JP2000219128A - Automatic brake controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect abnormalities of a hydraulic system, in an automatic brake controller. SOLUTION: Oil pressure in the automatic braking operation is detected by pressure sensors P1, P2, an oil pressure gradient is found (S204, S209) on the basis of the oil pressure detected by the pressure sensors P1, P2 and compared (S205, S210) with a set value found in the increase or decrease of pressure in the normal state, and therefore, abnormalities of a hydraulic system are accurately detected in consideration of a time component in the increase or decrease of oil pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic brake control device, and more particularly to an automatic brake control device for decelerating a vehicle by applying a hydraulic pressure to a vehicle brake device when a vehicle deceleration is requested.

[0002]

2. Description of the Related Art Conventionally, a vehicle detects a preceding vehicle by a laser radar, an ultrasonic sensor, or the like, and travels while maintaining a distance from the preceding vehicle, or follows a preceding vehicle in traffic jam according to the speed of the preceding vehicle. In the case where it is determined that the vehicle collides with a preceding vehicle or an obstacle while traveling,
An automatic brake control device for automatically operating a brake on a wheel has been proposed, and such a device is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-107141.

[0003] The apparatus disclosed in this publication is provided with a preliminary pressurizing means for operating a brake under a predetermined condition and applying pressure by the preliminary pressurizing means when a failure of the pressurizing means is determined. The failure of the hydraulic system that supplies pressure to the wheels can be determined by determining whether the booster solenoid is abnormal based on whether the brake pressure applied to the wheels can increase to the set pressure when the automatic brake is activated, and maintaining the hydraulic pressure at a constant pressure. An abnormality of the pressure reducing solenoid is determined based on whether or not.

[0004]

However, when the failure is determined by the method of determining whether or not the brake pressure has reached the set pressure during the automatic braking operation as described above, time is taken into consideration. For example, when the pressure of the hydraulic pressure supply source is not sufficient, when the solenoid leaks, or when the orifice is provided in the hydraulic system, it takes time to increase the pressure due to clogging of the orifice, etc. If the pressure reaches the set pressure, it is determined to be normal. Therefore, when it is desired to operate the brake urgently, it is not noticed that the brake is abnormal, a sufficient braking force cannot be obtained, and the operation of the brake is delayed.

Accordingly, the present invention has been made in view of the above problems, and has as its technical object to accurately detect an abnormality in a hydraulic system so as not to cause a brake delay.

[0006]

In order to solve the above-mentioned problems, a first technical means is to detect a hydraulic pressure at the time of an automatic brake operation by a pressure detecting means, and to perform a normal pressure increase and a normal pressure decrease. The hydraulic gradient is stored in advance, a hydraulic gradient is obtained based on the hydraulic pressure detected by the pressure detecting means, the hydraulic gradient is compared with the stored hydraulic gradient, and if the deviation is equal to or greater than a set value, a hydraulic system abnormality is determined. That is, it is determined.

According to this, the oil pressure at the time of automatic brake operation is detected by the pressure detecting means, and the hydraulic pressure gradient is obtained based on the oil pressure detected by the pressure detecting means. By performing the comparison, it is possible to accurately detect an abnormality in the hydraulic system without delaying the determination in consideration of the time component at the time of increasing or decreasing the hydraulic pressure.

A second technical means taken to solve the above problem is to detect acceleration / deceleration of the vehicle by means of acceleration / deceleration detecting means, and to determine acceleration / deceleration gradients during normal pressure increase / decrease during pressure reduction. The acceleration / deceleration gradient is calculated based on the acceleration / deceleration detected by the acceleration / deceleration detection means, and the acceleration / deceleration gradient is compared with the stored acceleration / deceleration gradient. Is determined.

According to this, the acceleration / deceleration applied to the vehicle at the time of the automatic braking operation is detected by the acceleration / deceleration detecting means, and the acceleration / deceleration gradient is obtained based on the acceleration / deceleration detected by the acceleration / deceleration detecting means, and is obtained when the hydraulic pressure is normal. By comparing with the set value of the acceleration / deceleration gradient at the time of pressure increase or pressure reduction, it is possible to accurately detect abnormality in the hydraulic system without delay in judgment, considering the time component at the time of hydraulic pressure increase or pressure reduction. Become. Therefore, it is possible to prevent a brake delay from occurring.

