JPH07117653A - Brake hydraulic pressure controller - Google Patents

Abstract

PURPOSE:To prevent the generation of an over-decompression phenomenon in the antiskid control in the sharp brake application by calculating the control quantity of the brake hydraulic pressure, using the integration component corresponding to the integration value of the difference between the wheel speed and the target wheel speed, as the integration term in the PI control or PID control. CONSTITUTION:A wheel cylinder is operared by the brake hydraulic pressure obtained by a decompression control valve, and the brake power corresponding to the decompression is generated on the corresponding wheel. When the output instruction voltage Ve for the brake hydraulic pressure control is calculated by a controller, the difference epsilon between the wheel soped Vw and the target wheel speed Vwo is calculated. Then, the ABS decompression quantity, DELTAPabc is calculated from the equation DELTAPabc=DELTAPI+DELTAPp+DELTAPd, having the integration component Ki.fepsilon obtained in accordance with the difference epsilon as one element, and ABS control is carried out through the PID control. In thisc ase, if the wheel speed and the target wheel speed become equal, the DELTAPI of the integration term is set to 0, and the over-decompression phenomenon is eliminated, and the trouble of the reduction of the brake power is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device, and more particularly to a vehicle brake fluid pressure control device which performs anti-skid control to prevent wheel lock during braking.

[0002]

2. Description of the Related Art As a brake fluid pressure control for controlling a brake fluid pressure of a vehicle, for example, there is one disclosed in Japanese Patent Laid-Open No. 4-87867.

FIG. 6 diagrammatically shows the structure. In FIG.
Reference numeral 1 is a brake pedal, 2 is a master cylinder, which receives the master cylinder hydraulic pressure Pm from the master cylinder 2 in accordance with the pedaling force of the brake pedal 1 as a pilot pressure in one direction (pressure increasing direction), and further in the same direction, a spring 3 Spring force Fs
pi, the electromagnetic force Fso of the solenoid 4 and the spring force Fspd of the spring 5 are received in the other direction (pressure reduction direction), and the balance of these forces causes the hydraulic pressure from the pump 6 to be the original pressure for the wheel cylinder of the wheel 7. It has a stepped spool type hydraulic control valve 9 for determining the brake hydraulic pressure Pw to the (W / C) 8.

Here, if the operation principle is expressed by a formula, the brake hydraulic pressure Pw is calculated from the balance formula of the forces acting on the hydraulic pressure control valve 9.
When the master cylinder hydraulic pressure receiving area is Am and the brake hydraulic pressure receiving area is Aw, it is expressed by the following equation.

## EQU1 ## Pw = (Am / Aw) Pm + (Fspi-Fspd-Fso) / Aw (1) As is apparent from this equation, in this device, the brake fluid pressure Pw is the master cylinder fluid pressure Pm. On the other hand, it is controlled as shown in FIG. Then, normally, the current I to the solenoid 4 is set to Fso = Fs so that the second term on the right side of the equation (1) becomes 0.
It is set to a reference current Ib at which pi-Fspd is achieved, which causes the a characteristic. In this case, the brake fluid pressure Pw has a value obtained by multiplying the master cylinder fluid pressure Pm by (Am / Aw).

When the solenoid current I is made larger than the reference current Ib, the brake fluid pressure Pw is controlled according to the b characteristic which is decreased from the a characteristic by a corresponding value due to the increase of the electromagnetic force Fso corresponding to the increase amount ΔI. Conversely, when the solenoid current I is made smaller than the reference current Ib, the brake fluid pressure Pw is reduced due to the decrease in the electromagnetic force Fso according to the decrease amount.
Control is performed along the c characteristic which is increased by a corresponding value from the a characteristic.

The solenoid current I is the controller 10
According to the anti-skid (ABS) control in which the pressure is reduced to avoid the wheel lock, the controller 10 calculates the target brake hydraulic pressure change amount based on the wheel speed and the like obtained from the wheel speed sensor 11, The brake fluid pressure Pw is controlled by controlling the solenoid current I.

