheels more lockingly than usual, in other words, so that the braking efficiency of the wheels becomes higher, the vehicle is controlled more than usual. It can be stopped with a short braking distance.

In this case, the wheels tend to lock up, making it impossible to secure a sufficient lateral force necessary for cornering. However, when the brake pedal is suddenly pressed down, it means that the driver has inadvertently pressed the brake pedal hard to avoid danger, for example, in a state of panic; Turning the vehicle by operating the steering wheel is usually not very useful for avoiding danger. Therefore, even if the turning performance is somewhat sacrificed, sufficient braking force is obtained to stop the vehicle as quickly as possible.

In addition, when the amount of brake pedal depression exceeds the limit amount, the control threshold value is set so that the braking efficiency of the i-J'g wheel becomes higher when the value obtained by subtracting the limit amount of depression from the detected amount of depression is large. If this is done, the degree of panic of the driver can be determined from the amount of depression of the brake pedal, and ABS control can be performed in accordance with the degree of panic.

In addition, in changing the control threshold when the brake pedal is suddenly depressed, when the detected steering amount exceeds the steering limit ■, the larger the value obtained by subtracting the limit steering amount from the detected steering amount, the larger the By changing the control threshold to increase the braking efficiency of the wheels, that is, to deepen the locking, the braking efficiency can be adjusted to match the degree of the driver's panic state.

In addition, as mentioned above, when changing the control threshold based on the brake pedal depression speed, if the higher the vehicle speed, the higher the braking efficiency of the wheels, it is possible to maintain appropriate turning performance when the vehicle speed is low. When the vehicle speed is high, braking efficiency can be increased to quickly stop the vehicle.

Even when determining the amount of change in the control threshold according to the amount of depression of the brake pedal, if this amount of change is corrected so that the braking efficiency of the wheels increases as the vehicle speed increases, the A will change according to the vehicle speed.
BS control can be performed.

Furthermore, even when the brake pedal depression speed is higher than a predetermined value, if it is determined whether or not to make the above change by looking at the amount of steering or the amount of depression of the brake pedal, it is possible to truly drive the vehicle. Only if the driver is in a panic, or if it is actually difficult to steer the vehicle out of danger, will the locking controls allow the driver to avoid the danger.

In other words, when the amount of steering is less than a predetermined value, or when the amount of depression of the brake pedal is less than a predetermined value, it is determined that the steering is performed by the driver's normal intention or as a result of depression of the brake pedal. Since the driver is not in a panic, the control threshold value changing means is prohibited from changing the control threshold value, so that the driver can avoid danger by turning the steering wheel.

(Effects of the Invention) Therefore, according to the present invention, in the anti-skid brake system for a vehicle, the threshold value for braking pressure control is changed based on the depression state of the brake pedal, so that the depression speed of the brake pedal is changed. When the brake pressure is high, when the amount of pressure on the brake pedal is large, for example when the driver is in a panic, the brake pressure is controlled so that the brake pressure is slightly locked to ensure braking performance, and when it is not, normal A is applied.
It becomes possible to carry out control according to the situation in which the driver or the vehicle is located, such as by performing BS control to ensure the steering stability of the vehicle.

In addition, when the brake pedal depression speed is high and the amount of steering exceeds the limit steering amount, if the amount of change in the control threshold value is determined according to the amount that exceeds the limit, it is possible to reduce the driver's panic level. ABS control can be performed by understanding the actual situation more accurately.

In addition, when the brake pedal depression speed is high, the higher the vehicle speed, the higher the braking efficiency of the wheels, or when determining the amount of change in the control threshold according to the amount of brake pedal depression. By correcting this so that the higher the vehicle speed, the higher the braking efficiency of the wheels, it is possible to perform ABS control according to the actual situation of the vehicle.

In addition, when changing the control threshold value, if it is determined whether or not to make the above change by looking at the amount of steering or the amount of depression of the brake pedal, the situation of the driver or vehicle can be more accurately understood. It will be possible to understand and control the situation in accordance with the situation.

(Example) Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 2, in the vehicle according to this embodiment, the left and right front wheels 11 and 12 are driven wheels, and the left and right rear wheels 13 and 14 are driving wheels, and the output torque of the engine 15 is transmitted to the automatic transmission 16.
The power is transmitted to the left and right rear wheels 13.14 via the propeller shaft 17, the differential gear 18, and the left and right drive shafts 19.20.

