JPS6171264A - Anti-skid controller - Google Patents

Abstract

PURPOSE:To prevent non-brake condition immediately after erroneous function by lowering the control response of an anti-skid controller with correspondence to the wheel speed variation width. CONSTITUTION:Anti-skid control circuit will perform change-over control of flow-in valve 14 and flow-out valve 15 on the basis of a signal to be detected through a wheel speed sensor 1 upon braking. Upon exceeding of the wheel speed variation due to wheel spin over predetermined level, the target wheel speed is set lower than that under normal anti-skid control for predetermined time. Consequently, even if the anti-skid control is started erroneously through reset of wheel speed, pressure reduction control in braking liquid pressure system is never executed thus to prevent non-brake conditon immediately after start of anti-skid control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in an anti-skid control device that starts braking control including pressure reduction control of a brake hydraulic system when wheel slip occurs. .

[Conventional technology]

The coefficient of friction μ between the wheels of a vehicle and the road surface is generally the 22nd
As shown in the figure, when the slip ratio λO (approximately 15%) is the maximum, μ (max) is reached, and at this time, the braking efficiency in the vehicle is maximum. Therefore, in normal anti-skid control, when braking the vehicle, the wheel slip rate λ
so that the value is always around the predetermined slip rate lo,
It controls braking fluid pressure by increasing, decreasing, or maintaining it.

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. . A specific example of anti-skid control is disclosed in Japanese Patent Publication No. 51-6308, for example. This is because, as shown in Figure 1, the wheel speed Vw decreases as the brake fluid pressure P increases due to the depression of the brake pedal (braking operation), and the wheel deceleration decreases to a predetermined deceleration (-
When the amount b (amount) is reached (time t]), a large mouth valve (not shown) installed in the path from the master cylinder linked to the brake pedal of the brake hydraulic system to the foil cylinder that operates the brake pad, etc. At the same time, the outlet valve (not shown) provided in the hydraulic pressure recovery path from the foil cylinder to the master cylinder' is closed (the signal a that controls the outlet valve is closed). is L level)
, open (the signal a is at H level) are repeated in short cycles. As a result, the wheel deceleration becomes the predetermined deceleration (
- The brake fluid pressure P changes from time tl when it reaches b (amount) to time t1.
The fluid pressure gradually decreases from the point at (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 (-bx) (time tz), 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. )
, After that, pressure increase control (slow pressure increase: signal e is pulse-like, signal a is L level) is performed until the wheel deceleration reaches a predetermined deceleration (-b (amount)).Furthermore, after that, In addition to the above-mentioned brake fluid pressure control (slow pressure reduction, slow pressure increase, hold), the wheel deceleration is controlled at a predetermined deceleration (-b (amount)) greater than (
-bz) or more (signal e is H)
control (signal e is at H level, signal a is at L level) when the wheel acceleration is equal to or higher than a predetermined acceleration (+b) are sequentially repeated.

In a brake control system that performs such anti-skid control, when braking, basically the wheel speed to the vehicle body speed V
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 addition to controlling the pressure, the characteristics of the pressure reduction control are set to be slow pressure reduction characteristics and rapid pressure reduction characteristics according to the degree of decrease in the wheel speed Vw, and the brake fluid pressure is maintained and controlled as appropriate according to the wheel acceleration/deceleration. , it becomes possible to perform braking while maintaining the slip ratio at a value near the slip ratio λO at which the braking efficiency is maximized.

[Problem that the invention seeks to solve]

However, as mentioned above, the wheel deceleration is the predetermined deceleration (
In a vehicle braking control system that starts anti-skid control including pressure reduction control when the amount -b (amount) is reached, when the vehicle is traveling on a rough or uneven road, for example, as shown in FIG. When the wheel speed Vw suddenly increases due to wheel spin, when the wheel deceleration reaches a predetermined deceleration (-b (amount)) when the wheel speed Vw returns, at that point (
The anti-skid control starts from time to) in FIG. 24, and the brake hydraulic pressure system is controlled to reduce the pressure.

As a result, immediately after the wheel spin, for example, the 24th
Even if the brake pedal is depressed at time tl in the figure, the large mouth valve of the brake fluid pressure system remains closed until time t2 in order to perform the pressure reduction control (following holding control), and during that time the wheel cylinder fluid is transferred from the master cylinder side. pressure is not transmitted,
There was a problem that the vehicle would end up with no brakes.

[Failure to solve the problem]

In view of the above-mentioned problems, the present invention has been made to increase or decrease the braking fluid pressure based on a comparative calculation of wheel acceleration/deceleration and/or slip ratio.
In an anti-skid control device that determines each control mode of control mode and/or hold mode, even if the control operation of the control hydraulic pressure is erroneously started due to wheel spin, etc., a no-brake state will occur immediately after that. The purpose is to provide an anti-skid control device that prevents skids as much as possible, and a configuration for achieving this purpose is such that, in the above-mentioned anti-skid control device, wheel speeds, wheel acceleration/decelerations, or fluctuation widths of signals based on wheel speeds are controlled. The apparatus is provided with a variation detecting means for detecting the change in temperature, and a changing means for changing the threshold value of the comparison calculation so as to reduce the control response in accordance with the detection output of the variation detecting means.

[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 provided in the path from the mask cylinder 101 of the brake hydraulic pressure system to the wheel cylinder 103 based on a detection signal with a frequency proportional to the rotational speed of the wheel 102 output from the wheel speed increaser 1 during braking. Switching control of the inflow valve 14 (corresponding to the inlet valve, hereinafter referred to as EV valve 14), and control of switching from the foil cylinder 103 to the reservoir tank 10
4. Mask cylinder 1 via pump 17 for hydraulic pressure recovery
the reservoir tank 104 of the hydraulic pressure recovery path leading to 01;
It performs switching control of an outflow valve 15 (corresponding to the outlet valve, hereinafter referred to as AV valve 15) provided upstream of the pump 17. Then, the hydraulic pressure in the foil cylinder 103, that is, the braking hydraulic pressure, is determined as shown in the following table by the switching signal of the Ev valve 14 (hereinafter referred to as the EV double signal) and the switching signal of the AV valve 15 (hereinafter referred to as the AV scratch signal). will be controlled by.

