JP2757737B2 - Brake pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a brake pressure of a brake for suppressing rotation of a wheel, and more particularly to an improvement in control accuracy.

[0002]

2. Description of the Related Art A brake pressure control device includes, for example, an anti-lock control device for shortening a braking distance and improving running stability when braking a vehicle, and improving a vehicle's startability and acceleration. Acceleration slip control device. The brake pressure control device controls the brake pressure in order to suppress excessive slip generated on the wheels. Conventionally, in general, a target wheel speed is set by shifting a traveling speed of a vehicle, and a target wheel speed and an actual wheel speed are generally set. The control is performed based on the relationship. Slip is a phenomenon in which the wheels slip on the road surface and the actual wheel speed becomes larger or smaller than the running speed of the vehicle. The slip can be reduced by bringing the actual wheel speed closer to the running speed of the vehicle. In order to optimally perform braking and driving, it is necessary to set the slip to an appropriate amount. Therefore, the traveling speed is shifted and the target wheel speed is set. The target wheel speed is obtained by multiplying the running speed by a coefficient smaller than 1 or subtracting a constant value from the running speed.
The target wheel speed is obtained by multiplying by a larger coefficient or adding a constant value, and the brake pressure is controlled so that the actual wheel speed becomes the target wheel speed.

[0003] One type of such a brake pressure control device is as follows.
(A) a ground speed sensor for detecting a ground speed, which is a relative speed of the vehicle to the road surface; (b) a wheel speed sensor for detecting the actual wheel speed of the wheels; and (c) a brake pressure for the wheels, which is electrically controlled. Electromagnetic valve control means for controlling the electromagnetic valve based on a relationship between an electromagnetic valve and (d) a target wheel speed obtained by shifting the ground vehicle speed detected by the ground vehicle speed sensor and an actual wheel speed detected by the wheel speed sensor. There is a device including:

[0004] The running speed of a vehicle can also be obtained by estimation from a plurality of actual wheel speeds. For example, at the time of control during straight traveling, since the actual wheel speed of the wheel having the largest actual wheel speed among the plurality of wheels of the vehicle is closest to the traveling speed of the vehicle, the traveling speed of the vehicle is estimated based on this. Is done. However, slip also exists on the wheel with the highest actual wheel speed, and since the wheel has less inertia and a large speed change compared to the vehicle body, it is difficult to accurately estimate the traveling speed of the vehicle, Since the controllability of the antilock control is reduced, the ground vehicle speed is used.

[0005] When the traveling speed of the vehicle is acquired by the ground vehicle speed sensor in this manner, control cannot be performed if the ground vehicle speed sensor becomes abnormal and the ground vehicle speed cannot be obtained. Therefore, in the anti-skid control device described in JP-A-63-149251, when an abnormality occurs in the ground vehicle speed sensor, the control is performed based on the estimated vehicle speed estimated from the actual wheel speed. Have been. The brake pressure is controlled so that the actual wheel speed becomes the target wheel speed obtained by shifting the estimated vehicle speed.

[0006]

However, if the brake pressure control is performed using the estimated vehicle speed instead of the ground vehicle speed, there is a problem that the control accuracy is reduced. For example, in the anti-lock control device, instead of setting the target wheel speed by multiplying the ground vehicle speed by a coefficient smaller than 1, the target wheel speed is set by multiplying the estimated vehicle speed by the same coefficient. Occasionally, the wheels will slip and the estimated vehicle speed will be lower than the ground speed, so the target wheel speed will also be lower, the start of the antilock control will be delayed, the brake pressure will be greatly changed, and the fluctuations in the actual wheel speed will increase. The control accuracy deteriorates. SUMMARY OF THE INVENTION It is an object of the present invention to reduce deterioration of control accuracy when an estimated vehicle speed is used instead of a ground vehicle speed when a ground vehicle speed sensor is abnormal.