Each of the wheels 11 to 14 has discs 21a to 24a that rotate integrally with these wheels, and a caliper 2 that brakes the rotation of the discs 21a to 24a by receiving braking pressure.
1b to 24b are provided.

The brake control system for operating the brake devices 21 to 24 includes a brake pedal 26 operated by the driver.
a booster 27 that increases the stepping force of the booster 2;
A master cylinder 28 generates braking pressure in response to the force increased by 7. Mastern Linda 28
The front wheel brake pressure supply line 29 extended from the left front wheel brake pressure supply line 29a and the right front wheel brake pressure supply line 2
9b, and are connected to calipers 21a and 22b of brake devices 21 and 22, respectively. A first valve unit 30 consisting of an electromagnetic on-off valve 30a and an electromagnetic relief valve 30b is provided in the left front wheel braking pressure supply line 29a, and the right front wheel braking pressure supply line 29b includes:
A second valve unit 31 consisting of an electromagnetic on-off valve 31a and an electromagnetic relief valve 31b is provided.

A rear wheel braking pressure supply line 32 extending from the master cylinder 28 is provided with a third valve unit 33 consisting of an electromagnetic on-off valve 33a and an electromagnetic relief valve 33b. And this rear wheel braking pressure supply line 3
2 is a braking pressure supply line 32a for the left rear wheel and a braking pressure supply line 3 for the right rear wheel on the downstream side of the third valve unit 33.
2b, and are connected to calipers 23a and 24b of a brake device 2324, respectively.

That is, in this embodiment, the first channel adjusts the braking pressure of the brake device 21 of the left front wheel 11 by the operation of the first valve unit 30, and the second valve unit 3
1, the second channel adjusts the braking pressure of the brake device 22 of the right front wheel 12, and the third valve unit 33 adjusts the braking pressure of the brake devices 23, 24 of the left and right rear wheels 13, 14 by the operation of the third valve unit 33. and a third channel, and each of these channels is controlled independently of each other. The first to third valve units 30, 31, and 33 constitute the braking pressure adjusting means 3.

The control unit 34 that controls the first to third channels receives a brake signal from a brake sensor 35 that detects whether the brake pedal 26 is being depressed, the speed and amount of depression of the brake pedal 26, and a brake signal from each wheel. 1
Wheel speed signals from wheel speed sensors 37 to 40 as wheel speed detection means 1 for detecting rotational speeds 1 to 14 and steering angle signals (steering amount, turning speed) from a steering angle sensor 41 are input. , ABS control is performed in parallel for each channel.

That is, the control unit 34 controls each wheel 1
Based on the wheel speeds 1 to 14, each wheel 11 to
Each of the first to third valve units 30 includes a control means 3 for increasing or decreasing the braking pressure of 14, a control threshold change means 5, a control threshold change prohibition means 6, and a control threshold correction means 7.
．． The opening/closing valves 30a, 31a, 33a and the relief valves 30b, 31b, 33b of 3133 are controlled to open/close by duty control. The brake oil discharged from the relief valves 30b, 31b, and 33b is as follows. It is returned to the reservoir tank 28a of the master cylinder 28 by a drain line (not shown).

The control unit 34 will be specifically explained below.

The control means 3 includes a pseudo vehicle speed setting section and a control threshold setting section, and determines whether phase 0 (ABS non-control state) or phase I by comparing the control threshold with wheel acceleration/deceleration and slip rate.
Select a phase from (decreased braking pressure state during ABS control), Phase ■ (maintained state after pressure reduction), Phase ■ (sudden pressure state after holding reduced pressure), and Phase ■ (slow pressure increase state after sudden pressure increase) However, braking pressure control signals corresponding to each phase are output to the first to third valve units 30, 31, and 33.

Pseudo-vehicle speed setting> The above-mentioned pseudo-vehicle speed Vr is set as a convenient vehicle speed based on the above-mentioned wheel speeds, since the vehicle speed cannot be accurately detected when the wheels 11 to 14 are slipping. The highest wheel speed among the four wheels 11 to 14 is set as the pseudo vehicle speed Vr, and the speed change amount is varied from 1 or 2 G·Δt at a high friction coefficient to 1 or 2 G·Δt at a low friction coefficient depending on the friction coefficient of the road surface. It is set between 0.3G and Δt and corrected as follows. Note that Δt is the sampling period of the control unit 34 (for example, 7 m5).

