JPH09301148A - Anti-skid control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent instability of anti-skid control caused by variation of a road surface μ, unevenness of the road surface, or vehicle turning and an error in tire diameter. SOLUTION: At the time of increasing and adjusting the brake fluid pressure in anti-skid control, the brake fluid pressure is increased pulsatively in she case where a correction integrated value ΣS** (S1808) including a value ΣSX** obtained by integrating a slip rate deviation ΔSW** (S1804) exceeds a determination value KSI ('yes' in S1812). Accordingly, even when the slip state is temporarily switched to the state of increasing and adjusting the brake fluid pressure due to a little variation of road surface μor the unevenness of the road surface, the brake fluid pressure is not increased instantaneously, so than stable anti-skid control is enabled. Furthermore, as the period when the correction integrated value ΣS** exceeds the determination value KSI (S1812) becomes shorter according to the increase gradient of the correction integrated value ΣS**, the high and low speed of change of slip rate can be suitably managed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is characterized by adjusting a brake fluid pressure for applying a wheel braking force to a wheel so that an appropriate slip ratio can be obtained according to a slip state of the wheel during vehicle braking. The present invention relates to an anti-skid control device.

[0002]

2. Description of the Related Art Conventionally, a vehicle is controlled by detecting a slip ratio of each wheel at the time of braking of a vehicle and reducing, increasing, and holding brake fluid pressure of each wheel according to the detected slip ratio. 2. Description of the Related Art An anti-skid control device that controls a slip ratio (generally, about 10% to 20%) that can be safely and quickly braked is known.

In such control, if the wheel acceleration is negative when the slip ratio exceeds a target slip ratio (for example, 15%) during braking, the brake fluid pressure of the wheel is reduced, If the acceleration is other than minus, the process of holding the brake fluid pressure of the wheel is performed, and if the target slip ratio is less than, the process of increasing the brake fluid pressure of the wheel is performed. In addition,
Thus, instead of directly comparing the actual slip ratio and the target slip ratio, the actual slip ratio may be compared with a physical quantity corresponding to the slip ratio, for example, wheel speed (rotation speed). That is, the target wheel speed corresponding to the target slip ratio is calculated,
The target wheel speed and the actual wheel speed may be compared.

[0004]

As described above, the increase / decrease / holding of the brake fluid pressure is controlled by comparing the values such as the target slip ratio and the target wheel speed with the actual wheel slip ratio or the wheel speed. Therefore, if the wheel speed is disturbed by a slight change in the friction coefficient (hereinafter referred to as μ) of the road surface during braking, the comparison judgment with the target slip ratio and the target wheel speed is immediately affected, and the anti-skid There was a problem of unstable control.

This also means that even when the road surface is a bad road, the wheel speed is disturbed due to the unevenness of the road surface, or when the wheel speed is disturbed when the vehicle is turning or due to an error in the tire diameter, the anti-skid control is also performed. There was a problem that became unstable. The present invention prevents the instability of the antiskid control caused by a slight fluctuation of the road surface μ, the unevenness of the road surface or the error of the vehicle turning or the tire diameter, and an antiskid control device that enables stable antiskid control is provided. The purpose is to provide.

[0006]

Means for Solving the Problems and Effects of the Invention The anti-skid control device of the present invention is designed to obtain an appropriate slip ratio according to the slip state integrated value obtained by integrating the slip states of the wheels during vehicle braking. It is characterized in that the brake fluid pressure that gives the wheel braking force to the wheels is adjusted.

That is, the judgment is not made based on the slip state of the wheel itself, but the slip state is repeated and integrated, and as a result of the integration, an integrated value determined to be a slip state in which the brake fluid pressure should be adjusted is obtained. If so, adjust the brake fluid pressure. For this reason, the brake fluid pressure is not adjusted immediately by a mere one-time determination of the slip state, and the brake fluid pressure is not adjusted until it is determined that the brake fluid pressure should be adjusted based on the integrated result of the slip state. I am adjusting.

That is, even if the slip state temporarily becomes a state where the brake fluid pressure should be adjusted due to a slight fluctuation of the road surface μ, unevenness of the road surface, vehicle turning, or an error in tire diameter, the brake fluid pressure is immediately adjusted. Since it is not performed, instability of anti-skid control is prevented, and stable anti-skid control is possible.