Table Here, the specific configuration of the anti-skid control circuit 100 is shown in FIG. In the same figure, 2 is a wheel speed detection circuit that calculates the wheel speed Vw based on the output signal from the wheel speed sensor height 1, and 3 is a wheel speed detection circuit that calculates the wheel speed Vw based on the output signal from the wheel speed sensor height 1. This is an acceleration/deceleration detection circuit that detects all acceleration and deceleration (negative acceleration), and 200 indicates a predetermined constant value δ for the fluctuation within a predetermined cycle of the detected wheel speed output from the wheel speed detection circuit 2. This is a wheel speed fluctuation detection circuit that outputs a detection signal when the above conditions occur. Reference numeral 4 indicates a pseudo vehicle speed generation circuit that generates a pseudo vehicle speed Vi (pseudo vehicle speed) necessary for detecting the slibbing ratio λ, and 5 indicates a circuit in which the detected deceleration from the acceleration/deceleration detection circuit 3 is equal to or higher than the reference deceleration b1. When the H level signal (hereinafter, b1
Each time the bl signal from the comparison circuit 5 is input, the pseudo vehicle speed generation circuit 4 generates a predetermined value based on the detected wheel speed value output from the wheel speed detection circuit 2 at that time. It is designed to output a pseudo vehicle speed vi1, which is a speed straight line with a constant slope, or a pseudo vehicle speed Vi, which is a speed straight line connecting the detected wheel speed when the above bt multiplied signal was input last time and the detected wheel speed this time. . Reference numeral 6 denotes a target wheel speed generation circuit. As will be described later, this target wheel speed generation circuit 6 has a configuration as shown in FIG. Slip ratio λOλo = where the braking efficiency is near the maximum
1-(Vwo/V i ) A target wheel speed Vwo f, which is a control target corresponding to Vwo/V i , 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 a1 signal) when the detected acceleration from the acceleration/deceleration detection circuit 3 exceeds the reference acceleration 81, 9 a comparison circuit 5, the detected deceleration from the acceleration/deceleration detection circuit 3 is the reference deceleration b1.
This is a comparator circuit that outputs an H level signal (bl signal) when the above conditions occur. Then, an AND signal (AV (no.
The signal is input to the AV valve 15 via the AV valve 15. 16 is an output signal from the AND gate 10 (every time the AV multiplied signal is input, it is activated at the rising edge and outputs an H level signal (hereinafter referred to as the MR multiplied signal) for a predetermined period of time (for example, about 2 seconds). This is a triggerable timer, and this retriggerable timer 1
The pump 1T for hydraulic pressure recovery is activated by the MR multiplied signal from 6, while the pseudo vehicle speed generation circuit 4 is further controlled by this MR multiplied signal (M
When the R-times signal is at H level, the original pseudo vehicle speed Vi is generated). Further, 18 is a pulse generator that outputs a pulse signal of a predetermined period, and the pulse signal from this pulse generator 18 is gate-controlled by the MR multiplied signal from the above-mentioned IJ' It comes to be input to the OR gate 11 via the AND gate 19, and the + from the comparator circuit 8 is also input to this OR gate 11.
The lLl signal and the output signal from the bx multiplied signal AND gate 10 from the comparator circuit 9 are input. Then, the output signal of this or game Nuk et al. (the EV multiplied signal is the driver 12
A configuration in which the electric power is inputted to the EV valve 14 via the electric current is shown in FIG. 3, for example. In the same figure, 2
01 is a peak hold configured to hold the maximum value of the detected wheel speed from the wheel speed detection circuit 2 and to clear the held wheel speed value every time a pulse signal of a predetermined period is input from the self-propelled counter 204. In the circuit, this information V
W (voltage value) is charged to the capacitor C via the buffer 220 and the third diode D, and the voltage value charged to the capacitor C is output via the buffer 221 as maximum wheel speed 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 transferred to the resistor R and the analog switch 2.
22.

202 is a peak hold circuit having the same configuration as the peak hold circuit 201, and this peak hold circuit 202 receives the detected wheel speed Vw 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 from the self-running counter 204 is 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 201; The OR signal from the OR gate 209 of the output signal of the comparison circuit 20γ and the output signal of this timer 208 is output from the target wheel speed generation circuit 6.
It is designed to output to.

Further, the specific configuration of the target wheel speed generating circuit 6 is as shown in FIG. 5, for example.

In the figure, 61 is a multiplication circuit that multiplies the pseudo vehicle speed Vi sequentially output from the pseudo vehicle speed generation circuit 4 by 0.85, and the target wheel speed Vw output from this multiplication circuit 61.
Vi X O, 85 as o corresponds to the slip ratio λ0 (=15 coefficient) at which the braking efficiency is considered to be maximum. Reference numeral 62 is an arithmetic circuit which multiplies the pseudo vehicle speed Vi by 0.85 and then further reduces the vehicle speed value corresponding to 1 oklll/h. X O, 85-10 tan/h corresponds to a slip rate larger than the above-mentioned slip rate λ0. Further, 63 indicates the target wheel speed Vwo output to the comparison circuit 7 in FIG.
This selector switch 63 holds the multiplier circuit 61 side when the detection signal from the wheel speed fluctuation detection circuit 200 is at L level, and outputs the same detection signal. is switched to the arithmetic circuit 62 side when is at H level.