Vr "Vr - (1,2G ・Δt ~0.3 G-
∆t) Control threshold setting> Control threshold setting is performed independently for each channel, and in this example, the control threshold is from phase 0 (CABS non-control) to phase 1 (depressurization). the first wheel deceleration threshold G1 for determining the transition from phase I to phase ■ (holding), the second wheel deceleration threshold G2 for determining the transition from phase I to phase ■ (holding), and the transition determination from phase ■ to phase ■ (sudden pressure). a first slip rate threshold S1 for determining the transition from phase ■ to phase ■ (slow pressure increase), a wheel acceleration threshold G3 for determining the transition from phase ■ to phase ■ (slow pressure increase), and a second slip rate threshold S2 for determining the transition from phase ■ to phase I. The control threshold value is appropriately set according to the pseudo vehicle speed Vr and the friction coefficient of the road surface.

Regarding the wheel speed of the rear wheels 13, 14, the smaller of the two wheel speeds is selected as the rear wheel speed. Further, the slip rate is calculated according to the following formula.

Slip rate = (1 - wheel speed ÷ pseudo vehicle speed) x 100 In the second case, the setting of the above control threshold value in normal ABS control is to set the lateral drag coefficient μL of the wheel against the road surface excessively, as shown in Fig. 3. It is set so that the coefficient of friction μ between the road surface and the wheels can be increased without decreasing it, that is, so as to obtain characteristics in the range of Ss. In other words, a high friction coefficient μ means high braking efficiency, and a high lateral drag coefficient μL means good stability or steering performance when cornering.
As shown in FIG. 3, it is difficult to achieve both braking efficiency and cornering performance, and in the normal ABS control, the control threshold is set so as to achieve both of these as much as possible.

The deceleration and acceleration of the wheels are obtained by dividing the difference between the previous value and the current value of the wheel speed by the sampling period Δt, and converting the result into gravitational acceleration.

When detecting the friction coefficient of the road surface, when ABS control is not performed, the road surface is uniformly determined to be a high-friction road surface, and after ABS control is entered, the friction coefficient of the road surface is detected based on wheel deceleration and wheel acceleration. It is.

That is, when the wheel deceleration is large and the wheel acceleration is small, the road is determined to be a low-friction road, when the wheel deceleration is small and the wheel acceleration is large, the road is determined to be a high-friction road, and in other cases, the road is determined to be a medium-friction road.

Normal ABS Control> Therefore, braking pressure increase/decrease control as shown in FIG. 4 is normally performed.

(2) That is, when the brake pedal 26 is depressed while the vehicle is running at a constant speed, the braking pressure generated by the master cylinder 28 increases, and the wheel speed decreases accordingly.

■ When the wheel deceleration becomes larger than the first wheel deceleration threshold Gl, the system shifts to ABS control and selects Phase I;
The braking pressure is reduced according to a predetermined pressure reduction pattern.

(2) When the wheel deceleration becomes smaller than the second wheel deceleration threshold G2, phase (2) is selected and the braking pressure is maintained in a reduced pressure state.

■ When the slip rate decreases as the reduced pressure is maintained and exceeds the first slip rate threshold S1, phase ■ is selected.
A sudden increase in braking pressure takes place.

(2) When the wheel acceleration decreases due to the sudden pressure increase and becomes equal to or less than the wheel acceleration threshold G3, phase (2) is selected and the braking pressure is gradually increased.

(2) When the slip rate exceeds the second slip rate threshold S2 due to the above-mentioned gradual pressure increase, Phase I is selected.

As described above, the braking pressure is controlled to increase or decrease independently for each of the first to third channels, thereby preventing each wheel from locking or skidding, without losing directional stability. This will allow the vehicle to stop within a short braking distance.

Change of Control Threshold Value> The change control threshold value based on the pedal depression speed is basically changed according to the depression speed By of the brake pedal 26 obtained by the brake sensor 35. That is, the depression speed Bv is the predetermined value Bv.
o or more, the control threshold value is changed in a direction that increases the braking efficiency of the wheels (deepens the locking).

In this case, the depression speed equal to or higher than the predetermined value Bvo means, for example,
The pedal depression speed when the vehicle suddenly jumps from the side of the road to the front of the vehicle, the driver temporarily panics, and the driver involuntarily depresses the pre-ki pedal forcefully to avoid danger. It is. [7] Regarding the control threshold value, the slip ratio threshold value is increased and the slope of the pseudo vehicle speed Vr is changed so as to become larger on the negative side.