A more specific structure of the anti-skid control device of the present invention will be described. A brake fluid pressure generating means for generating a brake fluid pressure according to a braking operation state by an occupant and the brake fluid pressure generating means are provided. Wheel braking force generation means for generating a braking force on a wheel in response to brake fluid pressure, wheel speed detection means for detecting a wheel speed at the wheel, and wheel speed detection for optimally adjusting a braking state of the wheel And a brake fluid pressure adjusting means for adjusting the brake fluid pressure applied to the wheel braking force generating means in accordance with the slip state integrated value obtained by integrating the slip state of the wheel obtained based on the wheel speed detected by the means. The configuration can be mentioned.

Here, in order to optimally adjust the braking state of the wheel, the brake fluid pressure adjusting means integrates the slip state of the wheel obtained based on the wheel speed detected by the wheel speed detecting means. Since the brake hydraulic pressure applied to the wheel braking force generating means is adjusted according to the state integrated value, the above-described operational effects can be achieved.

In adjusting the brake fluid pressure described above, first, the slip ratio of the wheel obtained based on the wheel speed detected by the wheel speed detecting means or the value of the physical quantity corresponding to the slip ratio is evaluated. When it is determined that the brake hydraulic pressure needs to be changed, the brake hydraulic pressure may be changed according to the slip state integrated value obtained by integrating the slip states of the wheels. The determination that it is necessary to change the brake fluid pressure to the wheels may be made based on, for example, the slip ratio itself, or may be made using the wheel speed, which is one of the physical quantities corresponding to the slip ratio. . Since the actual adjustment of the brake fluid pressure thereafter is performed according to the slip state integrated value, the above-described effects can be obtained.

In particular, if the fluctuation in the brake fluid pressure is a fluctuation in the increasing direction, the braking force may rapidly increase due to a slight fluctuation of the road surface μ, unevenness of the road surface, a vehicle turning, or an error in the tire diameter. Since the braking force is prevented and the braking force is gently increased, it becomes easy to maintain the actual slip ratio (actual slip ratio) near the target slip ratio.

More specifically, when the slip state integrated value exceeds a predetermined value, the adjustment for increasing the brake fluid pressure is performed in a pulsed manner, and the slip state integrated value is cleared to newly add a pulse. It may be performed by repeating the increasing process (exemplified as the process of FIG. 8 in the embodiment).

By limiting the number of repetitions of the pulse increasing process to a predetermined number, a more appropriate amount of brake fluid pressure can be increased. In addition, the slip state integrated value (illustrated as the slip ratio deviation integrated value ΣSX ** in the embodiment) is further added with the fluctuation associated with the rough road (illustrated as the rough road index B ** (n) in the embodiment). As a result, instability due to a rough road can be prevented. The fluctuations associated with the rough road include, for example, the average wheel acceleration (illustrated as the filtered wheel acceleration dVW ** in the embodiment) and the actual wheel acceleration (the wheel acceleration dV before the filter in the embodiment) in a predetermined period.
It can be set based on the deviation from X **). It should be noted that the value obtained by adding the variation due to the rough road to the slip state integrated value is exemplified as the corrected integrated value ΣS ** in the embodiment.

Examples of the above-mentioned slip state include a deviation between the target slip rate and the actual slip rate (exemplified as slip rate deviation ΔSW ** in the embodiment). In addition, a deviation between a target wheel speed, which is a physical quantity corresponding to the target slip rate, and an actual wheel speed, which is a physical quantity corresponding to the actual slip rate, may be used.

Further, the slip state may be the reciprocal of the actual slip ratio or the reciprocal of the difference between the vehicle body speed and the actual wheel speed. This has the advantage that it can be set regardless of the target slip. That is, as the slip becomes larger, the slip state in this case becomes smaller, and the integrated value becomes smaller, so that the pressure increase is delayed and the purpose can be qualitatively achieved.

When the vehicle is provided with a plurality of wheels, for example, the above-mentioned anti-skid control device is provided for each wheel, and each slip ratio of the wheels is based on the estimated vehicle body speed and each wheel speed. Is calculated as follows.
Here, the estimated vehicle body speed may be common to each wheel, but based on the vehicle body speed estimated from the behavior of all wheels (exemplified as vehicle body speed VB common to all four wheels in the embodiment) and each wheel speed. The estimated vehicle body speed provided for each wheel (illustrated as the vehicle body speed VBW ** for each of the four wheels in the embodiment) may be obtained. By using the estimated vehicle body speed provided for each wheel, more precise control can be performed for each wheel in the above-described anti-skid control.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing the overall configuration of an anti-skid control device according to an embodiment to which the present invention is applied. The present embodiment is an example in which the present invention is applied to a four-wheeled vehicle of a front engine / front drive system.