Therefore, for example, in the case of the pressure reduction control in FIG. 7, the pressure reduction amount Δ of the brake fluid pressure necessary for slip prevention is
P1 is calculated, and in order to achieve this pressure reduction, the solenoid current I is increased by ΔI from the current value (reference current Ib in FIG. 7) by an amount commensurate with it, and the brake fluid pressure Pw is reduced to. Thereby, the required reduced pressure is realized. By increasing the current I by ΔI in this way, the brake fluid pressure Pw is reduced by ΔP1 even if the master cylinder fluid pressure Pm is maintained at the value indicated by Pm1 in the figure, and anti-skid for avoiding wheel slippage. Control can be performed.

In the yaw rate feedback control in the anti-skid control area, the yaw rate feedback control of the vehicle can be performed as follows. That is, the controller 10 calculates the yaw rate target value that the vehicle should originally generate from the steering wheel steering angle and the vehicle speed, and obtains the left and right wheel braking force difference for matching the actual yaw rate of the vehicle obtained from the yaw rate sensor with the target value. . In order to generate this braking force difference, for example, one of the left and right wheels is used to reduce the brake fluid pressure Pw by increasing the solenoid current I, and the actuator by the fluid pressure control valve 9 also performs such control. You can Further, in the case of the non-anti-skid control region, conversely, it is possible to obtain the required left / right wheel braking force difference by decreasing the solenoid current I and increasing the brake fluid pressure Pw.

As described above, the solenoid current I is increased to reduce the pressure, or the solenoid current I is decreased to increase the pressure. By controlling the yaw rate feedback braking force, the yaw rate of the vehicle during braking can be made equal to the target value.

In the above configuration, the hydraulic pressure control valve 9 uses the master cylinder hydraulic pressure Pm as the pilot pressure and controls the brake hydraulic pressure Pw based on the pilot pressure. Therefore, even during the yaw rate feedback control, the driver is controlled. It is advantageous that the master cylinder pressure Pm and the brake fluid pressure Pw also change by operating the brake pedal. When the driver desires to change the braking force and changes the depression force of the brake pedal 1 during the control of the brake fluid pressure Pw by the controller 10, the change in the master cylinder fluid pressure Pm accompanying this changes the brake fluid pressure Pw. Therefore, the braking force change corresponding to the brake pedal operation can be generated even during the control by the controller 10. Therefore, even during yaw rate feedback, it is possible to obtain a braking force that matches the driver's will.

The brake fluid pressure control characteristic of the above apparatus is as shown in FIG. 8 when it is expressed as a variation characteristic with respect to the solenoid current I using the master cylinder fluid pressure Pm as a parameter. This also shows one of the other advantages, and shows that the relationship between the brake fluid pressure and the control current I due to the difference in master cylinder fluid pressure is as shown in the figure. As is clear from this figure, the solenoid current change amount ΔI for achieving the target change value ΔPw of the brake fluid pressure necessary for the purpose of control, that is, the control current amount with respect to the target reduced pressure amount (or increased pressure amount) is , Master cylinder hydraulic pressure P
It is uniquely determined only by the target brake fluid pressure change amount ΔPw regardless of the value of m, whereby the target pressure reduction control is possible even if the current brake fluid pressure Pw and master cylinder fluid pressure Pm at the time of braking are not known. Is easily possible.

[0012]

By the way, in the case of controlling the brake fluid pressure during braking so as not to cause the brake lock of the wheel, the pressure is reduced if it is likely to be locked and is increased if the wheel speed is restored. And the target wheel speed deviation is 0
Therefore, for example, if anti-skid control is performed by proportional / integral / derivative (PID) control, the target brake fluid pressure change amount according to the control law is set as follows: "Target brake fluid pressure change according to ABS control law". "Amount" = "deviation between wheel speed and target wheel speed" x "constant 1" + "integral value of deviation between wheel speed and target wheel speed" x "constant 2" + "differential value of deviation between wheel speed and target wheel speed" “× 3” can be set.

