JPS6171263A - Vehicle brake control system - Google Patents

Abstract

PURPOSE:To prevent delayed braking due to wheel spin by correcting the boosting characteristic in boost control into sharp one upon exceeding of the variation of wheel rotary condition within predetermined period over predetermined level. CONSTITUTION:Upon abrupt variation of the wheel speed due to wheel spin to cause exceeding of the variation within the pulse period of self-run counter over predetermined level (d) at the time (to), the output from comparison circuit will go to H thus to bring the output of OR gate or a wheel speed variation detecting circuit 200 to H-level. Thereafter, boost control is executed on the basis of a pulse signal from pulse generating circuit 18b having smaller duty ratio than the pulse signal from pulse generating circuit 18a under normal control, thereby the boosting characteristic will be sharper than that under normal anti-skid control resulting in lagged braking.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a vehicle in which anti-skid control including pressure increase control with a gradual pressure increase characteristic of a brake hydraulic pressure system is started when wheel deceleration reaches a predetermined deceleration. Concerning improvements to braking control systems.

[Conventional technology]

The coefficient of friction μ between the wheels of a vehicle and the road surface is generally the 11th
As shown in the figure, a predetermined slip rate λ.

(approximately 15%), the maximum μ (max) is reached, and at this time, the braking efficiency in the vehicle becomes maximum. Therefore, in normal anti-skid control, when the vehicle is braked, the slip rate λ of the wheels is always the predetermined slip rate λ. The braking fluid pressure is controlled to be increased, decreased, or maintained so as to maintain the same value.

Conventionally, as a vehicle braking control system that performs vehicle braking control using anti-skid control as described above, there is a system in which the anti-skid control is started when wheel deceleration reaches a predetermined deceleration during braking of the vehicle. . As specific anti-skid control, for example,
There is one disclosed in Japanese Patent Publication No. 51-6308. As shown in Fig. 12, as the brake fluid pressure P increases due to the depression of the brake pedal (braking operation), the wheel speed VW force decreases, and the wheel deceleration decreases by a predetermined deceleration (- , ) (time '+), the large mouth valve (not shown) provided in the path from the mask cylinder linked to the brake pedal of the brake fluid main system to the foil cylinder that operates the brake pad, etc. is closed ( The signal e that controls the inlet valve is at level 5), and the outlet valve (not shown) provided in the hydraulic pressure recovery path from the foil cylinder to the mask cylinder is closed (the signal a that controls the outlet valve is at L level). ) and opening (the signal a is at H level Iv) are repeated in short cycles. As a result, the brake fluid pressure P changes from time t when the wheel deceleration reaches the predetermined deceleration (-bt).
The fluid pressure gradually decreases from , (slow depressurization).

Then, by controlling the brake fluid pressure P to reduce the pressure, the wheel speed VW
is recovered and the wheel deceleration falls below the predetermined deceleration (bt) (time t2), the hydraulic pressure at time t1 is maintained for a predetermined time T (signal e is at H level and signal a is at L level). ,
Thereafter, pressure increase control is performed until the wheel deceleration reaches the predetermined deceleration (-bt) again. At this time, in this pressure increase control, in order to prevent an extreme decrease in wheel speed VW, the signal e that controls the large outlet valve is made into a pulse signal with a predetermined period, and the signal a that controls the outlet valve is held at the L level. Therefore, the pressure increase control of the brake fluid pressure has a slow pressure increase characteristic.

Furthermore, after that, in addition to the above-mentioned braking fluid pressure control (slow pressure reduction, slow pressure increase, holding), sudden pressure reduction is performed when the wheel deceleration exceeds a predetermined deceleration (-b2) that is larger than (-b, ). control (signal e is H level, signal a is H level), holding control when wheel acceleration is equal to or higher than a predetermined acceleration (+b)
The signal e is at H level and the signal a is at L level) are repeated in sequence.