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 fluid 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 b
When the bx signal reaches 1, the b1 signal is output from the comparator circuit 9, and the EV valve 14 is operated by the bx multiplication signal EV multiplication signal via the OR gate 11, and the brake fluid pressure is maintained at that point. At this time, when the wheel deceleration reaches a predetermined value blK, the pseudo vehicle speed generation circuit 4 outputs a pseudo vehicle speed Vi having a predetermined slope from the detected wheel speed at that time, and at the same time, the target wheel speed generation circuit 6, the target wheel speed Vwo (=ViX0.85) corresponding to the slip ratio λ0 is sequentially output (
The output of the wheel speed fluctuation detection circuit 200 maintains the L level, and the changeover switch 63 in the target wheel speed generation circuit 6
is held on the multiplication circuit 61 side. ). 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 γ, and a slip signal is output via the AND gate 10. The AV valve 15 is activated by the slip signal (AM double signal).
At the same time as operating, or gate 11t? The operating state of the EV valve 14 is maintained by the same slip signal (EV double signal) and the brake fluid pressure is reduced. When the brake fluid pressure is reduced in this way, the wheel speed and wheel acceleration are restored accordingly. When the wheel acceleration reaches a predetermined value al, an al signal is output from the comparator circuit 8, and the operation of the EV valve 14 is further continued by the mat signal (EV multiplication signal) via the OR gate 11t. by andgate10
AV valve 15 returns to its initial state, and the brake fluid pressure is maintained. In this way, if the control pressure is maintained even though it is a relatively low hydraulic pressure, the wheel speed will increase to a certain extent beyond the target wheel speed (at this point the slip signal disappears), and then it will decrease again. At the same time as the start, the wheel acceleration also decreases from a value that is greater than or equal to the upper predetermined value at. Here, when this wheel acceleration falls below a predetermined value a1, the al signal from the comparator circuit 8 falls and the outputs from each comparator circuit 1 and 9 at that time become L level, but the initial AV times The pulse signal from the pulse generator 18 becomes an EV multiplied signal and acts on the EV valve 14 via the AND gate 19 and the OR gate 11 which are activated by a signal or enabled by an MR signal from the triggerable timer 16. The braking fluid pressure is increased and maintained repeatedly at the pulse cycle, resulting in a so-called gradual pressure increase. 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 brake fluid pressure 9 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/V i ) as shown in FIG.

Next, the operation of this system will be explained with reference to FIG. 7, assuming that the wheel speed changes suddenly due to wheel spin, for example, while the vehicle is traveling on a rough or uneven road.

While the vehicle is running, the wheel speed fluctuation detection circuit 200
A detection operation (output of the subtraction circuit 206) of wheel speed fluctuations within the pulse period of the self-propelled kakunta 204 is performed, and it is confirmed whether or not this fluctuation value exceeds a predetermined constant value δ (comparison). circuit 20γ 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 δ at time to, the output of the comparison circuit 20γ 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. 9, and then peak hold times u 201 , 202 by pulse signals from the free-running counter 204 .

Since the timer 208 outputs an H level signal for a predetermined time Tl7 from 9 (time 11) when the comparison circuit 207 falls due to clearing, the wheel speed fluctuation detection circuit 200 detects the signal after the fall of the comparison circuit 20γ. The predetermined time T
(until time t5).

On the other hand, after the wheel speed rapidly increases due to wheel spin, when the wheel speed returns, the wheel deceleration reaches the predetermined value bl.
When the value of the wheel speed is reached, the pseudo vehicle speed generation circuit 4 outputs a pseudo vehicle speed Vi'(1) having a predetermined slope based on the detected wheel speed value at that time. Then, in response to this pseudo vehicle speed Vi, (1), the target wheel speed generation circuit 6 outputs the target wheel speed Vyo, which is the control target, but at this time, as described above, the wheel speed fluctuation detection circuit 200 Since the output of is at H level, the switching switch 3 in the target wheel speed generating circuit 6 is switched to the calculation circuit 62 side, and the target wheel speed Vwo is Vwo = Vi (1) X O,85- 10km/
h. That is, the target wheel speed Vwo is set to a value lower than Vi (IIX O, 85) in normal anti-skid control by LO km/h.

When the target wheel speed Vwo is set to a relatively low level in this way, even if the wheel speed that has increased by a certain amount due to the wheel rotation speed returns again, the wheel speed will not reach the target wheel speed Vwo. For this reason, for example, when the brake pedal is depressed at time t2, the wheel acceleration/deceleration is in the range of bl to al at this point, and the wheel speed has not reached the target wheel speed Vwo, so the EV multiplication signal AV multiplication signal Since both of them are maintained at the L level, the brake fluid pressure P is increased in accordance with the depression of the brake pedal. Then, when the brake fluid pressure P is increased, the wheel speed Vw decreases and the wheel deceleration increases and reaches a predetermined value bl (time t3), a new pseudo vehicle speed Vi ( 21 occurs, and from then on, normal anti-skid control is performed.It should be noted that at time t
3 to time t5, the output of the wheel speed fluctuation detection circuit 200 maintains the H level. Therefore, from time t3 to time t5, the target wheel speed Vwo is Vwo = Vi (2
1x O, 85-10 km/h, but after time t5, the target wheel speed corresponding to the slip ratio λ0 (=15%) at which the braking efficiency is maximum is Vwo = Vi f21 X O,
Switched to 85. Then, the wheel speed or the target wheel speed Vw
o = V i (21X 0, time t6 when 85 is reached
Thereafter, pressure reduction control in normal anti-skid control is 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 return of the wheel speed. Even if the anti-skid control is started by mistake when the anti-skid control reaches bl, the target wheel speed VwO will be 1 OklTl/h lower than that during normal anti-skid control for a predetermined period of time.
Since the wheel speed is set low, the wheel speed after recovery will not reach the target wheel speed Vwo, and the brake hydraulic pressure system will not be controlled to reduce the pressure, so that a no-brake state immediately after the anti-skid control starts can be prevented. Become. (In the past, in FIG. 7, pressure reduction control was performed until the time t4 when the wheel speed Vi fil The configuration is not limited to that shown in FIG. 5, and for example, as shown in FIG. 8, the changeover switch 63 is activated by multiplying the pseudo vehicle speed Vi by 0.85 using the H level output signal from the wheel speed fluctuation detection circuit 200. Alternatively, the changeover switch 63 may be switched from the output side of the multiplication circuit 61 that multiplies the pseudo vehicle speed Vi by 0.60 to the output side of the multiplication circuit 64 that multiplies the pseudo vehicle speed Vi by 0.60. In response to the H level output signal from the circuit 200, the output side of the subtraction circuit 65 that subtracts lokm/h from the pseudo vehicle speed Vi is switched to the output side of the subtraction circuit 66 that subtracts 20 k1ml/h't from the pseudo vehicle speed Vi. Also good. Furthermore, as shown in FIG. 10, the pseudo vehicle speed Vi is 0.8
After multiplying by 5, the output from the subtraction circuit 206 in the wheel speed fluctuation detection circuit 200 is further calculated as follows: ΔVwΔVw = Vw (
max ) -Vw(min) may be provided, and the output of this calculation circuit 67 may be used as the output of the target wheel speed generation circuit 6. That is, the target wheel speed generation circuit 6 outputs an H level output when the wheel speed fluctuation detection circuit 200 detects that the fluctuation in wheel speed within the pulse period of the self-propelled counter 204 has exceeded the constant value δ. It may be sufficient to generate a target wheel speed that is lower than the target wheel speed output during normal anti-skid control.