As shown, the right front wheel (FR) of the vehicle
1, each of the left rear wheel (RL) 2, the right rear wheel (RR) 3 and the left front wheel (FL) 4 generates a pulse signal (rotation speed signal) corresponding to the rotation of each wheel 1 to 4, Rotational speed sensors 5, 6, 7, 8 of electromagnetic type or magnetic resistance type are provided. Further, each of the wheels 1 to 4 is provided with a brake device 11, 12, 13, and 14 which receives the brake fluid pressure from the master cylinder 16 and brakes each of the wheels 1 to 4, respectively. Brake fluid pressure from the master cylinder 16 is applied to the wheel cylinders in
It is sent via the actuators 21, 22, 23, 24 and the brake hydraulic pressure lines.

Further, the brake pedal 25 for generating the brake fluid pressure from the master cylinder 16 is provided with a stop switch 26 which detects the stepped state of the brake pedal 25 and outputs an ON signal during braking and an OFF signal during non-braking. ing. In the present embodiment, the brake fluid pressure from the master cylinder 16 is applied to the actuator 21 of each wheel 1 to 4.
Brake fluid pressure lines for leading to the right front wheel 1 and the left rear wheel 2 and the right rear wheel 3 and the left front wheel 4
It is a so-called X pipe, which is separated into two systems including a brake hydraulic pressure line for use.

Next, each of the actuators 21 to 24 is composed of an electromagnetic three-position valve. When not energized, the actuators 21 to 24 are in the A position, and the brake fluid pressure conduits from the master cylinder 16 to the brake devices 11 to 14 of the wheels 1 to 4 are communicated with each other, and the brake devices 11 to 14 are connected. Brake fluid pressure (so-called wheel cylinder pressure, hereinafter also simply referred to as W / C pressure) is increased by the brake fluid pressure from the master cylinder 16.

During energization, the B position or C position is switched according to the current level. When the B position is reached by energization, the brake fluid pressure lines are cut off to maintain the W / C pressures of the brake devices 11 to 14 in the current state. The brake fluid in the wheel cylinder 14 is released to the reservoirs 28a and 28b provided for each of the two systems of brake fluid pressure conduits, and the brake devices 11 to 14 are released.
The W / C pressure of is reduced.

The actuators 21 to 24 described above
Is switched to the C position (decompression position) once during the anti-skid control by the operation of the electronic control unit 40 to release the brake fluid in the wheel cylinders of the brake devices 11 to 14 to the reservoirs 28a and 28b. 28
When a and 28b are full, the pressure cannot be reduced. Therefore, between the brake fluid pressure lines on the reservoir 28a, 28b side and the brake fluid pressure line on the master cylinder 16 side, the reservoirs 28a, 28b side are driven by the electric motor. Motor pump 27 that pumps the brake fluid from the master cylinder 16 side
a, 27b are provided.

Next, the electronic control unit 40 for controlling each of the actuators 21 to 24 to any one of the pressure increasing position, the pressure reducing position and the holding position is composed of a microcomputer including a CPU, a ROM, a RAM, an input / output interface and the like. When the ignition switch (not shown) is turned on, it receives power and operates. That is, the electronic control unit 4
0 receives signals from the rotation speed sensors 5 to 8 of the wheels and the stop switch 26, performs arithmetic processing for antiskid control based on these signals, and switches the valve positions of the actuators 21 to 24. .

The arithmetic processing executed by the electronic control unit 40 for anti-skid control will be described below with reference to FIG.
~ It demonstrates according to the flowchart shown in FIG. As shown in FIG. 2, when the electronic control unit 40 is activated, first, S
At 1000 (S: represents step), initialization processing such as memory clear and flag reset is performed, and then S11
00, the subsequent calculation processing is performed for a predetermined time Ta (for example, 5 m
In order to execute each time s), it waits until the predetermined time Ta elapses by determining whether or not the predetermined time Ta elapses.

When it is determined that the predetermined time Ta has elapsed ("YES" in S1100), the process proceeds to S1200, in which the wheels 1 to 4 are driven based on the rotation speed signals from the rotation speed sensors 5 to 8. Each rotation speed (hereinafter, referred to as wheel speed) VW ** (VWFR, VWRL, VWRR, VWFL is a general term. "**" is a general term for symbols FR, RL, RR, FL indicating each wheel. FR, RL, RR, and FL are values for the right front wheel 1, the left rear wheel 2, the right rear wheel 3, and the left front wheel 4, respectively.), And in subsequent S1300, as shown in FIG. First, in S1310, the rotational acceleration (hereinafter, referred to as wheel acceleration) dVX ** of each of the wheels 1 to 4 is calculated based on the calculated wheel speed VW ** as in the following Expression 1.