In a brake control system that performs such anti-skid control, the wheel speed VW is basically equal to the vehicle body speed V during braking.
When the brake fluid pressure significantly decreases with respect to c (increase in the slip ratio λ), the brake fluid pressure is controlled to be reduced, and when the wheel speed VW recovers due to the pressure reduction control (the slip ratio λ decreases), the brake fluid pressure is increased. In particular, the pressure increase control has a gradual pressure increase characteristic to prevent a sudden drop in wheel speed VW.
Depending on the degree of decrease in the wheel speed Vw, the characteristics of the pressure reduction control are set to be gradual pressure reduction characteristics and sudden pressure reduction characteristics, and the slip rate λ is controlled to maintain the brake fluid pressure as appropriate depending on the wheel acceleration/deceleration. Slip ratio λ that maximizes efficiency. Braking can be maintained at a value close to that value.

[Problem that the invention seeks to solve]

However, as mentioned above, the wheel deceleration is the predetermined deceleration (
-bt), the vehicle brake control system starts anti-skid control that includes pressure increase control of the brake fluid pressure system, which has a gradual pressure increase characteristic. For example, when the wheel speed Vw suddenly increases due to wheel spin as shown in FIG. 13, when the wheel speed Vw returns, the wheel deceleration becomes the predetermined deceleration (
-bt), the time t in Fig. 3 is reached.
. ), the anti-skid control will start. As a result, immediately after the wheel spin, for example, the wheel deceleration becomes equal to or higher than the predetermined deceleration c - bt ), and after a predetermined time T after returning to the predetermined wheel deceleration (bt) again,
That is, even if the brake pedal is depressed at time t in FIG. 13 and subsequent time t2, the system controls the large mouth valve and outlet valve of the brake fluid main system so that the brake fluid has a slow pressure increase characteristic after time 1°. As a result, there is a problem in that the effectiveness of the brake at the initial stage of braking is delayed.

[Means for solving problems]

The present invention solves the above-mentioned problems and detects whether the wheel deceleration has reached a predetermined deceleration or In the vehicle braking side m system, which starts anti-skid control including pressure increase control that has a gradual pressure increase characteristic of the brake hydraulic thread when it is determined that the wheel slip has reached a predetermined value, the wheel spin The purpose of the present invention is to provide a vehicle braking control system that prevents as much as possible the delay in brake effectiveness immediately after the start of anti-skid control even if anti-skid control is started erroneously due to such reasons. In order to achieve this, the above-mentioned brake control system has the following configuration: a state change detection means for detecting a change in the wheel rotation state detected by the wheel rotation detection means; and a state detected by the state change detection means. The pressure increasing characteristic correction means corrects the gradual pressure increasing characteristic of the pressure increasing control to a rapid pressure increasing characteristic when the fluctuation exceeds a predetermined constant fluctuation.

[Effect]

The state change detection means detects a change in a wheel rotation state such as wheel speed or wheel acceleration/deceleration detected by the wheel rotation detection means, and the state change detected by the state change detection means exceeds a predetermined constant change. At times, the pressure increase characteristic modifying means modifies the gradual pressure increase control characteristic in the anti-skid control to a rapid pressure increase control characteristic, and after the detected state fluctuation exceeds a certain level of fluctuation, the pressure increase characteristic is adjusted according to the rapid pressure increase characteristic. The brake fluid main system is controlled.

[Embodiments of the invention]

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

FIG. 1 is a block diagram showing an example of a vehicle braking control system according to the present invention. Anti-skid control device (anti-skid control circuit 1) adopted in the brake control system
00'') is an inflow provided in a path from the master cylinder 101 of the brake hydraulic system to the wheel cylinder 103 based on a detection signal with a frequency proportional to the rotational speed of the wheel 1020 output from the wheel speed sensor 1 during braking. Switching control of the valve 14 (corresponding to the inlet valve, hereinafter referred to as the EV valve 14) and liquid flowing from the foil cylinder 103 to the mask cylinder 101 via the server tank 104 and the pump 17 for recovering hydraulic pressure. It performs switching control of the outflow valve 15 (corresponding to the outlet valve, hereinafter referred to as AV valve 15) provided upstream of the reservoir tank 104 and pump 17 in the pressure recovery path. 14
switching signal (hereinafter referred to as Ev signal) and AM valve 15
The hydraulic pressure of the foil cylinder 103, that is, the braking hydraulic pressure, is controlled as shown in the following table by the switching signal (hereinafter referred to as the AV multiplication signal).