FIG. 11 is a block diagram showing an anti-skid control device employed in another example of the vehicle braking control system according to the present invention. In this example, the wheel acceleration/deceleration conditions, which are the EV multiplied signal AV multiplied signal output conditions in anti-skid control, are made variable based on the detection output of the wheel speed fluctuation detection circuit 200.

Its basic configuration is the same as that shown in FIG. 2, but in particular, depending on the detection output of the wheel speed fluctuation detection circuit 200 (the configuration is similar to that shown in FIGS. 3 and 4), An acceleration/deceleration setting value correction circuit 300 is provided which makes the reference deceleration for the comparison circuits 5 and 9 variable and the reference acceleration a for the comparison circuit 8 variable. The specific configuration of this acceleration/deceleration set value correction circuit 300 is shown in FIG. 12, for example. In the figure, 301 is a1 as described above in normal anti-skid control.
A predetermined acceleration a1 (for example, 1.0
302 is a second acceleration setter that has set an acceleration value al' (for example, 3.0 G) higher than the predetermined acceleration +1L1 (==, 1.0 G). Further, 303 is a first deceleration setter that sets a predetermined deceleration bl (for example, -1,0G) corresponding to the signal output condition as described above in normal anti-skid control, and 304 is a first deceleration setter that sets a predetermined deceleration bl (for example, -1,0G) Deceleration bl
(=-1,0G) Even higher deceleration value bx' (
For example, the second deceleration setting device is set to -3.0G). 305 is a reference acceleration value a for the comparison circuit 8;
Output from the first acceleration setter 301 (al=1.0
G) or the output from the second acceleration setter 302 (al
' = 3.0 G ) changeover switch, 306
is the reference deceleration value for comparison circuits 5 and 9, and
Output from deceleration setter 303 (b1=-1,0G
) or the output from the second deceleration setter 304 (bl'=
-3,0G), and the respective changeover switches 305 and 306 are used normally, that is, when the output of the wheel speed fluctuation detection circuit 200 is low, the first acceleration setter 301 side and the first 9, the second acceleration setter 302 side, and the second deceleration setter 304 when the output of the wheel speed fluctuation detection circuit 200 becomes H level. It is designed to switch to the side.

Note that the target wheel speed generation circuit 6 in this example always generates the target wheel speed Vw corresponding to the slip ratio λ0 at which the braking efficiency is maximized.

Vwo = Vi X O, 85 It is designed to output .

In a brake control system employing the anti-skid control device as described above, during braking, while the output of the wheel speed fluctuation detection circuit 200 is maintained at the L level, that is, within the pulse period of the self-running counter 204, When the wheel speed fluctuation is less than the constant value δ, the changeover switches 305 and 306 in the acceleration/deceleration setting value correction circuit 300 hold the first acceleration setter 301 side and the first deceleration setter 303 side, respectively. Therefore, the reference acceleration value for the comparator circuit 8 is al (
Since the reference deceleration value for comparison circuits 5 and 9 is bl (=-1.0G), normal anti-skid control is performed according to the control pattern shown in FIG.

On the other hand, when the wheel speed fluctuation within the pulse period of the self-running counter 204 exceeds a certain value δ due to wheel spin or driving on an uneven road, the output of the wheel speed fluctuation detection circuit 200 becomes H level. Acceleration/deceleration set value correction circuit 300
Each changeover switch 305, 306 in
The acceleration setter 302 side is switched to the second deceleration setter 304 side 9, and the reference acceleration value for the comparison circuit 8 is al'
(=3.0G), and the reference deceleration for comparison circuits 5 and 9 is bx' (=-3,0G), so
The pseudo vehicle speed Vi is not generated from the pseudo vehicle speed generating circuit 4 until the wheel deceleration reaches a deceleration b1' higher than the predetermined deceleration bl when the wheel speed returns. Therefore, the pseudo vehicle speed vi that occurs when the deceleration b1' is reached is at a lower level than that during normal anti-skid control under the same wheel condition, and accordingly, the target wheel speed Vwo is also lower than that during normal anti-skid control. Since the level is lower than that during control, it is difficult to reach the target wheel speed Vwo after recovery, as in the above embodiment.
That is, the brake hydraulic pressure system becomes difficult to perform pressure reduction control, and a no-brake state immediately after the anti-skid control starts when the wheel deceleration reaches b1' can be prevented as much as possible.

Moreover, since the reference values of wheel acceleration/deceleration for comparison circuits 5 and 8.9 each become larger, the pressure increase control region in the control pattern shown in FIG. 6 expands F) (b
(from l to al to bl' to al'), it becomes difficult to receive a signal to maintain braking pressure while driving on an uneven road, and the braking fluid is used as a substitute for brake operation.

FIG. 13 is a block diagram showing an anti-skid control device employed in still another example of the vehicle braking control system according to the present invention. In this example, the wheel speed fluctuation detection circuit 20
The pseudo vehicle speed Vi is made variable based on the detection output of 0.

Its basic configuration is the same as that shown in FIG. 2, but in particular, the pseudo vehicle speed generation circuit 4 is
00 (the configuration is similar to that shown in FIGS. 3 and 4), the wheel speed value at which the pseudo vehicle speed Vi is generated can be made variable. Basically, when the wheel deceleration reaches bl for the first time during braking, this pseudo vehicle speed generation circuit 4 generates a pseudo vehicle speed Vi with a predetermined slope (0,4G) from the detected wheel speed at that time. On the other hand, from then on, each time the wheel deceleration reaches bl, a straight line is drawn from the detected vehicle speed at that point, connecting the detected wheel speed and the detected wheel speed that is the point of occurrence of the first pseudo vehicle speed Vi. The configuration is shown in FIG. 14.