[0027]

[Equation 1]

Next, in S1320, a filtering process for averaging the wheel acceleration dVX ** for a predetermined period (here, the period from n to n-3) is performed as shown in the following equation 2, and the wheel acceleration after filtering is performed. Calculate dVW **.

[0029]

[Equation 2]

In Expressions 1 and 2, n represents the current processing timing, n-1 represents the previous processing timing, n-2 represents the processing timing of the previous two times, and n-3 represents the processing timing of the previous two times. There is. The same applies to other expressions. Next, in S1400, the vehicle body speed VB common to the four wheels is calculated as shown in FIG. First, in S1410, the following equation 3
The maximum wheel speed VSW of the four wheels is obtained as shown in FIG.

[0031]

(Equation 3)

Here, MAX () represents an operator for obtaining the maximum value among the values in (). Then, in S1420,
It is determined whether the anti-skid control is being performed. If anti-skid control is in progress (“YES” in S1420), S1
At 430, the upper limit acceleration KU is set to K2 (for example, 2.0).
G) is set. If anti-skid control is not in progress (S
1420 “NO”), S1440 upper limit acceleration KU
Is set to K1 (for example, 0.5 G).

Next, in S1450, as in the following equation 4,
The vehicle speed VB common to the four wheels is calculated.

[0034]

(Equation 4)

Here, MED () represents an operator for finding an intermediate value among the values in (). The lower limit acceleration KD is set to, for example, 1.2G. Next, in S1500, 4
The vehicle body speed VBW ** of each wheel is calculated as shown in FIG. First, in S1510, the vehicle body acceleration dVB common to the four wheels is calculated as in the following Expression 5.

[0036]

(Equation 5)

Next, in S1520, it is determined whether the vehicle body acceleration dVB is negative. If the vehicle body acceleration dVB is negative (“YES” in S1520), the value of the vehicle body acceleration dVB is cleared in S1530, and the process proceeds to S1540. If the vehicle body acceleration dVB is not negative (S15)
If “20” is “NO”), the process directly proceeds to S1540.

In S1540, the vehicle body deceleration side guard value KDW is set as in the following equation (6).

[0039]

(Equation 6)

Here, the correction value KG1 is set to 0.1 G, for example. Next, in S1550, it is determined whether or not anti-skid control is in progress. If anti-skid control is in progress (“YES” in S1550), a predetermined value K4 (for example, 2.0 G) is set to the vehicle body acceleration side guard value KUW in S1560, and if anti-skid control is not in progress (“NO” in S1550). )), The vehicle body acceleration side guard value KUW in S1570
Is set to a predetermined value K3 (for example, 0.5 G).

Next, in S1580, the vehicle body speed VBW ** for each wheel is calculated as shown in the following equation (7).

[0042]

(Equation 7)

Next, in S1600, the slip ratio SW ** for each wheel is calculated as shown in FIG. That is, S
At 1610, the slip ratio SW ** is calculated as in the following Expression 8.

[0044]

(Equation 8)

Next, in S1700, control mode calculation for anti-skid control is performed for each wheel as shown in FIG. First, in S1702, it is determined whether or not the in-control mode has been set for the target wheel 1, 2, 3 or 4 and anti-skid control (brake hydraulic pressure control) has already been executed. If the in-control mode is not set (“NO” in S1702), S
At 1704, the slip ratio SW ** of the wheel obtained at S1600 is set to the preset first target slip ratio KS0.
(For example, 20%) is exceeded, and if the slip ratio SW ** does not exceed the first target slip ratio KS0 (“NO” in S1704), the brake fluid pressure control for the wheel is executed. Since it is not necessary, the in-control mode is reset in S1706, and in S1708, the pressure increasing mode for holding the actuator at the position A (pressure increasing position) shown in FIG. 1 is set, and the process ends. .

On the other hand, in S1704, the slip ratio SW **
Is determined to have exceeded the first target slip ratio KS0 (“YES” in S1704), it is determined that the wheels have started to slip excessively, and it is necessary to execute the brake fluid pressure control. Set the medium mode. Then, after the control mode is set in S1710 or when it is determined in S1702 that the control mode is currently in progress, the process proceeds to S1712, and the slip ratio SW ** of the wheel is the second target slip. It is determined whether or not the rate KS1 (for example, 15%) is exceeded.

At S1712, the slip ratio SW ** is set to the second value.
If it is determined that the target slip ratio KS1 has been exceeded (S
1712, “YES”), the process proceeds to S1714, and S13
Whether or not the wheel acceleration dVW ** of the wheel calculated in 00 is not decelerated by the brake fluid pressure control so that the changing direction of the wheel speed VW ** is reversed from the deceleration direction to the acceleration direction. That is, it is determined whether or not the acceleration is smaller than zero (0G).