[0007]

In order to solve this problem, the present invention, as shown in FIG. 1, employs (a) a ground speed sensor 1, (b) a wheel speed sensor 2 and (c) an electromagnetic valve 3 as shown in FIG. (D) If the ground vehicle speed sensor 1 is normal,
By the shift of the ground speed detected by the vehicle speed sensor 1
Target wheel speed obtained and detected by wheel speed sensor 2
The electromagnetic valve 3 is controlled based on the relationship with the actual wheel speed,
If the ground vehicle speed sensor 1 is abnormal, based on the actual wheel speed,
Target wheels obtained by shifting the estimated vehicle body speed
The electromagnetic valve 3 is controlled based on the relationship between the speed and the actual wheel speed.
A brake pressure control device including the electromagnetic valve control means 4
Here, the electromagnetic valve control means 4 is set to (e)
When the first shift amount is normal, the shift amount is set to the first shift amount.
However, if abnormal, the absolute value is smaller than the first shift amount.
Target wheel speed to obtain the target wheel speed as the second shift amount
Acquisition means 5 and (f) the target wheel speed acquisition means 5
Ground vehicle speed sensor 1 of the obtained target wheel speed and actual wheel speed
Is normal and abnormal based on a common relationship.
Control mode determining means for determining the control mode of the magnetic valve 3
6 is included .

[0008]

In the brake pressure control device according to the present invention,
If the ground speed sensor is abnormal, the target wheel speed obtained by shifting the estimated vehicle speed is used for control.However, the absolute value of the shift amount of the estimated vehicle speed is made smaller than when the ground speed sensor is normal. Therefore, even if the estimated vehicle speed becomes low or high due to wheel slip, the target wheel speed is set to a value close to the target wheel speed set when the ground vehicle speed sensor is normal.

When the actual wheel speed becomes lower than the running speed of the vehicle due to the slip of the wheels and the target wheel speed is set to a value lower than the running speed of the vehicle as in the anti-lock control, the target wheel speed is reduced. The actual wheel speed becomes higher than the running speed of the vehicle due to the slip of the driving wheels, and the target wheel speed becomes higher than the running speed of the vehicle, as in the acceleration slip control. When set, the amount of increase in speed for obtaining the target wheel speed is reduced.

The "shift amount" is determined from the target slip ratio or the target slip amount, and is determined by a combination of the target slip ratio and the target slip amount and the like.

[0011]

As described above, according to the present invention, even if an abnormality occurs in the ground vehicle speed sensor, the start delay of the control can be reduced, and the fluctuation of the brake pressure and the fluctuation of the actual wheel speed can be reduced. Can be improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An anti-lock brake device including an anti-lock control device according to one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 2, reference numeral 10 denotes a brake pedal as a brake operating member. The brake pedal 10 is linked to a master cylinder 14 via a booster 12. The master cylinder 14 is of a tandem type in which two pressurizing chambers are arranged in series with each other, and one of the pressurizing chambers passes through each electromagnetic valve 20 and passes through the left and right front wheels 2.
2 and 24 are connected to a front wheel cylinder 26 for operating brakes.
, Are connected to the rear wheel cylinders 34 of the left and right rear wheels 30, 32.

The electromagnetic valves 20 and 28 are always in a pressure increasing state in which the wheel cylinders 26 and 34 communicate with the master cylinder 14 and are cut off from the reservoirs 36 and 38. , 34 are switched between a holding state in which both the master cylinder 14 and the reservoirs 36, 38 are shut off, and a depressurized state in which the wheel cylinders 26, 34 are connected to the reservoirs 36, 38 and shut off from the master cylinder 14.

Although the solenoid valves 20 and 28 are illustrated as three-position valves in the drawings, this is merely for convenience, and actually, the booster valve and the normally closed solenoid open / close valve of a normally open type are actually used. It is configured in combination with a pressure reducing valve which is a type of electromagnetic on-off valve. In the electromagnetic valves 20 and 28 configured as described above, the pressure increasing state is realized by setting both the pressure increasing valve and the pressure reducing valve to the non-energized state, and the holding state is realized by setting only the pressure increasing valve to the energized state. The depressurized state is realized by setting both the pressure increasing valve and the pressure reducing valve to the energized state. In other words, the brake pressure of each wheel can be selectively realized in a pressure-increasing state, a holding state, and a pressure-reducing state by a combination of two electromagnetic on-off valves.
Hereinafter, signals supplied to the solenoids of the electromagnetic valves 20 and 28 to realize the pressure increasing state, the holding state, and the pressure reducing state will be referred to as a pressure increasing signal, a holding signal, and a pressure reducing signal, respectively.