In the figure, 40a is an AND gate G between the inverted signal of the MR signal from the retriggerable timer 16 in FIG. 2 via the inverter G2 and the bl signal from the comparison circuit 5.
A sample hold circuit 40 extracts and holds the detected wheel speed from the wheel speed detection circuit 2 in synchronization with the AND signal from the wheel speed detection circuit 2;
b is a sample hold circuit that extracts and holds the detected wheel speed in synchronization with the b1 signal, 41 is a timer counter that increments at a predetermined period, and 40C is a sample and hold circuit that is synchronized with the output signal from the AND gate G1. a sample hold circuit that extracts and holds the numerical value of the timer counter 41;
40d is a sample and hold circuit that extracts and holds all the numerical values of the timer counter 41 in synchronization with the bl signal. 42
is a subtraction circuit that subtracts the sampled value ■ of the sample hold circuit 40b from the sampled wheel speed value ■0 of the sample hold circuit 40a, and 43 is the sample hold circuit 4
From the sampling value To of 0c, the sample hold circuit 4
A subtraction circuit that subtracts the sampling value Tb of 0d,
44 is a division circuit that divides the subtracted value (Vo - Vb) from the subtracting circuit 42 by the subtracted value (To - Tb) from the subtracting circuit 43. Further, 45 is a predetermined wheel speed slope signal;
For example, a slope generation circuit 46 generates a slope signal corresponding to 0.4G, and 46 is a slope signal from the slope generation circuit 45 and an operation output (Vo-vb) / (To
47 is a subtraction circuit for subtracting the output value from the timer counter 41 from the sampling value Tb(n) held in the sample hold circuit 40b, and 48 is a subtraction circuit 4γ for subtracting the output value from the timer counter 41.
49 is a multiplication circuit that multiplies the subtracted value from the division value from the division circuit 44 or the slope value from the slope generation circuit 45 via the changeover switch 46, and 49 is a multiplication circuit that multiplies the subtraction value from This is a subtraction circuit that subtracts the calculated value from the multiplication circuit 48 from the sampled wheel speed value in the hold circuit 40b or from the wheel speed value from a subtraction circuit 51, which will be described later. Then, 50 is set by the rising edge of the bl signal and the AND signal by the MR double signal AND gate G3, and the R37 lip 70 block (hereinafter simply referred to as FF50) is set by the falling edge of the MR double signal r'ff-h. The changeover switch 46 is configured to be switched to the slope generation circuit 45 side when the output Q of the FF 50 is at L level, and to the division circuit 44 side when the output Q is at H level. There is.

The subtraction circuit 51 is for subtracting a value equivalent to 5klll/h from the detected wheel speed value Vb sampled by the temple hold circuit 40b, and the changeover switch 52 is for subtracting a value equivalent to 5 klll/h from the detected wheel speed value Vb sampled by the temple hold circuit 40b. When the detection output is at L level, the sample and hold circuit 40b side is held, while when the detection output is at H level, it is switched to the subtraction circuit 51 side. Furthermore, 53 is a retriggerable timer that is activated every time the BL signal is input and outputs an H level signal for a predetermined time; 54 is an output value to the target wheel speed generation circuit 6; an output value from the subtraction circuit 49; Alternatively, the changeover switch 54 can be used to switch to the detected wheel speed value Vw from the wheel speed detection circuit 2. This changeover switch 54 holds the wheel speed detection circuit 2 side when the output from the retriggerable timer 53 is at the L level. Subtraction circuit 49 when the output is at H level
It is designed to switch to the side.

Next, the operation of this system will be explained. During normal sudden braking, anti-skid control is performed according to a control pattern as shown in FIG. Here, the specific operation of the pseudo vehicle speed generating circuit 4 in the process of this anti-skid control will be explained with reference to the timing chart shown in FIG. 15.

When braking is started and the wheel deceleration reaches the predetermined deceleration bl for the first time at time to, the sample and hold circuits 40 & 40b are activated in synchronization with the rise of the bt multiplied signal from the comparator circuit 5.
The detected wheel speed value from the wheel speed detection circuit 2 is Vb (0).
= sampled as Vo, and sample and hold circuit 40C in synchronization with the rising edge of the bx signal.
Count from time counter 41 at 40d @T
(0) =To is sampled. Furthermore, since the OAV signal is at the L level in the control device at this point, the FF 50 is not set, and the output Q of this FF 50 is held at the L level and the changeover switch 46 is set to the slope generation circuit 45 side. It has become. Then, as time elapses until the wheel deceleration reaches the predetermined value bl again, the subtraction circuit 4
7, the count value Tc corresponding to the elapsed time Tc = T - T (0) T: The output value of the time counter 41 is sequentially output, and this count value Tc and the slope value Ao (0) from the slope generation circuit 45 , 4G), the multiplier circuit 48 sequentially outputs a value oXTc corresponding to the speed reduction value. Furthermore, Vb (0) - Ao X Tc is outputted from the subtraction circuit 49 to the target wheel speed generation circuit 6 as the pseudo vehicle speed Vi.

That is, in the first skid cycle from when the wheel deceleration reaches the predetermined value b1 at time to until the wheel deceleration reaches the predetermined value b1 again, the slope Aot- is changed from the detected wheel speed value v(0) at time to. As a result, a pseudo vehicle speed vi having a decreasing characteristic is output.

Next, when the wheel deceleration reaches the predetermined value bx again at time t1, the detected wheel speed value Vbtll at that time is newly sampled in the sample and hold circuit 40b in synchronization with the bl signal, and at the same time time counter 41
The count value Tbtll from the same bl signal (synchronously,
Newly sampled n to the sample hold circuit 40d
Ru. Also, at this time, the MR from the retriggerable timer 16
The double signal is at H level, the AND gate G1 is disabled, the values vb(o) and Tb(0) in the sample and hold circuits 40a1 and 40c are further held, and the FF 50 is set. switch 4
6 is switched to the division circuit 44 side and held (this state continues thereafter). Here, from the subtraction circuit 42, the above time to
The difference value ΔVb (11ΔVb
(11=Vb (0) -Vb fil is output, and the subtraction circuit 43 outputs the above-mentioned time t.