Then, in S1714, the wheel acceleration dV
If W ** is smaller than 0G and it is determined that the wheel speed VW ** is in the decelerating direction (“YES” in S1714), S1 is set.
In step 716, the actuator is controlled to the C position (pressure reducing position) shown in FIG. 1 to set the pressure reducing mode for reducing the W / C pressure of the brake device, and the process ends.

On the other hand, in S1714, the wheel acceleration dVW
** becomes 0 G or more, and when it is determined that the changing direction of the wheel speed VW ** is from the deceleration direction to the acceleration direction (S1
If “NO” in step 714), the process advances to step S1718 to set a holding mode for holding the W / C pressure of the brake device by controlling the actuator to the B position (holding position) shown in FIG. 1 and ending the processing. To do.

Next, in S1712, the slip ratio S
When it is determined that W ** is less than or equal to the second target slip ratio KS1 (“NO” in S1712), S172
After shifting to 0, the actuator is pulse-wise changed from the B position (holding position) shown in FIG. 1 to the A position (pressure increasing position) to increase the W / C pressure of the brake device according to the change. It is determined whether or not the control in the pulse increasing mode for gradually increasing the pressure in a pattern has been executed a predetermined number of times (a predetermined pattern).

Then, in S1720, when it is determined that the control in the pulse increasing mode has been executed for the predetermined pattern (S1720).
1720, "YES"), assuming that the slip of the wheel is completely suppressed, and that the wheel hardly slips even after the brake fluid pressure control is finished, S1
In step S170, the control mode is reset and the process proceeds to step S170.
After the pressure increase mode is set at 8, the process ends.

On the other hand, if it is determined in S1720 that the control in the pulse increasing mode has not been executed for the predetermined pattern ("NO" in S1720), the pulse increasing mode is set as the control mode for the wheel in S1722. Then, in step S1800, a pulse increase mode calculation for determining the pressure increase pulse output request timing is performed for each wheel, and then the process ends.

The process of S1800 is shown in FIG. First, in S1802, the target slip ratio KTSW (for example, 12%) and the slip ratio S of the target wheel obtained in S1610.
The slip rate deviation ΔSW ** from W ** is calculated by the following equation 9.

[0054]

[Equation 9]

Next, in S1804, the slip ratio deviation Δ
The integration process of SW ** is performed as in the following Expression 10.

[0056]

(Equation 10)

Here, ΣSX ** is the slip ratio deviation ΔSW.
Indicates the integrated value of **. Next, in S1806, the rough road index B ** (n) indicating the unevenness of the road is calculated as shown in the following Expression 11.

[0058]

[Equation 11]

Next, the rough road index B calculated in S1808
Based on ** (n), the slip ratio deviation integrated value ΣSX ** is corrected to obtain a corrected integrated value ΣS ** as in the following Expression 12.

[0060]

(Equation 12)

Here, K is a correction coefficient and is set to 1, for example. Next, in S1810, the count upper limit value KTM for setting the interval of the boosting pulse output within a predetermined range.
Counter CT for timing rather than AX (for example, 1000 ms)
It is determined whether the value of ** is large. If not larger (“NO” in S1810), it is determined in S1812 whether the correction integrated value ΣS ** is larger than the determination value KSI (for example, 100) that determines the pressure boosting pulse output.

If the corrected integrated value ΣS ** is less than or equal to the judgment value KSI ("NO" in S1812), it is determined that the actual slip ratio of the wheel is not yet sufficiently small to increase the pulse pressure, and the output is held in S1814. A request set is made.
Then, in step S1816, the clock counter CT ** is incremented and the processing is terminated.

The clock counter CT ** has the count upper limit value K.
The correction integrated value ΣS ** is the judgment value K before it exceeds TMAX.
If SI is exceeded (“YES” in S1812), S
At 1818, a count lower limit value KTMIN (for example, 50 m) for setting the pressure increase pulse output interval within a predetermined range.
It is determined whether the value of the clock counter CT ** is larger than that in s). If it is larger ("YES" in S1818),
In step S1820, the pressure increase pulse output request is set, and subsequently, in step S1822, the slip ratio deviation integrated value ΣSX ** and the clock counter CT ** are cleared, and the processing is temporarily ended.

If it is determined to be "YES" in S1810 before being determined to be "YES" in S1812, it is also "YES" in S1818.
At 0, the boost pulse output request is set. Therefore, it is possible to prevent a situation in which the required pressure increase is not performed because the interval between the pressure increase pulse outputs becomes too long due to some cause of noise.