The reservoirs 36 and 38 are connected to the master cylinder 14 via pumps 40 and 42, respectively, and the hydraulic fluid in the reservoirs 36 and 38 is supplied to the pumps 40 and 42, respectively.
And is recirculated to the master cylinder 14. That is, this anti-lock type brake device is a recirculation type. The pumps 40 and 42 are driven by a common motor 44.

The electromagnetic valves 20, 28 are controlled by a controller 50. The controller 50 includes a CPU,
It mainly comprises a computer including a ROM, a RAM, an input interface and an output interface, and a solenoid drive circuit, and the solenoids of the electromagnetic valves 20 and 28 are connected to the solenoid drive circuit. A brake switch 54, four wheel speed sensors 56, and a ground vehicle speed sensor 58 are connected to the input interface. The brake switch 54 is always in the OFF state, and is turned on when the brake pedal 10 is depressed. The wheel speed sensor 56 detects the rotation speed of the rotating body that rotates together with each wheel, and thereby detects the left and right front wheels 22, 24 and the left and right rear wheels 30, 32.
The actual wheel speeds _VW are detected. The ground vehicle speed sensor 58 detects the ground vehicle speed V _GS by, for example, an ultrasonic Doppler system or a spatial filter system.

The controller 50 has an anti-lock control routine, a brake pressure control routine, and the like stored in advance in its ROM, and the anti-lock control is executed by the CPU executing them. Also, RA
M includes a target slip ratio memory 6 as shown in FIG.
0, a ground speed memory 62, a target wheel speed memory 64, a target wheel acceleration memory 66, an actual wheel speed memory 68, an actual wheel acceleration memory 70, and the like.

FIG. 4 shows the antilock control routine.
A description will be given based on the flowchart of FIG. The antilock control routine is repeatedly executed at regular intervals. At the time of each execution, first, in step S1 (hereinafter simply referred to as "S1").
Expressed by In other steps, the same processing is performed), initial processing such as clearing various memories of the RAM, resetting various flags, and the like is performed. Subsequently, in S2, it is determined whether the ground vehicle speed sensor 58 is abnormal. Will be The abnormality diagnosis of the ground vehicle speed sensor 58 is performed by a computer different from the computer that performs the anti-lock control. For example, when an output signal is not obtained from the ground vehicle speed sensor 58, a state in which the ground vehicle speed suddenly changes is considered. It is determined to be abnormal, for example, when it continues for a set time or more.
In S2, the result of the abnormality diagnosis is read and it is determined whether or not the abnormality is abnormal.

If the ground vehicle speed sensor 58 is normal, the result of the determination in S2 is NO, and S3 is executed to calculate the ground vehicle speed _VGS based on the output signal from the ground vehicle speed sensor 58 and store it in the ground vehicle speed memory 62. Is done. Next, S4 is executed, the target slip ratio α is set to 12%, and stored in the target slip ratio memory 60. After setting the target slip ratio alpha, the target wheel speed V _R on the basis of the ground speed V _GS and the target slip ratio alpha in S5 is calculated, the target wheel speed V
_R is set to a value 12% lower than the ground vehicle speed _VGS . In the present embodiment, it is the shift amount is determined from the target slip ratio, calculated target wheel speed V _R is stored in the target wheel speed memory 64.

On the other hand, if the ground vehicle speed sensor 58 is abnormal, the determination result in S2 is YES, and S6 is executed to calculate the estimated vehicle speed _VSO . When the vehicle is not braked and when the anti-lock control is not started even during the braking, the maximum value of the four actual wheel speeds V _W detected by the wheel speed sensor 56 is the estimated vehicle body speed V _{W. SO} . After the start of antilock control, among the four wheels, the maximum value of the actual wheel speed V _W of the wheel deceleration does not exceed the set value is the estimated vehicle speed V _SO. When the deceleration of all the wheels exceeds the set value, the deceleration of the wheel whose deceleration lastly exceeded the set value is based on the actual wheel speed and the deceleration set value when the deceleration exceeded the set value. Thus, the vehicle speed is estimated. Wheel slip is restored, if the wheel speed is greater than the estimated value based on the set value of the actual wheel speed and deceleration is Namazure, actual wheel speed of the wheel is the estimated vehicle speed V _SO.

Next, in step S7, the target slip ratio α is set to 5%, and stored in the target slip ratio memory 60. If the ground vehicle speed sensor 58 is abnormal, the shift amount of the estimated vehicle speed V _SO is reduced. Subsequently S8 is being executed, the estimated vehicle speed and the target wheel speed V _R on the basis of the target slip ratio α is stored is calculated in the target wheel speed memory 64.