The difference value ΔTb [11 ΔTb +11 = Tb (0) −Tb [1] between the counter value Tb (0) at time 11 and the counter value Tb (11) at time 11 is output, and these difference values ΔVNII and ΔTb (1+ The division circuit 44 calculates ΔVb[ll/ΔTb fil based on , and converts this calculated value Al from Vb (0) to ■
It is output as slope information leading to (1). Then, as time elapses until the wheel deceleration further reaches the predetermined value b1, a count value T corresponding to the elapsed time is output from the subtraction circuit 47.
c Tc = T Tb ill is outputted once, and the speed reduction value is output from the multiplication circuit 48 based on this count value Tc and the slope information A1 (A] = ΔVb 111/Tb 11+ ) from the division circuit 44. A value A1×Tc corresponding to the value A1×Tc is sequentially output. Further, the subtraction circuit 49 outputs Vb tll -AI X Tc as a pseudo vehicle speed.

That is, in the second skid cycle from when the wheel deceleration reaches the predetermined value b1 at time t until the wheel deceleration reaches the same value blVC again, the detected wheel speed value Vb at time 11
(Pseudo vehicle speed V with the characteristic of decreasing from li with slope AI
i will be output.

Similarly, every time the wheel deceleration reaches the predetermined value b1 in each skid cycle, the difference between the detected wheel speed value at that time and the first detected wheel speed value ■(0) under the same conditions and the time interval ( Calculate the slope information based on the count value) and
Next, until the wheel deceleration reaches the predetermined value b1, a pseudo vehicle speed Vi that decreases with the above-mentioned slope from the detected wheel speed value at that time is output.

On the other hand, before the above-described anti-skid control starts, the wheel speed fluctuation detection circuit 200
When the wheel speed fluctuation within the pulse period of the self-propelled counter 204 exceeds the constant value δ, the wheel speed fluctuation detection circuit 2
00 becomes H level, and the changeover switch 52 in the pseudo vehicle speed generation circuit 4 is switched to the subtraction circuit 51 side.

Thereafter, as the wheel speed returns, the wheel deceleration increases to a predetermined value bl.
When it reaches, the point of generation of the pseudo vehicle speed Vi is the detected wheel speed at that time, that is, during normal anti-skid control.j)5
km/h, and accordingly, the target wheel speed Vwo also becomes a lower level than that during normal anti-skid control.

As a result, as in the first embodiment, it is difficult for the wheel speed after the return I @ to reach the target wheel speed Vwo9. Therefore, immediately after the start of the anti-skid control that starts when the wheel deceleration reaches bl, A no-brake state can be prevented as much as possible.

In addition, the configuration of the pseudo vehicle speed generation circuit 4 may include, for example, the first
It may be arranged as shown in FIG. The basic configuration related to generating the pseudo vehicle speed is the same as that of the stripe diagram, but the sampling value in the sample hold circuit 40b is directly subtracted by the subtraction circuit without using the changeover switch 52 as shown in FIG. 4
9 (subtraction circuit 51 is also not required). Then, the first slope generating circuit 45a is set with the slope detailed information A1 (approximately 0.4 G) and the slope information Az, which has a value larger than the slope information A1 (approximately 1.0 G).
A second slope generation circuit 45b is provided, and the first and second slope generation circuits 45a and 45b are
Each output is connected via the changeover switch 46a to a contact that should be held when the FF 50 in the changeover switch 46 is at the L level. The changeover switch 46a holds the first slope generation circuit 45 side when the detection output of the wheel speed fluctuation detection circuit 200 is at the L level, and holds the side of the second slope generation circuit 45 when the detection output is at the H level. 45b side.

If the pseudo vehicle speed generation circuit 4 is configured as described above, when the wheel speed fluctuation within the pulse period of the self-running counter 204 in the wheel speed fluctuation detection circuit 200 becomes equal to or greater than the constant value δ due to wheel spin or the like, the wheel speed fluctuation is detected. The output of the detection circuit 200 becomes H level, and the changeover switch 46a in the pseudo vehicle speed generation circuit 4 is switched to the second slope generation circuit 45b.

Thereafter, as the wheel speed returns, the wheel deceleration increases to a predetermined value bl.
When K is reached, the pseudo vehicle speed Vi is output from the pseudo vehicle speed generation circuit 4.
However, in this case, the slope of the pseudo vehicle speed Vi is A2 (=1.0 G) which is larger than the slope d at the start of normal anti-skid control, that is, A1 (=0-4 G).
). As described above, when the slope of the pseudo i-speed Vi becomes larger than that at the start of normal anti-skid control, the slope of the target wheel speed Vwo also becomes larger than that at the start of normal anti-skid control. As a result, as shown in FIG. 17, the wheel speed after recovery is different from the target wheel speed Vwo (Vi' X O, 85) K.
Therefore, it is possible to prevent as much as possible a no-brake state immediately after the anti-skid control starts when the wheel deceleration reaches btK.

Furthermore, the retriggerable timer 53 in the pseudo vehicle speed generation circuit 4 is programmed with the time T1 (
For example, 2 seconds) and a time Tz smaller than this time T1
(for example, 0.5 seconds), and this retriggerable timer 53 is activated when the detection output of the wheel speed fluctuation detection circuit 200 is L.
It may be arranged to operate based on the above-mentioned time T1 when the detection output is at the H level, or to operate based on the above-mentioned time T2 when the detection output is at the H level. In this way, if anti-skid control is accidentally started during wheel spin as described above, the pseudo vehicle speed Vi is fixed to the wheel speed Vw immediately after the above time T2 (the target wheel speed Vwo is always lower than the wheel speed). pressure reduction control of the brake hydraulic pressure system is prohibited.