In these cases, if the notification is made when the hydraulic system is abnormal, the occupant can be notified when the hydraulic system has an abnormality, and the safety is improved.

That is, in this automatic brake control device,
A pressure detecting unit (S201), a normal-time hydraulic gradient storage unit (set value of S205, set value of S210), a hydraulic gradient comparison unit (S205, 210), and a hydraulic system abnormality determination unit (S206, 211). Is desirable.

The acceleration / deceleration detecting means (S401) and the normal acceleration / deceleration gradient storage means (set value of S405, S4
10 set value 2), acceleration / deceleration gradient comparing means (S405,
410), it is desirable to include hydraulic system abnormality determination means (S406, 411).

In the above parentheses, the step numbers of the corresponding elements shown in the drawings and described later are added for reference.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a system configuration of the present invention, in which an X pipe is used for an FR wheel and an RL wheel (FR-RL system), an FL wheel and an RR wheel (FL-RR system), and a front wheel and a rear wheel. Between them, proportioning valves PV1 and PV2 for suppressing the brake pressure of the rear wheels with respect to the front wheels are provided.

The control hydraulic system (hereinafter referred to as hydraulic system)
Pressure sensors P1 and P2 for detecting oil pressure applied to wheels of the FR-RL system and the FL-RR system are provided. Based on information from these sensors, a solenoid (SOL) is energized / deenergized (on / off). ) To supply brake fluid to a wheel cylinder serving as a brake device for each wheel or discharge the brake fluid to the reservoirs RV1 and RV2, thereby controlling the brake pressure. The SOLs 1 to 8 used here are normally-closed solenoid valves, and when turned on (energized), the inlet and the outlet of the solenoid communicate with each other. In this case, the pressure sensors P1 and P2 are used for detecting the pressure of the hydraulic system. However, the pressure sensor may be any type that detects the pressure (a pressure switch or the like), and is not limited thereto.

(FR-RL system) A brake pressure is supplied from an accumulator (ACC1) as a pressure source to the FR-RL system via a pressure regulating valve AV1 and SOL1 for reducing the pressure to a constant pressure. , ACC1 and pressure regulating valve AV1 are provided with an orifice OF1, and between pressure regulating valve AV1 and SOL1 are orifices OF2 and S1.
A filter FL1 for preventing foreign matter from passing is provided on the OL1 side.

Further, the pressure of the brake fluid supplied to the wheels of the FR-RL system (discharge to the reservoir RV1) is reduced to SOL2.
By turning on SOL2, the brake fluid is released to the reservoir RV1 through the orifice OF3, and the brake pressure applied to the wheels can be reduced.

The brake fluid accumulated in the reservoir RV1 is pumped up by the drive of the pump motor PM1, and is stored in the accumulator ACC1 at a high pressure. In this case, between the reservoir RV1 and the pump PP1, a check valve CV11 and a filter FL11 for preventing the flow of foreign matter in the pipe are provided so that the brake fluid flows only from the reservoir RV1 to the pump side. ACC is provided between the pump PP1 and the ACC1.
A check valve CV1 through which brake fluid flows is provided only on one side, and a relief valve RR1 that releases to the reservoir RV1 when the pressure of the ACC1 becomes higher than a predetermined pressure is provided between the ACC1 and the reservoir RV1. It is provided in.

Further, SOL3 is provided for fail-safe operation of SOL1, and SOL4 is provided for fail-safe operation of SOL2. If SOL1 fails, SOL3 passes the pressure of ACC1 to the orifices OF1 and SOL3. FL11 to prevent noise
Is a solenoid for increasing the pressure supplied to the FR-RL system via the. If SOL2 fails, SOL4 becomes FR
-A pressure reducing solenoid for releasing the brake pressure supplied to the RL system to the RV1 and reducing the pressure.

(FL-RR system) A brake pressure is supplied from an accumulator (ACC2) serving as a pressure source to the FL-RR system via a pressure regulating valve AV2 and SOL5 for reducing the pressure to a constant pressure. , ACC2 and pressure regulating valve AV2 are provided with an orifice OF4, and between pressure regulating valve AV2 and SOL5 are orifices OF5 and S5.
A filter FL2 for preventing foreign matter from passing is provided on the OL5 side.

Further, the pressure of the brake fluid supplied to the wheels of the FL-RR system (discharge to the reservoir RV2) is reduced to SOL6.
When the SOL 6 is turned on, the brake fluid is released to the reservoir RV2 through the orifice OF6, and the brake pressure applied to the wheels can be reduced.

The brake fluid accumulated in the reservoir 2 is pumped up by the drive of the pump motor PM2, and is stored in the accumulator ACC2 at a high pressure. In this case, between the reservoir RV2 and the pump PP2, a check valve CV22 and a filter FL22 for preventing the flow of foreign matter in the pipe are provided so that the brake fluid flows only from the RV2 to the pump side. A check valve CV2 through which the brake fluid flows only on the ACC2 side is provided between the pump PP2 and the ACC2. Further, when the pressure of the ACC2 becomes higher than a certain pressure, a relief valve is released to the reservoir RV2. Valve RR2
Is provided between the ACC2 and the reservoir RV2.

Further, SOL7 is provided for fail-safe operation of SOL5, and SOL8 is provided for fail-safe operation of SOL6. When SOL5 fails, SOL7 passes the pressure of ACC2 to the orifices OF4 and SOL7. FL22 that prevents noise
Is a solenoid for increasing pressure to be supplied to the FL-RR system via the. When SOL6 fails, SOL8 becomes FL
-A pressure reducing solenoid for releasing the brake pressure supplied to the RR system to the RV2 and reducing the pressure, and the hydraulic system can perform brake control independently for each diagonal wheel. In this configuration, the pressure-increasing and pressure-reducing solenoids are of a dual system in consideration of the fail-safe of the hydraulic system. When SOL1 and SOL2 are normal, the brake pressure is increased in the FR-RL system (the pressure-increasing control is In this case, the brake pressure is increased by turning on SOL1 using the accumulated pressure of ACC1 as a supply source. When the brake pressure is reduced (pressure reduction control is performed), the brake fluid is released to RV1 by turning off SOL1 and turning on SOL2 to reduce the pressure applied to the wheel cylinder W / C.

When SOL5 and SOL6 are normal, FL-RR
When increasing the brake pressure (performing pressure increase control) in the system, the brake pressure is increased by turning on SOL5 using the accumulated pressure of ACC2 as a supply source, and the brake pressure is reduced (pressure reduction). Control)
In this case, SOL5 is turned off and SOL6 is turned on to release the brake fluid to RV2 and reduce the pressure.
Further, holding control can be performed by turning off both SOL1 to SOL8 for increasing and decreasing the pressure.

In this embodiment, the accumulator A
CC1 and CC2 are pump motors P when the internal pressure drops.
M1 and PM2 are independently driven to accumulate pressure so as to be always at a constant pressure during an automatic braking operation, and when the vehicle control computer CPT requests a depressurization to output a target deceleration, the braking force W is always kept at a substantially constant pressure. / C is controlled.

Next, the connection relationship between the automatic brake control device 100 and the controller 3 will be described with reference to FIG. The controller 3 that controls the automatic brake control sends an ignition switch (IGS) from the battery BT of the vehicle.
W), power is supplied via the IG
Turning on the SW supplies power to the controller 3.

The controller 3 receives information from a vehicle speed sensor 4 for detecting a vehicle speed. This vehicle speed information only needs to know the speed of the vehicle, and the signal may be a rotation signal from the rotation of the gear of the transmission, or a signal from a wheel speed sensor rotating during traveling. Further, the controller 3 includes pressure sensors (wheel cylinder pressure sensors) P1, P for detecting oil pressure applied to the wheel cylinders of the FR-RL system and the FL-RR system.
2. G sensor 7 for detecting acceleration / deceleration applied to the vehicle when the vehicle is running, reservoirs RV1 and RV2 for storing brake fluid
Level sensors LVL1 and LVL for detecting the liquid amount of
2, and the target deceleration information calculated based on the information of the stop position to stop on a predetermined traveling road surface is input from the vehicle control computer CPT.

Here, the G sensor 7 is used to detect the acceleration / deceleration of the vehicle, but any sensor that can detect the deceleration of the vehicle may be used. In addition, the automatic brake control device 100 performs automatic traveling of the circuit in a specific traveling pattern on a traveling road surface of a predetermined circuit here, but is not limited thereto.

The controller 3 uses the input information (signals) to control the FR-RL solenoids SOL1 to SOL1.
4. While operating the pump motor PM1, the FL-R
When the solenoids SOL5 to SOL8 of the R system and the pump motor PM2 are operated, and an abnormality occurs in these hydraulic systems, an external notification is given by a buzzer BZ or the like in order to notify an occupant of the abnormality.

Next, the processing of the controller 3 will be described with reference to FIG. When power is supplied by IG ON, the controller 3 executes the flowchart shown in FIG. First, initial processing is performed in step S101. Here, the ROM and R in the controller are
The AM is checked, an initial value is set in a memory required for processing, and then a check is made to determine whether the controller 3 operates normally. In step S102, input processing of a signal input to the controller 3 is performed, and the vehicle speed sensor 4, the W / C pressure sensors P1 and P2, the acceleration / deceleration (G)
Signals from the sensor 7 and the oil level sensors LVL1 and LVL2 are input and stored in a necessary memory. Step S1
At 03, the vehicle speed of the own vehicle is obtained by the vehicle speed calculation processing based on the vehicle speed signal (vehicle speed pulse) from the vehicle speed sensor 4, and then
In step S104, the vehicle control computer CPT
The target deceleration is input from. The target deceleration is
The information is obtained from the vehicle control computer CPT based on the predetermined stop position on the traveling road surface and the vehicle speed of the own vehicle, but is not limited to this, and the state of the preceding vehicle is detected using a laser, ultrasonic waves, or the like. Vehicle speed sensor 4, G sensor 7, W
The target deceleration may be determined inside the controller based on information from the / C pressure sensors P1, P2 and the like.

Next, in step S105, a fail determination shown in FIG. 4 is performed. This failure judgment is first made by FR-
After the processing of the RL system is performed, the processing of the FL-RR system is repeatedly performed twice. Here, the first processing will be described. In step S201, the current brake pressure applied to the wheel cylinder W / C is detected by the W / C pressure sensors P1 and P2. In this case, FR-
The value of the pressure sensor P1 is stored in the PRS that stores the W / C pressure during the operation of the RL system and the value of the pressure sensor P2 during the operation of the FL-RR system. Then, in step S202, it is checked whether the automatic brake control flag is ON. If the automatic brake control is not being performed, the process proceeds to step S207, the W / C current pressure memory is updated, and the process ends. On the other hand, when the automatic brake control is being performed in step S202, it is determined whether the pressure increase control is being performed next. If the pressure increase control is being performed, step S204 is performed. If not, the process proceeds to step S208.

If the pressure increase control is being performed, step S2
At 04, a pressure increase gradient calculation is performed. Pressure increase gradient GAIN-
A is calculated from the value obtained by taking the deviation between the current hydraulic pressure value PRS and the previous hydraulic pressure value PRSO, and dividing the deviation by the operation cycle ΔT. In the next step S205, the pressure increase gradient GAIN-A obtained by the calculation is compared with the set value 1 stored in the memory in advance. This set value 1 can be obtained by previously obtaining a pressure increase gradient when pressure is increased from the accumulators ACC1 and ACC2 in a normal state, and multiplying it by a safety factor of about 0.9. If the pressure increase gradient GAIN-A is equal to or larger than the set value 1 in step S205, the W / C at the time of pressure increase is used.
It is assumed that the pressure supplied to
When the pressure increase gradient GAIN-A is smaller than the set value 1, it is determined that the hydraulic system is abnormal, the hydraulic pressure increase abnormality flag is turned on (set), and the process proceeds to step S207. In this case, there is an abnormality in the supply pressure of the ACCs 1 and 2 or an abnormality in the pressure increase or the pressure decrease SOL, or whether a foreign matter is mixed in the hydraulic piping.

On the other hand, if the pressure increase control is not being performed, it is determined in step S208 whether the pressure reduction control is being performed. If the pressure reduction control is not being performed, the process proceeds to step S207. If the pressure reduction control is being performed, a pressure reduction gradient calculation is performed in step S209. The pressure reduction gradient GAIN-R is calculated from the difference between the previous oil pressure value PRSO and the current oil pressure value PRS, and dividing the difference by the operation cycle ΔT. Thereafter, in step S210, the decompression gradient GAIN-R obtained by the calculation is set to a set value 2 previously stored in the memory.
Compare with This set value 2 is SOL2, 6
Is turned on, a pressure reduction gradient when pressure reduction is performed is obtained in advance, and a safety factor of about 0.9 can be applied to obtain the pressure reduction gradient.
If the pressure reduction gradient GAIN-R is equal to or more than the set value 2 in step S210, it is considered that the pressure reduction is normal, and the process proceeds to step S207. If the pressure reduction gradient GAIN-R is smaller than the set value 2, the hydraulic system is abnormal. Is assumed to be
After turning on (set) the hydraulic pressure reduction abnormality flag, in step S207, the old / new W / C current pressure memory is updated.

Thereafter, returning to the main routine shown in FIG. 3, it is determined in step S106 whether an abnormality has occurred based on the abnormality flag. If there is an abnormality in the hydraulic system, backup control is performed in step S108. This backup control performs pressure increase by turning on SOL3 instead of SOL1 when the pressure increase is abnormal in the FR-RL system.
SOL4 is turned on in place of OL2. Also, FL-R
If the R system is abnormally pressurized, SO5 is used instead of SOL5.
When L7 is turned on, the pressure is increased. In the case of a pressure reduction abnormality, SOL8 is turned on instead of SOL6, so that the optimal braking force for W / C can be obtained using a double hydraulic configuration. We are trying to secure. When an abnormality occurs, the buzzer BZ is sounded in the backup control to notify the occupant that the failure has occurred.

On the other hand, if there is no abnormality, step S10
At 7, the automatic brake control shown in FIG. In this automatic brake control, it is determined in step S301 whether the target deceleration sent from the vehicle control computer is not 0G. If the target deceleration is 0G, step S30 is performed.
In step 6, the automatic brake control is stopped, the automatic brake control flag is turned off (cleared), and the process is terminated. If not, the automatic brake control is performed.
In step S302, the automatic brake control flag is turned on (set), and in step S303, the value of the deceleration of the own vehicle from the G sensor 7 is stored in the memory Gc.

In the next step S304, the target deceleration Gt
And the actual deceleration Gc is compared with the set value 3. The set value 3 is a hysteresis of the own vehicle deceleration with respect to the target deceleration, and is set smaller as the accuracy requirement is higher.
Here, for example, the pressure is set to 0.02 G. In this range, in order to prevent hunting, pressure increase and pressure reduction control is not performed.

In step S304, Gt-Gc is set to 3
If it is larger, the target deceleration has not been sufficiently reached, so that in steps S305, SOL1 and SOL5 are turned on and pressure increase control for supplying the pressure of ACC1 and ACC2 to the wheel cylinders is performed. If Gt-Gc is equal to or smaller than the set value 3, the value of Gc-Gt is compared with the set value 3 in step S307. If Gc-Gt is larger than the set value 3, deceleration is performed with respect to the target deceleration. Too much,
The pressure reduction control is performed by turning on SOL2 and SOL6. If the pressure falls within the hysteresis range, the pressure increase SOL1 and SOL5 and the pressure reduction SOL2 and 6 are turned off and the holding control is performed in step S309. Then, step S of the main routine
The processing from step 102 to step S108 is repeated at a constant cycle. When a deceleration request is issued from the external vehicle control computer CPT to achieve the target deceleration, the pressure increase, pressure decrease, and holding control are performed according to the surrounding conditions. Then, control is performed so as to obtain an optimum braking force.

The set values 1 and 2 for comparing the pressure increase gradient and the pressure decrease gradient are set by multiplying the pressure increase gradient and the pressure decrease gradient in the normal state by a safety factor of about 0.9 in consideration of the product variation of the apparatus. By doing so, it is possible to accurately determine the abnormality of the hydraulic system when the hydraulic pressure is increased or decreased.

The failure determination shown in FIG. 4 can similarly determine an abnormality in the hydraulic system by the gradient of the G sensor 7. That is, steps S401 to S4 shown in FIG.
Step 11 is the same as the basic processing of the fail determination shown in FIG. This is because the current pressure of W / C is detected and the gradient of the increase / decrease is compared with a predetermined value at normal time. However, the acceleration / deceleration is obtained from the G sensor 7 and the acceleration / deceleration gradient is compared with the predetermined value at normal time. It has been replaced. That is, the gradient of the acceleration / deceleration at the time of increasing or decreasing the pressure is obtained by taking the deviation of the current accumulator pressure ACC from the previous accumulator pressure ACCO and dividing it by the calculation cycle ΔT, and obtaining in steps S404 and S409. By comparing the set value 1 of the gradient at the time of pressure increase and the set value 2 of the gradient at the time of pressure decrease, the hydraulic system pressure increase or pressure decrease abnormality is determined, and the same effect as in the case of FIG. 4 can be obtained. it can.

[0041]

According to the present invention, the oil pressure at the time of automatic brake operation is detected by the pressure sensor, the oil pressure gradient is obtained based on the oil pressure detected by the pressure sensor, and compared with the set value obtained at the time of normal pressure increase or pressure reduction. By doing so, it is possible to accurately detect an abnormality in the hydraulic system without delaying the determination in consideration of the time component at the time of increasing or decreasing the hydraulic pressure.

Further, the acceleration / deceleration applied to the vehicle at the time of the automatic braking operation is detected by an acceleration / deceleration sensor, and the acceleration / deceleration gradient is obtained based on the acceleration / deceleration detected by the acceleration / deceleration sensor. By comparing with the set value of the acceleration / deceleration gradient, it is possible to accurately detect the abnormality of the hydraulic system without delaying the determination in consideration of the time component at the time of increasing or decreasing the hydraulic pressure.

Further, in these cases, if the notification is made when the hydraulic system is abnormal, the occupant can be notified when the hydraulic system is abnormal, and the safety is improved.

[Brief description of the drawings]

FIG. 1 is a hydraulic configuration diagram of an automatic brake control device according to an embodiment of the present invention.

FIG. 2 is an external connection diagram of the automatic brake control device according to the embodiment of the present invention.

FIG. 3 is a main flowchart showing processing of a controller shown in FIG. 2;

FIG. 4 is a flowchart of a fail determination shown in FIG. 3;

FIG. 5 is a flowchart of the automatic brake control shown in FIG.

FIG. 6 is another flowchart of the fail determination shown in FIG. 3;

[Explanation of symbols]

 3 Controller 7 Acceleration / deceleration (G) sensor (acceleration / deceleration detecting means) 100 Automatic brake control device P1, P2 Pressure sensor (pressure detecting means) W / C Wheel cylinder (braking device) GAIN-A Pressure increasing gradient (hydraulic gradient) GAIN -R Decompression gradient (hydraulic gradient) SOL1,5 Booster solenoid SOL2,6 Decompression solenoid

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D046 BB01 BB17 CC04 HH02 HH16 HH26 KK07 MM03 MM08 3D049 BB06 CC02 CC04 HH10 HH20 HH25 HH31 HH47 HH48 HH52 RR02 RR04 RR08 RR10 RR13

Claims (3)

[Claims] An automatic brake control device for supplying a substantially constant hydraulic pressure to a brake device of a vehicle when a request to decelerate the vehicle and decelerating the vehicle is provided. The hydraulic pressure gradient at the time of pressure increase and pressure reduction is stored in advance, a hydraulic pressure gradient is obtained based on the hydraulic pressure detected by the pressure detecting means, the hydraulic pressure gradient is compared with the stored hydraulic pressure gradient, and the deviation is set. An automatic brake control device that determines that the hydraulic system is abnormal when the value is equal to or greater than the value. 2. An automatic brake control device for supplying a substantially constant oil pressure to a brake device of a vehicle at the time of a request for deceleration of the vehicle and decelerating the vehicle. The acceleration / deceleration gradient at the time of pressure increase and pressure reduction is stored in advance, an acceleration / deceleration gradient is obtained based on the acceleration / deceleration detected by the acceleration / deceleration detecting means, and the acceleration / deceleration gradient is compared with the stored acceleration / deceleration gradient. An automatic brake control device that determines that the hydraulic system is abnormal when the deviation is equal to or greater than a set value. 3. The automatic brake control device according to claim 1, wherein an alarm is issued in the case of a hydraulic system abnormality.