After setting the target wheel speed V _R , S9 is executed to calculate the target wheel acceleration G _R by differentiating the target wheel speed V _R with respect to time. The target wheel acceleration G _R Specifically, it is being computed by subtracting the previous value from the current value of the target wheel speed V _R (which is previously RAM in the memory), the value calculated is the target wheel acceleration memory 66.

Thereafter, steps S10 to S14 are executed, and the steps S10 to S14 are performed on the right front wheel 24 and the left front wheel 2
2, the right rear wheel 32 and the left rear wheel 30 are executed once in this order. First, in S10, among these four wheels, the current execution target wheel is determined. Subsequently, in S11, based on the output signal from the wheel speed sensor 56 corresponding to the execution target wheels, the actual wheel speed V _W to be executed wheel is calculated and stored in the actual wheel speed memory 68. afterwards,
In S12, by differentiating with respect to time the actual wheel speed V _W, the actual wheel acceleration G _W is calculated. The actual wheel acceleration G _W Specifically, computed by subtracting the previous value from the current value of the actual wheel speed V _W (is previously RAM in the memory), computed values stored in the actual wheel acceleration memory 70 Is done.

Subsequently, step S13 is executed, and processing is performed on the control target wheel. The processing is the determination of the start of the antilock control, the determination of the control mode of the electromagnetic valves 20 and 28, and the determination of the duty control time of the electromagnetic valves 20 and 28, which are the applications of the present applicant.
Since this is performed in principle in the same manner as the antilock control device described in the specification of JP-A-32288, a brief description will be given.

[0026] The anti-lock control, the actual wheel speed V _W is determined to be started when the fallen than the target wheel speed V _R.

The brake pressure control mode is determined as follows. In a state where the actual wheel speed V _W is dropped than the target wheel speed V _R, executes the decompression mode, the result actual wheel speed V _W is larger than the target wheel speed V _R, the vehicle speed V
_In the state where it has become too close to _GS , the pressure increase mode is executed. That is, the deviation in respect to the speed deviation ΔV is from the target wheel speed V _R of the actual wheel speed V _W, is the mode is determined. However, the actual wheel speed VW is _equal to the target wheel speed V
Even while depressed than _R, after the actual wheel acceleration G _W is equal to or higher than the target wheel acceleration G _R performs the holding mode to stop the pressure reduction mode.

The pressure increase and pressure reduction are performed by the electromagnetic valves 20 and 28.
Is performed by the duty control. "Duty control"
In this embodiment, the term “Japanese Patent Application No. 4-32128” is used.
Unlike the No. 8 antilock control device, the electromagnetic valve 2
Outputting the pressure increase signal or the pressure decrease signal and the holding signal to the solenoid drive circuits 0 and 28 once, respectively, in that order is one duty cycle, and
By setting the duration of the pressure-increasing signal or the pressure-decreasing signal in the one duty cycle to an invariable transformation time and the duration of the holding signal to a variable holding time (hereinafter referred to as “duty time”), Of the duty cycle, which is the ratio of the occupation time of the transforming signal in the duty cycle time.

The duty time is determined so as to be shorter as the speed deviation or the acceleration deviation is larger. As a result, as the speed deviation or the acceleration deviation is larger, the brake pressure increasing / decreasing gradient becomes steeper. The speed deviation is a deviation from the target wheel speed V _R of the actual wheel speed V _W, the acceleration deviation which is a deviation from the target wheel acceleration G _R of the actual wheel acceleration G _R. Specifically, the actual wheel speed V _W is not less target wheel speed V _R above, and the pressure increase actual wheel acceleration G _W is the target wheel acceleration G _R above, the duty time DUTY is speed deviation ΔV and acceleration The brake pressure is suddenly increased as determined by both the deviation ΔG and the actual wheel speed V _W
And the _R or more and, in the pressure increase actual wheel acceleration G _W is less than the target wheel acceleration G _R, the brake pressure duty time DUTY is determined only by the speed deviation ΔV is gradually being increased, also, actual wheel Speed V _W is the target wheel speed V
Less than _R, and, at the time of decompression actual wheel acceleration G _W is less than the target wheel acceleration G _R, so that the duty time DUTY is determined only by the acceleration deviation .DELTA.G.