Table Here, the specific configuration of the anti-skid control circuit 100 is shown in FIG. In the figure, 2 is a wheel speed detection circuit that calculates the wheel speed Vw based on the output signal from the wheel speed sensor 1, and 3 is a wheel speed detection circuit that calculates the wheel speed Vw by differentially processing the detected wheel speed signal from the wheel speed detection circuit 2. and an acceleration/deceleration detection circuit that detects deceleration (negative acceleration), and 200 is an acceleration/deceleration detection circuit that detects deceleration (negative acceleration), and 200 is an acceleration/deceleration detection circuit that detects a predetermined acceleration rate λ based on fluctuations within a predetermined cycle of the detected wheel speed output from the wheel speed detection circuit 2. When the detected deceleration from the 5-digit acceleration/deceleration detection circuit 3, which generates the pseudo vehicle speed Vi (pseudo vehicle speed) necessary for This is a comparator circuit that outputs a signal (referred to as "b" and "signal"), and each time a signal is inputted from the above-mentioned pseudo vehicle speed generating circuit 4-digit comparator circuit 5, for example, from the detected wheel speed value output from the wheel speed detecting circuit 2 at that time. A pseudo vehicle speed vi1, which is a speed straight line with a predetermined constant slope, or a pseudo vehicle speed vi, which is a speed straight line connecting the detected wheel speed when the signal was input last time and the current detected wheel speed, is output. It has become. 6 is a target wheel speed generation circuit, and this target wheel speed generation circuit 6 is based on the pseudo vehicle speed Vi from the pseudo vehicle speed generation circuit 4 to determine the slip ratio λ at which the braking efficiency is near the maximum.

It outputs the target wheel speed vWO, which is a control target corresponding to λo = 1-(Vwo/Vi), and specifically, λ. is approximately Q,.15 (15%), so the calculation of Vwo = Vi X O,85 is performed and the calculated value is output.

7 inputs the target wheel speed vWO from the target wheel speed generation circuit 6 and the detected wheel speed VW from the wheel speed detection circuit 2, and when the detected wheel speed Vw becomes lower than the target wheel speed Vwo, an H level signal (hereinafter referred to as , a comparison circuit that outputs a slip signal); 8 a comparison circuit that outputs an H level signal (hereinafter referred to as signal a) when the detected acceleration from the acceleration/deceleration detection circuit 3 is equal to or higher than the reference acceleration 31; 9 a comparison circuit; Similarly to circuit 5, the detected deceleration from acceleration/deceleration detection circuit 3 is the reference deceleration S2.
This is a comparator circuit that outputs an H level signal (bt times signal) when the above is reached. Then, an AND signal (AV signal ) is input to the AT valve 15 via the driver 13.