Even if "YES" is determined in S1812, if "NO" is determined in S1818, S1 is set.
The flow shifts to 814 and the hold output state is maintained. Therefore, it is possible to prevent an abnormality such that the pressure increase of the brake fluid pressure cannot be followed mechanically due to the pressure increase pulse output being performed at an excessively short interval due to some noise-like cause.

When the processing of S1700 is completed, next, S1
At 900, braking devices 12, 13 for the left and right rear wheels 2, 3
S1100 is executed again by performing low-select control for simultaneously controlling the above according to the slip state of the rear wheels having a large slip tendency.
Return to Next, FIG. 9 drives the actuators 21 to 24 of the wheels 1 to 4 respectively according to the control mode of the wheels 1 to 4 set by the series of processes in S1700 to brake the wheels 1 to 4. To control the W / C pressure of each of the devices 11 to 14, a predetermined time (for example, 1 ms) Tb
It represents the interrupt processing executed by each timer interrupt.

In this interrupt processing, first in S2010, the control mode of the right front wheel (FR) 1 is read, and in accordance with this control mode, the solenoid of the actuator 21 is driven with the drive output shown in FIG. The valve position is controlled according to the control mode. Further, in subsequent S2020 and thereafter, similarly to this S2010, the drive output (S2020) to the actuator 24 of the left front wheel (FL) 4 and the actuator 2 of the right rear wheel (RR) 3 are performed.
3 drive output (S2030), left rear wheel (RL) 2
Drive output of the actuator 22 (S2040)
Are sequentially executed to end the interrupt processing.

FIG. 10 shows the drive output to the solenoid of the actuator in the pressure increasing mode, the pressure reducing mode, the holding mode and the pulse increasing mode in this embodiment. That is, when the pressure increasing mode is set as the control mode, the pressure increasing output, that is, the energization of the solenoid is prohibited and the actuator is fixed at the pressure increasing position A.

When the pressure reducing mode is set, the pressure reducing output and the holding output are alternately and repeatedly output. That is, a predetermined current for pressure reduction is supplied to the solenoid for a predetermined time TD (for example, 15 ms), and then a holding current is supplied to the solenoid for a predetermined time TH (for example, 15 ms). Switch to and alternately. In the decompression mode, the decompression output may be continuously output. That is, the actuator may be maintained at the reduced pressure position C.

When the holding mode is set, the holding output, that is, a predetermined current for holding is continuously applied to the solenoid to fix the actuator at the holding position B. When the pulse increase mode is set, at the timing when the pressure increase pulse output request set is made in S1820,
A predetermined current for increasing pressure is supplied to the solenoid for a predetermined time KU (for example, 3 ms) to set the actuator to the pressure increasing position A,
Thereafter, a predetermined holding current is supplied to the solenoid to set the actuator to the holding position B until the next pressure increase pulse output request is set in S1820.

The boosting pulse output is limited to a predetermined number of times (for example, 10 times) as a pulse boosting mode pattern and the number of pulse outputs. Therefore, when the boosting pulse is output a predetermined number of times ("YE" in S1720).
S "), the control mode is reset in S1706,
Returning to the setting of the pressure increasing mode in S1708.

FIG. 11 shows an operation example of the above-mentioned control. In this example, when the rough road index B ** (n) = 0, the timing chart is shown when the pulse increasing mode is changed to the pressure reducing mode during the anti-skid control. That is,
Up to time t1, the slip ratio deviation integrated value ΣSX ** gradually increases in a wavy manner by the integrating process of S1804, and further, S18.
The correction integrated value ΣS ** gradually increases in a wavy shape by the correction process of 08. The correction integrated value ΣS at time t1 when the clock counter CT ** is larger than the count lower limit value KTMIN.
When ** exceeds the determination value KSI ("YES" in S1812, "YES" in S1818), S1820 is executed, and the pressure-increasing pulse is output to the solenoid sol. As a result, the braking device 1 for the corresponding wheel
W / C pressure PW / C ** of 1 to 14 rises a little.

Next, in S1822, after the slip ratio deviation integrated value ΣSX ** and the timing counter CT ** are cleared, “YES” in S1702 and “NO” in S1712.
And if the condition of "NO" continues in S1720,
Again, the slip ratio deviation integrated value ΣSX ** gradually increases wavy by the integration processing of S1804, and the correction integrated value ΣS ** gradually increases wavy by the correction processing of S1808. Then, the clock counter CT ** displays the count lower limit value KT.
When the corrected integrated value ΣS ** exceeds the determination value KSI at time t2 in the state of being larger than MIN, S1820 is executed and the pressure increasing pulse is output to the solenoid. As a result, the W / C pressure PW /
C ** rises a little more.