Specifically, when information about the depression speed Bvo or higher is obtained, the first wheel deceleration threshold G1 for determining the transition from phase 0 (when ABS is not controlled) to phase J (depressurization) and the phase change from fuse I to The deceleration threshold C2 for determining the transition to ■ (hold) should be set higher than the phase ■ (decompression hold).
The first slip rate threshold S2 for determining the transition from phase ■ to phase ■ (sudden pressure) and the second slip rate threshold S2 for determining transition from phase ■ to phase I are high; Each threshold value is changed in a predetermined manner so that the threshold value G3 becomes deeper, and the wheel acceleration threshold value G3 for determining the transition from phase (2) to phase (2) (slow pressure increase) is lowered.

To explain the change in the control threshold value with reference to FIG. 3, this change will increase the slip ratio 5 at which the highest friction coefficient μ (maximum braking efficiency) is achieved even if the lateral drag coefficient μm is sacrificed.
Aim for a slip ratio of U or higher (deeper lock).

FIG. 5 is a flowchart showing the change control of the control threshold value,
Input the brake signal and each wheel speed signal, and if the brake pedal depression speed Bv is greater than the predetermined value Bvo,
ABS control is performed by changing the control threshold value in the direction of deepening the lock (steps 81 to S3). When the depression speed Bv is less than the predetermined value Bvo, normal ABS control is performed without changing the control threshold (step S4).

Therefore, for example, when the vehicle suddenly jumps from the side of the road to the front of the vehicle and the driver temporarily panics and suddenly depresses the brake pedal 26, the brake pedal 26 may By performing ABS control that deepens the lock, the braking efficiency of the wheels increases and the vehicle can be stopped in a short braking distance. On the other hand, when the brake pedal 26 is stepped on by the driver's will, normal ABS control is performed, which makes it possible to obtain an appropriate amount of lateral force on the wheels necessary for cornering, thereby improving the stability of cornering. Alternatively, it is possible to improve the steering performance.

Change based on pedal depression speed and steering amount This control threshold value is changed by taking into account the steering amount obtained by the steering angle sensor 41 in addition to the brake pedal depression speed described above. In other words, when the actual steering amount θH exceeds the limit steering amount θHm, the control threshold is set so that the lock becomes deeper as the difference between the actual steering amount θH and the limit steering amount θHm increases. is subject to change.

In this case, the above-mentioned limit steering amount θHm is a steering amount such that turning corresponding to the steering angle cannot be carried out (for example, oversteering occurs), and is determined by the vehicle speed V and the friction coefficient μ of the road surface. Based on this, calculations are made from the map shown in FIG.

FIG. 7 is a flowchart of this change control, and in step S2, the brake pedal depression speed Bv is set to a predetermined value Bv.

If the above value is less than zero, normal ABS control is performed without changing the control threshold (step S7). Then, the second period jifi b is larger than zero, that is, the actual steering amount θH is the limit steering amount θHm.
When the value exceeds the value b, the control-to-control one-shift change amount β is calculated from the map by /lr, and the control threshold value is changed (steps 82 to S6).

The magnitude of the above value can be considered to represent the extent to which the driver is in a state of panic. Therefore, in this example, in which the amount of change in the C control threshold value is changed in accordance with the magnitude of this value, ABS control can be performed in accordance with the driver's panic state.

Change based on pedal depression speed and vehicle speed This control threshold value is changed by taking into account the vehicle speed in addition to the above-mentioned brake pedal depression speed.

That is, the brake pedal depression speed Bv is the predetermined value Bvo
When the value is greater than , the control threshold value is changed so that the lock becomes deeper as the vehicle speed increases.

FIG. 8 is a flowchart of this change control, and in step S2, the brake pedal depression speed Bv is set to a predetermined value Bv.

When it is larger than , the control threshold change amount γ is calculated from the map based on the vehicle speed V, and the control threshold is changed (steps 82 to S6).

1.Prohibition of change of control threshold The parameters for prohibiting change of control threshold are as follows:
There are steering amount, steering speed, and brake pedal depression amount.

Specifically, based on the signal from the steering angle sensor 4,
The steering speed dθH/dt is less than the predetermined value A, or the steering amount θ
When information is obtained that H is less than a predetermined value θHo, or when information is obtained from the brake sensor 35 that the amount of depression of the brake pedal Bt is less than a predetermined value Bto,
An operation prohibition command is issued to the control threshold value changing means 5 so that the control threshold value is not changed.