16 is an IJ that is activated at the rising edge every time the output signal (AV signal) from the AND gate 10 is input, and outputs an H level signal (hereinafter referred to as MR multiplied signal) for a predetermined period of time (for example, about 2 seconds). This is a triggerable timer, and the MR multiplied signal from this retriggerable timer 16 causes the hydraulic pressure recovery pump 17 to operate, while the pseudo vehicle speed generation circuit 4 is further controlled by this MR multiplied signal. (When the MR multiplication signal is at H level, the original pseudo vehicle speed Vi is generated). Further, 18a is a pulse generation circuit that outputs a pulse signal with a predetermined period, and 18b is a pulse generation circuit that outputs a pulse signal with the same period as the pulse signal from the pulse generation circuit 18a and has a smaller duty ratio than the pulse signal (H level time is shorter) Generation circuit 18a flJ! This is a changeover switch that holds 1 and switches to the pulse generation circuit 18b side when the output is at H level, and the pulse signal from the pulse generation circuit 18a or 18b via this changeover switch 19 is transferred to the above-mentioned IJ coupler timer. MR from 16
AND gate 2 gate controlled by double signal
0 to the OR gate 11, and the OR gate 11 also receives the a signal from the comparator circuit 8, the b1 signal from the comparator circuit 9, and the output signal from the AND gate 10. There is. And this or gate 1
The output signal from 1 (the EV multiplier signal is sent via the driver 12 to the BY valve) is shown in FIG. 3, for example. While holding the maximum value, the self-running counter 204
The peak hold circuit 201 is configured to clear the held wheel speed value every time a pulse signal of a predetermined period is input from the peak hold circuit 201, as shown in FIG. The detected wheel speed fi'7 signal Vw (voltage value) from the detection circuit 2 is charged to the capacitor C via the buffer 220 and the guide D, and the voltage value charged to the capacitor C is transferred via the buffer 221 to the maximum wheel speed. I am trying to output it as quick information. Then, each time a pulse signal from the free-running counter 204 is input, the analog switch 222 is turned on, and the voltage charged in the capacitor C is discharged via the resistor R and the analog switch 222. .

202 is a peak hold circuit having the same configuration as the peak hold circuit 201, and this peak hold circuit 202 includes a detected wheel MvW from the wheel speed detection circuit 2.
is inputted via the inversion circuit 203 (which is raised to the power of -1). 206 is a peak hold circuit 201
This is a subtraction circuit that further subtracts the output value from the peak hold circuit 202 via the inversion circuit 205 (multiplying by -1) from the output value from the peak hold circuit 201. The output of the self-running counter 204 becomes the maximum value of the detected wheel speed within the pulse period, and the peak hold circuit 2 via the inverting circuit 205
Since the output from 02 is the minimum value of the detected wheel speed within the same pulse period, it is a fluctuation value within the same pulse period. 207 is a comparison circuit that outputs an H level signal when the output value from the subtraction circuit 206 exceeds a predetermined constant value δ (experimentally determined); 208 is a falling edge of the output signal from the comparison circuit 207; This is a timer that outputs an H level signal for a predetermined period of time T, and the OR signal from the OR gate 209 of the output signal of the comparison circuit 207 and the output signal of this timer 208 is output from the target wheel speed generation circuit 6.
It is designed to output to.

Next, the operation of this system will be explained.

First, normal anti-skid control will be explained.

When the driver depresses the brake pedal and the braking hydraulic pressure (hydraulic pressure in the foil cylinder 103) increases, the wheel speed decreases and the wheel deceleration (negative acceleration) increases accordingly. Here, the wheel deceleration further increases to a predetermined value,
When the signal reaches the comparator circuit 9, a signal is output, and the corresponding b1 signal (EV multiplied by the EV multiplication signal) is output via the OR gate 11.
The V-valve 14 operates, and the brake fluid pressure can be maintained at that point.