Then, again, by the integrating process of S1804, the slip ratio deviation integrated value ΣSX ** gradually increases in a wavy manner,
When the correction integrated value ΣS ** gradually increases like a wave due to the correction process of S1808, the slip ratio S is increased in S1712.
When it is determined that W ** exceeds the second target slip ratio KS1 ("YES" in S1712), the process proceeds to S1714, and the wheel acceleration dV of the wheel calculated in S1300.
W ** indicates whether or not the deceleration of the wheel is suppressed by the brake fluid pressure control so that the changing direction of the wheel speed VW ** is not reversed from the deceleration direction to the acceleration direction, that is, zero acceleration (0G).
It is determined whether the wheel acceleration is smaller than
If it is determined that W ** is smaller than 0G and the wheel speed VW ** is changing in the deceleration direction (“YE” in S1714).
S ”) and S1716, the actuator is moved to the position shown in FIG.
The pressure reduction mode is set to control the C position (pressure reduction position) shown in to reduce the W / C pressure of the brake device. Therefore, as long as it is in the pressure reducing mode, the pressure reducing output and the holding output are alternately output, and the W / C pressure PW / C ** gradually decreases.

As described above, in the present embodiment, when it is determined that it is necessary to increase the brake fluid pressure when adjusting the brake fluid pressure in the anti-skid control (“NO” in S1712), wheel slippage occurs. The brake fluid pressure is increased according to the correction integrated value ΣS ** including the slip state integrated value obtained by integrating the states. Therefore, the road surface μ
Anti-skid control, because the brake fluid pressure is not immediately increased even if the slip state temporarily increases and the brake fluid pressure should be adjusted to increase due to slight fluctuations in the Instability is prevented, and stable anti-skid control is possible.

Moreover, the brake fluid pressure is increased in a pulsed manner, and if the correction integrated value ΣS ** rapidly increases, the correction integrated value ΣS ** is determined according to the increasing gradient.
Since the cycle over SI is shortened, the pressure boost pulse output frequency, that is, the brake fluid pressure adjustment speed also changes. Therefore, it is possible to appropriately deal with the change in the slip ratio.

Further, in S1808, the corrected integrated value ΣS **
Since the bad road index B ** (n) is taken into consideration, even if there is a rapid decrease in the wheel speed due to the bad road, the wheel acceleration amount due to the bad road is added to the correction integrated value ΣS **. As a result, the pressure increase is not delayed more than necessary, and stable anti-skid control that is not affected by a bad road is possible.

Since the vehicle body speed VBW ** is individually set for each wheel in S1580, more precise control can be performed for each wheel in the above-described anti-skid control. In the present embodiment, the master cylinder 16 corresponds to the brake fluid pressure generating means, and the brake devices 11 to 1 are used.
4 corresponds to the wheel braking force generating means, and the rotation speed sensors 5 to 5
Reference numeral 8 corresponds to wheel speed detecting means, and electronic control unit 40 corresponds to brake fluid pressure adjusting means.

[Others] In the above embodiment, when the brake fluid pressure is increased when the pulse increasing mode is set,
The value of the slip ratio deviation integrated value ΣSX ** (actually, the corrected integrated value ΣS ** with the rough road index B ** (n) added) was judged to adjust the pressure increase pulse output, but Also the value of the slip ratio deviation integrated value ΣSX ** (or the corrected integrated value ΣS * in consideration of the rough road index B ** (n)) corresponding to the increase of the slip ratio.
*) May be judged and the decompression output may be adjusted. That is,
If "YES" is determined in S1714, S17
Similarly to 22 and S1800, the pressure reduction may be executed by the pulse having the frequency according to the corrected integrated value ΣS **.

Further, in the above embodiment, the slip ratio deviation integrated value ΣS in a state where the rough road index B ** (n) is not taken into consideration
The determination of S1812 may be performed with the value of X ** as it is.
Although the vehicle body speed VBW ** is set individually for each wheel in S1580, the vehicle body speed VB common to the four wheels may be used instead.

In the above embodiment, the deviation between the target slip rate and the actual slip rate (slip rate deviation ΔSW **) is used as the slip state, but in addition to this, a physical quantity corresponding to the target slip rate is used. It may be a deviation between a certain target wheel speed and an actual wheel speed which is a physical quantity corresponding to the actual slip ratio.

Further, the slip state may be the reciprocal of the actual slip ratio or the reciprocal of the difference between the vehicle body speed and the actual wheel speed. This has the advantage that it can be set regardless of the target slip. That is, as the slip becomes larger, the slip state in this case becomes smaller, and the integrated value becomes smaller, so that the pressure increase is delayed and the purpose can be qualitatively achieved.

The above embodiment shows an example of a four-wheeled vehicle of the front engine / front drive type.
It can be applied to two-wheeled vehicles, three-wheeled vehicles, and vehicles having five or more wheels. Also, with the front engine and rear drive system,
It is also applicable to all-wheel drive. The brake piping system is a two-system brake system (for example,
It may be a two-system system such as front and rear.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an anti-skid control device of an embodiment to which the present invention is applied.

FIG. 2 is a flowchart of an anti-skid control process performed by an electronic control device.

FIG. 3 is a flowchart of a wheel acceleration calculation process for each of the four wheels.

FIG. 4 is a flowchart of a four-wheel common vehicle body speed calculation process.

FIG. 5 is a flowchart of a vehicle body speed calculation process for each of the four wheels.

FIG. 6 is a flowchart of slip ratio calculation processing for each of the four wheels.

FIG. 7 is a flowchart of control mode calculation processing for each of the four wheels.

FIG. 8 is a flowchart of pulse increase mode calculation processing.

FIG. 9 is a flowchart of a timer interrupt process for four-wheel solenoid drive output.

FIG. 10 is an explanatory diagram of a solenoid drive output pattern.

FIG. 11 is a timing chart showing an operation example of anti-skid control.

[Explanation of symbols]

1 ... right front wheel 2 ... left rear wheel 3 ... right rear wheel 4
... left front wheel 5, 6, 7, 8 ... rotational speed sensor 11, 12, 13, 14 ... brake device 16 ... master cylinder 21, 22, 23, 24 ... actuator 25 ... brake pedal 26 ... stop switch 27a, 27b ... motor Pumps 28a, 28b ... Reservoir 40 ... Electronic control device

Claims (11)

[Claims] 1. A brake fluid pressure for applying a wheel braking force to the wheel is adjusted so as to obtain an appropriate slip ratio in accordance with a slip state integrated value obtained by integrating the slip state of the wheel during vehicle braking. Anti-skid control device. 2. A brake fluid pressure generating means for generating a brake fluid pressure according to a brake operation state by an occupant, and a wheel braking force for receiving a brake fluid pressure from the brake fluid pressure generating means to generate a braking force on a wheel. Generating means, wheel speed detecting means for detecting the wheel speed of the wheel, and slip of the wheel obtained based on the wheel speed detected by the wheel speed detecting means in order to optimally adjust the braking state of the wheel. An anti-skid control device comprising: a brake fluid pressure adjusting means for adjusting a brake fluid pressure applied to the wheel braking force generating means according to a slip state integrated value obtained by integrating the states. 3. The brake fluid pressure adjusting means evaluates the slip ratio of the wheel obtained based on the wheel speed detected by the wheel speed detecting means or the value of a physical quantity corresponding to the slip ratio, and the brake is applied. 3. The anti-skid according to claim 1, wherein when it is determined that the hydraulic pressure needs to be changed, the brake hydraulic pressure is changed according to a slip state integrated value obtained by integrating the slip states of the wheels. Control device. 4. The anti-skid control device according to claim 3, wherein the fluctuation in the brake fluid pressure is an increase in the brake fluid pressure. 5. When the slip state integrated value exceeds a predetermined value, the adjustment for increasing the brake fluid pressure is performed in a pulse manner, and the pulse increase for clearing the slip state integrated value and newly integrating the value is performed. The antiskid control device according to claim 4, wherein the process is repeated. 6. The anti-skid control device according to claim 5, wherein the number of repetitions of the pulse increasing process is limited to a predetermined number. 7. The anti-skid control device according to claim 1, wherein the slip state integrated value further includes a variation caused by a bad road. 8. The anti-skid control device according to claim 7, wherein the fluctuation associated with the rough road is set based on a deviation between the average wheel acceleration and the actual wheel acceleration for a predetermined period. 9. The slip condition is a deviation between a target slip ratio and an actual slip ratio.
8. The anti-skid control device according to any one of 8. 10. A vehicle is provided with a plurality of wheels, each wheel is provided with the anti-skid control device according to claim 9, and each slip ratio of the wheels is estimated vehicle speed and each wheel speed. An anti-skid controller characterized in that it is calculated based on 11. The estimated vehicle body speed is an estimated vehicle body speed obtained for each wheel based on the vehicle body speed estimated from the behavior of all wheels and each wheel speed. Anti-skid control device.