That is, even when the brake pedal 26 is suddenly depressed, if the steering or the depression of the brake pedal 26 is performed by the driver's normal intention, the steering speed, the amount of steering, or the amount of depression of the brake pedal 26 is kept below a predetermined value. In such a case, normal ABS control is executed,
The control threshold value is changed when the steering speed, the amount of steering, or the amount of depression of the brake pedal 26 exceeds a predetermined value.

FIG. 9 is a flowchart showing prohibition control for changing the control threshold;
In step S2, the brake pedal depression speed Bv is set to a predetermined value B.
When larger than vo, the steering speed dθH/d
When it is determined that i is greater than or equal to a predetermined value A, steering amount θH is greater than or equal to a predetermined value θHO, and brake pedal depression amount Bt is greater than or equal to a predetermined value Bto, the control threshold is changed to a direction of deepening the lock and ABS control is performed. , - is less than a predetermined value, normal ABS control is performed without changing the control threshold (steps 83 to S7).

In this example, the control threshold is changed when all of the steering speed, steering amount, and brake pedal depression amount are greater than a predetermined value. The control threshold value may be changed when the control threshold value is obtained.

- Change based on the amount of pedal depression This control threshold value is changed when the amount of depression of the brake pedal 26 obtained by the brake sensor 35 exceeds a predetermined limit amount of depression. The changes will be made to:

In other words, when the actual brake pedal depression amount Bt exceeds the limit depression amount BtL that would cause the wheels to lock, the control threshold is changed in such a direction that the larger the value a obtained by subtracting Btl from this Bt, the deeper the locking becomes. . in this case,
ABS control starts when the wheels start to lock.
Brake pedal depression amount or limit depression ftBtl at this time
It is. Then, the control threshold change amount is corrected in accordance with the magnitude of the vehicle speed V. Note that Btl>Bt
It is O.

FIG. 10 is a flowchart showing this change control. When the value a is larger than zero, the control threshold change amount α is calculated from the map based on this value a, and the control threshold change amount is determined. Then, a correction amount is calculated in accordance with the vehicle speed ■, and the above-mentioned change amount is corrected (steps 82 to S6). If a≦0, normal ABS control is performed without changing the control threshold (step S7).

In this case, when a>0%, that is, when the brake pedal depression amount Bt is larger than the limit depression amount Btl, the magnitude of the value a can be considered to represent the extent to which the driver is in a panic state. Therefore, in this example in which the amount of change in the control threshold value is changed in accordance with the magnitude of the value a, A B S # control can be performed in accordance with the panic state of the driver.

-Comprehensive control- The above control threshold change control is an example of performing it separately depending on each control parameter, but in some cases, the control threshold may be changed in the direction of deepening the lock, taking into account all the conditions based on each of the above parameters. It would be better to do it. 11th
The figure shows the control flow in that case.

That is, after inputting various data, if the brake pedal depression speed Bv is greater than a predetermined value Bvo, check whether the value a obtained by subtracting the limit depression amount Btl from the actual brake pedal depression amount Bt is greater than zero. , if large,
Find the control threshold change amount α corresponding to a (step 81 to
S4). Next, from the actual steering amount θH to the limit steering amount θHm
It is checked whether or not the value obtained by subtracting b is greater than zero, and if so, the control threshold change amount β corresponding to b is determined (steps S5 and S6). Next, the control threshold change amount γ corresponding to the vehicle speed V is determined (step S7).

Then, the steering speed dθH/dt is greater than or equal to a predetermined value A, the amount of steering θH is greater than or equal to a predetermined value θHo, and the brake pedal is depressed H.
When it is determined that Bt is greater than or equal to the predetermined value Bto, calculate the above α + β + γ to determine the final control threshold change amount,
Based on this, the control threshold is changed and ABS control is performed (
Steps 88 to 512), and if the above determination cannot be obtained, normal ABS control is performed without changing the control threshold (Step 813).