At this time, when the wheel deceleration reaches a predetermined value,
The pseudo vehicle speed generating circuit 4 outputs a pseudo vehicle speed Vi having a predetermined slope from the detected wheel speed at that point, and at the same time, the target wheel speed generating circuit 6 outputs a slip rate λ. Target wheel speeds Vwo (=vi X 0.85) corresponding to are sequentially output. When the wheel speed further decreases and falls below the target wheel speed Vwo by maintaining the brake fluid pressure at a high level as described above, a slip signal is output from the comparator circuit 7, and a slip signal is output via the AND gate 10. The AV valve 15 is actuated by the slip signal (AJ double signal), and the EV valve 14 is actuated by the slip signal (EV double signal) via the OR gate 11.
The operating state is maintained and the brake fluid pressure is reduced. When the brake fluid pressure is reduced in this way, the wheel speed and wheel acceleration return accordingly, and when the wheel acceleration reaches the predetermined value a1, the comparison circuit 8 outputs the signal a, and the OR gate 1
1 through the EV valve 1 by the double signal EV double signal
While the operation of step 4 continues, the AND gate 10 is inhibited by the signal a, so that the AV valve returns to its initial state and the brake fluid pressure is maintained. If the brake fluid pressure is maintained at a relatively low pressure in this way, when the wheel speed increases to a certain degree (at which point the slip signal disappears), it starts to decrease again. , the wheel acceleration also decreases from a value equal to or higher than the value a2. Here, this wheel acceleration is a predetermined value a
When it becomes less than 1, the 31 signal from the comparison circuit 8 falls and the outputs from each comparison circuit 7 and 9 at that point become L.
level, but the IJ was activated by the changeover switch 19 and the first AV multiplication signal.) Writable timer 1
The pulse signal from the pulse generator 18a becomes an EV multiplied signal and acts on the EV valve 14 via AND gate 4 and OR gate 11, which is set to an allowable state by the MR multiplied signal from 6, and the braking fluid pressure is increased or maintained. is repeated in the relevant pulse period,
The pressure is so-called slowly increased. Then, due to this gradual increase in brake fluid pressure, the wheel speed and wheel acceleration are further reduced, and thereafter, the same brake fluid pressure control as described above is sequentially repeated.

That is, the braking hydraulic pressure switching control during braking is performed according to a control mode determined based on the wheel acceleration/deceleration αW and the slip ratio λ (actually Vw/Vi) as shown in FIG.

Next, we will explain the operation of this system according to the timing chart shown in Figure 6, assuming a case where the wheel speed changes suddenly due to wheel spin, for example, when the vehicle is traveling on a rough or uneven road. do.

While the vehicle is running, the wheel speed fluctuation detection circuit 200
It detects wheel speed fluctuations within the pulse period of the self-propelled counter 204 (output from the subtraction circuit 206), and checks whether this fluctuation value exceeds a predetermined constant value δ (comparison circuit 207 output). Here, the wheel speed changes rapidly due to wheel spin, and the self-propelled counter 20
When the fluctuation value within the pulse period of 4 becomes equal to or higher than the constant value 6 at time t, the output of the comparison circuit 207 becomes H level, and the output of the OR gate 209, that is, the output of the wheel speed fluctuation detection circuit 200 becomes H level. After that, the timer 208 outputs an H level signal for a predetermined time T from the fall of the comparison circuit 207 (time tI) caused by the clearing of the peak hold circuits 201 and 202 by the pulse signal from the free-running counter 204. Therefore, the wheel speed fluctuation detection circuit 200 holds its H level output for the predetermined time T after the fall of the comparison circuit 207 (
until time t4).

On the other hand, after the wheel speed suddenly increases due to wheel spin, when the wheel speed returns, the wheel deceleration is set to the predetermined value b1.
When the value of the detected wheel speed reaches the value of the detected wheel speed at that time, a pseudo vehicle speed Vi having a predetermined slope is output from the pseudo vehicle speed generation circuit 4, and a target wheel speed V corresponding to this pseudo vehicle speed Vi is output.
WO=Vi X O, 85 is output from the target wheel speed generation circuit 6. If the wheel speed falls below the target wheel speed Vwo in the process of restoring the wheel speed, the AND gate 10
At the same time that the V signal is output, the IJ) 'J pull timer 16 is activated, and this retriggerable timer 16
The MR multiplied signal is output from. After that, when the wheel speed returns to a nearly steady state, the braking hydraulic system is maintained and controlled by maintaining the output of the EV double signal A4 signal.
When the target wheel speed VWO decreases according to the slope of the pseudo vehicle speed Vi and the wheel speed in the substantially steady state exceeds the target wheel speed Vwo (at time t), the A4 signal falls, and at that point, wheel speed fluctuation is detected. Since the output of the circuit 200 is held at H level and the changeover switch 19 is switched to the pulse generation circuit 18b side, the EV multiplied signal is
This is similar to the pulse signal output from b. Then, when the occupant performs a braking operation at, for example, time t, the brake fluid pressure P is increased when the EV multiplication signal is at the L level, and is maintained when the EV signal is at the H level, based on the EV multiplication signal having the above-mentioned pulse waveform. As the process is repeated, the pressure increases as a whole. Thereafter, when the wheel speed decreases and the wheel deceleration reaches a predetermined value (at time "J") due to this increase in brake fluid pressure, a new pseudo vehicle speed Vi is generated starting from the detected wheel speed at that time, Normal anti-skid control will now be performed.