In such a control law, a good control operation can be obtained by selecting the constants of the proportional term, the integral term, and the differential term to optimal values. On the other hand, the control amount is uniformly calculated according to it. When the brake fluid pressure actuator is determined and driven, the phase of the integral term occurs with a delay, so even if the deviation becomes zero, an effect will occur after that. Depending on the effect, the ABS control accuracy This may cause a decrease in the braking force or a decrease in the braking force. In particular, during control operation during sudden braking accompanied by a sudden change in wheel speed, if the drop in wheel speed during sudden braking accumulates as a deviation in the direction of pressure reduction within the ABS control law, excessive decompression phenomenon occurs after the wheel speed is restored. Occurs, and the braking force also weakens, and accordingly, it becomes difficult to secure the braking deceleration when the driver strongly depresses the brake pedal to decelerate as fast as possible.

The present invention has been made in view of the above points, and can avoid the occurrence of such an over-decompression phenomenon even with anti-skid control at the time of sudden braking, so that the deviation between the wheel speed and the target wheel speed can be avoided. An object of the present invention is to provide a brake fluid pressure control device that can appropriately achieve this even when anti-skid control is performed by PI or PID control.

[0015]

According to the present invention, the following brake fluid pressure control device is provided. That is, the deviation between the wheel speed and the target wheel speed is calculated, and the PI control or PID is calculated.
A control device for controlling brake fluid pressure at the time of braking by an actuator so as to perform anti-skid control by control, wherein an integral component according to an integral value of the calculated deviation is used as an integral term in the PI control or PID control. The brake fluid pressure control device is characterized by having a control amount calculation means for calculating a control amount of pressure and calculating the control amount by setting the integral term to 0 when the wheel speed and the target wheel speed become equal.

[0016]

In the present invention, the deviation between the wheel speed and the target wheel speed is calculated, and the brake fluid pressure during braking is controlled by the actuator so that anti-skid control is performed by PI control or PID control. The means performs PI control or PI control of the integral component according to the integral value of the deviation.
The control amount of the brake fluid pressure is calculated as an integral term in the D control, and in that case, when the wheel speed and the target wheel speed become equal, the integral term is set to 0 and the control amount is calculated.

Therefore, in the present brake fluid pressure control, the anti-skid control can be performed by the PI or PID control using the deviation between the wheel speed and the target wheel speed, and in the case of sudden braking accompanied by a sudden drop in wheel speed. Even when the anti-skid control is activated, the integral term can be set to 0 when the wheel speed becomes equal to the target wheel speed, and it is possible to easily prevent the over-decompression phenomenon when the wheel speed is restored. It is also possible to avoid blunting.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 3 show an embodiment of a brake fluid pressure control device of the present invention, and FIG. 1 shows a hardware configuration. 2 is a control block diagram, and FIG. 3 is an example of a control program of the controller.

Although only the brake fluid pressure control system for one wheel is shown in FIG. 1, the other channels are also
A similar brake fluid pressure control system exists, and anti-skid control (ABS control) is, for example, 4 channels 4
In the case of the sensor type, it goes without saying that the same brake fluid pressure control system exists for the other three wheels of the vehicle, and there are a total of four systems for the left and right wheels on the front wheel side and the rear wheel side.

In the apparatus of this embodiment, as shown in FIG. 1, the basic hardware structure may be the same as that in the case of FIG. 6, and the actuator to be applied is not limited here, and FIGS. Operating principle described above ((1)
(Equation) and hydraulic pressure control characteristics are used, and the same parts are denoted by the same reference numerals.

Therefore, the hydraulic pressure control valve 9 shown in FIG. 1 is also a proportional pressure control valve in which the master cylinder hydraulic pressure Pm is used as the pilot pressure and can be externally controlled by the solenoid 4, and the master cylinder hydraulic pressure corresponding to the brake operating force is used. The pressure Pm is used as a pilot pressure, and the brake operating pressure is created by using the pressure from the pump 6 as a pressure source as an original pressure, and this brake operating pressure is controlled by adjusting the control force by the solenoid 4 acting in the direction opposite to the pilot pressure. It is a possible hydraulic control valve.

That is, the hydraulic pressure control valve 9 is the brake pedal 1
The master cylinder hydraulic pressure Pm from the master cylinder (M / C) 2 corresponding to the pedaling force is received as a pilot pressure in one direction (pressure increasing direction), and the spring force (F
spi), the electromagnetic force (Fso) of the solenoid 4 and the spring force (Fspd) of the spring 5 are received in the other direction (decompression direction), and the balance of the forces generated by these results in the pump 6 based on the equation (1). The brake hydraulic pressure Pw to the wheel cylinder (W / C) 8 of the wheel 7 is generated using the hydraulic pressure of the above as the original pressure. In this way, the master cylinder 2 interlocks with the brake operation by depressing the brake pedal 1, and applies the master cylinder hydraulic pressure Pm, which is the pressure corresponding to the brake operating force corresponding to the operating force, to the hydraulic control valve 9 as the pilot pressure, The cylinder 7 is operated by the brake fluid pressure Pw obtained by the fluid pressure control valve 9 to generate a braking force corresponding to the fluid pressure on the corresponding wheel.

The energization amount I to the solenoid 4 for controlling the wheel cylinder pressure by adjusting the supply hydraulic pressure by the hydraulic pressure control valve 9 is a controller 6 which is composed of a microcomputer, an actuator drive circuit and the like.
Determined by 1. Here, the controller 61 includes an arithmetic processing unit 61a and a power amplifier 61b regarding the control of the hydraulic pressure control valve 9, and the command voltage Ve (CMD) to be input to the power amplifier 61b that supplies the solenoid current I is the microcomputer. The arithmetic processing unit 61a calculates this and outputs it.

A signal from a wheel speed sensor 11 for detecting the rotational peripheral speed of the corresponding wheel is input to the controller 61,
The controller 61 performs arithmetic processing according to a control program stored in advance in the storage unit of the microcomputer,
Based on the input wheel speed information, ABS control is executed so that the wheel speed of the corresponding wheel becomes the target wheel speed.

In the case of the four-channel four-sensor ABS control, the wheel speed Vw detection value is obtained from the wheel speed sensor 11 for each channel of the front, rear, left and right four wheels, and the vehicle speed is calculated based on these values. It is possible to perform lock prevention control for each wheel so that the wheel slip ratio falls within a target predetermined range (around the ideal slip ratio at which the wheel slip ratio provides the maximum road surface friction coefficient, etc.) When the rate exceeds the target slip rate, the brake fluid pressure Pw is reduced below the normal level. That is, the target brake hydraulic pressure change amount by the ABS control for achieving the wheel lock prevention pressure reduction is calculated, and the output command voltage Ve (CMD) value to the power amplifier 61b is determined based on the calculated target brake hydraulic pressure change amount. (Thus, the electromagnetic force Fso in the equation (1) is variably controlled to execute the brake fluid pressure control during the ABS control. In braking, depressurize if the wheels are about to lock in this way, and increase when wheel speeds recover,
By controlling the brake fluid pressure by the skid cycle, the brake fluid pressure Pw of each of the front, rear, left and right wheels can be adjusted and controlled, whereby the maximum braking efficiency is achieved for each wheel.

In this case, for the ABS control, the controller 61 controls the proportional / integral control (PI control) or the proportional / integral / derivative control (PID control) by adding at least the integral (I) control to the proportional (P) control. Here, the deviation between the target wheel speed and the actual wheel speed is calculated, and ABS control is performed by PID control.
When the target brake hydraulic pressure change amount is calculated when the D control law is used, when the wheel speed becomes equal to the target wheel speed, the integral term (I term) is set to 0.

This will be described with reference to FIG. 2 and subsequent figures. FIG. 2 shows the arithmetic processing unit 61 a of the controller 61.
However, the output command voltage Ve (CM
In the calculation of D), an example of a control block diagram in the case of performing calculations for calculating and determining various amounts such as calculation of the target brake hydraulic pressure change amount based on the ABS control law as described above, which is necessary for the calculation Yes, and the respective arithmetic expressions are as follows.

The solenoid current I for the hydraulic control valve 9 is determined by the input voltage to the power amplifier 61b.
The command voltage Ve (C
MD) is calculated by the following equation.