Note that in vehicles equipped with a four-wheel steering system that also steers the rear wheels when the front wheels are steered, when changing the control threshold to a deeper lock, the steering ratio of the rear wheels relative to the front wheels is changed at the same time. may be corrected to the same phase side to improve the running stability of the vehicle. This correction of the steering ratio is especially suitable for vehicles when traveling at high speeds.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the present invention, Fig. 2 and subsequent figures show examples of the present invention, Fig. 2 is an overall block diagram of an anti-skid brake device, and Fig. 3 is a diagram showing the slip ratio, friction coefficient, and lateral drag coefficient. Figure 4 is a time chart of normal ABS control, Figures 5, 7 to 11 are flowcharts of control threshold change control, and Figure 6 is the limit steering amount. It is a characteristic diagram. 1... Wheel speed detection means 2... Braking pressure adjustment means 3... Control means 5... Control threshold value changing means 6... Control threshold value change prohibiting means 7... Control Threshold value correction means 11-14... Wheels 21-24... Brake device 26... Brake pedal 33... Valve unit (braking pressure adjustment means) 35... Brake sensor (pedal depression speed (depression amount detection means) 41... Rudder angle sensor (detection means for steering amount and steering speed) Fig. 4...Wheel speed detection means Braking correct adjustment η] Means auxiliary means control threshold value changing means・Control threshold value change prohibition means Control threshold value correction means Wheel brake device Brake pedal 1 ・ 5 ・ 6... ] ] ~ 14 21 ~ 24 30. 31 33 ・ Valve unit (braking pressure 71! 1 node means) Brake controller (pedal Fig. 10

Claims (1)

[Scope of Claims] (1) Wheel speed detection means for detecting the rotational speed of the wheels, braking pressure adjustment means for adjusting the braking pressure of the wheels, and a predetermined speed detection means based on the wheel speed detected by the wheel speed detection means. An anti-skid brake device for a vehicle, comprising: a control means for controlling the braking pressure adjusting means to increase or decrease the braking pressure according to a control threshold; brake pedal depression state detection means for detecting a depression state of the brake pedal; An anti-skid brake device for a vehicle, comprising: control threshold value changing means for changing the control threshold value based on the depression state of the brake pedal detected by the brake pedal depression state detection means. (2) The brake pedal depression state detection means detects the depression speed of the brake pedal, and the control threshold value changing means sets the control threshold value so that the braking efficiency of the wheels becomes high when the depression speed is equal to or higher than a predetermined value. The anti-skid brake device for a vehicle according to claim 1, wherein the anti-skid brake device changes: (3) The brake pedal depression state detection means detects the amount of depression of the brake pedal, and the control threshold value changing means detects the amount of depression from the detected amount of depression when the amount of depression exceeds a predetermined limit amount. The anti-skid brake system for a vehicle according to claim 1, wherein the control threshold is changed such that the greater the value obtained by subtracting the amount of depression, the higher the braking efficiency of the wheel. (4) The steering amount detection means detects the amount of steering, the brake pedal depression state detection means detects the depression speed of the brake pedal, and the control threshold changing means detects the depression speed when the depression speed is equal to or higher than a predetermined value. And when the steering amount detected by the steering amount detection means exceeds a predetermined limit steering amount, the larger the value obtained by subtracting the limit steering amount from the detected steering amount, the higher the braking efficiency of the wheels. The anti-skid brake system for a vehicle according to claim 1, wherein the control threshold value is changed so as to increase the control threshold value. (5) The vehicle speed detecting means detects the vehicle speed, the brake pedal depression state detection means detects the depression speed of the brake pedal, and the control threshold value changing means detects the depression speed when the depression speed is equal to or higher than a predetermined value. The anti-skid brake system for a vehicle according to claim 1, wherein the control threshold is changed such that the higher the vehicle speed detected by the vehicle speed detection means, the higher the braking efficiency of the wheels. (6) Vehicle speed detection means for detecting vehicle speed, and control threshold correction means for correcting the amount of change in the control threshold by the control threshold change means in a direction that increases the braking efficiency of the wheels as the vehicle speed detected by the vehicle speed detection means increases. The anti-skid brake device for a vehicle according to claim 3, comprising: (7) A steering amount detection means for detecting a steering amount, and a control threshold change that prohibits the control threshold changing means from changing the control threshold when the steering amount detected by the steering amount detection means is less than a predetermined value. The anti-skid brake device for a vehicle according to claim 2, further comprising a prohibiting means. (8) Brake pedal depression amount detection means for detecting the amount of depression of the brake pedal, and when the depression amount detected by the brake pedal depression amount detection means is less than a predetermined value, the control threshold value changing means is prohibited from changing the control threshold value. The anti-skid brake device for a vehicle according to claim 4, further comprising control threshold change prohibition means.