As described above, according to this embodiment, when the wheel speed fluctuation within the pulse period of the self-propelled counter 204 becomes equal to or greater than the constant value δ due to wheel spin or the like, the wheel deceleration is reduced by the restoration of the wheel speed. Even if the anti-skid control is started by mistake when the anti-skid control is started, the pressure increase control immediately after the start of the anti-skid control has a smaller duty ratio (shorter H level time) than the pulse signal during normal control from the pulse generation circuit 18a. ) Since the operation is performed based on the pulse signal from the pulse generation circuit 18b, its pressure increase characteristic is 1ifi.
The characteristic is that the slope rises more steeply than during normal anti-skid control. As a result, it is possible to prevent as much as possible the delay in brake effectiveness immediately after the start of the anti-skid control.

In addition to changing the EV multiplication signal duty ratio as described above, for example, when the output from the wheel speed fluctuation detection circuit 200 is at the H level, the pressure increase characteristic may be modified by fixing the EV multiplication signal to the L level. You can do it like this. In this way, the pressure increase characteristics will be modified to be even more rapid.

Furthermore, in the above-described specific embodiment, the wheel speed variation circuit 20
0 is the one that operates all the time, that is, the peak hold circuit 20
1, 202 operated virtually all the time,
Since the main purpose of the present invention is to take measures against wheelspin during normal driving of a vehicle, the wheel speed fluctuation detection circuit 200 is configured to detect a peak speed during a braking operation when the brake pedal is depressed, for example, as shown in FIG. Hold circuit 201
a, 202a so as to prohibit substantial operation of the
In addition, as shown in FIG. 8, during anti-skid control, that is, while outputting the MR multiplied signal, the peak hold circuit 201b,
The actual operation of 202b may be prohibited.

Here, in FIG. 7, when the switch S linked to the brake pedal is turned on, the brake lamp L lights up and the transistor Tr, which is normally on, turns off, and at this time the power supply potential is fixed at E. The peak hold circuit 2 is activated by the collector output of the transistor Tr.
01a.

202aνWl is prohibited. Specifically, for example, the OR signal of this transistor Tra collector output and the pulse signal from the free-running counter controls the analog switch 2220 in the peak hold circuit shown in FIG. In addition, in Fig. 8, when the MR multiplied signal is at H level, the peak hold circuit 2
01b.

For example, this M
The OR signal with the pulse signal from the R-fold signal free-running counter is input as a control signal to the analog switch 222 in the peak hold circuit shown in FIG.
Ru.

Furthermore, as shown in FIG. 9, for example, this wheel speed fluctuation detection circuit 200 shortens the pulse period of the self-running counter 204a during anti-skid control, that is, when outputting the MR multiplied signal, compared to during non-anti-skid control. The reference value of the comparator circuit 207 may be set to a value δ2 larger than the value δ1 during non-anti-skid control using the changeover switch 210 which is controlled by the MR multiplication signal.

Furthermore, as is clear from FIG. 6, when the wheel speed changes rapidly due to wheel spin or the like, the wheel acceleration/deceleration also changes rapidly. Variations in wheel acceleration/deceleration may be used as the wheel acceleration/deceleration.

FIG. 10 is a block diagram showing another example of the anti-skid control device employed in the vehicle braking control system according to the present invention.

This embodiment operates by detecting fluctuations in wheel acceleration/deceleration. The configuration other than the wheel acceleration/deceleration fluctuation detection circuit indicated by 300 in the figure is the same as the configuration shown in FIG. In place of the detection circuit 2,
It is only necessary to change the acceleration/deceleration detection circuit 3 so that the configuration of the wheel speed fluctuation detection circuit shown in FIGS. 3 and 4 can be used, and the wheel speed fluctuation shown in FIGS. 7 to 9 can be used. Detection circuit configurations may also be utilized.

In this embodiment, since uneven road detection is detected by changes in wheel acceleration/deceleration, unevenness of the road surface can be detected more sensitively with respect to changes in wheel speed, and uneven roads can be more clearly recognized. can be set.

〔Effect of the invention〕

As explained above, according to the present invention, when the fluctuation of the wheel rotation state within a predetermined period exceeds a predetermined constant fluctuation, the pressure increase characteristic in pressure increase control is corrected to a rapid pressure increase characteristic. As a result, even if anti-skid control is accidentally started due to wheelspin, etc., it is possible to prevent as much as possible the delay in brake effectiveness immediately after anti-skid control starts, resulting in safer braking control. It becomes possible to realize the system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a brake control system according to the present invention, FIG. 2 is a block diagram showing an example of an anti-skid control device employed in the brake control system according to the present invention, and FIG. 4 is a block diagram showing an example of a specific configuration of the wheel speed fluctuation detection circuit in FIG. 3, FIG. 5 is a block diagram showing an example of a specific configuration of the peak hold circuit in FIG. An explanatory diagram showing the control mode of brake fluid pressure by the skid control device, Figure 6 is the first
7 to 9 are block diagrams showing other examples of specific configurations of the wheel speed fluctuation detection circuit in FIG. 2,
FIG. 10 is a block diagram showing another example of the anti-skid control device employed in the brake control system according to the present invention;
Fig. 11 is a graph showing the relationship between the friction coefficient μ between the wheels and the road surface and the slip ratio λ, and Figs. 12 and 13 are explanations showing the operating state of a braking control system employing a conventional anti-skid control device. It is a diagram. 1... Wheel speed sensor 2... Wheel speed detection circuit 3... Acceleration/deceleration detection circuit 4... Pseudo vehicle speed generation circuit 5.7.8.9... Comparison circuit 6... Target vehicle @ Speed generation circuit 12, 13...Driver 14...Inflow valve (EV valve) 15...Outflow valve (A
V valve) 16... Retriggerable timer 17... Pump 18a, 18b... Pulse generation circuit 19...
・Choice switch 20...AND gate 200
... Vehicle @ speed fluctuation detection circuit 201, 202... Peak hold circuit 203,
205... Inverting circuit 204... Free running counter 2
06... Subtraction circuit 207... Comparison circuit 2
08...-Timer 209...OR gate 220, 221...Buffer 222...Analog switch 300...Wheel acceleration/deceleration fluctuation detection circuit Fig. 110?

Claims (1)

[Claims] that the wheel deceleration has reached a predetermined deceleration and/or that the wheel slip has reached a predetermined value based on detection information corresponding to the wheel rotation state from a wheel rotation detection means that detects the wheel rotation state; In a vehicle brake control system that starts anti-skid control including pressure increase control that has a gradual pressure increase characteristic of the brake fluid pressure system when it determines that and a state change detection means for detecting the change in pressure, and a state change detection means for changing the gradual pressure increase characteristic of the pressure increase control to a rapid pressure increase characteristic when the state change detected by the state change detection means exceeds a predetermined constant change. A vehicle braking control system comprising: a pressure increase characteristic correction means for correcting pressure increase characteristics.