Although not shown, the control mode determined by the antilock control routine is instructed by turning on and off a flag provided in the RAM, and the duty time is also stored in the RAM and stored in the ROM. The brake pressure control routine sequentially monitors these commands and duty times via the RAM, and outputs signals to the solenoid drive circuits of the electromagnetic valves 20 and 28 so that the commands and duty times are realized.

[0031] When the control mode and the duty time as described above is determined, the target wheel speed V _R and the target wheel acceleration G _R is used. These target wheel speed V _R and the target wheel acceleration G _R, if ground vehicle velocity sensor 58 is normal, is calculated based on the ground speed V _GS and 12% target slip rate set in the alpha, the control mode and the duty time accordance with the electromagnetic valve 20, 28 is controlled, as representatively shown for the front wheels 5 and 6, the brake pressure varies gently, the actual wheel speed V _W along the target wheel speed V _R Can be changed.

[0032] In contrast, when the ground vehicle velocity sensor 58 is abnormal, the target wheel speed V _R is ground speed V _GS without it is calculated on the basis of the estimated vehicle speed V _SO, the target slip ratio α is ground vehicle velocity The sensor 58 is set to 5%, which is smaller than the normal case, and the shift amount of the estimated vehicle speed V _SO is reduced. Therefore, the estimated vehicle body speed V _SO estimated from the actual wheel speed including the slip is lower than the ground vehicle speed V _GS , but as shown in FIG. 8, the target wheel speed V _R can be obtained if the ground vehicle speed sensor 58 is normal. It is set without greatly deviating from the ground vehicle speed _VGS .

The abnormality occurs in the ground vehicle velocity sensor 58, even when calculating the target wheel speed V _R on the basis of the estimated vehicle speed V _SO, same city as if the target slip ratio α ground vehicle velocity sensor 58 is normal, the shift amount to be reduced, and due to the low estimated vehicle speed V _sO, the target wheel speed V _R as shown in FIG. 10
There deviate significantly from vehicle ground speed V _GS of vehicle ground speed sensor 58 is obtained if the normal. Therefore, a delay occurs in the start of the antilock control, and the brake pressure is rapidly changed as shown in FIGS. 9 and 10, and the actual wheel speed _VW is reduced while being rapidly changed, thereby deteriorating the control accuracy. . On the other hand, even if the estimated vehicle speed V _SO is used when the ground vehicle speed sensor 58 is abnormal as in the present embodiment, the start delay of the antilock control is reduced by reducing the shift amount, and FIG. As shown in FIG. 8, the fluctuation of the brake pressure is reduced, and the actual wheel speed _VW is reduced with less abrupt fluctuation, so that the deterioration of the control accuracy is reduced.

The above effect can be obtained by providing a step for setting the target slip ratio to a different value depending on whether or not the ground vehicle speed sensor 58 is abnormal in the antilock control routine. In preparation for the case where the sensor 58 is abnormal, a routine for performing antilock control without depending on the ground vehicle speed V _GS is provided. When the sensor 58 is abnormal, the program capacity is not increased as compared with the case where the execution routine is switched. The effect of reducing the deterioration of control accuracy can be obtained.

As is apparent from the above description, in the present embodiment, the ROM of the computer of the controller 50 is used.
The part storing S1 to S3, S5, S6, S8 to S14 and the part of the CPU executing these steps constitute the electromagnetic valve control means 4 and store S2 to S8 of the ROM.
Part that executes these steps of the CPU
Constitute the target wheel speed acquisition means 5, and S9 to S1 of the ROM
4 and the steps to execute those steps of the CPU
Are the control mode determining means 6.
You.

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other embodiments.

For example, in the above embodiment, the target slip rates are set to 12% and 5% when the ground vehicle speed sensor 58 is normal and abnormal, respectively. Should be set to the value of.

The target slip ratio and the target slip amount for obtaining the shift amount are not limited to one type. For example, the target slip ratio and the target slip amount may be changed stepwise or linearly according to the running speed of the vehicle when an excessive slip occurs. , May be changed in a curved line.

Further, in the above embodiment, whether or not the ground vehicle speed sensor 58 is abnormal is determined by a computer different from the computer performing the antilock control. May perform an abnormality diagnosis.