As in each of the above embodiments, when the detection output of the wheel speed fluctuation detection circuit 200 is at the H level, for example, the target wheel speed is directly changed to a low level, and the set value of the wheel deceleration, which is the condition for generating a pseudo vehicle speed, is changed. Change the wheel speed value that is the point at which the pseudo vehicle speed occurs to a lower value, change the slope of the pseudo vehicle speed to a larger value, or change the time at which the actual pseudo vehicle speed occurs to a shorter time. Since the target wheel speed, which is the upper limit condition for pressure reduction control of the brake fluid pressure system, is set to a low level, even if anti-skid control is started by mistake due to wheelspin, etc., the no-brake state immediately after the start is minimized. 200 operates all the time, that is, the peak hold circuits 201 and 202 operate virtually all the time, but the main purpose of the present invention is to provide a countermeasure against wheelspin during normal driving of the vehicle and immediately after driving on an uneven road. For this reason, the wheel speed fluctuation detection circuit 200 is configured such that, as shown in FIG. 18, for example, the peak hold circuits 201a and 202a are prohibited from substantially operating during a braking operation in which the brake pedal is depressed. Furthermore, as shown in FIG. 19, the peak hold circuits 201b and 202b may be substantially inhibited from operating during anti-skid control, that is, while the MR signal is being output.

Here, in FIG. 18, 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 source is fixed at the level E. For example, the OR signal of the collector output of the transistor Tr and the pulse signal from the free-running counter is input as a control signal to the analog switch 2220 in the peak hold circuit shown in FIG. Further, in FIG. 19, when the MR multiplied signal is at H level, the peak hold circuit 201b.

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

Furthermore, this wheel speed fluctuation detection circuit 200 is configured to detect, for example, the 20th
As shown in the figure, during anti-skid control, that is, when the MR multiplied signal is output, the pulse period of the free-running counter 204a is made shorter than during non-antiskid control, and the changeover switch 210 controlled by the MR multiplied signal is used for comparison. The reference value of the circuit 207 may be set to a value δ2 larger than the value δl during non-anti-skid control.

Furthermore, as is clear from FIG. 7, when the wheel speed changes rapidly due to wheel spin or the like, the wheel acceleration/deceleration also changes rapidly. As a result, fluctuations in wheel acceleration/deceleration may be used.

FIG. 21 is a block diagram showing an anti-skid control device employed in still another embodiment of the vehicle braking control system according to the present invention.

This embodiment detects fluctuations in wheel acceleration/deceleration, makes the output setting deceleration of the pseudo vehicle speed signal Vi variable, lowers the target wheel speed, and furthermore,
The condition of the wheel acceleration/deceleration, which is the condition for outputting the double signal AV double signal, is made variable. Of course, in practical use, it is better to select and use any one of the above three conditions, or even to design a design that has all of them. It will be explained below as follows.

In the figure, wheel speed sensor 1, wheel speed detection circuit 2, acceleration/deceleration detection circuit 3, pseudo vehicle speed generation circuit 4, comparison circuits 5, 7, 8.
, 9, AND gate 10, OR gate 11, Tryber 1
2, 13, the EV valve 14, the AV valve 15, the retriggerable timer 16, the pump 17, the pulse generator 18, and the AND gate 19 have the same configuration as in each of the previously described embodiments, and function in the same manner.

Reference numeral 400 indicates a wheel acceleration/deceleration variation detection circuit, which outputs a detection signal when the variation within a predetermined cycle of each detected acceleration/deceleration signal from the acceleration/deceleration detection circuit 3 exceeds a predetermined constant value δ. 3.4 in the first embodiment can be used as is by changing the input signal to the detected acceleration/deceleration signal Vw.
The wheel speed fluctuation detection circuit 200 shown in FIGS. In this example, the configurations shown in FIGS. 3 and 4 in the first example are used. The detection signal is then output to the acceleration/deceleration setting value correction circuit 300 and the target wheel speed generation circuit 6.

Reference numeral 300 indicates an acceleration/deceleration set value correction circuit, which has the same configuration as the acceleration/deceleration set value correction circuit shown in FIG. 12 in the second embodiment). It operates to make the reference acceleration a for the circuit 8 variable.

The target wheel speed generation circuit 6 has the above-mentioned configuration, for example, as shown in FIG. 5, and based on the pseudo vehicle speed Vi from the pseudo vehicle speed generation circuit 4, the slip ratio λ0 λo = 1 at which the braking efficiency is near the maximum is determined. - It outputs a target wheel speed Vwo which is a control target corresponding to (Vwo / Vi), and further increases the target wheel speed to km when the detection signal from the wheel acceleration/deceleration fluctuation detection circuit 400 becomes H level.
The vehicle speed value corresponding to /h is decreased. Of course, this target wheel speed generation circuit 6 is not limited to the one shown in FIG. As shown in , from the pseudo vehicle speed vi to lOkm/h or 20
Switching to a value that reduces km/h may also be used.

In the braking control system employing the anti-skid control device as described above, while the output of the wheel acceleration/deceleration fluctuation detection circuit 400 maintains the L level, that is, the wheel acceleration/deceleration is controlled within the pulse period of the self-running counter. In a state where the fluctuation is less than the constant value δ, the acceleration/deceleration set value correction circuit 300 is held on the first deceleration setter side, and the reference acceleration value for the comparison circuit 8 is al (=1.0 G), and the comparison The reference deceleration value for circuits 5 and 9 is bl (=-1,0G). Here, when braking is performed, when the deceleration exceeds the value of bl, the pseudo vehicle speed generation circuit 4 generates the pseudo vehicle speed Vi as usual, and the target wheel speed generation circuit 6 generates the normal value of Vi X O,85. A constant target wheel speed signal is generated, and normal anti-skid control is performed according to the control sequence shown in FIG.

On the other hand, if the wheel acceleration/deceleration changes exceed a certain value δ within the pulse period of the self-running counter due to wheel spin or driving on an uneven road (changes in the wheel acceleration/deceleration are more sensitive to changes in the wheel speed). ), wheel acceleration/deceleration fluctuation detection circuit 4.
00 becomes H level, each switch in the acceleration/deceleration set value correction circuit 300 is switched to the second acceleration setter side and the second deceleration setter side, respectively, and the reference acceleration for the comparison circuit 8 is set. The value is al' (=3.0 G
), the reference deceleration for comparison circuits 5 and 9 is b1'
(=-3,0G). Therefore, if braking is started here, the deceleration will be a deceleration b that is higher than the predetermined deceleration b1.
The pseudo vehicle speed Vi is not generated from the pseudo vehicle speed generation circuit 4 until the time when the pseudo vehicle speed Vi reaches 1'. Therefore, the pseudo vehicle speed vl that occurs when the deceleration b]' is reached is at a lower level than that during normal anti-skid control under the same wheel condition, and the target wheel speed Vwo is also at the normal value. (0,85X Vi) further 10k[l]/
Since h decreases, the target wheel speed Vwo decreases in a double sense, and the wheel speed becomes the target wheel speed Vw.

In other words, it becomes difficult for the brake fluid pressure system to enter the pressure reduction mode in the control pattern shown in Figure 6, which prevents unnecessary pressure reduction control caused by uneven road surfaces, and improves braking performance on uneven road surfaces. can be improved.

Furthermore, since the reference values of the acceleration/deceleration toward the console 41 for the comparison circuits 8 and 9 become larger, the pressure increase control region in the control pattern shown in FIG. 6 expands p (from bl or al to bl' or a1' ), it becomes difficult to receive a signal to maintain the brake pressure while driving on an uneven road, and the brake fluid pressure can be increased sufficiently in response to brake operation.

Moreover, in this embodiment, since the irregular road is detected by the fluctuation of wheel acceleration/deceleration, it is possible to provide a feature that allows the irregular road to be recognized more reliably.

〔Effect of the invention〕

As described above, according to the present invention, the wheel speed, the wheel acceleration/deceleration, or the fluctuation range of the signal that increases the wheel speed is detected, and the wheel Since the threshold value for comparison calculation of acceleration/deceleration and/or slip ratio is changed, even if anti-skid control is started by mistake due to wheel spin or driving on an uneven road, the no-brake state will occur immediately after the start of anti-skid control. It becomes possible to prevent this as much as possible, and it becomes possible to realize a safer Annaskind control device.

[Brief explanation of drawings]

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 adopted in the brake control system according to the present invention, and FIG. 2 is a block diagram showing an example of a specific configuration of the vehicle 1 theoretical speed fluctuation detection circuit, FIG. 4 is a block diagram showing an example of a specific configuration of the peak hold circuit in FIG. 3, and FIG. 6 is an explanatory diagram showing the control mode of the brake fluid pressure by the anti-skid control device shown in FIG. 2, and FIG. 7 is a block diagram showing a specific configuration of the target wheel speed generation circuit in FIG. FIG. 5 is a timing chart showing the operation of the control system, FIGS. 8 to 10 are block diagrams showing other examples of specific configurations of the 4J vehicle speed generation circuit in FIG. 2, and FIG. 11 is a timing chart showing the operation of the control system shown in FIG. A block diagram showing another example of the anti-skid control device employed in the braking control system according to the present invention, FIG. 12 shows an example of a specific configuration of the acceleration/deceleration set value correction circuit in FIG. 11. Block diagram, FIG. 13 is a block diagram showing still another example of the anti-skid control device employed in the brake control system according to the present invention, and FIGS. 1 and 1 are specific configurations of the pseudo vehicle speed generation circuit in FIG. 13. An example of the block diagram shown in FIG. 15 is a timing chart showing the operation of the pseudo vehicle speed generation circuit shown in FIG. 4 during anti-skin control;
FIG. 16 is a block diagram showing another example of the specific configuration of the pseudo vehicle speed generation circuit in FIG. Explanatory diagrams showing the operation when the circuit is adopted, Figures 18 to 20 are shown in Figure 2, Figure 11, and Figure 13.
FIG. 21 is a block diagram showing another example of the specific configuration of the wheel speed fluctuation detection circuit according to the present invention, and FIG. Figure 22 shows the friction coefficient μ between the wheels and the road surface.
Graphs showing the relationship between the slip rate λ and the slip ratio λ, FIG. 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... Eye, talking wheel speed generation circuit 12.13... Driver 14... Inflow valve (EV valve) 15... Outflow valve (A
V valve) 16... Retriggerable timer 17... Pump 61... Multiplier circuit 62... Arithmetic circuit 63
...Selector switch 200...Wheel speed fluctuation detection circuit 201.202...Peak hold circuit 203.20
5... Inverting circuit 204... Self-running counter 206.
...Subtraction circuit 207...Comparison circuit 208...
Timer 209...or gate 220.221
...Buffer 222...Analog switch

Claims (11)

[Claims] (1) In an anti-skid control device that determines each control mode of increasing, decreasing, and/or maintaining brake fluid pressure based on a comparative calculation of wheel acceleration/deceleration and/or slip ratio,
a fluctuation detection means for detecting wheel speed, wheel acceleration/deceleration, or a fluctuation range of a signal based on the wheel speed; and a changing means for changing the threshold value of the comparison calculation so as to reduce the control response according to the detection output of the fluctuation detection means. An anti-skid control device characterized by being provided with. (2) The anti-skid control device according to claim 1, wherein the changing means changes the set deceleration value used in the control mode comparison calculation to a larger deceleration value. (3) The anti-skid control device according to claim 1, wherein the changing means changes the set acceleration value used in the control mode comparison calculation to a larger acceleration value. (4) The anti-skid according to claim 1, wherein the changing means changes the set deceleration value for generating the pseudo vehicle speed used for calculating the slip ratio to a larger deceleration value. Control device. (5) The changing means changes the value of the slip ratio (amount) used in the comparison calculation of the control mode to a value of a larger slip ratio (amount). Skid control device. (6) The anti-skid according to claim 1, wherein the changing means sets the generation point of the pseudo vehicle speed used for calculating the slip ratio to a wheel speed lower than the wheel speed at which the set deceleration occurs. Control device. (7) The anti-skid control device according to claim 1, wherein the changing means changes the slope of the pseudo vehicle speed used for calculating the slip ratio to a larger value. (8) The anti-skid control device according to claim 1, wherein the changing means sets a generation time of the pseudo vehicle speed used for calculating the slip ratio to a shorter time. (9) The anti-skid control device according to any one of claims 1 to 8, wherein the fluctuation detection means operates only when braking is not applied. (10) The anti-skid control device according to any one of claims 1 to 8, wherein the fluctuation detection means stops when anti-skid operation starts. (11) The fluctuation detection means is characterized in that the fluctuation width of the wheel speed or wheel acceleration/deceleration is made different between when the anti-skid is not activated and when the anti-skid is activated. 9. The anti-skid control device according to claim 8.