## EQU00002 ## Ve (CMD) = Veo + .DELTA.Ve (abc) (2) where Veo is a normal voltage (for example, a voltage value corresponding to the reference current Ib (a characteristic) in FIG. 7) .DELTA.Ve (abc) : ABS command voltage

Here, the ABS command voltage ΔVe (ab
It is assumed that c) is determined by the PID control law shown in the following equation so that the deviation ε between the wheel speed Vw and the target wheel speed Vwo becomes 0.

(3) ΔPabc = ΔPi + ΔPp + ΔPd (3)

[Formula 4] ΔPi = Ki · ∫ε (4)

[Formula 5] ΔPp = Kp · ε (5)

(6) ΔPd = Kd · (d / dt) ε (6)

## EQU00007 ## .DELTA.Ve (abc) =. DELTA.Pabc / Kv (7) where .DELTA.Pabc is the target brake fluid pressure change amount according to the ABS control law .DELTA.Pi: Integral term (pressure reduction amount due to integral component) .DELTA.Pp: Proportional term (proportional component) Decompression amount by ΔPd: Differential term (decompression amount by differential component) Kp, Ki, Kd: PID control constant (gain) (d / dt) ε: Differential value of deviation ε (ε = Vw-Vwo) Kv: Liquid pressure (Pressure / voltage) gain of control valve (proportional control valve) 9 (negative value)

The target wheel speed Vwo is the vehicle body speed Vc.
It is determined by the following formula from ar (vehicle speed) and the target slip ratio λo.
That is, the target wheel speed is calculated from the vehicle body speed Vcar and the target slip ratio λo determined by the road surface μ, for example.

[Equation 8] Vwo = (1-λo) × Vcar (8) Further, when non-braking, ε> 0 (because Vw> Vwo), and a command for increasing pressure is issued. , ΔVe
A conditional expression of (abc) ≧ 0 is required.

In this way, the command voltage change amount determined by the ABS control law is obtained as described above, and the command voltage Ve (C
MD), and therefore the solenoid current I, is determined on the basis of the above-mentioned normal Veo component and the ΔVe (abc) component determined by the above-mentioned PID control law, based on the above (2).
Veo + ΔVe (abc) according to the formula, and the result P
ABS control is executed by ID control. Then, this A
During the BS control, when the wheel speed Vw becomes equal to the target wheel speed Vwo, ΔPi of the integral term (I term) of the first term on the right side of the equation (3) is set to 0. This is the control constant K of the equation (4).
This can be performed by selectively switching i from a predetermined value to a value 0, and at the corresponding timing, such selective Ki value switching can be performed.

FIG. 3 concretely shows the ABS control program based on the PID control law executed by the controller 61 in this example. Note that this control program is shown as an example of a program relating only to the wheels (self-wheels) related to the brake system shown in FIG. 1, but command voltage calculation and output processing are also executed for other wheels in the same manner. Is. Further, this is performed by an operating system (not shown) at regular time intervals.

In the figure, first, in step 101, the wheel speed Vw detected by the wheel speed sensor 11 is read. Next, at step 102, the vehicle speed Vcar is calculated by a known method using the wheel speed of each wheel.

Then, in step 103, the target wheel speed Vwo is obtained from the equation (8) using the vehicle body speed Vcar, and in the next step S104, the deviation ε between the own wheel speed Vw and the target wheel speed Vwo is ε =. It is calculated by Vw-Vwo. Next, using the thus obtained deviation ε, the pressure reduction amounts of the I, P and D terms in the PID control are calculated. That is, based on the equations (4), (5), and (6), the integral term ΔPi component, which is a value obtained by multiplying the integral value of the deviation ε by a preset constant Ki, similarly, the deviation ε is set to the constant Kp. The proportional term ΔPp component obtained by multiplication and the differential term ΔPd component obtained by multiplying the differential value of the deviation ε by a constant Kd are obtained.

Then, in the following step 106,
The product of the deviation ε (current value) calculated in step 104 and the deviation εo one cycle before (previously calculated value) ε × εo is calculated to determine whether the sign is positive or negative. Then, the processing on the step 107 side or the step 120 side is selected based on the result, and ε × εo> 0.
If is satisfied, the process proceeds to step 107, and if not, the process proceeds to step 107 via step 120.

Here, the fact that the product value ε × εo is negative means that the wheel speed crosses the target wheel speed (see FIG. 4). In other words, there is a point in time when the wheel speed becomes equal to the target wheel speed between the previous loop and the current loop. As a result, in this program example, it is known that the wheel speed Vw has become equal to the target wheel speed Vwo, and at this time, in step 120, the value ΔPi of the integral term is set to 0 (regardless of the integral value ∫ε, The control constant Ki (integral gain) that is the multiplication coefficient is set to 0, and the calculated ΔPi value in step 105 is ΔPi = 0.
Then, in step 107, the ABS pressure reduction amount is calculated.

That is, the target brake fluid pressure change amount ΔPabc according to the ABS control law is expressed by the above equation (3) ΔPabc = ΔPi.
When calculating with + ΔPp + ΔPd, at this timing,
ΔPabc = 0 + ΔPp + ΔPd, therefore the calculated values ΔPp (= Kp · ε) and ΔPd (= K in step 105)
Applying d · (d / dt) ε), ΔPabc = ΔPp
It will be calculated by + ΔPd.

On the other hand, if the product value ε × εo is positive as a result of the determination in step 106, the ABS decompression amount calculation process is performed in step 107 as it is. Therefore, at this time, the value ΔPi (= K
i · ∫ε), ΔPp (= Kp · ε), ΔPd (= Kd ·
(D / dt) ε) is applied as it is, and PI
Target brake fluid pressure change amount Δ according to ABS control law of D control
Pabc is calculated by ΔPabc = ΔPi + ΔPp + ΔPd.

Thus, after the calculation processing in step 107, the processing in steps 108 to 110 is executed. In step 108, the ABS command voltage ΔVe (ab
s) is calculated (equation (3)), in step 109 the final command voltage Ve (CMD) is calculated in accordance with the formula (2), and in step 110 the command voltage Ve (CM) is calculated.
D) is output to the power amplifier 61b. The command voltage Ve (CM) applied to the solenoid 4 of the hydraulic control valve 9 of the corresponding wheel
The solenoid current I corresponding to D) is output, whereby the ABS control is executed by the PID control in the ABS region.

Then, in the next step 111,
Every time this program is executed, step 104 in this loop
The deviation value ε calculated in the processing is stored as εo = ε so as to be used as the deviation value εo one loop before in the processing of step 106 in the next loop, and thus applied to the arithmetic processing in the next loop. The program is updated sequentially and this program ends. Thus, what was stored in the previous loop is read out sequentially in the next loop each time,
It will be used to check if the wheel speed and the target wheel speed have become equal as described above.

According to the above control, the hydraulic pressure control valve 9 is controlled so that the wheel speed Vw during braking becomes the target wheel speed Vwo.
When the ABS pressure control is performed by controlling the brake fluid pressure Pw, the combination of the integral operation and the derivative operation in addition to the proportional control based on the deviation ε is performed so that a good control operation can be obtained by the proportional + integral + derivative operation. A according to the brake fluid pressure control system of the vehicle to which each control gain is applied
It is possible to set an appropriate value that is most suitable for the BS system to improve responsiveness and stability, and set the integral term to 0 when the wheel speed Vw becomes equal to the target wheel speed Vwo. Even in the ABS operation at the time of sudden braking, it is possible to avoid a situation in which the braking force becomes dull due to an overpressure reduction phenomenon when the wheel speed is restored after the wheel speed has dropped.

4A to 4C show the ABS control state in the case of the present control, and FIG. 5 shows the ABS control state in comparison therewith. Therefore, comparison without the processing of steps 106, 120 and 111 in FIG. The ABS control states in the example are shown respectively. Here, the transition of the wheel speed, the target wheel speed, etc., the brake fluid pressure, and the command voltage at the time of sudden braking is shown, and the first drop of the wheel speed at the beginning of the ABS control is mainly caused by the depression of the brake pedal. Also, the state when the wheel speed is restored is shown.

In the example of FIG. 5, when the ABS control is started by depressing the brake pedal, the drop in wheel speed during sudden braking is accumulated as a deviation in the pressure reducing direction in the ABS control law by the PID control (integral term). Occurs because the phase is delayed, even if the deviation becomes zero, then the effect will occur). Therefore, as shown in FIGS.
At the time of recovery following the first drop in wheel speed ((a) in the figure), the control is such that an over-reduction phenomenon of the brake fluid pressure ((b) in the figure) occurs. Due to such over-decompression phenomenon, it is delayed for the next increase in pressure in the skid cycle.
A state (sticking state) in which the wheel speed does not decrease toward the target wheel speed for a while is brought about ((a) in the same figure).

On the other hand, steps 106 and 12 in FIG.
In the case of the control of FIG. 4 incorporating the processing of 0,111,
Even during ABS operation by sudden braking, such a situation is properly resolved. In FIG. 4, it can be seen that the over-decompression phenomenon (FIG. 5 (b)) as in the comparative example seen in FIG. 5 (b) at the time of recovery after the first drop in wheel speed disappears. The sticking phenomenon of the wheel speed as shown in FIG. 5A does not occur. In this way, in this control, since the integral term is set to 0 when the wheel speed and the target wheel speed become equal to each other, it becomes possible to eliminate the over-decompression phenomenon, and the braking deceleration can be performed without slowing the braking force. The accuracy can be further improved.

The present invention is not limited to the above example. For example, the PID control has been described, but the present invention is not limited to this, and PI control may be used. Therefore, the deviation between the target wheel speed and the actual wheel speed is calculated, and the ABS pressure control is performed by the PI or PID control. Applicable to

The hardware configuration of the ABS system is not limited to that of the embodiment. Therefore, the ABS system using the actuator other than the hydraulic pressure control valve exemplified as the actuator can be similarly applied as long as the PI or PID control is performed, and the same effect can be obtained. Needless to say, the present invention can be applied not only to the 4-channel 4-sensor type but also to the 3-channel ABS.

[0047]

According to the present invention, the anti-skid control is a PI or PI using the deviation between the wheel speed and the target wheel speed.
The D control can be effectively performed, and even in the anti-skid control by the PI or PID control, the integral term can be set to 0 when the wheel speed becomes equal to the target wheel speed. It is possible to eliminate the over-pressure reduction phenomenon even during skid operation, to provide braking deceleration without slowing the braking force, to secure deceleration during braking, and to easily improve anti-skid control accuracy. realizable.

[Brief description of drawings]

FIG. 1 is a system diagram of a hydraulic brake system relating to only one wheel, showing an embodiment of a brake hydraulic pressure control device of the present invention.

FIG. 2 is an example of a control block diagram in a control system.

FIG. 3 is a flowchart showing an example of an ABS control program executed by a controller.

FIG. 4 is an operation time chart showing an example of a control state when the anti-skid control is operated by the apparatus of the embodiment.

FIG. 5 is an operation time chart in comparative control for comparison with FIG. 4.

FIG. 6 is a system diagram of a hydraulic brake system using an electronic hydraulic control valve, which is used for explaining a conventional example.

FIG. 7 is a diagram showing the brake fluid pressure control characteristic.

FIG. 8 is a characteristic diagram that similarly expresses the hydraulic pressure control characteristic in another manner.

[Explanation of symbols] 1 brake pedal 2 master cylinder 3 spring 4 solenoid 5 spring 6 pump 7 wheel 8 wheel cylinder 9 hydraulic pressure control valve 11 wheel speed sensor 61 controller 61a arithmetic processing unit 61b power amplifier

Claims (1)

[Claims] 1. A controller for controlling a brake fluid pressure during braking by an actuator so as to calculate a deviation between a wheel speed and a target wheel speed, and to perform anti-skid control by PI control or PID control. The brake fluid pressure control amount is calculated using the integral component corresponding to the integral value of the deviation as an integral term in the PI control or PID control, and when the wheel speed and the target wheel speed become equal, the integral term is set to 0 and the control quantity of the control amount is changed. A brake fluid pressure control device comprising a control amount calculation means for performing calculation.