Further, in the above-described embodiment, the electromagnetic valves 20, 28 are constituted by a combination of two two-position valves, but may be constituted by, for example, one three-position valve. it can. Further, each of them is a state switching type that switches the flow state of the hydraulic fluid between the hydraulic pressure source, the wheel cylinder, and the reservoir to a plurality of states, for example, a magnetic force acting on the spool in opposite directions to each other. By balancing the force based on the hydraulic pressure, a linear control type that changes the height of the hydraulic pressure linearly with respect to the magnetic force can also be used.

Further, the present invention can be applied not only to the antilock control device but also to another brake pressure control device such as an acceleration slip control device. When applied to an acceleration slip control device, it is suitable for an acceleration slip control device provided in a vehicle in which all wheels are drive wheels. Since the estimated vehicle speed becomes higher than the traveling speed of the vehicle due to the slip of the driving wheels, when the ground vehicle speed sensor is abnormal, the estimated vehicle speed is reduced to obtain the target wheel speed, contrary to the case of the antilock control device. The shift amount is reduced by reducing the multiplication factor or reducing the speed added to the estimated vehicle speed.

In addition, without departing from the scope of the claims, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a block diagram conceptually showing the configuration of the present invention.

FIG. 2 is a system diagram showing an anti-lock brake device including an anti-lock control device according to one embodiment of the present invention.

FIG. 3 is a diagram conceptually showing a configuration of a RAM of a computer of a controller of the antilock control device.

FIG. 4 is a flowchart showing an antilock control routine stored in a ROM of the computer.

FIG. 5 is a graph showing a relationship between a time and a brake pressure during antilock control performed when the ground vehicle speed sensor is normal in the antilock control device.

FIG. 6 is a graph showing the relationship between the time during antilock control performed when the ground vehicle speed sensor is normal in the antilock control device, the ground vehicle speed, the estimated vehicle body speed, the target wheel speed, and the actual wheel speed.

FIG. 7 is a graph showing a relationship between a time and a brake pressure during antilock control performed when the ground vehicle speed sensor is abnormal in the antilock control device.

FIG. 8 is a graph showing the relationship between the time during antilock control performed when the ground vehicle speed sensor is abnormal in the antilock control device, the ground vehicle speed, the estimated vehicle body speed, the target wheel speed, and the actual wheel speed.

FIG. 9 is a graph showing a relationship between a time and a brake pressure during antilock control performed when a ground speed sensor is abnormal in a conventional antilock control device.

FIG. 10 is a graph showing the relationship between the time during antilock control performed when the ground vehicle speed sensor is abnormal in the conventional antilock control device, the ground vehicle speed, the estimated vehicle body speed, the target wheel speed, and the actual wheel speed. .

[Explanation of symbols]

 Reference Signs List 20 electromagnetic valve 22 left front wheel 24 right front wheel 28 electromagnetic valve 30 left rear wheel 32 right rear wheel 50 controller 56 wheel speed sensor 58 ground speed sensor

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60T 8/96 B60T 8/66

Claims (1)

(57) [Claims] A ground vehicle speed sensor that detects a ground vehicle speed that is a relative speed of the vehicle to a road surface; a wheel speed sensor that detects an actual wheel speed of a wheel; and an electromagnetic valve that electrically controls a brake pressure of the wheel. When the ground vehicle speed sensor is normal, the electromagnetic valve is based on a relationship between a target wheel speed obtained by shifting the ground vehicle speed detected by the ground vehicle speed sensor and an actual wheel speed detected by the wheel speed sensor. If the ground vehicle speed sensor is abnormal, the electromagnetic valve that controls the electromagnetic valve based on the relationship between the target wheel speed and the actual wheel speed obtained by shifting the estimated vehicle speed estimated based on the actual wheel speed is controlled. A brake pressure control device including: a valve control unit, wherein the electromagnetic valve control unit includes: (a) when the ground vehicle speed sensor is normal, the shift
Is the first shift amount, and if abnormal, the first shift amount
The second shift amount whose absolute value is smaller than the shift amount
A target wheel speed obtaining means for obtaining a target wheel speed, and (b) a target wheel speed obtained by the target wheel speed obtaining means.
When the ground vehicle speed sensor between the vehicle speed and the actual wheel speed is normal
The electromagnetic valve based on a common relationship between
Also includes a control mode determining means for determining a control mode
A brake pressure control device, characterized in that: